From 1852a170b757104935369ef2edb3210aac7b7ef0 Mon Sep 17 00:00:00 2001 From: Ryan Foster Date: Fri, 23 Aug 2024 14:06:40 -0400 Subject: [PATCH] libobs/graphics: Update libnsgif to 1.0.0 --- libobs/CMakeLists.txt | 8 +- libobs/cmake/os-windows.cmake | 8 + libobs/graphics/image-file.c | 88 +- libobs/graphics/image-file.h | 8 +- libobs/graphics/libnsgif/gif.c | 2076 +++++++++++++++++++++++++++ libobs/graphics/libnsgif/libnsgif.c | 1291 ----------------- libobs/graphics/libnsgif/libnsgif.h | 142 -- libobs/graphics/libnsgif/lzw.c | 613 ++++++++ libobs/graphics/libnsgif/lzw.h | 137 ++ libobs/graphics/libnsgif/nsgif.h | 527 +++++++ 10 files changed, 3422 insertions(+), 1476 deletions(-) create mode 100644 libobs/graphics/libnsgif/gif.c delete mode 100644 libobs/graphics/libnsgif/libnsgif.c delete mode 100644 libobs/graphics/libnsgif/libnsgif.h create mode 100644 libobs/graphics/libnsgif/lzw.c create mode 100644 libobs/graphics/libnsgif/lzw.h create mode 100644 libobs/graphics/libnsgif/nsgif.h diff --git a/libobs/CMakeLists.txt b/libobs/CMakeLists.txt index c07ae6dab21792..f7ead9d663b19d 100644 --- a/libobs/CMakeLists.txt +++ b/libobs/CMakeLists.txt @@ -212,8 +212,10 @@ target_sources( graphics/image-file.c graphics/image-file.h graphics/input.h - graphics/libnsgif/libnsgif.c - graphics/libnsgif/libnsgif.h + graphics/libnsgif/gif.c + graphics/libnsgif/lzw.c + graphics/libnsgif/lzw.h + graphics/libnsgif/nsgif.h graphics/math-defs.h graphics/math-extra.c graphics/math-extra.h @@ -295,7 +297,7 @@ set( graphics/graphics.h graphics/image-file.h graphics/input.h - graphics/libnsgif/libnsgif.h + graphics/libnsgif/nsgif.h graphics/math-defs.h graphics/math-extra.h graphics/matrix3.h diff --git a/libobs/cmake/os-windows.cmake b/libobs/cmake/os-windows.cmake index 89a985b904efac..2c093cd2d13fe6 100644 --- a/libobs/cmake/os-windows.cmake +++ b/libobs/cmake/os-windows.cmake @@ -67,6 +67,14 @@ set_source_files_properties( PROPERTIES COMPILE_DEFINITIONS OBS_VERSION="${OBS_VERSION_CANONICAL}" ) +set_source_files_properties( + graphics/libnsgif/gif.c + graphics/libnsgif/lzw.c + graphics/libnsgif/lzw.h + graphics/libnsgif/nsgif.h + PROPERTIES COMPILE_OPTIONS "/wd4244;/wd4267" +) + target_link_libraries( libobs PRIVATE Avrt Dwmapi Dxgi winmm Rpcrt4 OBS::obfuscate OBS::winhandle OBS::COMutils diff --git a/libobs/graphics/image-file.c b/libobs/graphics/image-file.c index a07fb004f0320f..fb5808a344203a 100644 --- a/libobs/graphics/image-file.c +++ b/libobs/graphics/image-file.c @@ -57,7 +57,7 @@ static void bi_def_bitmap_modified(void *bitmap) static inline int get_full_decoded_gif_size(gs_image_file_t *image) { - return image->gif.width * image->gif.height * 4 * image->gif.frame_count; + return image->gif_info->width * image->gif_info->height * 4 * image->gif_info->frame_count; } static inline void *alloc_mem(gs_image_file_t *image, uint64_t *mem_usage, size_t size) @@ -73,19 +73,20 @@ static bool init_animated_gif(gs_image_file_t *image, const char *path, uint64_t enum gs_image_alpha_mode alpha_mode) { bool is_animated_gif = true; - gif_result result; + nsgif_error result; uint64_t max_size; size_t size, size_read; FILE *file; + nsgif_bitmap_t *bitmap; - image->bitmap_callbacks.bitmap_create = bi_def_bitmap_create; - image->bitmap_callbacks.bitmap_destroy = bi_def_bitmap_destroy; - image->bitmap_callbacks.bitmap_get_buffer = bi_def_bitmap_get_buffer; - image->bitmap_callbacks.bitmap_modified = bi_def_bitmap_modified; - image->bitmap_callbacks.bitmap_set_opaque = bi_def_bitmap_set_opaque; - image->bitmap_callbacks.bitmap_test_opaque = bi_def_bitmap_test_opaque; + image->bitmap_callbacks.create = bi_def_bitmap_create; + image->bitmap_callbacks.destroy = bi_def_bitmap_destroy; + image->bitmap_callbacks.get_buffer = bi_def_bitmap_get_buffer; + image->bitmap_callbacks.modified = bi_def_bitmap_modified; + image->bitmap_callbacks.set_opaque = bi_def_bitmap_set_opaque; + image->bitmap_callbacks.test_opaque = bi_def_bitmap_test_opaque; - gif_create(&image->gif, &image->bitmap_callbacks); + nsgif_create(&image->bitmap_callbacks, NSGIF_BITMAP_FMT_R8G8B8A8, &image->gif); file = os_fopen(path, "rb"); if (!file) { @@ -105,7 +106,7 @@ static bool init_animated_gif(gs_image_file_t *image, const char *path, uint64_t } do { - result = gif_initialise(&image->gif, size, image->gif_data); + result = nsgif_data_scan(image->gif, size, image->gif_data); if (result < 0) { blog(LOG_WARNING, "Failed to initialize gif '%s', " @@ -113,39 +114,48 @@ static bool init_animated_gif(gs_image_file_t *image, const char *path, uint64_t path); goto fail; } - } while (result != GIF_OK); + } while (result != NSGIF_OK); - if (image->gif.width > 4096 || image->gif.height > 4096) { - blog(LOG_WARNING, "Bad texture dimensions (%dx%d) in '%s'", image->gif.width, image->gif.height, path); + nsgif_data_complete(image->gif); + + image->gif_info = nsgif_get_info(image->gif); + + if (image->gif_info->width > 4096 || image->gif_info->height > 4096) { + blog(LOG_WARNING, "Bad texture dimensions (%dx%d) in '%s'", image->gif_info->width, + image->gif_info->height, path); goto fail; } - max_size = (uint64_t)image->gif.width * (uint64_t)image->gif.height * (uint64_t)image->gif.frame_count * 4LLU; + max_size = (uint64_t)image->gif_info->width * (uint64_t)image->gif_info->height * + (uint64_t)image->gif_info->frame_count * 4LLU; if ((uint64_t)get_full_decoded_gif_size(image) != max_size) { blog(LOG_WARNING, "Gif '%s' overflowed maximum pointer size", path); goto fail; } - image->is_animated_gif = (image->gif.frame_count > 1 && result >= 0); + image->is_animated_gif = (image->gif_info->frame_count > 1 && result >= 0); if (image->is_animated_gif) { - gif_decode_frame(&image->gif, 0); + nsgif_frame_decode(image->gif, 0, &bitmap); - image->animation_frame_cache = alloc_mem(image, mem_usage, image->gif.frame_count * sizeof(uint8_t *)); + image->animation_frame_cache = + alloc_mem(image, mem_usage, image->gif_info->frame_count * sizeof(uint8_t *)); image->animation_frame_data = alloc_mem(image, mem_usage, get_full_decoded_gif_size(image)); - for (unsigned int i = 0; i < image->gif.frame_count; i++) { - if (gif_decode_frame(&image->gif, i) != GIF_OK) + for (unsigned int i = 0; i < image->gif_info->frame_count; i++) { + if (nsgif_frame_decode(image->gif, i, &bitmap) != NSGIF_OK) blog(LOG_WARNING, "Couldn't decode frame %u " "of '%s'", i, path); } - gif_decode_frame(&image->gif, 0); + nsgif_frame_decode(image->gif, 0, &bitmap); - image->cx = (uint32_t)image->gif.width; - image->cy = (uint32_t)image->gif.height; + image->gif_frame_image = (const uint8_t *)bitmap; + + image->cx = (uint32_t)image->gif_info->width; + image->cy = (uint32_t)image->gif_info->height; image->format = GS_RGBA; if (mem_usage) { @@ -154,12 +164,12 @@ static bool init_animated_gif(gs_image_file_t *image, const char *path, uint64_t } if (alpha_mode == GS_IMAGE_ALPHA_PREMULTIPLY_SRGB) { - gs_premultiply_xyza_srgb_loop(image->gif.frame_image, (size_t)image->cx * image->cy); + gs_premultiply_xyza_srgb_loop((uint8_t *)bitmap, (size_t)image->cx * image->cy); } else if (alpha_mode == GS_IMAGE_ALPHA_PREMULTIPLY) { - gs_premultiply_xyza_loop(image->gif.frame_image, (size_t)image->cx * image->cy); + gs_premultiply_xyza_loop((uint8_t *)bitmap, (size_t)image->cx * image->cy); } } else { - gif_finalise(&image->gif); + nsgif_destroy(image->gif); bfree(image->gif_data); image->gif_data = NULL; is_animated_gif = false; @@ -226,7 +236,7 @@ void gs_image_file_free(gs_image_file_t *image) if (image->loaded) { if (image->is_animated_gif) { - gif_finalise(&image->gif); + nsgif_destroy(image->gif); bfree(image->animation_frame_cache); bfree(image->animation_frame_data); } @@ -266,7 +276,7 @@ void gs_image_file_init_texture(gs_image_file_t *image) if (image->is_animated_gif) { image->texture = gs_texture_create(image->cx, image->cy, image->format, 1, - (const uint8_t **)&image->gif.frame_image, GS_DYNAMIC); + (const uint8_t **)&image->gif_frame_image, GS_DYNAMIC); } else { image->texture = gs_texture_create(image->cx, image->cy, image->format, 1, @@ -278,7 +288,8 @@ void gs_image_file_init_texture(gs_image_file_t *image) static inline uint64_t get_time(gs_image_file_t *image, int i) { - uint64_t val = (uint64_t)image->gif.frames[i].frame_delay * 10000000ULL; + const nsgif_frame_info_t *gif_frame_info = nsgif_get_frame_info(image->gif, i); + uint64_t val = (uint64_t)gif_frame_info->delay * 10000000ULL; if (!val) val = 100000000; return val; @@ -295,7 +306,7 @@ static inline int calculate_new_frame(gs_image_file_t *image, uint64_t elapsed_t break; image->cur_time -= t; - if ((unsigned int)++new_frame == image->gif.frame_count) { + if ((unsigned int)++new_frame == image->gif_info->frame_count) { if (!loops || ++image->cur_loop < loops) { new_frame = 0; } else if (image->cur_loop == loops) { @@ -312,29 +323,32 @@ static void decode_new_frame(gs_image_file_t *image, int new_frame, enum gs_imag { if (!image->animation_frame_cache[new_frame]) { int last_frame; + nsgif_bitmap_t *bitmap; /* if looped, decode frame 0 */ last_frame = (new_frame < image->last_decoded_frame) ? 0 : image->last_decoded_frame + 1; /* decode missed frames */ for (int i = last_frame; i < new_frame; i++) { - if (gif_decode_frame(&image->gif, i) != GIF_OK) + if (nsgif_frame_decode(image->gif, i, &bitmap) != NSGIF_OK) return; } /* decode actual desired frame */ - if (gif_decode_frame(&image->gif, new_frame) == GIF_OK) { - const size_t area = (size_t)image->gif.width * image->gif.height; + if (nsgif_frame_decode(image->gif, new_frame, &bitmap) == NSGIF_OK) { + const size_t area = (size_t)image->gif_info->width * image->gif_info->height; size_t pos = new_frame * area * 4; image->animation_frame_cache[new_frame] = image->animation_frame_data + pos; if (alpha_mode == GS_IMAGE_ALPHA_PREMULTIPLY_SRGB) { - gs_premultiply_xyza_srgb_loop(image->gif.frame_image, area); + gs_premultiply_xyza_srgb_loop((uint8_t *)bitmap, area); } else if (alpha_mode == GS_IMAGE_ALPHA_PREMULTIPLY) { - gs_premultiply_xyza_loop(image->gif.frame_image, area); + gs_premultiply_xyza_loop((uint8_t *)bitmap, area); } - memcpy(image->animation_frame_cache[new_frame], image->gif.frame_image, area * 4); + image->gif_frame_image = (const uint8_t *)bitmap; + + memcpy(image->animation_frame_cache[new_frame], (const uint8_t *)bitmap, area * 4); image->last_decoded_frame = new_frame; } @@ -351,7 +365,7 @@ static bool gs_image_file_tick_internal(gs_image_file_t *image, uint64_t elapsed if (!image->is_animated_gif || !image->loaded) return false; - loops = image->gif.loop_count; + loops = image->gif_info->loop_max; if (loops >= 0xFFFF) loops = 0; @@ -395,7 +409,7 @@ static void gs_image_file_update_texture_internal(gs_image_file_t *image, enum g if (!image->animation_frame_cache[image->cur_frame]) decode_new_frame(image, image->cur_frame, alpha_mode); - gs_texture_set_image(image->texture, image->animation_frame_cache[image->cur_frame], image->gif.width * 4, + gs_texture_set_image(image->texture, image->animation_frame_cache[image->cur_frame], image->gif_info->width * 4, false); } diff --git a/libobs/graphics/image-file.h b/libobs/graphics/image-file.h index 0353f0d1363e93..2c085bf24d7336 100644 --- a/libobs/graphics/image-file.h +++ b/libobs/graphics/image-file.h @@ -18,7 +18,7 @@ #pragma once #include "graphics.h" -#include "libnsgif/libnsgif.h" +#include "libnsgif/nsgif.h" #ifdef __cplusplus extern "C" { @@ -33,8 +33,10 @@ struct gs_image_file { bool frame_updated; bool loaded; - gif_animation gif; + nsgif_t *gif; + const nsgif_info_t *gif_info; uint8_t *gif_data; + const uint8_t *gif_frame_image; uint8_t **animation_frame_cache; uint8_t *animation_frame_data; uint64_t cur_time; @@ -43,7 +45,7 @@ struct gs_image_file { int last_decoded_frame; uint8_t *texture_data; - gif_bitmap_callback_vt bitmap_callbacks; + nsgif_bitmap_cb_vt bitmap_callbacks; }; struct gs_image_file2 { diff --git a/libobs/graphics/libnsgif/gif.c b/libobs/graphics/libnsgif/gif.c new file mode 100644 index 00000000000000..73814bf352aef3 --- /dev/null +++ b/libobs/graphics/libnsgif/gif.c @@ -0,0 +1,2076 @@ +/* + * Copyright 2004 Richard Wilson + * Copyright 2008 Sean Fox + * Copyright 2013-2022 Michael Drake + * + * This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/ + * Licenced under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + */ + +#include +#include +#include +#include +#include + +#include "lzw.h" +#include "nsgif.h" + +/** Default minimum allowable frame delay in cs. */ +#define NSGIF_FRAME_DELAY_MIN 2 + +/** + * Default frame delay to apply. + * + * Used when a frame delay lower than the minimum is requested. + */ +#define NSGIF_FRAME_DELAY_DEFAULT 10 + +/** GIF frame data */ +typedef struct nsgif_frame { + struct nsgif_frame_info info; + + /** offset (in bytes) to the GIF frame data */ + size_t frame_offset; + /** whether the frame has previously been decoded. */ + bool decoded; + /** whether the frame is totally opaque */ + bool opaque; + /** whether a full image redraw is required */ + bool redraw_required; + + /** Amount of LZW data found in scan */ + uint32_t lzw_data_length; + + /** the index designating a transparent pixel */ + uint32_t transparency_index; + + /** offset to frame colour table */ + uint32_t colour_table_offset; + + /* Frame flags */ + uint32_t flags; +} nsgif_frame; + +/** Pixel format: colour component order. */ +struct nsgif_colour_layout { + uint8_t r; /**< Byte offset within pixel to red component. */ + uint8_t g; /**< Byte offset within pixel to green component. */ + uint8_t b; /**< Byte offset within pixel to blue component. */ + uint8_t a; /**< Byte offset within pixel to alpha component. */ +}; + +/** GIF animation data */ +struct nsgif { + struct nsgif_info info; + + /** LZW decode context */ + void *lzw_ctx; + /** callbacks for bitmap functions */ + nsgif_bitmap_cb_vt bitmap; + /** decoded frames */ + nsgif_frame *frames; + /** current frame */ + uint32_t frame; + /** current frame decoded to bitmap */ + uint32_t decoded_frame; + + /** currently decoded image; stored as bitmap from bitmap_create callback */ + nsgif_bitmap_t *frame_image; + /** Row span of frame_image in pixels. */ + uint32_t rowspan; + + /** Minimum allowable frame delay. */ + uint16_t delay_min; + + /** Frame delay to apply when delay is less than \ref delay_min. */ + uint16_t delay_default; + + /** number of animation loops so far */ + int loop_count; + + /** number of frames partially decoded */ + uint32_t frame_count_partial; + + /** + * Whether all the GIF data has been supplied, or if there may be + * more to come. + */ + bool data_complete; + + /** pointer to GIF data */ + const uint8_t *buf; + /** current index into GIF data */ + size_t buf_pos; + /** total number of bytes of GIF data available */ + size_t buf_len; + + /** current number of frame holders */ + uint32_t frame_holders; + /** background index */ + uint32_t bg_index; + /** image aspect ratio (ignored) */ + uint32_t aspect_ratio; + /** size of global colour table (in entries) */ + uint32_t colour_table_size; + + /** current colour table */ + uint32_t *colour_table; + /** Client's colour component order. */ + struct nsgif_colour_layout colour_layout; + /** global colour table */ + uint32_t global_colour_table[NSGIF_MAX_COLOURS]; + /** local colour table */ + uint32_t local_colour_table[NSGIF_MAX_COLOURS]; + + /** previous frame for NSGIF_FRAME_RESTORE */ + void *prev_frame; + /** previous frame index */ + uint32_t prev_index; +}; + +/** + * Helper macro to get number of elements in an array. + * + * \param[in] _a Array to count elements of. + * \return NUlber of elements in array. + */ +#define NSGIF_ARRAY_LEN(_a) ((sizeof(_a)) / (sizeof(*_a))) + +/** + * + * \file + * \brief GIF image decoder + * + * The GIF format is thoroughly documented; a full description can be found at + * http://www.w3.org/Graphics/GIF/spec-gif89a.txt + * + * \todo Plain text and comment extensions should be implemented. + */ + +/** Internal flag that the colour table needs to be processed */ +#define NSGIF_PROCESS_COLOURS 0xaa000000 + +/** Internal flag that a frame is invalid/unprocessed */ +#define NSGIF_FRAME_INVALID UINT32_MAX + +/** Transparent colour */ +#define NSGIF_TRANSPARENT_COLOUR 0x00 + +/** No transparency */ +#define NSGIF_NO_TRANSPARENCY (0xFFFFFFFFu) + +/* GIF Flags */ +#define NSGIF_COLOUR_TABLE_MASK 0x80 +#define NSGIF_COLOUR_TABLE_SIZE_MASK 0x07 +#define NSGIF_BLOCK_TERMINATOR 0x00 +#define NSGIF_TRAILER 0x3b + +/** + * Convert an LZW result code to equivalent GIF result code. + * + * \param[in] l_res LZW response code. + * \return GIF result code. + */ +static nsgif_error nsgif__error_from_lzw(lzw_result l_res) +{ + static const nsgif_error g_res[] = { + [LZW_OK] = NSGIF_OK, + [LZW_NO_MEM] = NSGIF_ERR_OOM, + [LZW_OK_EOD] = NSGIF_ERR_END_OF_DATA, + [LZW_NO_DATA] = NSGIF_ERR_END_OF_DATA, + [LZW_EOI_CODE] = NSGIF_ERR_DATA_FRAME, + [LZW_BAD_ICODE] = NSGIF_ERR_DATA_FRAME, + [LZW_BAD_CODE] = NSGIF_ERR_DATA_FRAME, + }; + assert(l_res != LZW_BAD_PARAM); + assert(l_res != LZW_NO_COLOUR); + return g_res[l_res]; +} + +/** + * Updates the sprite memory size + * + * \param gif The animation context + * \param width The width of the sprite + * \param height The height of the sprite + * \return NSGIF_ERR_OOM for a memory error NSGIF_OK for success + */ +static nsgif_error nsgif__initialise_sprite( + struct nsgif *gif, + uint32_t width, + uint32_t height) +{ + /* Already allocated? */ + if (gif->frame_image) { + return NSGIF_OK; + } + + assert(gif->bitmap.create); + gif->frame_image = gif->bitmap.create(width, height); + if (gif->frame_image == NULL) { + return NSGIF_ERR_OOM; + } + + return NSGIF_OK; +} + +/** + * Helper to get the rendering bitmap for a gif. + * + * \param[in] gif The gif object we're decoding. + * \return Client pixel buffer for rendering into. + */ +static inline uint32_t* nsgif__bitmap_get( + struct nsgif *gif) +{ + nsgif_error ret; + + /* Make sure we have a buffer to decode to. */ + ret = nsgif__initialise_sprite(gif, gif->info.width, gif->info.height); + if (ret != NSGIF_OK) { + return NULL; + } + + gif->rowspan = gif->info.width; + if (gif->bitmap.get_rowspan) { + gif->rowspan = gif->bitmap.get_rowspan(gif->frame_image); + } + + /* Get the frame data */ + assert(gif->bitmap.get_buffer); + return (void *)gif->bitmap.get_buffer(gif->frame_image); +} + +/** + * Helper to tell the client that their bitmap was modified. + * + * \param[in] gif The gif object we're decoding. + */ +static inline void nsgif__bitmap_modified( + const struct nsgif *gif) +{ + if (gif->bitmap.modified) { + gif->bitmap.modified(gif->frame_image); + } +} + +/** + * Helper to tell the client that whether the bitmap is opaque. + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame that has been decoded. + */ +static inline void nsgif__bitmap_set_opaque( + const struct nsgif *gif, + const struct nsgif_frame *frame) +{ + if (gif->bitmap.set_opaque) { + gif->bitmap.set_opaque( + gif->frame_image, frame->opaque); + } +} + +/** + * Helper to get the client to determine if the bitmap is opaque. + * + * \todo: We don't really need to get the client to do this for us. + * + * \param[in] gif The gif object we're decoding. + * \return true if the bitmap is opaque, false otherwise. + */ +static inline bool nsgif__bitmap_get_opaque( + const struct nsgif *gif) +{ + if (gif->bitmap.test_opaque) { + return gif->bitmap.test_opaque( + gif->frame_image); + } + + return false; +} + +static void nsgif__record_frame( + struct nsgif *gif, + const uint32_t *bitmap) +{ + size_t pixel_bytes = sizeof(*bitmap); + size_t height = gif->info.height; + size_t width = gif->info.width; + uint32_t *prev_frame; + + if (gif->decoded_frame == NSGIF_FRAME_INVALID || + gif->decoded_frame == gif->prev_index) { + /* No frame to copy, or already have this frame recorded. */ + return; + } + + bitmap = nsgif__bitmap_get(gif); + if (bitmap == NULL) { + return; + } + + if (gif->prev_frame == NULL) { + prev_frame = realloc(gif->prev_frame, + width * height * pixel_bytes); + if (prev_frame == NULL) { + return; + } + } else { + prev_frame = gif->prev_frame; + } + + memcpy(prev_frame, bitmap, width * height * pixel_bytes); + + gif->prev_frame = prev_frame; + gif->prev_index = gif->decoded_frame; +} + +static nsgif_error nsgif__recover_frame( + const struct nsgif *gif, + uint32_t *bitmap) +{ + const uint32_t *prev_frame = gif->prev_frame; + size_t pixel_bytes = sizeof(*bitmap); + size_t height = gif->info.height; + size_t width = gif->info.width; + + memcpy(bitmap, prev_frame, height * width * pixel_bytes); + + return NSGIF_OK; +} + +/** + * Get the next line for GIF decode. + * + * Note that the step size must be initialised to 24 at the start of the frame + * (when y == 0). This is because of the first two passes of the frame have + * the same step size of 8, and the step size is used to determine the current + * pass. + * + * \param[in] height Frame height in pixels. + * \param[in,out] y Current row, starting from 0, updated on exit. + * \param[in,out] step Current step starting with 24, updated on exit. + * \return true if there is a row to process, false at the end of the frame. + */ +static inline bool nsgif__deinterlace(uint32_t height, uint32_t *y, uint8_t *step) +{ + *y += *step & 0xf; + + if (*y < height) return true; + + switch (*step) { + case 24: *y = 4; *step = 8; if (*y < height) return true; + /* Fall through. */ + case 8: *y = 2; *step = 4; if (*y < height) return true; + /* Fall through. */ + case 4: *y = 1; *step = 2; if (*y < height) return true; + /* Fall through. */ + default: + break; + } + + return false; +} + +/** + * Get the next line for GIF decode. + * + * \param[in] interlace Non-zero if the frame is not interlaced. + * \param[in] height Frame height in pixels. + * \param[in,out] y Current row, starting from 0, updated on exit. + * \param[in,out] step Current step starting with 24, updated on exit. + * \return true if there is a row to process, false at the end of the frame. + */ +static inline bool nsgif__next_row(uint32_t interlace, + uint32_t height, uint32_t *y, uint8_t *step) +{ + if (!interlace) { + return (++*y != height); + } else { + return nsgif__deinterlace(height, y, step); + } +} + +/** + * Get any frame clip adjustment for the image extent. + * + * \param[in] frame_off Frame's X or Y offset. + * \param[in] frame_dim Frame width or height. + * \param[in] image_ext Image width or height constraint. + * \return the amount the frame needs to be clipped to fit the image in given + * dimension. + */ +static inline uint32_t gif__clip( + uint32_t frame_off, + uint32_t frame_dim, + uint32_t image_ext) +{ + uint32_t frame_ext = frame_off + frame_dim; + + if (frame_ext <= image_ext) { + return 0; + } + + return frame_ext - image_ext; +} + +/** + * Perform any jump over decoded data, to accommodate clipped portion of frame. + * + * \param[in,out] skip Number of pixels of data to jump. + * \param[in,out] available Number of pixels of data currently available. + * \param[in,out] pos Position in decoded pixel value data. + */ +static inline void gif__jump_data( + uint32_t *skip, + uint32_t *available, + const uint8_t **pos) +{ + uint32_t jump = (*skip < *available) ? *skip : *available; + + *skip -= jump; + *available -= jump; + *pos += jump; +} + +static nsgif_error nsgif__decode_complex( + struct nsgif *gif, + uint32_t width, + uint32_t height, + uint32_t offset_x, + uint32_t offset_y, + uint32_t interlace, + const uint8_t *data, + uint32_t transparency_index, + uint32_t *restrict frame_data, + uint32_t *restrict colour_table) +{ + lzw_result res; + nsgif_error ret = NSGIF_OK; + uint32_t clip_x = gif__clip(offset_x, width, gif->info.width); + uint32_t clip_y = gif__clip(offset_y, height, gif->info.height); + const uint8_t *uncompressed; + uint32_t available = 0; + uint8_t step = 24; + uint32_t skip = 0; + uint32_t y = 0; + + if (offset_x >= gif->info.width || + offset_y >= gif->info.height) { + return NSGIF_OK; + } + + width -= clip_x; + height -= clip_y; + + if (width == 0 || height == 0) { + return NSGIF_OK; + } + + /* Initialise the LZW decoding */ + res = lzw_decode_init(gif->lzw_ctx, data[0], + gif->buf, gif->buf_len, + data + 1 - gif->buf); + if (res != LZW_OK) { + return nsgif__error_from_lzw(res); + } + + do { + uint32_t x; + uint32_t *frame_scanline; + + frame_scanline = frame_data + offset_x + + (y + offset_y) * gif->rowspan; + + x = width; + while (x > 0) { + unsigned row_available; + while (available == 0) { + if (res != LZW_OK) { + /* Unexpected end of frame, try to recover */ + if (res == LZW_OK_EOD || + res == LZW_EOI_CODE) { + ret = NSGIF_OK; + } else { + ret = nsgif__error_from_lzw(res); + } + return ret; + } + res = lzw_decode(gif->lzw_ctx, + &uncompressed, &available); + + if (available == 0) { + return NSGIF_OK; + } + gif__jump_data(&skip, &available, &uncompressed); + } + + row_available = x < available ? x : available; + x -= row_available; + available -= row_available; + if (transparency_index > 0xFF) { + while (row_available-- > 0) { + *frame_scanline++ = + colour_table[*uncompressed++]; + } + } else { + while (row_available-- > 0) { + register uint32_t colour; + colour = *uncompressed++; + if (colour != transparency_index) { + *frame_scanline = + colour_table[colour]; + } + frame_scanline++; + } + } + } + + skip = clip_x; + gif__jump_data(&skip, &available, &uncompressed); + } while (nsgif__next_row(interlace, height, &y, &step)); + + return ret; +} + +static nsgif_error nsgif__decode_simple( + struct nsgif *gif, + uint32_t height, + uint32_t offset_y, + const uint8_t *data, + uint32_t transparency_index, + uint32_t *restrict frame_data, + uint32_t *restrict colour_table) +{ + uint32_t pixels; + uint32_t written = 0; + nsgif_error ret = NSGIF_OK; + lzw_result res; + + if (offset_y >= gif->info.height) { + return NSGIF_OK; + } + + height -= gif__clip(offset_y, height, gif->info.height); + + if (height == 0) { + return NSGIF_OK; + } + + /* Initialise the LZW decoding */ + res = lzw_decode_init_map(gif->lzw_ctx, data[0], + transparency_index, colour_table, + gif->buf, gif->buf_len, + data + 1 - gif->buf); + if (res != LZW_OK) { + return nsgif__error_from_lzw(res); + } + + frame_data += (offset_y * gif->info.width); + pixels = gif->info.width * height; + + while (pixels > 0) { + res = lzw_decode_map(gif->lzw_ctx, + frame_data, pixels, &written); + pixels -= written; + frame_data += written; + if (res != LZW_OK) { + /* Unexpected end of frame, try to recover */ + if (res == LZW_OK_EOD || res == LZW_EOI_CODE) { + ret = NSGIF_OK; + } else { + ret = nsgif__error_from_lzw(res); + } + break; + } + } + + if (pixels == 0) { + ret = NSGIF_OK; + } + + return ret; +} + +static inline nsgif_error nsgif__decode( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t *data, + uint32_t *restrict frame_data) +{ + nsgif_error ret; + uint32_t width = frame->info.rect.x1 - frame->info.rect.x0; + uint32_t height = frame->info.rect.y1 - frame->info.rect.y0; + uint32_t offset_x = frame->info.rect.x0; + uint32_t offset_y = frame->info.rect.y0; + uint32_t transparency_index = frame->transparency_index; + uint32_t *restrict colour_table = gif->colour_table; + + if (frame->info.interlaced == false && offset_x == 0 && + width == gif->info.width && + width == gif->rowspan) { + ret = nsgif__decode_simple(gif, height, offset_y, + data, transparency_index, + frame_data, colour_table); + } else { + ret = nsgif__decode_complex(gif, width, height, + offset_x, offset_y, frame->info.interlaced, + data, transparency_index, + frame_data, colour_table); + } + + if (gif->data_complete && ret == NSGIF_ERR_END_OF_DATA) { + /* This is all the data there is, so make do. */ + ret = NSGIF_OK; + } + + return ret; +} + +/** + * Restore a GIF to the background colour. + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame to clear, or NULL. + * \param[in] bitmap The bitmap to clear the frame in. + */ +static void nsgif__restore_bg( + struct nsgif *gif, + struct nsgif_frame *frame, + uint32_t *bitmap) +{ + size_t pixel_bytes = sizeof(*bitmap); + + if (frame == NULL) { + size_t width = gif->info.width; + size_t height = gif->info.height; + + memset(bitmap, NSGIF_TRANSPARENT_COLOUR, + width * height * pixel_bytes); + } else { + uint32_t width = frame->info.rect.x1 - frame->info.rect.x0; + uint32_t height = frame->info.rect.y1 - frame->info.rect.y0; + uint32_t offset_x = frame->info.rect.x0; + uint32_t offset_y = frame->info.rect.y0; + + if (frame->info.display == false || + frame->info.rect.x0 >= gif->info.width || + frame->info.rect.y0 >= gif->info.height) { + return; + } + + width -= gif__clip(offset_x, width, gif->info.width); + height -= gif__clip(offset_y, height, gif->info.height); + + if (frame->info.transparency) { + for (uint32_t y = 0; y < height; y++) { + uint32_t *scanline = bitmap + offset_x + + (offset_y + y) * gif->info.width; + memset(scanline, NSGIF_TRANSPARENT_COLOUR, + width * pixel_bytes); + } + } else { + for (uint32_t y = 0; y < height; y++) { + uint32_t *scanline = bitmap + offset_x + + (offset_y + y) * gif->info.width; + for (uint32_t x = 0; x < width; x++) { + scanline[x] = gif->info.background; + } + } + } + } +} + +static nsgif_error nsgif__update_bitmap( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t *data, + uint32_t frame_idx) +{ + nsgif_error ret; + uint32_t *bitmap; + + gif->decoded_frame = frame_idx; + + bitmap = nsgif__bitmap_get(gif); + if (bitmap == NULL) { + return NSGIF_ERR_OOM; + } + + /* Handle any bitmap clearing/restoration required before decoding this + * frame. */ + if (frame_idx == 0 || gif->decoded_frame == NSGIF_FRAME_INVALID) { + nsgif__restore_bg(gif, NULL, bitmap); + + } else { + struct nsgif_frame *prev = &gif->frames[frame_idx - 1]; + + if (prev->info.disposal == NSGIF_DISPOSAL_RESTORE_BG) { + nsgif__restore_bg(gif, prev, bitmap); + + } else if (prev->info.disposal == NSGIF_DISPOSAL_RESTORE_PREV) { + ret = nsgif__recover_frame(gif, bitmap); + if (ret != NSGIF_OK) { + nsgif__restore_bg(gif, prev, bitmap); + } + } + } + + if (frame->info.disposal == NSGIF_DISPOSAL_RESTORE_PREV) { + /* Store the previous frame for later restoration */ + nsgif__record_frame(gif, bitmap); + } + + ret = nsgif__decode(gif, frame, data, bitmap); + + nsgif__bitmap_modified(gif); + + if (!frame->decoded) { + frame->opaque = nsgif__bitmap_get_opaque(gif); + frame->decoded = true; + } + nsgif__bitmap_set_opaque(gif, frame); + + return ret; +} + +/** + * Parse the graphic control extension + * + * \param[in] frame The gif frame object we're decoding. + * \param[in] data The data to decode. + * \param[in] len Byte length of data. + * \return NSGIF_ERR_END_OF_DATA if more data is needed, + * NSGIF_OK for success. + */ +static nsgif_error nsgif__parse_extension_graphic_control( + struct nsgif_frame *frame, + const uint8_t *data, + size_t len) +{ + enum { + GIF_MASK_TRANSPARENCY = 0x01, + GIF_MASK_DISPOSAL = 0x1c, + }; + + /* 6-byte Graphic Control Extension is: + * + * +0 CHAR Graphic Control Label + * +1 CHAR Block Size + * +2 CHAR __Packed Fields__ + * 3BITS Reserved + * 3BITS Disposal Method + * 1BIT User Input Flag + * 1BIT Transparent Color Flag + * +3 SHORT Delay Time + * +5 CHAR Transparent Color Index + */ + if (len < 6) { + return NSGIF_ERR_END_OF_DATA; + } + + frame->info.delay = data[3] | (data[4] << 8); + + if (data[2] & GIF_MASK_TRANSPARENCY) { + frame->info.transparency = true; + frame->transparency_index = data[5]; + } + + frame->info.disposal = ((data[2] & GIF_MASK_DISPOSAL) >> 2); + /* I have encountered documentation and GIFs in the + * wild that use 0x04 to restore the previous frame, + * rather than the officially documented 0x03. I + * believe some (older?) software may even actually + * export this way. We handle this as a type of + * "quirks" mode. */ + if (frame->info.disposal == NSGIF_DISPOSAL_RESTORE_QUIRK) { + frame->info.disposal = NSGIF_DISPOSAL_RESTORE_PREV; + } + + /* if we are clearing the background then we need to + * redraw enough to cover the previous frame too. */ + frame->redraw_required = + frame->info.disposal == NSGIF_DISPOSAL_RESTORE_BG || + frame->info.disposal == NSGIF_DISPOSAL_RESTORE_PREV; + + return NSGIF_OK; +} + +/** + * Check an app ext identifier and authentication code for loop count extension. + * + * \param[in] data The data to decode. + * \param[in] len Byte length of data. + * \return true if extension is a loop count extension. + */ +static bool nsgif__app_ext_is_loop_count( + const uint8_t *data, + size_t len) +{ + enum { + EXT_LOOP_COUNT_BLOCK_SIZE = 0x0b, + }; + + assert(len > 13); + (void)(len); + + if (data[1] == EXT_LOOP_COUNT_BLOCK_SIZE) { + if (strncmp((const char *)data + 2, "NETSCAPE2.0", 11) == 0 || + strncmp((const char *)data + 2, "ANIMEXTS1.0", 11) == 0) { + return true; + } + } + + return false; +} + +/** + * Parse the application extension + * + * \param[in] gif The gif object we're decoding. + * \param[in] data The data to decode. + * \param[in] len Byte length of data. + * \return NSGIF_ERR_END_OF_DATA if more data is needed, + * NSGIF_OK for success. + */ +static nsgif_error nsgif__parse_extension_application( + struct nsgif *gif, + const uint8_t *data, + size_t len) +{ + /* 14-byte+ Application Extension is: + * + * +0 CHAR Application Extension Label + * +1 CHAR Block Size + * +2 8CHARS Application Identifier + * +10 3CHARS Appl. Authentication Code + * +13 1-256 Application Data (Data sub-blocks) + */ + if (len < 17) { + return NSGIF_ERR_END_OF_DATA; + } + + if (nsgif__app_ext_is_loop_count(data, len)) { + enum { + EXT_LOOP_COUNT_SUB_BLOCK_SIZE = 0x03, + EXT_LOOP_COUNT_SUB_BLOCK_ID = 0x01, + }; + if ((data[13] == EXT_LOOP_COUNT_SUB_BLOCK_SIZE) && + (data[14] == EXT_LOOP_COUNT_SUB_BLOCK_ID)) { + gif->info.loop_max = data[15] | (data[16] << 8); + + /* The value in the source data means repeat N times + * after the first implied play. A value of zero has + * the special meaning of loop forever. (The only way + * to play the animation once is not to have this + * extension at all. */ + if (gif->info.loop_max > 0) { + gif->info.loop_max++; + } + } + } + + return NSGIF_OK; +} + +/** + * Parse the frame's extensions + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame to parse extensions for. + * \param[in] pos Current position in data, updated on exit. + * \param[in] decode Whether to decode or skip over the extension. + * \return NSGIF_ERR_END_OF_DATA if more data is needed, + * NSGIF_OK for success. + */ +static nsgif_error nsgif__parse_frame_extensions( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t **pos, + bool decode) +{ + enum { + GIF_EXT_INTRODUCER = 0x21, + GIF_EXT_GRAPHIC_CONTROL = 0xf9, + GIF_EXT_COMMENT = 0xfe, + GIF_EXT_PLAIN_TEXT = 0x01, + GIF_EXT_APPLICATION = 0xff, + }; + const uint8_t *nsgif_data = *pos; + const uint8_t *nsgif_end = gif->buf + gif->buf_len; + int nsgif_bytes = nsgif_end - nsgif_data; + + /* Initialise the extensions */ + while (nsgif_bytes > 0 && nsgif_data[0] == GIF_EXT_INTRODUCER) { + bool block_step = true; + nsgif_error ret; + + nsgif_data++; + nsgif_bytes--; + + if (nsgif_bytes == 0) { + return NSGIF_ERR_END_OF_DATA; + } + + /* Switch on extension label */ + switch (nsgif_data[0]) { + case GIF_EXT_GRAPHIC_CONTROL: + if (decode) { + ret = nsgif__parse_extension_graphic_control( + frame, + nsgif_data, + nsgif_bytes); + if (ret != NSGIF_OK) { + return ret; + } + } + break; + + case GIF_EXT_APPLICATION: + if (decode) { + ret = nsgif__parse_extension_application( + gif, nsgif_data, nsgif_bytes); + if (ret != NSGIF_OK) { + return ret; + } + } + break; + + case GIF_EXT_COMMENT: + /* Move the pointer to the first data sub-block Skip 1 + * byte for the extension label. */ + ++nsgif_data; + block_step = false; + break; + + default: + break; + } + + if (block_step) { + /* Move the pointer to the first data sub-block Skip 2 + * bytes for the extension label and size fields Skip + * the extension size itself + */ + if (nsgif_bytes < 2) { + return NSGIF_ERR_END_OF_DATA; + } + nsgif_data += 2 + nsgif_data[1]; + } + + /* Repeatedly skip blocks until we get a zero block or run out + * of data. This data is ignored by this gif decoder. */ + while (nsgif_data < nsgif_end && nsgif_data[0] != NSGIF_BLOCK_TERMINATOR) { + nsgif_data += nsgif_data[0] + 1; + if (nsgif_data >= nsgif_end) { + return NSGIF_ERR_END_OF_DATA; + } + } + nsgif_data++; + nsgif_bytes = nsgif_end - nsgif_data; + } + + if (nsgif_data > nsgif_end) { + nsgif_data = nsgif_end; + } + + /* Set buffer position and return */ + *pos = nsgif_data; + return NSGIF_OK; +} + +/** + * Parse a GIF Image Descriptor. + * + * The format is: + * + * +0 CHAR Image Separator (0x2c) + * +1 SHORT Image Left Position + * +3 SHORT Image Top Position + * +5 SHORT Width + * +7 SHORT Height + * +9 CHAR __Packed Fields__ + * 1BIT Local Colour Table Flag + * 1BIT Interlace Flag + * 1BIT Sort Flag + * 2BITS Reserved + * 3BITS Size of Local Colour Table + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame to parse an image descriptor for. + * \param[in] pos Current position in data, updated on exit. + * \param[in] decode Whether to decode the image descriptor. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static nsgif_error nsgif__parse_image_descriptor( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t **pos, + bool decode) +{ + const uint8_t *data = *pos; + size_t len = gif->buf + gif->buf_len - data; + enum { + NSGIF_IMAGE_DESCRIPTOR_LEN = 10u, + NSGIF_IMAGE_SEPARATOR = 0x2Cu, + NSGIF_MASK_INTERLACE = 0x40u, + }; + + assert(gif != NULL); + assert(frame != NULL); + + if (len < NSGIF_IMAGE_DESCRIPTOR_LEN) { + return NSGIF_ERR_END_OF_DATA; + } + + if (decode) { + uint32_t x, y, w, h; + + if (data[0] != NSGIF_IMAGE_SEPARATOR) { + return NSGIF_ERR_DATA_FRAME; + } + + x = data[1] | (data[2] << 8); + y = data[3] | (data[4] << 8); + w = data[5] | (data[6] << 8); + h = data[7] | (data[8] << 8); + frame->flags = data[9]; + + frame->info.rect.x0 = x; + frame->info.rect.y0 = y; + frame->info.rect.x1 = x + w; + frame->info.rect.y1 = y + h; + + frame->info.interlaced = frame->flags & NSGIF_MASK_INTERLACE; + + /* Allow first frame to grow image dimensions. */ + if (gif->info.frame_count == 0) { + if (x + w > gif->info.width) { + gif->info.width = x + w; + } + if (y + h > gif->info.height) { + gif->info.height = y + h; + } + } + } + + *pos += NSGIF_IMAGE_DESCRIPTOR_LEN; + return NSGIF_OK; +} + +/** + * Extract a GIF colour table into a LibNSGIF colour table buffer. + * + * \param[in] colour_table The colour table to populate. + * \param[in] layout la. + * \param[in] colour_table_entries The number of colour table entries. + * \param[in] data Raw colour table data. + */ +static void nsgif__colour_table_decode( + uint32_t colour_table[NSGIF_MAX_COLOURS], + const struct nsgif_colour_layout *layout, + size_t colour_table_entries, + const uint8_t *data) +{ + uint8_t *entry = (uint8_t *)colour_table; + + while (colour_table_entries--) { + /* Gif colour map contents are r,g,b. + * + * We want to pack them bytewise into the colour table, + * according to the client colour layout. + */ + + entry[layout->r] = *data++; + entry[layout->g] = *data++; + entry[layout->b] = *data++; + entry[layout->a] = 0xff; + + entry += sizeof(uint32_t); + } +} + +/** + * Extract a GIF colour table into a LibNSGIF colour table buffer. + * + * \param[in] colour_table The colour table to populate. + * \param[in] layout The target pixel format to decode to. + * \param[in] colour_table_entries The number of colour table entries. + * \param[in] data Current position in data. + * \param[in] data_len The available length of `data`. + * \param[out] used Number of colour table bytes read. + * \param[in] decode Whether to decode the colour table. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static inline nsgif_error nsgif__colour_table_extract( + uint32_t colour_table[NSGIF_MAX_COLOURS], + const struct nsgif_colour_layout *layout, + size_t colour_table_entries, + const uint8_t *data, + size_t data_len, + size_t *used, + bool decode) +{ + if (data_len < colour_table_entries * 3) { + return NSGIF_ERR_END_OF_DATA; + } + + if (decode) { + nsgif__colour_table_decode(colour_table, layout, + colour_table_entries, data); + } + + *used = colour_table_entries * 3; + return NSGIF_OK; +} + +/** + * Get a frame's colour table. + * + * Sets up gif->colour_table for the frame. + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame to get the colour table for. + * \param[in] pos Current position in data, updated on exit. + * \param[in] decode Whether to decode the colour table. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static nsgif_error nsgif__parse_colour_table( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t **pos, + bool decode) +{ + nsgif_error ret; + const uint8_t *data = *pos; + size_t len = gif->buf + gif->buf_len - data; + size_t used_bytes; + + assert(gif != NULL); + assert(frame != NULL); + + if ((frame->flags & NSGIF_COLOUR_TABLE_MASK) == 0) { + gif->colour_table = gif->global_colour_table; + return NSGIF_OK; + } + + if (decode == false) { + frame->colour_table_offset = *pos - gif->buf; + } + + ret = nsgif__colour_table_extract( + gif->local_colour_table, &gif->colour_layout, + 2 << (frame->flags & NSGIF_COLOUR_TABLE_SIZE_MASK), + data, len, &used_bytes, decode); + if (ret != NSGIF_OK) { + return ret; + } + *pos += used_bytes; + + if (decode) { + gif->colour_table = gif->local_colour_table; + } else { + frame->info.local_palette = true; + } + + return NSGIF_OK; +} + +/** + * Parse the image data for a gif frame. + * + * Sets up gif->colour_table for the frame. + * + * \param[in] gif The gif object we're decoding. + * \param[in] frame The frame to parse image data for. + * \param[in] pos Current position in data, updated on exit. + * \param[in] decode Whether to decode the image data. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static nsgif_error nsgif__parse_image_data( + struct nsgif *gif, + struct nsgif_frame *frame, + const uint8_t **pos, + bool decode) +{ + const uint8_t *data = *pos; + size_t len = gif->buf + gif->buf_len - data; + uint32_t frame_idx = frame - gif->frames; + uint8_t minimum_code_size; + nsgif_error ret; + + assert(gif != NULL); + assert(frame != NULL); + + if (!decode) { + gif->frame_count_partial = frame_idx + 1; + } + + /* Ensure sufficient data remains. A gif trailer or a minimum lzw code + * followed by a gif trailer is treated as OK, although without any + * image data. */ + switch (len) { + default: if (data[0] == NSGIF_TRAILER) return NSGIF_OK; + break; + case 2: if (data[1] == NSGIF_TRAILER) return NSGIF_OK; + /* Fall through. */ + case 1: if (data[0] == NSGIF_TRAILER) return NSGIF_OK; + /* Fall through. */ + case 0: return NSGIF_ERR_END_OF_DATA; + } + + minimum_code_size = data[0]; + if (minimum_code_size >= LZW_CODE_MAX) { + return NSGIF_ERR_DATA_FRAME; + } + + if (decode) { + ret = nsgif__update_bitmap(gif, frame, data, frame_idx); + } else { + uint32_t block_size = 0; + + /* Skip the minimum code size. */ + data++; + len--; + + while (block_size != 1) { + if (len < 1) { + return NSGIF_ERR_END_OF_DATA; + } + block_size = data[0] + 1; + /* Check if the frame data runs off the end of the file */ + if (block_size > len) { + frame->lzw_data_length += len; + return NSGIF_ERR_END_OF_DATA; + } + + len -= block_size; + data += block_size; + frame->lzw_data_length += block_size; + } + + *pos = data; + + gif->info.frame_count = frame_idx + 1; + gif->frames[frame_idx].info.display = true; + + return NSGIF_OK; + } + + return ret; +} + +static struct nsgif_frame *nsgif__get_frame( + struct nsgif *gif, + uint32_t frame_idx) +{ + struct nsgif_frame *frame; + + if (gif->frame_holders > frame_idx) { + frame = &gif->frames[frame_idx]; + } else { + /* Allocate more memory */ + size_t count = frame_idx + 1; + struct nsgif_frame *temp; + + temp = realloc(gif->frames, count * sizeof(*frame)); + if (temp == NULL) { + return NULL; + } + gif->frames = temp; + gif->frame_holders = count; + + frame = &gif->frames[frame_idx]; + + frame->info.local_palette = false; + frame->info.transparency = false; + frame->info.display = false; + frame->info.disposal = 0; + frame->info.delay = 10; + + frame->transparency_index = NSGIF_NO_TRANSPARENCY; + frame->frame_offset = gif->buf_pos; + frame->redraw_required = false; + frame->lzw_data_length = 0; + frame->decoded = false; + } + + return frame; +} + +/** + * Attempts to initialise the next frame + * + * \param[in] gif The animation context + * \param[in] frame_idx The frame number to decode. + * \param[in] decode Whether to decode the graphical image data. + * \return NSGIF_OK on success, appropriate error otherwise. +*/ +static nsgif_error nsgif__process_frame( + struct nsgif *gif, + uint32_t frame_idx, + bool decode) +{ + nsgif_error ret; + const uint8_t *pos; + const uint8_t *end; + struct nsgif_frame *frame; + + frame = nsgif__get_frame(gif, frame_idx); + if (frame == NULL) { + return NSGIF_ERR_OOM; + } + + end = gif->buf + gif->buf_len; + + if (decode) { + pos = gif->buf + frame->frame_offset; + + /* Ensure this frame is supposed to be decoded */ + if (frame->info.display == false) { + return NSGIF_OK; + } + + /* Ensure the frame is in range to decode */ + if (frame_idx > gif->frame_count_partial) { + return NSGIF_ERR_END_OF_DATA; + } + + /* Done if frame is already decoded */ + if (frame_idx == gif->decoded_frame) { + return NSGIF_OK; + } + } else { + pos = gif->buf + gif->buf_pos; + + /* Check if we've finished */ + if (pos < end && pos[0] == NSGIF_TRAILER) { + return NSGIF_OK; + } + } + + ret = nsgif__parse_frame_extensions(gif, frame, &pos, !decode); + if (ret != NSGIF_OK) { + goto cleanup; + } + + ret = nsgif__parse_image_descriptor(gif, frame, &pos, !decode); + if (ret != NSGIF_OK) { + goto cleanup; + } + + ret = nsgif__parse_colour_table(gif, frame, &pos, decode); + if (ret != NSGIF_OK) { + goto cleanup; + } + + ret = nsgif__parse_image_data(gif, frame, &pos, decode); + if (ret != NSGIF_OK) { + goto cleanup; + } + +cleanup: + if (!decode) { + gif->buf_pos = pos - gif->buf; + } + + return ret; +} + +/* exported function documented in nsgif.h */ +void nsgif_destroy(nsgif_t *gif) +{ + if (gif == NULL) { + return; + } + + /* Release all our memory blocks */ + if (gif->frame_image) { + assert(gif->bitmap.destroy); + gif->bitmap.destroy(gif->frame_image); + gif->frame_image = NULL; + } + + free(gif->frames); + gif->frames = NULL; + + free(gif->prev_frame); + gif->prev_frame = NULL; + + lzw_context_destroy(gif->lzw_ctx); + gif->lzw_ctx = NULL; + + free(gif); +} + +/** + * Check whether the host is little endian. + * + * Checks whether least significant bit is in the first byte of a `uint16_t`. + * + * \return true if host is little endian. + */ +static inline bool nsgif__host_is_little_endian(void) +{ + const uint16_t test = 1; + + return ((const uint8_t *) &test)[0]; +} + +static struct nsgif_colour_layout nsgif__bitmap_fmt_to_colour_layout( + nsgif_bitmap_fmt_t bitmap_fmt) +{ + bool le = nsgif__host_is_little_endian(); + + /* Map endian-dependant formats to byte-wise format for the host. */ + switch (bitmap_fmt) { + case NSGIF_BITMAP_FMT_RGBA8888: + bitmap_fmt = (le) ? NSGIF_BITMAP_FMT_A8B8G8R8 + : NSGIF_BITMAP_FMT_R8G8B8A8; + break; + case NSGIF_BITMAP_FMT_BGRA8888: + bitmap_fmt = (le) ? NSGIF_BITMAP_FMT_A8R8G8B8 + : NSGIF_BITMAP_FMT_B8G8R8A8; + break; + case NSGIF_BITMAP_FMT_ARGB8888: + bitmap_fmt = (le) ? NSGIF_BITMAP_FMT_B8G8R8A8 + : NSGIF_BITMAP_FMT_A8R8G8B8; + break; + case NSGIF_BITMAP_FMT_ABGR8888: + bitmap_fmt = (le) ? NSGIF_BITMAP_FMT_R8G8B8A8 + : NSGIF_BITMAP_FMT_A8B8G8R8; + break; + default: + break; + } + + /* Set up colour component order for bitmap format. */ + switch (bitmap_fmt) { + default: + /* Fall through. */ + case NSGIF_BITMAP_FMT_R8G8B8A8: + return (struct nsgif_colour_layout) { + .r = 0, + .g = 1, + .b = 2, + .a = 3, + }; + + case NSGIF_BITMAP_FMT_B8G8R8A8: + return (struct nsgif_colour_layout) { + .b = 0, + .g = 1, + .r = 2, + .a = 3, + }; + + case NSGIF_BITMAP_FMT_A8R8G8B8: + return (struct nsgif_colour_layout) { + .a = 0, + .r = 1, + .g = 2, + .b = 3, + }; + + case NSGIF_BITMAP_FMT_A8B8G8R8: + return (struct nsgif_colour_layout) { + .a = 0, + .b = 1, + .g = 2, + .r = 3, + }; + } +} + +/* exported function documented in nsgif.h */ +nsgif_error nsgif_create( + const nsgif_bitmap_cb_vt *bitmap_vt, + nsgif_bitmap_fmt_t bitmap_fmt, + nsgif_t **gif_out) +{ + nsgif_t *gif; + + gif = calloc(1, sizeof(*gif)); + if (gif == NULL) { + return NSGIF_ERR_OOM; + } + + gif->bitmap = *bitmap_vt; + gif->decoded_frame = NSGIF_FRAME_INVALID; + gif->prev_index = NSGIF_FRAME_INVALID; + + gif->delay_min = NSGIF_FRAME_DELAY_MIN; + gif->delay_default = NSGIF_FRAME_DELAY_DEFAULT; + + gif->colour_layout = nsgif__bitmap_fmt_to_colour_layout(bitmap_fmt); + + *gif_out = gif; + return NSGIF_OK; +} + +/* exported function documented in nsgif.h */ +void nsgif_set_frame_delay_behaviour( + nsgif_t *gif, + uint16_t delay_min, + uint16_t delay_default) +{ + gif->delay_min = delay_min; + gif->delay_default = delay_default; +} + +/** + * Read GIF header. + * + * 6-byte GIF file header is: + * + * +0 3CHARS Signature ('GIF') + * +3 3CHARS Version ('87a' or '89a') + * + * \param[in] gif The GIF object we're decoding. + * \param[in,out] pos The current buffer position, updated on success. + * \param[in] strict Whether to require a known GIF version. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static nsgif_error nsgif__parse_header( + struct nsgif *gif, + const uint8_t **pos, + bool strict) +{ + const uint8_t *data = *pos; + size_t len = gif->buf + gif->buf_len - data; + + if (len < 6) { + return NSGIF_ERR_END_OF_DATA; + } + + if (strncmp((const char *) data, "GIF", 3) != 0) { + return NSGIF_ERR_DATA; + } + data += 3; + + if (strict == true) { + if ((strncmp((const char *) data, "87a", 3) != 0) && + (strncmp((const char *) data, "89a", 3) != 0)) { + return NSGIF_ERR_DATA; + } + } + data += 3; + + *pos = data; + return NSGIF_OK; +} + +/** + * Read Logical Screen Descriptor. + * + * 7-byte Logical Screen Descriptor is: + * + * +0 SHORT Logical Screen Width + * +2 SHORT Logical Screen Height + * +4 CHAR __Packed Fields__ + * 1BIT Global Colour Table Flag + * 3BITS Colour Resolution + * 1BIT Sort Flag + * 3BITS Size of Global Colour Table + * +5 CHAR Background Colour Index + * +6 CHAR Pixel Aspect Ratio + * + * \param[in] gif The GIF object we're decoding. + * \param[in,out] pos The current buffer position, updated on success. + * \return NSGIF_OK on success, appropriate error otherwise. + */ +static nsgif_error nsgif__parse_logical_screen_descriptor( + struct nsgif *gif, + const uint8_t **pos) +{ + const uint8_t *data = *pos; + size_t len = gif->buf + gif->buf_len - data; + + if (len < 7) { + return NSGIF_ERR_END_OF_DATA; + } + + gif->info.width = data[0] | (data[1] << 8); + gif->info.height = data[2] | (data[3] << 8); + gif->info.global_palette = data[4] & NSGIF_COLOUR_TABLE_MASK; + gif->colour_table_size = 2 << (data[4] & NSGIF_COLOUR_TABLE_SIZE_MASK); + gif->bg_index = data[5]; + gif->aspect_ratio = data[6]; + gif->info.loop_max = 1; + + *pos += 7; + return NSGIF_OK; +} + +/* exported function documented in nsgif.h */ +nsgif_error nsgif_data_scan( + nsgif_t *gif, + size_t size, + const uint8_t *data) +{ + const uint8_t *nsgif_data; + nsgif_error ret; + uint32_t frames; + + if (gif->data_complete) { + return NSGIF_ERR_DATA_COMPLETE; + } + + /* Initialize values */ + gif->buf_len = size; + gif->buf = data; + + /* Get our current processing position */ + nsgif_data = gif->buf + gif->buf_pos; + + /* See if we should initialise the GIF */ + if (gif->buf_pos == 0) { + /* We want everything to be NULL before we start so we've no + * chance of freeing bad pointers (paranoia) + */ + gif->frame_image = NULL; + gif->frames = NULL; + gif->frame_holders = 0; + + /* The caller may have been lazy and not reset any values */ + gif->info.frame_count = 0; + gif->frame_count_partial = 0; + gif->decoded_frame = NSGIF_FRAME_INVALID; + gif->frame = NSGIF_FRAME_INVALID; + + ret = nsgif__parse_header(gif, &nsgif_data, false); + if (ret != NSGIF_OK) { + return ret; + } + + ret = nsgif__parse_logical_screen_descriptor(gif, &nsgif_data); + if (ret != NSGIF_OK) { + return ret; + } + + /* Remember we've done this now */ + gif->buf_pos = nsgif_data - gif->buf; + + /* Some broken GIFs report the size as the screen size they + * were created in. As such, we detect for the common cases and + * set the sizes as 0 if they are found which results in the + * GIF being the maximum size of the frames. + */ + if (((gif->info.width == 640) && (gif->info.height == 480)) || + ((gif->info.width == 640) && (gif->info.height == 512)) || + ((gif->info.width == 800) && (gif->info.height == 600)) || + ((gif->info.width == 1024) && (gif->info.height == 768)) || + ((gif->info.width == 1280) && (gif->info.height == 1024)) || + ((gif->info.width == 1600) && (gif->info.height == 1200)) || + ((gif->info.width == 0) || (gif->info.height == 0)) || + ((gif->info.width > 2048) || (gif->info.height > 2048))) { + gif->info.width = 1; + gif->info.height = 1; + } + + /* Set the first colour to a value that will never occur in + * reality so we know if we've processed it + */ + gif->global_colour_table[0] = NSGIF_PROCESS_COLOURS; + + /* Check if the GIF has no frame data (13-byte header + 1-byte + * termination block) Although generally useless, the GIF + * specification does not expressly prohibit this + */ + if (gif->buf_len == gif->buf_pos + 1) { + if (nsgif_data[0] == NSGIF_TRAILER) { + return NSGIF_OK; + } + } + } + + /* Do the colour map if we haven't already. As the top byte is always + * 0xff or 0x00 depending on the transparency we know if it's been + * filled in. + */ + if (gif->global_colour_table[0] == NSGIF_PROCESS_COLOURS) { + /* Check for a global colour map signified by bit 7 */ + if (gif->info.global_palette) { + size_t remaining = gif->buf + gif->buf_len - nsgif_data; + size_t used; + + ret = nsgif__colour_table_extract( + gif->global_colour_table, + &gif->colour_layout, + gif->colour_table_size, + nsgif_data, remaining, &used, true); + if (ret != NSGIF_OK) { + return ret; + } + + nsgif_data += used; + gif->buf_pos = (nsgif_data - gif->buf); + } else { + /* Create a default colour table with the first two + * colours as black and white. */ + uint8_t *entry = (uint8_t *)gif->global_colour_table; + + /* Black */ + entry[gif->colour_layout.r] = 0x00; + entry[gif->colour_layout.g] = 0x00; + entry[gif->colour_layout.b] = 0x00; + entry[gif->colour_layout.a] = 0xFF; + + entry += sizeof(uint32_t); + + /* White */ + entry[gif->colour_layout.r] = 0xFF; + entry[gif->colour_layout.g] = 0xFF; + entry[gif->colour_layout.b] = 0xFF; + entry[gif->colour_layout.a] = 0xFF; + + gif->colour_table_size = 2; + } + + if (gif->info.global_palette && + gif->bg_index < gif->colour_table_size) { + size_t bg_idx = gif->bg_index; + gif->info.background = gif->global_colour_table[bg_idx]; + } else { + gif->info.background = gif->global_colour_table[0]; + } + } + + if (gif->lzw_ctx == NULL) { + lzw_result res = lzw_context_create( + (struct lzw_ctx **)&gif->lzw_ctx); + if (res != LZW_OK) { + return nsgif__error_from_lzw(res); + } + } + + /* Try to initialise all frames. */ + do { + frames = gif->info.frame_count; + ret = nsgif__process_frame(gif, frames, false); + } while (gif->info.frame_count > frames); + + if (ret == NSGIF_ERR_END_OF_DATA && gif->info.frame_count > 0) { + ret = NSGIF_OK; + } + + return ret; +} + +/* exported function documented in nsgif.h */ +void nsgif_data_complete( + nsgif_t *gif) +{ + if (gif->data_complete == false) { + uint32_t start = gif->info.frame_count; + uint32_t end = gif->frame_count_partial; + + for (uint32_t f = start; f < end; f++) { + nsgif_frame *frame = &gif->frames[f]; + + if (frame->lzw_data_length > 0) { + frame->info.display = true; + gif->info.frame_count = f + 1; + + if (f == 0) { + frame->info.transparency = true; + } + break; + } + } + } + + gif->data_complete = true; +} + +static void nsgif__redraw_rect_extend( + const nsgif_rect_t *frame, + nsgif_rect_t *redraw) +{ + if (redraw->x1 == 0 || redraw->y1 == 0) { + *redraw = *frame; + } else { + if (redraw->x0 > frame->x0) { + redraw->x0 = frame->x0; + } + if (redraw->x1 < frame->x1) { + redraw->x1 = frame->x1; + } + if (redraw->y0 > frame->y0) { + redraw->y0 = frame->y0; + } + if (redraw->y1 < frame->y1) { + redraw->y1 = frame->y1; + } + } +} + +static uint32_t nsgif__frame_next( + const nsgif_t *gif, + bool partial, + uint32_t frame) +{ + uint32_t frames = partial ? + gif->frame_count_partial : + gif->info.frame_count; + + if (frames == 0) { + return NSGIF_FRAME_INVALID; + } + + frame++; + return (frame >= frames) ? 0 : frame; +} + +static nsgif_error nsgif__next_displayable_frame( + const nsgif_t *gif, + uint32_t *frame, + uint32_t *delay) +{ + uint32_t next = *frame; + + do { + next = nsgif__frame_next(gif, false, next); + if (next <= *frame && *frame != NSGIF_FRAME_INVALID && + gif->data_complete == false) { + return NSGIF_ERR_END_OF_DATA; + + } else if (next == *frame || next == NSGIF_FRAME_INVALID) { + return NSGIF_ERR_FRAME_DISPLAY; + } + + if (delay != NULL) { + *delay += gif->frames[next].info.delay; + } + + } while (gif->frames[next].info.display == false); + + *frame = next; + return NSGIF_OK; +} + +static inline bool nsgif__animation_complete(int count, int max) +{ + if (max == 0) { + return false; + } + + return (count >= max); +} + +nsgif_error nsgif_reset( + nsgif_t *gif) +{ + gif->loop_count = 0; + gif->frame = NSGIF_FRAME_INVALID; + + return NSGIF_OK; +} + +/* exported function documented in nsgif.h */ +nsgif_error nsgif_frame_prepare( + nsgif_t *gif, + nsgif_rect_t *area, + uint32_t *delay_cs, + uint32_t *frame_new) +{ + nsgif_error ret; + nsgif_rect_t rect = { + .x1 = 0, + .y1 = 0, + }; + uint32_t delay = 0; + uint32_t frame = gif->frame; + + if (gif->frame != NSGIF_FRAME_INVALID && + gif->frame < gif->info.frame_count && + gif->frames[gif->frame].info.display) { + rect = gif->frames[gif->frame].info.rect; + } + + if (nsgif__animation_complete( + gif->loop_count, + gif->info.loop_max)) { + return NSGIF_ERR_ANIMATION_END; + } + + ret = nsgif__next_displayable_frame(gif, &frame, &delay); + if (ret != NSGIF_OK) { + return ret; + } + + if (gif->frame != NSGIF_FRAME_INVALID && frame < gif->frame) { + gif->loop_count++; + } + + if (gif->data_complete) { + /* Check for last frame, which has infinite delay. */ + + if (gif->info.frame_count == 1) { + delay = NSGIF_INFINITE; + } else if (gif->info.loop_max != 0) { + uint32_t frame_next = frame; + + ret = nsgif__next_displayable_frame(gif, + &frame_next, NULL); + if (ret != NSGIF_OK) { + return ret; + } + + if (gif->data_complete && frame_next < frame) { + if (nsgif__animation_complete( + gif->loop_count + 1, + gif->info.loop_max)) { + delay = NSGIF_INFINITE; + } + } + } + } + + gif->frame = frame; + nsgif__redraw_rect_extend(&gif->frames[frame].info.rect, &rect); + + if (delay < gif->delay_min) { + delay = gif->delay_default; + } + + *frame_new = gif->frame; + *delay_cs = delay; + *area = rect; + + return NSGIF_OK; +} + +/* exported function documented in nsgif.h */ +nsgif_error nsgif_frame_decode( + nsgif_t *gif, + uint32_t frame, + nsgif_bitmap_t **bitmap) +{ + uint32_t start_frame; + nsgif_error ret = NSGIF_OK; + + if (frame >= gif->info.frame_count) { + return NSGIF_ERR_BAD_FRAME; + } + + if (gif->decoded_frame == frame) { + *bitmap = gif->frame_image; + return NSGIF_OK; + + } else if (gif->decoded_frame >= frame || + gif->decoded_frame == NSGIF_FRAME_INVALID) { + /* Can skip to first frame or restart. */ + start_frame = 0; + } else { + start_frame = nsgif__frame_next( + gif, false, gif->decoded_frame); + } + + for (uint32_t f = start_frame; f <= frame; f++) { + ret = nsgif__process_frame(gif, f, true); + if (ret != NSGIF_OK) { + return ret; + } + } + + *bitmap = gif->frame_image; + return ret; +} + +/* exported function documented in nsgif.h */ +const nsgif_info_t *nsgif_get_info(const nsgif_t *gif) +{ + return &gif->info; +} + +/* exported function documented in nsgif.h */ +const nsgif_frame_info_t *nsgif_get_frame_info( + const nsgif_t *gif, + uint32_t frame) +{ + if (frame >= gif->info.frame_count) { + return NULL; + } + + return &gif->frames[frame].info; +} + +/* exported function documented in nsgif.h */ +void nsgif_global_palette( + const nsgif_t *gif, + uint32_t table[NSGIF_MAX_COLOURS], + size_t *entries) +{ + size_t len = sizeof(*table) * NSGIF_MAX_COLOURS; + + memcpy(table, gif->global_colour_table, len); + *entries = gif->colour_table_size; +} + +/* exported function documented in nsgif.h */ +bool nsgif_local_palette( + const nsgif_t *gif, + uint32_t frame, + uint32_t table[NSGIF_MAX_COLOURS], + size_t *entries) +{ + const nsgif_frame *f; + + if (frame >= gif->frame_count_partial) { + return false; + } + + f = &gif->frames[frame]; + if (f->info.local_palette == false) { + return false; + } + + *entries = 2 << (f->flags & NSGIF_COLOUR_TABLE_SIZE_MASK); + nsgif__colour_table_decode(table, &gif->colour_layout, + *entries, gif->buf + f->colour_table_offset); + + return true; +} + +/* exported function documented in nsgif.h */ +const char *nsgif_strerror(nsgif_error err) +{ + static const char *const str[] = { + [NSGIF_OK] = "Success", + [NSGIF_ERR_OOM] = "Out of memory", + [NSGIF_ERR_DATA] = "Invalid source data", + [NSGIF_ERR_BAD_FRAME] = "Requested frame does not exist", + [NSGIF_ERR_DATA_FRAME] = "Invalid frame data", + [NSGIF_ERR_END_OF_DATA] = "Unexpected end of GIF source data", + [NSGIF_ERR_DATA_COMPLETE] = "Can't add data to completed GIF", + [NSGIF_ERR_FRAME_DISPLAY] = "Frame can't be displayed", + [NSGIF_ERR_ANIMATION_END] = "Animation complete", + }; + + if (err >= NSGIF_ARRAY_LEN(str) || str[err] == NULL) { + return "Unknown error"; + } + + return str[err]; +} + +/* exported function documented in nsgif.h */ +const char *nsgif_str_disposal(enum nsgif_disposal disposal) +{ + static const char *const str[] = { + [NSGIF_DISPOSAL_UNSPECIFIED] = "Unspecified", + [NSGIF_DISPOSAL_NONE] = "None", + [NSGIF_DISPOSAL_RESTORE_BG] = "Restore background", + [NSGIF_DISPOSAL_RESTORE_PREV] = "Restore previous", + [NSGIF_DISPOSAL_RESTORE_QUIRK] = "Restore quirk", + }; + + if (disposal >= NSGIF_ARRAY_LEN(str) || str[disposal] == NULL) { + return "Unspecified"; + } + + return str[disposal]; +} diff --git a/libobs/graphics/libnsgif/libnsgif.c b/libobs/graphics/libnsgif/libnsgif.c deleted file mode 100644 index 6b36e8a539d051..00000000000000 --- a/libobs/graphics/libnsgif/libnsgif.c +++ /dev/null @@ -1,1291 +0,0 @@ -/* - * Copyright 2003 James Bursa - * Copyright 2004 John Tytgat - * Copyright 2004 Richard Wilson - * Copyright 2008 Sean Fox - * - * This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/ - * Licenced under the MIT License, - * http://www.opensource.org/licenses/mit-license.php - */ - -//#include -#include -#include -#include -#include -#include -#include "libnsgif.h" - - -#ifdef NDEBUG -# define LOG(x) ((void) 0) -#else -# define LOG(x) do { fprintf(stderr, x), fputc('\n', stderr); } while (0) -#endif /* NDEBUG */ - - - -/* READING GIF FILES - ================= - - The functions provided by this file allow for efficient progressive GIF - decoding. Whilst the initialisation does not ensure that there is - sufficient image data to complete the entire frame, it does ensure that - the information provided is valid. Any subsequent attempts to decode an - initialised GIF are guaranteed to succeed, and any bytes of the image - not present are assumed to be totally transparent. - - To begin decoding a GIF, the 'gif' structure must be initialised with - the 'gif_data' and 'buffer_size' set to their initial values. The - 'buffer_position' should initially be 0, and will be internally updated - as the decoding commences. The caller should then repeatedly call - gif_initialise() with the structure until the function returns 1, or - no more data is available. - - Once the initialisation has begun, the decoder completes the variables - 'frame_count' and 'frame_count_partial'. The former being the total - number of frames that have been successfully initialised, and the - latter being the number of frames that a partial amount of data is - available for. This assists the caller in managing the animation whilst - decoding is continuing. - - To decode a frame, the caller must use gif_decode_frame() which updates - the current 'frame_image' to reflect the desired frame. The required - 'disposal_method' is also updated to reflect how the frame should be - plotted. The caller must not assume that the current 'frame_image' will - be valid between calls if initialisation is still occurring, and should - either always request that the frame is decoded (no processing will - occur if the 'decoded_frame' has not been invalidated by initialisation) - or perform the check itself. - - It should be noted that gif_finalise() should always be called, even if - no frames were initialised. Additionally, it is the responsibility of - the caller to free 'gif_data'. - - [rjw] - Fri 2nd April 2004 -*/ - -/* TO-DO LIST - ================= - - + Plain text and comment extensions could be implemented if there is any - interest in doing so. -*/ - - - - -/* Maximum colour table size -*/ -#define GIF_MAX_COLOURS 256 - -/* Internal flag that the colour table needs to be processed -*/ -#define GIF_PROCESS_COLOURS 0xaa000000 - -/* Internal flag that a frame is invalid/unprocessed -*/ -#define GIF_INVALID_FRAME -1 - -/* Transparent colour -*/ -#define GIF_TRANSPARENT_COLOUR 0x00 - -/* GIF Flags -*/ -#define GIF_FRAME_COMBINE 1 -#define GIF_FRAME_CLEAR 2 -#define GIF_FRAME_RESTORE 3 -#define GIF_FRAME_QUIRKS_RESTORE 4 -#define GIF_IMAGE_SEPARATOR 0x2c -#define GIF_INTERLACE_MASK 0x40 -#define GIF_COLOUR_TABLE_MASK 0x80 -#define GIF_COLOUR_TABLE_SIZE_MASK 0x07 -#define GIF_EXTENSION_INTRODUCER 0x21 -#define GIF_EXTENSION_GRAPHIC_CONTROL 0xf9 -#define GIF_DISPOSAL_MASK 0x1c -#define GIF_TRANSPARENCY_MASK 0x01 -#define GIF_EXTENSION_COMMENT 0xfe -#define GIF_EXTENSION_PLAIN_TEXT 0x01 -#define GIF_EXTENSION_APPLICATION 0xff -#define GIF_BLOCK_TERMINATOR 0x00 -#define GIF_TRAILER 0x3b - -/* Internal GIF routines -*/ -static gif_result gif_initialise_sprite(gif_animation *gif, unsigned int width, unsigned int height); -static gif_result gif_initialise_frame(gif_animation *gif); -static gif_result gif_initialise_frame_extensions(gif_animation *gif, const int frame); -static gif_result gif_skip_frame_extensions(gif_animation *gif); -static unsigned int gif_interlaced_line(int height, int y); - - - -/* Internal LZW routines -*/ -static void gif_init_LZW(gif_animation *gif); -static bool gif_next_LZW(gif_animation *gif); -static int gif_next_code(gif_animation *gif, int code_size); - -static const int maskTbl[16] = {0x0000, 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, - 0x00ff, 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff}; - -/** Initialises necessary gif_animation members. -*/ -void gif_create(gif_animation *gif, gif_bitmap_callback_vt *bitmap_callbacks) { - memset(gif, 0, sizeof(gif_animation)); - gif->bitmap_callbacks = *bitmap_callbacks; - gif->decoded_frame = GIF_INVALID_FRAME; -} - - -/** Initialises any workspace held by the animation and attempts to decode - any information that hasn't already been decoded. - If an error occurs, all previously decoded frames are retained. - - @return GIF_FRAME_DATA_ERROR for GIF frame data error - GIF_INSUFFICIENT_FRAME_DATA for insufficient data to process - any more frames - GIF_INSUFFICIENT_MEMORY for memory error - GIF_DATA_ERROR for GIF error - GIF_INSUFFICIENT_DATA for insufficient data to do anything - GIF_OK for successful decoding - GIF_WORKING for successful decoding if more frames are expected -*/ -gif_result gif_initialise(gif_animation *gif, size_t size, unsigned char *data) { - unsigned char *gif_data; - unsigned int index; - gif_result return_value; - - /* The GIF format is thoroughly documented; a full description - * can be found at http://www.w3.org/Graphics/GIF/spec-gif89a.txt - */ - - /* Initialize values - */ - gif->buffer_size = (unsigned int)size; - gif->gif_data = data; - - /* Check for sufficient data to be a GIF (6-byte header + 7-byte logical screen descriptor) - */ - if (gif->buffer_size < 13) return GIF_INSUFFICIENT_DATA; - - /* Get our current processing position - */ - gif_data = gif->gif_data + gif->buffer_position; - - /* See if we should initialise the GIF - */ - if (gif->buffer_position == 0) { - - /* We want everything to be NULL before we start so we've no chance - of freeing bad pointers (paranoia) - */ - gif->frame_image = NULL; - gif->frames = NULL; - gif->local_colour_table = NULL; - gif->global_colour_table = NULL; - - /* The caller may have been lazy and not reset any values - */ - gif->frame_count = 0; - gif->frame_count_partial = 0; - gif->decoded_frame = GIF_INVALID_FRAME; - - /* 6-byte GIF file header is: - * - * +0 3CHARS Signature ('GIF') - * +3 3CHARS Version ('87a' or '89a') - */ - if (strncmp((const char *) gif_data, "GIF", 3) != 0) - return GIF_DATA_ERROR; - gif_data += 3; - - /* Ensure GIF reports version 87a or 89a - */ -/* if ((strncmp(gif_data, "87a", 3) != 0) && - (strncmp(gif_data, "89a", 3) != 0)) - LOG(("Unknown GIF format - proceeding anyway")); -*/ gif_data += 3; - - /* 7-byte Logical Screen Descriptor is: - * - * +0 SHORT Logical Screen Width - * +2 SHORT Logical Screen Height - * +4 CHAR __Packed Fields__ - * 1BIT Global Colour Table Flag - * 3BITS Colour Resolution - * 1BIT Sort Flag - * 3BITS Size of Global Colour Table - * +5 CHAR Background Colour Index - * +6 CHAR Pixel Aspect Ratio - */ - gif->width = gif_data[0] | (gif_data[1] << 8); - gif->height = gif_data[2] | (gif_data[3] << 8); - gif->global_colours = (gif_data[4] & GIF_COLOUR_TABLE_MASK); - gif->colour_table_size = (2 << (gif_data[4] & GIF_COLOUR_TABLE_SIZE_MASK)); - gif->background_index = gif_data[5]; - gif->aspect_ratio = gif_data[6]; - gif->loop_count = 1; - gif_data += 7; - - /* Some broken GIFs report the size as the screen size they were created in. As - such, we detect for the common cases and set the sizes as 0 if they are found - which results in the GIF being the maximum size of the frames. - */ - if (((gif->width == 640) && (gif->height == 480)) || - ((gif->width == 640) && (gif->height == 512)) || - ((gif->width == 800) && (gif->height == 600)) || - ((gif->width == 1024) && (gif->height == 768)) || - ((gif->width == 1280) && (gif->height == 1024)) || - ((gif->width == 1600) && (gif->height == 1200)) || - ((gif->width == 0) || (gif->height == 0)) || - ((gif->width > 2048) || (gif->height > 2048))) { - gif->width = 1; - gif->height = 1; - } - - /* Allocate some data irrespective of whether we've got any colour tables. We - always get the maximum size in case a GIF is lying to us. It's far better - to give the wrong colours than to trample over some memory somewhere. - */ - gif->global_colour_table = (unsigned int *)calloc(GIF_MAX_COLOURS, sizeof(int)); - gif->local_colour_table = (unsigned int *)calloc(GIF_MAX_COLOURS, sizeof(int)); - if ((gif->global_colour_table == NULL) || (gif->local_colour_table == NULL)) { - gif_finalise(gif); - return GIF_INSUFFICIENT_MEMORY; - } - - /* Set the first colour to a value that will never occur in reality so we - know if we've processed it - */ - gif->global_colour_table[0] = GIF_PROCESS_COLOURS; - - /* Check if the GIF has no frame data (13-byte header + 1-byte termination block) - * Although generally useless, the GIF specification does not expressly prohibit this - */ - if (gif->buffer_size == 14) { - if (gif_data[0] == GIF_TRAILER) - return GIF_OK; - else - return GIF_INSUFFICIENT_DATA; - } - - /* Initialise enough workspace for 4 frames initially - */ - if ((gif->frames = (gif_frame *)malloc(sizeof(gif_frame))) == NULL) { - gif_finalise(gif); - return GIF_INSUFFICIENT_MEMORY; - } - gif->frame_holders = 1; - - /* Initialise the sprite header - */ - assert(gif->bitmap_callbacks.bitmap_create); - if ((gif->frame_image = gif->bitmap_callbacks.bitmap_create(gif->width, gif->height)) == NULL) { - gif_finalise(gif); - return GIF_INSUFFICIENT_MEMORY; - } - - /* Remember we've done this now - */ - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - } - - /* Do the colour map if we haven't already. As the top byte is always 0xff or 0x00 - depending on the transparency we know if it's been filled in. - */ - if (gif->global_colour_table[0] == GIF_PROCESS_COLOURS) { - /* Check for a global colour map signified by bit 7 - */ - if (gif->global_colours) { - if (gif->buffer_size < (gif->colour_table_size * 3 + 12)) { - return GIF_INSUFFICIENT_DATA; - } - for (index = 0; index < gif->colour_table_size; index++) { - /* Gif colour map contents are r,g,b. - * - * We want to pack them bytewise into the - * colour table, such that the red component - * is in byte 0 and the alpha component is in - * byte 3. - */ - unsigned char *entry = (unsigned char *) &gif-> - global_colour_table[index]; - - entry[0] = gif_data[0]; /* r */ - entry[1] = gif_data[1]; /* g */ - entry[2] = gif_data[2]; /* b */ - entry[3] = 0xff; /* a */ - - gif_data += 3; - } - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - } else { - /* Create a default colour table with the first two colours as black and white - */ - unsigned int *entry = gif->global_colour_table; - - entry[0] = 0x00000000; - /* Force Alpha channel to opaque */ - ((unsigned char *) entry)[3] = 0xff; - - entry[1] = 0xffffffff; - } - } - - /* Repeatedly try to initialise frames - */ - while ((return_value = gif_initialise_frame(gif)) == GIF_WORKING); - - /* If there was a memory error tell the caller - */ - if ((return_value == GIF_INSUFFICIENT_MEMORY) || - (return_value == GIF_DATA_ERROR)) - return return_value; - - /* If we didn't have some frames then a GIF_INSUFFICIENT_DATA becomes a - GIF_INSUFFICIENT_FRAME_DATA - */ - if ((return_value == GIF_INSUFFICIENT_DATA) && (gif->frame_count_partial > 0)) - return GIF_INSUFFICIENT_FRAME_DATA; - - /* Return how many we got - */ - return return_value; -} - - -/** Updates the sprite memory size - - @return GIF_INSUFFICIENT_MEMORY for a memory error - GIF_OK for success -*/ -static gif_result gif_initialise_sprite(gif_animation *gif, unsigned int width, unsigned int height) { - unsigned int max_width; - unsigned int max_height; - struct bitmap *buffer; - - /* Check if we've changed - */ - if ((width <= gif->width) && (height <= gif->height)) - return GIF_OK; - - /* Get our maximum values - */ - max_width = (width > gif->width) ? width : gif->width; - max_height = (height > gif->height) ? height : gif->height; - - /* Allocate some more memory - */ - assert(gif->bitmap_callbacks.bitmap_create); - if ((buffer = gif->bitmap_callbacks.bitmap_create(max_width, max_height)) == NULL) - return GIF_INSUFFICIENT_MEMORY; - assert(gif->bitmap_callbacks.bitmap_destroy); - gif->bitmap_callbacks.bitmap_destroy(gif->frame_image); - gif->frame_image = buffer; - gif->width = max_width; - gif->height = max_height; - - /* Invalidate our currently decoded image - */ - gif->decoded_frame = GIF_INVALID_FRAME; - return GIF_OK; -} - - -/** Attempts to initialise the next frame - - @return GIF_INSUFFICIENT_DATA for insufficient data to do anything - GIF_FRAME_DATA_ERROR for GIF frame data error - GIF_INSUFFICIENT_MEMORY for insufficient memory to process - GIF_INSUFFICIENT_FRAME_DATA for insufficient data to complete the frame - GIF_DATA_ERROR for GIF error (invalid frame header) - GIF_OK for successful decoding - GIF_WORKING for successful decoding if more frames are expected -*/ -static gif_result gif_initialise_frame(gif_animation *gif) { - int frame; - gif_frame *temp_buf; - - unsigned char *gif_data, *gif_end; - int gif_bytes; - unsigned int flags = 0; - unsigned int width, height, offset_x, offset_y; - unsigned int block_size, colour_table_size; - bool first_image = true; - gif_result return_value; - - /* Get the frame to decode and our data position - */ - frame = gif->frame_count; - - /* Get our buffer position etc. - */ - gif_data = (unsigned char *)(gif->gif_data + gif->buffer_position); - gif_end = (unsigned char *)(gif->gif_data + gif->buffer_size); - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Check if we've finished - */ - if ((gif_bytes > 0) && (gif_data[0] == GIF_TRAILER)) return GIF_OK; - - /* Check if we have enough data - * The shortest block of data is a 4-byte comment extension + 1-byte block terminator + 1-byte gif trailer - */ - if (gif_bytes < 6) return GIF_INSUFFICIENT_DATA; - - /* We could theoretically get some junk data that gives us millions of frames, so - we ensure that we don't have a silly number - */ - if (frame > 4096) return GIF_FRAME_DATA_ERROR; - - /* Get some memory to store our pointers in etc. - */ - if ((int)gif->frame_holders <= frame) { - /* Allocate more memory - */ - if ((temp_buf = (gif_frame *)realloc(gif->frames, - (frame + 1) * sizeof(gif_frame))) == NULL) - return GIF_INSUFFICIENT_MEMORY; - gif->frames = temp_buf; - gif->frame_holders = frame + 1; - } - - /* Store our frame pointer. We would do it when allocating except we - start off with one frame allocated so we can always use realloc. - */ - gif->frames[frame].frame_pointer = gif->buffer_position; - gif->frames[frame].display = false; - gif->frames[frame].virgin = true; - gif->frames[frame].disposal_method = 0; - gif->frames[frame].transparency = false; - gif->frames[frame].frame_delay = 100; - gif->frames[frame].redraw_required = false; - - /* Invalidate any previous decoding we have of this frame - */ - if (gif->decoded_frame == frame) - gif->decoded_frame = GIF_INVALID_FRAME; - - /* We pretend to initialise the frames, but really we just skip over all - the data contained within. This is all basically a cut down version of - gif_decode_frame that doesn't have any of the LZW bits in it. - */ - - /* Initialise any extensions - */ - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - if ((return_value = gif_initialise_frame_extensions(gif, frame)) != GIF_OK) - return return_value; - gif_data = (gif->gif_data + gif->buffer_position); - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Check if we've finished - */ - if ((gif_bytes = (unsigned int)(gif_end - gif_data)) < 1) - return GIF_INSUFFICIENT_FRAME_DATA; - else if (gif_data[0] == GIF_TRAILER) { - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - gif->frame_count = frame + 1; - return GIF_OK; - } - - /* If we're not done, there should be an image descriptor - */ - if (gif_data[0] != GIF_IMAGE_SEPARATOR) return GIF_FRAME_DATA_ERROR; - - /* Do some simple boundary checking - */ - offset_x = gif_data[1] | (gif_data[2] << 8); - offset_y = gif_data[3] | (gif_data[4] << 8); - width = gif_data[5] | (gif_data[6] << 8); - height = gif_data[7] | (gif_data[8] << 8); - - /* Set up the redraw characteristics. We have to check for extending the area - due to multi-image frames. - */ - if (!first_image) { - if (gif->frames[frame].redraw_x > offset_x) { - gif->frames[frame].redraw_width += (gif->frames[frame].redraw_x - offset_x); - gif->frames[frame].redraw_x = offset_x; - } - if (gif->frames[frame].redraw_y > offset_y) { - gif->frames[frame].redraw_height += (gif->frames[frame].redraw_y - offset_y); - gif->frames[frame].redraw_y = offset_y; - } - if ((offset_x + width) > (gif->frames[frame].redraw_x + gif->frames[frame].redraw_width)) - gif->frames[frame].redraw_width = (offset_x + width) - gif->frames[frame].redraw_x; - if ((offset_y + height) > (gif->frames[frame].redraw_y + gif->frames[frame].redraw_height)) - gif->frames[frame].redraw_height = (offset_y + height) - gif->frames[frame].redraw_y; - } else { - first_image = false; - gif->frames[frame].redraw_x = offset_x; - gif->frames[frame].redraw_y = offset_y; - gif->frames[frame].redraw_width = width; - gif->frames[frame].redraw_height = height; - } - - /* if we are clearing the background then we need to redraw enough to cover the previous - frame too - */ - gif->frames[frame].redraw_required = ((gif->frames[frame].disposal_method == GIF_FRAME_CLEAR) || - (gif->frames[frame].disposal_method == GIF_FRAME_RESTORE)); - - /* Boundary checking - shouldn't ever happen except with junk data - */ - if (gif_initialise_sprite(gif, (offset_x + width), (offset_y + height))) - return GIF_INSUFFICIENT_MEMORY; - - /* Decode the flags - */ - flags = gif_data[9]; - colour_table_size = 2 << (flags & GIF_COLOUR_TABLE_SIZE_MASK); - - /* Move our data onwards and remember we've got a bit of this frame - */ - gif_data += 10; - gif_bytes = (unsigned int)(gif_end - gif_data); - gif->frame_count_partial = frame + 1; - - /* Skip the local colour table - */ - if (flags & GIF_COLOUR_TABLE_MASK) { - gif_data += 3 * colour_table_size; - if ((gif_bytes = (unsigned int)(gif_end - gif_data)) < 0) - return GIF_INSUFFICIENT_FRAME_DATA; - } - - /* Ensure we have a correct code size - */ - if (gif_data[0] > GIF_MAX_LZW) - return GIF_DATA_ERROR; - - /* Move our pointer to the actual image data - */ - gif_data++; - if (--gif_bytes < 0) - return GIF_INSUFFICIENT_FRAME_DATA; - - /* Repeatedly skip blocks until we get a zero block or run out of data - * These blocks of image data are processed later by gif_decode_frame() - */ - block_size = 0; - while (block_size != 1) { - block_size = gif_data[0] + 1; - /* Check if the frame data runs off the end of the file - */ - if ((int)(gif_bytes - block_size) < 0) { - /* Try to recover by signaling the end of the gif. - * Once we get garbage data, there is no logical - * way to determine where the next frame is. - * It's probably better to partially load the gif - * than not at all. - */ - if (gif_bytes >= 2) { - gif_data[0] = 0; - gif_data[1] = GIF_TRAILER; - gif_bytes = 1; - ++gif_data; - break; - } else - return GIF_INSUFFICIENT_FRAME_DATA; - } else { - gif_bytes -= block_size; - gif_data += block_size; - } - } - - /* Add the frame and set the display flag - */ - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - gif->frame_count = frame + 1; - gif->frames[frame].display = true; - - /* Check if we've finished - */ - if (gif_bytes < 1) - return GIF_INSUFFICIENT_FRAME_DATA; - else - if (gif_data[0] == GIF_TRAILER) return GIF_OK; - return GIF_WORKING; -} - -/** Attempts to initialise the frame's extensions - - @return GIF_INSUFFICIENT_FRAME_DATA for insufficient data to complete the frame - GIF_OK for successful initialisation -*/ -static gif_result gif_initialise_frame_extensions(gif_animation *gif, const int frame) { - unsigned char *gif_data, *gif_end; - int gif_bytes; - unsigned int block_size; - - /* Get our buffer position etc. - */ - gif_data = (unsigned char *)(gif->gif_data + gif->buffer_position); - gif_end = (unsigned char *)(gif->gif_data + gif->buffer_size); - - /* Initialise the extensions - */ - while (gif_data[0] == GIF_EXTENSION_INTRODUCER) { - ++gif_data; - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Switch on extension label - */ - switch(gif_data[0]) { - /* 6-byte Graphic Control Extension is: - * - * +0 CHAR Graphic Control Label - * +1 CHAR Block Size - * +2 CHAR __Packed Fields__ - * 3BITS Reserved - * 3BITS Disposal Method - * 1BIT User Input Flag - * 1BIT Transparent Color Flag - * +3 SHORT Delay Time - * +5 CHAR Transparent Color Index - */ - case GIF_EXTENSION_GRAPHIC_CONTROL: - if (gif_bytes < 6) return GIF_INSUFFICIENT_FRAME_DATA; - gif->frames[frame].frame_delay = gif_data[3] | (gif_data[4] << 8); - if (gif_data[2] & GIF_TRANSPARENCY_MASK) { - gif->frames[frame].transparency = true; - gif->frames[frame].transparency_index = gif_data[5]; - } - gif->frames[frame].disposal_method = ((gif_data[2] & GIF_DISPOSAL_MASK) >> 2); - /* I have encountered documentation and GIFs in the wild that use - * 0x04 to restore the previous frame, rather than the officially - * documented 0x03. I believe some (older?) software may even actually - * export this way. We handle this as a type of "quirks" mode. - */ - if (gif->frames[frame].disposal_method == GIF_FRAME_QUIRKS_RESTORE) - gif->frames[frame].disposal_method = GIF_FRAME_RESTORE; - gif_data += (2 + gif_data[1]); - break; - - /* 14-byte+ Application Extension is: - * - * +0 CHAR Application Extension Label - * +1 CHAR Block Size - * +2 8CHARS Application Identifier - * +10 3CHARS Appl. Authentication Code - * +13 1-256 Application Data (Data sub-blocks) - */ - case GIF_EXTENSION_APPLICATION: - if (gif_bytes < 17) return GIF_INSUFFICIENT_FRAME_DATA; - if ((gif_data[1] == 0x0b) && - (strncmp((const char *) gif_data + 2, - "NETSCAPE2.0", 11) == 0) && - (gif_data[13] == 0x03) && - (gif_data[14] == 0x01)) { - gif->loop_count = gif_data[15] | (gif_data[16] << 8); - } - gif_data += (2 + gif_data[1]); - break; - - /* Move the pointer to the first data sub-block - * Skip 1 byte for the extension label - */ - case GIF_EXTENSION_COMMENT: - ++gif_data; - break; - - /* Move the pointer to the first data sub-block - * Skip 2 bytes for the extension label and size fields - * Skip the extension size itself - */ - default: - gif_data += (2 + gif_data[1]); - } - - /* Repeatedly skip blocks until we get a zero block or run out of data - * This data is ignored by this gif decoder - */ - gif_bytes = (unsigned int)(gif_end - gif_data); - block_size = 0; - while (gif_data[0] != GIF_BLOCK_TERMINATOR) { - block_size = gif_data[0] + 1; - if ((gif_bytes -= block_size) < 0) - return GIF_INSUFFICIENT_FRAME_DATA; - gif_data += block_size; - } - ++gif_data; - } - - /* Set buffer position and return - */ - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - return GIF_OK; -} - - -/** Decodes a GIF frame. - - @return GIF_FRAME_DATA_ERROR for GIF frame data error - GIF_INSUFFICIENT_FRAME_DATA for insufficient data to complete the frame - GIF_DATA_ERROR for GIF error (invalid frame header) - GIF_INSUFFICIENT_DATA for insufficient data to do anything - GIF_INSUFFICIENT_MEMORY for insufficient memory to process - GIF_OK for successful decoding - If a frame does not contain any image data, GIF_OK is returned and - gif->current_error is set to GIF_FRAME_NO_DISPLAY -*/ -gif_result gif_decode_frame(gif_animation *gif, unsigned int frame) { - unsigned int index = 0; - unsigned char *gif_data, *gif_end; - int gif_bytes; - unsigned int width, height, offset_x, offset_y; - unsigned int flags, colour_table_size, interlace; - unsigned int *colour_table; - unsigned int *frame_data = 0; // Set to 0 for no warnings - unsigned int *frame_scanline; - unsigned int save_buffer_position; - gif_result return_value = GIF_OK; - unsigned int x, y, decode_y, burst_bytes; - int last_undisposed_frame = (frame - 1); - register unsigned char colour; - - /* Ensure we have a frame to decode - */ - if (frame >= gif->frame_count_partial) - return GIF_INSUFFICIENT_DATA; - - /* Ensure this frame is supposed to be decoded - */ - if (gif->frames[frame].display == false) { - gif->current_error = GIF_FRAME_NO_DISPLAY; - return GIF_OK; - } - - if ((!gif->clear_image) && ((int)frame == gif->decoded_frame)) - return GIF_OK; - - /* Get the start of our frame data and the end of the GIF data - */ - gif_data = gif->gif_data + gif->frames[frame].frame_pointer; - gif_end = gif->gif_data + gif->buffer_size; - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Check if we have enough data - * The shortest block of data is a 10-byte image descriptor + 1-byte gif trailer - */ - if (gif_bytes < 12) return GIF_INSUFFICIENT_FRAME_DATA; - - /* Save the buffer position - */ - save_buffer_position = gif->buffer_position; - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - - /* Skip any extensions because we all ready processed them - */ - if ((return_value = gif_skip_frame_extensions(gif)) != GIF_OK) - goto gif_decode_frame_exit; - gif_data = (gif->gif_data + gif->buffer_position); - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Ensure we have enough data for the 10-byte image descriptor + 1-byte gif trailer - */ - if (gif_bytes < 12) { - return_value = GIF_INSUFFICIENT_FRAME_DATA; - goto gif_decode_frame_exit; - } - - /* 10-byte Image Descriptor is: - * - * +0 CHAR Image Separator (0x2c) - * +1 SHORT Image Left Position - * +3 SHORT Image Top Position - * +5 SHORT Width - * +7 SHORT Height - * +9 CHAR __Packed Fields__ - * 1BIT Local Colour Table Flag - * 1BIT Interlace Flag - * 1BIT Sort Flag - * 2BITS Reserved - * 3BITS Size of Local Colour Table - */ - if (gif_data[0] != GIF_IMAGE_SEPARATOR) { - return_value = GIF_DATA_ERROR; - goto gif_decode_frame_exit; - } - offset_x = gif_data[1] | (gif_data[2] << 8); - offset_y = gif_data[3] | (gif_data[4] << 8); - width = gif_data[5] | (gif_data[6] << 8); - height = gif_data[7] | (gif_data[8] << 8); - - /* Boundary checking - shouldn't ever happen except unless the data has been - modified since initialisation. - */ - if ((offset_x + width > gif->width) || (offset_y + height > gif->height)) { - return_value = GIF_DATA_ERROR; - goto gif_decode_frame_exit; - } - - /* Decode the flags - */ - flags = gif_data[9]; - colour_table_size = 2 << (flags & GIF_COLOUR_TABLE_SIZE_MASK); - interlace = flags & GIF_INTERLACE_MASK; - - /* Move our pointer to the colour table or image data (if no colour table is given) - */ - gif_data += 10; - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Set up the colour table - */ - if (flags & GIF_COLOUR_TABLE_MASK) { - if (gif_bytes < (int)(3 * colour_table_size)) { - return_value = GIF_INSUFFICIENT_FRAME_DATA; - goto gif_decode_frame_exit; - } - colour_table = gif->local_colour_table; - if (!gif->clear_image) { - for (index = 0; index < colour_table_size; index++) { - /* Gif colour map contents are r,g,b. - * - * We want to pack them bytewise into the - * colour table, such that the red component - * is in byte 0 and the alpha component is in - * byte 3. - */ - unsigned char *entry = - (unsigned char *) &colour_table[index]; - - entry[0] = gif_data[0]; /* r */ - entry[1] = gif_data[1]; /* g */ - entry[2] = gif_data[2]; /* b */ - entry[3] = 0xff; /* a */ - - gif_data += 3; - } - } else { - gif_data += 3 * colour_table_size; - } - gif_bytes = (unsigned int)(gif_end - gif_data); - } else { - colour_table = gif->global_colour_table; - } - - /* Check if we've finished - */ - if (gif_bytes < 1) { - return_value = GIF_INSUFFICIENT_FRAME_DATA; - goto gif_decode_frame_exit; - } else if (gif_data[0] == GIF_TRAILER) { - return_value = GIF_OK; - goto gif_decode_frame_exit; - } - - /* Get the frame data - */ - assert(gif->bitmap_callbacks.bitmap_get_buffer); - frame_data = (void *)gif->bitmap_callbacks.bitmap_get_buffer(gif->frame_image); - if (!frame_data) - return GIF_INSUFFICIENT_MEMORY; - - /* If we are clearing the image we just clear, if not decode - */ - if (!gif->clear_image) { - /* Ensure we have enough data for a 1-byte LZW code size + 1-byte gif trailer - */ - if (gif_bytes < 2) { - return_value = GIF_INSUFFICIENT_FRAME_DATA; - goto gif_decode_frame_exit; - /* If we only have a 1-byte LZW code size + 1-byte gif trailer, we're finished - */ - } else if ((gif_bytes == 2) && (gif_data[1] == GIF_TRAILER)) { - return_value = GIF_OK; - goto gif_decode_frame_exit; - } - - /* If the previous frame's disposal method requires we restore the background - * colour or this is the first frame, clear the frame data - */ - if ((frame == 0) || (gif->decoded_frame == GIF_INVALID_FRAME)) { - memset((char*)frame_data, GIF_TRANSPARENT_COLOUR, gif->width * gif->height * sizeof(int)); - gif->decoded_frame = frame; - /* The line below would fill the image with its background color, but because GIFs support - * transparency we likely wouldn't want to do that. */ - /* memset((char*)frame_data, colour_table[gif->background_index], gif->width * gif->height * sizeof(int)); */ - } else if ((frame != 0) && (gif->frames[frame - 1].disposal_method == GIF_FRAME_CLEAR)) { - gif->clear_image = true; - if ((return_value = gif_decode_frame(gif, (frame - 1))) != GIF_OK) - goto gif_decode_frame_exit; - gif->clear_image = false; - /* If the previous frame's disposal method requires we restore the previous - * image, find the last image set to "do not dispose" and get that frame data - */ - } else if ((frame != 0) && (gif->frames[frame - 1].disposal_method == GIF_FRAME_RESTORE)) { - while ((last_undisposed_frame != -1) && (gif->frames[last_undisposed_frame--].disposal_method == GIF_FRAME_RESTORE)) { - } - /* If we don't find one, clear the frame data - */ - if (last_undisposed_frame == -1) { - /* see notes above on transparency vs. background color */ - memset((char*)frame_data, GIF_TRANSPARENT_COLOUR, gif->width * gif->height * sizeof(int)); - } else { - if ((return_value = gif_decode_frame(gif, last_undisposed_frame)) != GIF_OK) - goto gif_decode_frame_exit; - /* Get this frame's data - */ - assert(gif->bitmap_callbacks.bitmap_get_buffer); - frame_data = (void *)gif->bitmap_callbacks.bitmap_get_buffer(gif->frame_image); - if (!frame_data) - return GIF_INSUFFICIENT_MEMORY; - } - } - gif->decoded_frame = frame; - - /* Initialise the LZW decoding - */ - gif->set_code_size = gif_data[0]; - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data + 1); - - /* Set our code variables - */ - gif->code_size = gif->set_code_size + 1; - gif->clear_code = (1 << gif->set_code_size); - gif->end_code = gif->clear_code + 1; - gif->max_code_size = gif->clear_code << 1; - gif->max_code = gif->clear_code + 2; - gif->curbit = gif->lastbit = 0; - gif->last_byte = 2; - gif->get_done = false; - gif->direct = gif->buf; - gif_init_LZW(gif); - - /* Decompress the data - */ - for (y = 0; y < height; y++) { - if (interlace) - decode_y = gif_interlaced_line(height, y) + offset_y; - else - decode_y = y + offset_y; - frame_scanline = frame_data + offset_x + (decode_y * gif->width); - - /* Rather than decoding pixel by pixel, we try to burst out streams - of data to remove the need for end-of data checks every pixel. - */ - x = width; - while (x > 0) { - burst_bytes = (unsigned int)(gif->stack_pointer - gif->stack); - if (burst_bytes > 0) { - if (burst_bytes > x) - burst_bytes = x; - x -= burst_bytes; - while (burst_bytes-- > 0) { - colour = *--gif->stack_pointer; - if (((gif->frames[frame].transparency) && - (colour != gif->frames[frame].transparency_index)) || - (!gif->frames[frame].transparency)) - *frame_scanline = colour_table[colour]; - frame_scanline++; - } - } else { - if (!gif_next_LZW(gif)) { - /* Unexpected end of frame, try to recover - */ - if (gif->current_error == GIF_END_OF_FRAME) - return_value = GIF_OK; - else - return_value = gif->current_error; - goto gif_decode_frame_exit; - } - } - } - } - } else { - /* Clear our frame - */ - if (gif->frames[frame].disposal_method == GIF_FRAME_CLEAR) { - for (y = 0; y < height; y++) { - frame_scanline = frame_data + offset_x + ((offset_y + y) * gif->width); - if (gif->frames[frame].transparency) - memset(frame_scanline, GIF_TRANSPARENT_COLOUR, width * 4); - else - memset(frame_scanline, colour_table[gif->background_index], width * 4); - } - } - } -gif_decode_frame_exit: - - /* Check if we should test for optimisation - */ - if (gif->frames[frame].virgin) { - if (gif->bitmap_callbacks.bitmap_test_opaque) - gif->frames[frame].opaque = gif->bitmap_callbacks.bitmap_test_opaque(gif->frame_image); - else - gif->frames[frame].opaque = false; - gif->frames[frame].virgin = false; - } - if (gif->bitmap_callbacks.bitmap_set_opaque) - gif->bitmap_callbacks.bitmap_set_opaque(gif->frame_image, gif->frames[frame].opaque); - if (gif->bitmap_callbacks.bitmap_modified) - gif->bitmap_callbacks.bitmap_modified(gif->frame_image); - - /* Restore the buffer position - */ - gif->buffer_position = save_buffer_position; - - /* Success! - */ - return return_value; - -} - -/** Skips the frame's extensions (which have been previously initialised) - - @return GIF_INSUFFICIENT_FRAME_DATA for insufficient data to complete the frame - GIF_OK for successful decoding -*/ -static gif_result gif_skip_frame_extensions(gif_animation *gif) { - unsigned char *gif_data, *gif_end; - int gif_bytes; - unsigned int block_size; - - /* Get our buffer position etc. - */ - gif_data = (unsigned char *)(gif->gif_data + gif->buffer_position); - gif_end = (unsigned char *)(gif->gif_data + gif->buffer_size); - gif_bytes = (unsigned int)(gif_end - gif_data); - - /* Skip the extensions - */ - while (gif_data[0] == GIF_EXTENSION_INTRODUCER) { - ++gif_data; - - /* Switch on extension label - */ - switch(gif_data[0]) { - /* Move the pointer to the first data sub-block - * 1 byte for the extension label - */ - case GIF_EXTENSION_COMMENT: - ++gif_data; - break; - - /* Move the pointer to the first data sub-block - * 2 bytes for the extension label and size fields - * Skip the extension size itself - */ - default: - gif_data += (2 + gif_data[1]); - } - - /* Repeatedly skip blocks until we get a zero block or run out of data - * This data is ignored by this gif decoder - */ - gif_bytes = (unsigned int)(gif_end - gif_data); - block_size = 0; - while (gif_data[0] != GIF_BLOCK_TERMINATOR) { - block_size = gif_data[0] + 1; - if ((gif_bytes -= block_size) < 0) - return GIF_INSUFFICIENT_FRAME_DATA; - gif_data += block_size; - } - ++gif_data; - } - - /* Set buffer position and return - */ - gif->buffer_position = (unsigned int)(gif_data - gif->gif_data); - return GIF_OK; -} - -static unsigned int gif_interlaced_line(int height, int y) { - if ((y << 3) < height) return (y << 3); - y -= ((height + 7) >> 3); - if ((y << 3) < (height - 4)) return (y << 3) + 4; - y -= ((height + 3) >> 3); - if ((y << 2) < (height - 2)) return (y << 2) + 2; - y -= ((height + 1) >> 2); - return (y << 1) + 1; -} - -/* Releases any workspace held by the animation -*/ -void gif_finalise(gif_animation *gif) { - /* Release all our memory blocks - */ - if (gif->frame_image) { - assert(gif->bitmap_callbacks.bitmap_destroy); - gif->bitmap_callbacks.bitmap_destroy(gif->frame_image); - } - gif->frame_image = NULL; - free(gif->frames); - gif->frames = NULL; - free(gif->local_colour_table); - gif->local_colour_table = NULL; - free(gif->global_colour_table); - gif->global_colour_table = NULL; -} - -/** - * Initialise LZW decoding - */ -void gif_init_LZW(gif_animation *gif) { - int i; - - gif->current_error = 0; - if (gif->clear_code >= (1 << GIF_MAX_LZW)) { - gif->stack_pointer = gif->stack; - gif->current_error = GIF_FRAME_DATA_ERROR; - return; - } - - /* initialise our table */ - memset(gif->table, 0x00, (1 << GIF_MAX_LZW) * 8); - for (i = 0; i < gif->clear_code; ++i) - gif->table[1][i] = i; - - /* update our LZW parameters */ - gif->code_size = gif->set_code_size + 1; - gif->max_code_size = gif->clear_code << 1; - gif->max_code = gif->clear_code + 2; - gif->stack_pointer = gif->stack; - do { - gif->firstcode = gif->oldcode = gif_next_code(gif, gif->code_size); - } while (gif->firstcode == gif->clear_code); - *gif->stack_pointer++ =gif->firstcode; -} - - -static bool gif_next_LZW(gif_animation *gif) { - int code, incode; - int block_size; - int new_code; - - code = gif_next_code(gif, gif->code_size); - if (code < 0) { - gif->current_error = code; - return false; - } else if (code == gif->clear_code) { - gif_init_LZW(gif); - return true; - } else if (code == gif->end_code) { - /* skip to the end of our data so multi-image GIFs work */ - if (gif->zero_data_block) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - block_size = 0; - while (block_size != 1) { - block_size = gif->gif_data[gif->buffer_position] + 1; - gif->buffer_position += block_size; - } - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - - incode = code; - if (code >= gif->max_code) { - if (gif->stack_pointer >= gif->stack + ((1 << GIF_MAX_LZW) * 2)) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - *gif->stack_pointer++ = gif->firstcode; - code = gif->oldcode; - } - - /* The following loop is the most important in the GIF decoding cycle as every - * single pixel passes through it. - * - * Note: our gif->stack is always big enough to hold a complete decompressed chunk. */ - while (code >= gif->clear_code) { - if (gif->stack_pointer >= gif->stack + ((1 << GIF_MAX_LZW) * 2)) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - *gif->stack_pointer++ = gif->table[1][code]; - new_code = gif->table[0][code]; - if (new_code < gif->clear_code) { - code = new_code; - break; - } - - if (gif->stack_pointer >= gif->stack + ((1 << GIF_MAX_LZW) * 2)) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - *gif->stack_pointer++ = gif->table[1][new_code]; - code = gif->table[0][new_code]; - if (code == new_code) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - } - - if (gif->stack_pointer >= gif->stack + ((1 << GIF_MAX_LZW) * 2)) { - gif->current_error = GIF_FRAME_DATA_ERROR; - return false; - } - *gif->stack_pointer++ = gif->firstcode = gif->table[1][code]; - - if ((code = gif->max_code) < (1 << GIF_MAX_LZW)) { - gif->table[0][code] = gif->oldcode; - gif->table[1][code] = gif->firstcode; - ++gif->max_code; - if ((gif->max_code >= gif->max_code_size) && (gif->max_code_size < (1 << GIF_MAX_LZW))) { - gif->max_code_size = gif->max_code_size << 1; - ++gif->code_size; - } - } - gif->oldcode = incode; - return true; -} - -static int gif_next_code(gif_animation *gif, int code_size) { - int i, j, end, count, ret; - unsigned char *b; - - (void)code_size; - - end = gif->curbit + gif->code_size; - if (end >= gif->lastbit) { - if (gif->get_done) - return GIF_END_OF_FRAME; - gif->buf[0] = gif->direct[gif->last_byte - 2]; - gif->buf[1] = gif->direct[gif->last_byte - 1]; - - /* get the next block */ - gif->direct = gif->gif_data + gif->buffer_position; - gif->zero_data_block = ((count = gif->direct[0]) == 0); - if ((gif->buffer_position + count) >= gif->buffer_size) - return GIF_INSUFFICIENT_FRAME_DATA; - if (count == 0) - gif->get_done = true; - else { - gif->direct -= 1; - gif->buf[2] = gif->direct[2]; - gif->buf[3] = gif->direct[3]; - } - gif->buffer_position += count + 1; - - /* update our variables */ - gif->last_byte = 2 + count; - gif->curbit = (gif->curbit - gif->lastbit) + 16; - gif->lastbit = (2 + count) << 3; - end = gif->curbit + gif->code_size; - } - - i = gif->curbit >> 3; - if (i < 2) - b = gif->buf; - else - b = gif->direct; - - ret = b[i]; - j = (end >> 3) - 1; - if (i <= j) { - ret |= (b[i + 1] << 8); - if (i < j) - ret |= (b[i + 2] << 16); - } - ret = (ret >> (gif->curbit % 8)) & maskTbl[gif->code_size]; - gif->curbit += gif->code_size; - return ret; -} diff --git a/libobs/graphics/libnsgif/libnsgif.h b/libobs/graphics/libnsgif/libnsgif.h deleted file mode 100644 index 562d486079e861..00000000000000 --- a/libobs/graphics/libnsgif/libnsgif.h +++ /dev/null @@ -1,142 +0,0 @@ -/* - * Copyright 2004 Richard Wilson - * Copyright 2008 Sean Fox - * - * This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/ - * Licenced under the MIT License, - * http://www.opensource.org/licenses/mit-license.php - */ - -/** \file - * Progressive animated GIF file decoding (interface). - */ - -#ifndef _LIBNSGIF_H_ -#define _LIBNSGIF_H_ - -#include -#include - -#if defined(__cplusplus) -extern "C" -{ -#endif -/* Error return values -*/ -typedef enum { - GIF_WORKING = 1, - GIF_OK = 0, - GIF_INSUFFICIENT_FRAME_DATA = -1, - GIF_FRAME_DATA_ERROR = -2, - GIF_INSUFFICIENT_DATA = -3, - GIF_DATA_ERROR = -4, - GIF_INSUFFICIENT_MEMORY = -5, - GIF_FRAME_NO_DISPLAY = -6, - GIF_END_OF_FRAME = -7 -} gif_result; - -/* Maximum LZW bits available -*/ -#define GIF_MAX_LZW 12 - -/* The GIF frame data -*/ -typedef struct gif_frame { - bool display; /**< whether the frame should be displayed/animated */ - unsigned int frame_delay; /**< delay (in 100th second intervals) before animating the frame */ - /** Internal members are listed below - */ - unsigned int frame_pointer; /**< offset (in bytes) to the GIF frame data */ - bool virgin; /**< whether the frame has previously been used */ - bool opaque; /**< whether the frame is totally opaque */ - bool redraw_required; /**< whether a forcable screen redraw is required */ - unsigned char disposal_method; /**< how the previous frame should be disposed; affects plotting */ - bool transparency; /**< whether we acknowledge transparency */ - unsigned char transparency_index; /**< the index designating a transparent pixel */ - unsigned int redraw_x; /**< x co-ordinate of redraw rectangle */ - unsigned int redraw_y; /**< y co-ordinate of redraw rectangle */ - unsigned int redraw_width; /**< width of redraw rectangle */ - unsigned int redraw_height; /**< height of redraw rectangle */ -} gif_frame; - -/* API for Bitmap callbacks -*/ -typedef void* (*gif_bitmap_cb_create)(int width, int height); -typedef void (*gif_bitmap_cb_destroy)(void *bitmap); -typedef unsigned char* (*gif_bitmap_cb_get_buffer)(void *bitmap); -typedef void (*gif_bitmap_cb_set_opaque)(void *bitmap, bool opaque); -typedef bool (*gif_bitmap_cb_test_opaque)(void *bitmap); -typedef void (*gif_bitmap_cb_modified)(void *bitmap); - -/* The Bitmap callbacks function table -*/ -typedef struct gif_bitmap_callback_vt { - gif_bitmap_cb_create bitmap_create; /**< Create a bitmap. */ - gif_bitmap_cb_destroy bitmap_destroy; /**< Free a bitmap. */ - gif_bitmap_cb_get_buffer bitmap_get_buffer; /**< Return a pointer to the pixel data in a bitmap. */ - /** Members below are optional - */ - gif_bitmap_cb_set_opaque bitmap_set_opaque; /**< Sets whether a bitmap should be plotted opaque. */ - gif_bitmap_cb_test_opaque bitmap_test_opaque; /**< Tests whether a bitmap has an opaque alpha channel. */ - gif_bitmap_cb_modified bitmap_modified; /**< The bitmap image has changed, so flush any persistent cache. */ -} gif_bitmap_callback_vt; - -/* The GIF animation data -*/ -typedef struct gif_animation { - gif_bitmap_callback_vt bitmap_callbacks; /**< callbacks for bitmap functions */ - unsigned char *gif_data; /**< pointer to GIF data */ - unsigned int width; /**< width of GIF (may increase during decoding) */ - unsigned int height; /**< height of GIF (may increase during decoding) */ - unsigned int frame_count; /**< number of frames decoded */ - unsigned int frame_count_partial; /**< number of frames partially decoded */ - gif_frame *frames; /**< decoded frames */ - int decoded_frame; /**< current frame decoded to bitmap */ - void *frame_image; /**< currently decoded image; stored as bitmap from bitmap_create callback */ - int loop_count; /**< number of times to loop animation */ - gif_result current_error; /**< current error type, or 0 for none*/ - /** Internal members are listed below - */ - unsigned int buffer_position; /**< current index into GIF data */ - unsigned int buffer_size; /**< total number of bytes of GIF data available */ - unsigned int frame_holders; /**< current number of frame holders */ - unsigned int background_index; /**< index in the colour table for the background colour */ - unsigned int aspect_ratio; /**< image aspect ratio (ignored) */ - unsigned int colour_table_size; /**< size of colour table (in entries) */ - bool global_colours; /**< whether the GIF has a global colour table */ - unsigned int *global_colour_table; /**< global colour table */ - unsigned int *local_colour_table; /**< local colour table */ - - - /* General LZW values. They are NO LONGER shared for all GIFs being decoded BECAUSE - THAT IS A TERRIBLE IDEA TO SAVE 10Kb or so per GIF. - */ - unsigned char buf[4]; - unsigned char *direct; - - int table[2][(1 << GIF_MAX_LZW)]; - unsigned char stack[(1 << GIF_MAX_LZW) * 2]; - unsigned char *stack_pointer; - int code_size, set_code_size; - int max_code, max_code_size; - int clear_code, end_code; - int curbit, lastbit, last_byte; - int firstcode, oldcode; - bool zero_data_block; - bool get_done; - - /* Whether to clear the decoded image rather than plot - */ - bool clear_image; -} gif_animation; - -void gif_create(gif_animation *gif, gif_bitmap_callback_vt *bitmap_callbacks); -gif_result gif_initialise(gif_animation *gif, size_t size, unsigned char *data); -gif_result gif_decode_frame(gif_animation *gif, unsigned int frame); -void gif_finalise(gif_animation *gif); - -#if defined(__cplusplus) -}; -#endif - -#endif diff --git a/libobs/graphics/libnsgif/lzw.c b/libobs/graphics/libnsgif/lzw.c new file mode 100644 index 00000000000000..3098ef505264fe --- /dev/null +++ b/libobs/graphics/libnsgif/lzw.c @@ -0,0 +1,613 @@ +/* + * This file is part of NetSurf's LibNSGIF, http://www.netsurf-browser.org/ + * Licensed under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + * + * Copyright 2017 Michael Drake + * Copyright 2021 Michael Drake + */ + +#include +#include +#include +#include + +#include "lzw.h" + +/** + * \file + * \brief LZW decompression (implementation) + * + * Decoder for GIF LZW data. + */ + +/** Maximum number of lzw table entries. */ +#define LZW_TABLE_ENTRY_MAX (1u << LZW_CODE_MAX) + +/** + * Context for reading LZW data. + * + * LZW data is split over multiple sub-blocks. Each sub-block has a + * byte at the start, which says the sub-block size, and then the data. + * Zero-size sub-blocks have no data, and the biggest sub-block size is + * 255, which means there are 255 bytes of data following the sub-block + * size entry. + * + * Note that an individual LZW code can be split over up to three sub-blocks. + */ +struct lzw_read_ctx { + const uint8_t *restrict data; /**< Pointer to start of input data */ + size_t data_len; /**< Input data length */ + size_t data_sb_next; /**< Offset to sub-block size */ + + const uint8_t *sb_data; /**< Pointer to current sub-block in data */ + size_t sb_bit; /**< Current bit offset in sub-block */ + uint32_t sb_bit_count; /**< Bit count in sub-block */ +}; + +/** + * LZW table entry. + * + * Records in the table are composed of 1 or more entries. + * Entries refer to the entry they extend which can be followed to compose + * the complete record. To compose the record in reverse order, take + * the `value` from each entry, and move to the entry it extends. + * If the extended entries index is < the current clear_code, then it + * is the last entry in the record. + */ +struct lzw_table_entry { + uint8_t value; /**< Last value for record ending at entry. */ + uint8_t first; /**< First value in entry's entire record. */ + uint16_t count; /**< Count of values in this entry's record. */ + uint16_t extends; /**< Offset in table to previous entry. */ +}; + +/** + * LZW decompression context. + */ +struct lzw_ctx { + struct lzw_read_ctx input; /**< Input reading context */ + + uint16_t prev_code; /**< Code read from input previously. */ + uint16_t prev_code_first; /**< First value of previous code. */ + uint16_t prev_code_count; /**< Total values for previous code. */ + + uint8_t initial_code_size; /**< Starting LZW code size. */ + + uint8_t code_size; /**< Current LZW code size. */ + uint16_t code_max; /**< Max code value for current code size. */ + + uint16_t clear_code; /**< Special Clear code value */ + uint16_t eoi_code; /**< Special End of Information code value */ + + uint16_t table_size; /**< Next position in table to fill. */ + + uint16_t output_code; /**< Code that has been partially output. */ + uint16_t output_left; /**< Number of values left for output_code. */ + + bool has_transparency; /**< Whether the image is opaque. */ + uint8_t transparency_idx; /**< Index representing transparency. */ + const uint32_t *restrict colour_map; /**< Index to colour mapping. */ + + /** LZW code table. Generated during decode. */ + struct lzw_table_entry table[LZW_TABLE_ENTRY_MAX]; + + /** Output value stack. */ + uint8_t stack_base[LZW_TABLE_ENTRY_MAX]; +}; + +/* Exported function, documented in lzw.h */ +lzw_result lzw_context_create(struct lzw_ctx **ctx) +{ + struct lzw_ctx *c = malloc(sizeof(*c)); + if (c == NULL) { + return LZW_NO_MEM; + } + + *ctx = c; + return LZW_OK; +} + +/* Exported function, documented in lzw.h */ +void lzw_context_destroy(struct lzw_ctx *ctx) +{ + free(ctx); +} + +/** + * Advance the context to the next sub-block in the input data. + * + * \param[in] ctx LZW reading context, updated on success. + * \return LZW_OK or LZW_OK_EOD on success, appropriate error otherwise. + */ +static lzw_result lzw__block_advance(struct lzw_read_ctx *restrict ctx) +{ + size_t block_size; + size_t next_block_pos = ctx->data_sb_next; + const uint8_t *data_next = ctx->data + next_block_pos; + + if (next_block_pos >= ctx->data_len) { + return LZW_NO_DATA; + } + + block_size = *data_next; + + if ((next_block_pos + block_size) >= ctx->data_len) { + return LZW_NO_DATA; + } + + ctx->sb_bit = 0; + ctx->sb_bit_count = block_size * 8; + + if (block_size == 0) { + ctx->data_sb_next += 1; + return LZW_OK_EOD; + } + + ctx->sb_data = data_next + 1; + ctx->data_sb_next += block_size + 1; + + return LZW_OK; +} + +/** + * Get the next LZW code of given size from the raw input data. + * + * Reads codes from the input data stream coping with GIF data sub-blocks. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] code_size Size of LZW code to get from data. + * \param[out] code_out Returns an LZW code on success. + * \return LZW_OK or LZW_OK_EOD on success, appropriate error otherwise. + */ +static inline lzw_result lzw__read_code( + struct lzw_read_ctx *restrict ctx, + uint16_t code_size, + uint16_t *restrict code_out) +{ + uint32_t code = 0; + uint32_t current_bit = ctx->sb_bit & 0x7; + + if (ctx->sb_bit + 24 <= ctx->sb_bit_count) { + /* Fast path: read three bytes from this sub-block */ + const uint8_t *data = ctx->sb_data + (ctx->sb_bit >> 3); + code |= *data++ << 0; + code |= *data++ << 8; + code |= *data << 16; + ctx->sb_bit += code_size; + } else { + /* Slow path: code spans sub-blocks */ + uint8_t byte_advance = (current_bit + code_size) >> 3; + uint8_t byte = 0; + uint8_t bits_remaining_0 = (code_size < (8u - current_bit)) ? + code_size : (8u - current_bit); + uint8_t bits_remaining_1 = code_size - bits_remaining_0; + uint8_t bits_used[3] = { + [0] = bits_remaining_0, + [1] = bits_remaining_1 < 8 ? bits_remaining_1 : 8, + [2] = bits_remaining_1 - 8, + }; + + assert(byte_advance <= 2); + + while (true) { + const uint8_t *data = ctx->sb_data; + lzw_result res; + + /* Get any data from end of this sub-block */ + while (byte <= byte_advance && + ctx->sb_bit < ctx->sb_bit_count) { + code |= data[ctx->sb_bit >> 3] << (byte << 3); + ctx->sb_bit += bits_used[byte]; + byte++; + } + + /* Check if we have all we need */ + if (byte > byte_advance) { + break; + } + + /* Move to next sub-block */ + res = lzw__block_advance(ctx); + if (res != LZW_OK) { + return res; + } + } + } + + *code_out = (code >> current_bit) & ((1 << code_size) - 1); + return LZW_OK; +} + +/** + * Handle clear code. + * + * \param[in] ctx LZW reading context, updated. + * \param[out] code_out Returns next code after a clear code. + * \return LZW_OK or error code. + */ +static inline lzw_result lzw__handle_clear( + struct lzw_ctx *ctx, + uint16_t *code_out) +{ + uint16_t code; + + /* Reset table building context */ + ctx->code_size = ctx->initial_code_size; + ctx->code_max = (1 << ctx->initial_code_size) - 1; + ctx->table_size = ctx->eoi_code + 1; + + /* There might be a sequence of clear codes, so process them all */ + do { + lzw_result res = lzw__read_code(&ctx->input, + ctx->code_size, &code); + if (res != LZW_OK) { + return res; + } + } while (code == ctx->clear_code); + + /* The initial code must be from the initial table. */ + if (code > ctx->clear_code) { + return LZW_BAD_ICODE; + } + + *code_out = code; + return LZW_OK; +} + +/* Exported function, documented in lzw.h */ +lzw_result lzw_decode_init( + struct lzw_ctx *ctx, + uint8_t minimum_code_size, + const uint8_t *input_data, + size_t input_length, + size_t input_pos) +{ + struct lzw_table_entry *table = ctx->table; + lzw_result res; + uint16_t code; + + if (minimum_code_size >= LZW_CODE_MAX) { + return LZW_BAD_ICODE; + } + + /* Initialise the input reading context */ + ctx->input.data = input_data; + ctx->input.data_len = input_length; + ctx->input.data_sb_next = input_pos; + + ctx->input.sb_bit = 0; + ctx->input.sb_bit_count = 0; + + /* Initialise the table building context */ + ctx->initial_code_size = minimum_code_size + 1; + + ctx->clear_code = (1 << minimum_code_size) + 0; + ctx->eoi_code = (1 << minimum_code_size) + 1; + + ctx->output_left = 0; + + /* Initialise the standard table entries */ + for (uint16_t i = 0; i < ctx->clear_code; i++) { + table[i].first = i; + table[i].value = i; + table[i].count = 1; + } + + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; + } + + /* Store details of this code as "previous code" to the context. */ + ctx->prev_code_first = ctx->table[code].first; + ctx->prev_code_count = ctx->table[code].count; + ctx->prev_code = code; + + /* Add code to context for immediate output. */ + ctx->output_code = code; + ctx->output_left = 1; + + ctx->has_transparency = false; + ctx->transparency_idx = 0; + ctx->colour_map = NULL; + + return LZW_OK; +} + +/* Exported function, documented in lzw.h */ +lzw_result lzw_decode_init_map( + struct lzw_ctx *ctx, + uint8_t minimum_code_size, + uint32_t transparency_idx, + const uint32_t *colour_table, + const uint8_t *input_data, + size_t input_length, + size_t input_pos) +{ + lzw_result res; + + if (colour_table == NULL) { + return LZW_BAD_PARAM; + } + + res = lzw_decode_init(ctx, minimum_code_size, + input_data, input_length, input_pos); + if (res != LZW_OK) { + return res; + } + + ctx->has_transparency = (transparency_idx <= 0xFF); + ctx->transparency_idx = transparency_idx; + ctx->colour_map = colour_table; + + return LZW_OK; +} + +/** + * Create new table entry. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] code Last value code for new table entry. + */ +static inline void lzw__table_add_entry( + struct lzw_ctx *ctx, + uint16_t code) +{ + struct lzw_table_entry *entry = &ctx->table[ctx->table_size]; + + entry->value = code; + entry->first = ctx->prev_code_first; + entry->count = ctx->prev_code_count + 1; + entry->extends = ctx->prev_code; + + ctx->table_size++; +} + +typedef uint32_t (*lzw_writer_fn)( + struct lzw_ctx *ctx, + void *restrict output_data, + uint32_t output_length, + uint32_t output_pos, + uint16_t code, + uint16_t left); + +/** + * Get the next LZW code and write its value(s) to output buffer. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] write_fn Function for writing pixels to output. + * \param[in] output_data Array to write output values into. + * \param[in] output_length Size of output array. + * \param[in,out] output_written Number of values written. Updated on exit. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +static inline lzw_result lzw__decode( + struct lzw_ctx *ctx, + lzw_writer_fn write_fn, + void *restrict output_data, + uint32_t output_length, + uint32_t *restrict output_written) +{ + lzw_result res; + uint16_t code; + + /* Get a new code from the input */ + res = lzw__read_code(&ctx->input, ctx->code_size, &code); + if (res != LZW_OK) { + return res; + } + + /* Handle the new code */ + if (code == ctx->eoi_code) { + /* Got End of Information code */ + return LZW_EOI_CODE; + + } else if (code > ctx->table_size) { + /* Code is invalid */ + return LZW_BAD_CODE; + + } else if (code == ctx->clear_code) { + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; + } + + } else if (ctx->table_size < LZW_TABLE_ENTRY_MAX) { + uint16_t size = ctx->table_size; + lzw__table_add_entry(ctx, (code < size) ? + ctx->table[code].first : + ctx->prev_code_first); + + /* Ensure code size is increased, if needed. */ + if (size == ctx->code_max && ctx->code_size < LZW_CODE_MAX) { + ctx->code_size++; + ctx->code_max = (1 << ctx->code_size) - 1; + } + } + + *output_written += write_fn(ctx, + output_data, output_length, *output_written, + code, ctx->table[code].count); + + /* Store details of this code as "previous code" to the context. */ + ctx->prev_code_first = ctx->table[code].first; + ctx->prev_code_count = ctx->table[code].count; + ctx->prev_code = code; + + return LZW_OK; +} + +/** + * Write values for this code to the output stack. + * + * If there isn't enough space in the output stack, this function will write + * the as many as it can into the output. If `ctx->output_left > 0` after + * this call, then there is more data for this code left to output. The code + * is stored to the context as `ctx->output_code`. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] output_data Array to write output values into. + * \param[in] output_length length Size of output array. + * \param[in] output_used Current position in output array. + * \param[in] code LZW code to output values for. + * \param[in] left Number of values remaining to output for this code. + * \return Number of pixel values written. + */ +static inline uint32_t lzw__write_fn(struct lzw_ctx *ctx, + void *restrict output_data, + uint32_t output_length, + uint32_t output_used, + uint16_t code, + uint16_t left) +{ + uint8_t *restrict output_pos = (uint8_t *)output_data + output_used; + const struct lzw_table_entry * const table = ctx->table; + uint32_t space = output_length - output_used; + uint16_t count = left; + + if (count > space) { + left = count - space; + count = space; + } else { + left = 0; + } + + ctx->output_code = code; + ctx->output_left = left; + + /* Skip over any values we don't have space for. */ + for (unsigned i = left; i != 0; i--) { + const struct lzw_table_entry *entry = table + code; + code = entry->extends; + } + + output_pos += count; + for (unsigned i = count; i != 0; i--) { + const struct lzw_table_entry *entry = table + code; + *--output_pos = entry->value; + code = entry->extends; + } + + return count; +} + +/* Exported function, documented in lzw.h */ +lzw_result lzw_decode(struct lzw_ctx *ctx, + const uint8_t *restrict *const restrict output_data, + uint32_t *restrict output_written) +{ + const uint32_t output_length = sizeof(ctx->stack_base); + + *output_written = 0; + *output_data = ctx->stack_base; + + if (ctx->output_left != 0) { + *output_written += lzw__write_fn(ctx, + ctx->stack_base, output_length, *output_written, + ctx->output_code, ctx->output_left); + } + + while (*output_written != output_length) { + lzw_result res = lzw__decode(ctx, lzw__write_fn, + ctx->stack_base, output_length, output_written); + if (res != LZW_OK) { + return res; + } + } + + return LZW_OK; +} + +/** + * Write colour mapped values for this code to the output. + * + * If there isn't enough space in the output stack, this function will write + * the as many as it can into the output. If `ctx->output_left > 0` after + * this call, then there is more data for this code left to output. The code + * is stored to the context as `ctx->output_code`. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] output_data Array to write output values into. + * \param[in] output_length Size of output array. + * \param[in] output_used Current position in output array. + * \param[in] code LZW code to output values for. + * \param[in] left Number of values remaining to output for code. + * \return Number of pixel values written. + */ +static inline uint32_t lzw__map_write_fn(struct lzw_ctx *ctx, + void *restrict output_data, + uint32_t output_length, + uint32_t output_used, + uint16_t code, + uint16_t left) +{ + uint32_t *restrict output_pos = (uint32_t *)output_data + output_used; + const struct lzw_table_entry * const table = ctx->table; + uint32_t space = output_length - output_used; + uint16_t count = left; + + if (count > space) { + left = count - space; + count = space; + } else { + left = 0; + } + + ctx->output_code = code; + ctx->output_left = left; + + for (unsigned i = left; i != 0; i--) { + const struct lzw_table_entry *entry = table + code; + code = entry->extends; + } + + output_pos += count; + if (ctx->has_transparency) { + for (unsigned i = count; i != 0; i--) { + const struct lzw_table_entry *entry = table + code; + --output_pos; + if (entry->value != ctx->transparency_idx) { + *output_pos = ctx->colour_map[entry->value]; + } + code = entry->extends; + } + } else { + for (unsigned i = count; i != 0; i--) { + const struct lzw_table_entry *entry = table + code; + *--output_pos = ctx->colour_map[entry->value]; + code = entry->extends; + } + } + + return count; +} + +/* Exported function, documented in lzw.h */ +lzw_result lzw_decode_map(struct lzw_ctx *ctx, + uint32_t *restrict output_data, + uint32_t output_length, + uint32_t *restrict output_written) +{ + *output_written = 0; + + if (ctx->colour_map == NULL) { + return LZW_NO_COLOUR; + } + + if (ctx->output_left != 0) { + *output_written += lzw__map_write_fn(ctx, + output_data, output_length, *output_written, + ctx->output_code, ctx->output_left); + } + + while (*output_written != output_length) { + lzw_result res = lzw__decode(ctx, lzw__map_write_fn, + output_data, output_length, output_written); + if (res != LZW_OK) { + return res; + } + } + + return LZW_OK; +} diff --git a/libobs/graphics/libnsgif/lzw.h b/libobs/graphics/libnsgif/lzw.h new file mode 100644 index 00000000000000..f19432f1c80320 --- /dev/null +++ b/libobs/graphics/libnsgif/lzw.h @@ -0,0 +1,137 @@ +/* + * This file is part of NetSurf's LibNSGIF, http://www.netsurf-browser.org/ + * Licensed under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + * + * Copyright 2017 Michael Drake + * Copyright 2021 Michael Drake + */ + +#ifndef LZW_H_ +#define LZW_H_ + +/** + * \file + * \brief LZW decompression (interface) + * + * Decoder for GIF LZW data. + */ + +/** Maximum LZW code size in bits */ +#define LZW_CODE_MAX 12 + +/* Declare lzw internal context structure */ +struct lzw_ctx; + +/** LZW decoding response codes */ +typedef enum lzw_result { + LZW_OK, /**< Success */ + LZW_OK_EOD, /**< Success; reached zero-length sub-block */ + LZW_NO_MEM, /**< Error: Out of memory */ + LZW_NO_DATA, /**< Error: Out of data */ + LZW_EOI_CODE, /**< Error: End of Information code */ + LZW_NO_COLOUR, /**< Error: No colour map provided. */ + LZW_BAD_ICODE, /**< Error: Bad initial LZW code */ + LZW_BAD_PARAM, /**< Error: Bad function parameter. */ + LZW_BAD_CODE, /**< Error: Bad LZW code */ +} lzw_result; + +/** + * Create an LZW decompression context. + * + * \param[out] ctx Returns an LZW decompression context. Caller owned, + * free with lzw_context_destroy(). + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_context_create( + struct lzw_ctx **ctx); + +/** + * Destroy an LZW decompression context. + * + * \param[in] ctx The LZW decompression context to destroy. + */ +void lzw_context_destroy( + struct lzw_ctx *ctx); + +/** + * Initialise an LZW decompression context for decoding. + * + * \param[in] ctx The LZW decompression context to initialise. + * \param[in] minimum_code_size The LZW Minimum Code Size. + * \param[in] input_data The compressed data. + * \param[in] input_length Byte length of compressed data. + * \param[in] input_pos Start position in data. Must be position + * of a size byte at sub-block start. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_decode_init( + struct lzw_ctx *ctx, + uint8_t minimum_code_size, + const uint8_t *input_data, + size_t input_length, + size_t input_pos); + +/** + * Read input codes until end of LZW context owned output buffer. + * + * Ensure anything in output is used before calling this, as anything + * there before this call will be trampled. + * + * \param[in] ctx LZW reading context, updated. + * \param[out] output_data Returns pointer to array of output values. + * \param[out] output_written Returns the number of values written to data. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_decode(struct lzw_ctx *ctx, + const uint8_t *restrict *const restrict output_data, + uint32_t *restrict output_written); + +/** + * Initialise an LZW decompression context for decoding to colour map values. + * + * For transparency to work correctly, the given client buffer must have + * the values from the previous frame. The transparency_idx should be a value + * of 256 or above, if the frame does not have transparency. + * + * \param[in] ctx The LZW decompression context to initialise. + * \param[in] minimum_code_size The LZW Minimum Code Size. + * \param[in] transparency_idx Index representing transparency. + * \param[in] colour_table Index to pixel colour mapping. + * \param[in] input_data The compressed data. + * \param[in] input_length Byte length of compressed data. + * \param[in] input_pos Start position in data. Must be position + * of a size byte at sub-block start. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_decode_init_map( + struct lzw_ctx *ctx, + uint8_t minimum_code_size, + uint32_t transparency_idx, + const uint32_t *colour_table, + const uint8_t *input_data, + size_t input_length, + size_t input_pos); + +/** + * Read LZW codes into client buffer, mapping output to colours. + * + * The context must have been initialised using \ref lzw_decode_init_map + * before calling this function, in order to provide the colour mapping table + * and any transparency index. + * + * Ensure anything in output is used before calling this, as anything + * there before this call will be trampled. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] output_data Client buffer to fill with colour mapped values. + * \param[in] output_length Size of output array. + * \param[out] output_written Returns the number of values written to data. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_decode_map(struct lzw_ctx *ctx, + uint32_t *restrict output_data, + uint32_t output_length, + uint32_t *restrict output_written); + +#endif diff --git a/libobs/graphics/libnsgif/nsgif.h b/libobs/graphics/libnsgif/nsgif.h new file mode 100644 index 00000000000000..e6873b68d3a1fe --- /dev/null +++ b/libobs/graphics/libnsgif/nsgif.h @@ -0,0 +1,527 @@ +/* + * Copyright 2004 Richard Wilson + * Copyright 2008 Sean Fox + * Copyright 2013-2022 Michael Drake + * + * This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/ + * Licenced under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + */ + +/** + * \file + * Interface to progressive animated GIF file decoding. + */ + +#ifndef NSNSGIF_H +#define NSNSGIF_H + +#include +#include +#include + +/** Representation of infinity. */ +#define NSGIF_INFINITE (UINT32_MAX) + +/** Maximum colour table size */ +#define NSGIF_MAX_COLOURS 256 + +/** + * Opaque type used by LibNSGIF to represent a GIF object in memory. + */ +typedef struct nsgif nsgif_t; + +/** + * LibNSGIF rectangle structure. + * + * * Top left coordinate is `(x0, y0)`. + * * Width is `x1 - x0`. + * * Height is `y1 - y0`. + * * Units are pixels. + */ +typedef struct nsgif_rect { + /** x co-ordinate of redraw rectangle, left */ + uint32_t x0; + /** y co-ordinate of redraw rectangle, top */ + uint32_t y0; + /** x co-ordinate of redraw rectangle, right */ + uint32_t x1; + /** y co-ordinate of redraw rectangle, bottom */ + uint32_t y1; +} nsgif_rect_t; + +/** + * LibNSGIF return codes. + */ +typedef enum { + /** + * Success. + */ + NSGIF_OK, + + /** + * Out of memory error. + */ + NSGIF_ERR_OOM, + + /** + * GIF source data is invalid, and no frames are recoverable. + */ + NSGIF_ERR_DATA, + + /** + * Frame number is not valid. + */ + NSGIF_ERR_BAD_FRAME, + + /** + * GIF source data contained an error in a frame. + */ + NSGIF_ERR_DATA_FRAME, + + /** + * Unexpected end of GIF source data. + */ + NSGIF_ERR_END_OF_DATA, + + /** + * Can't supply more data after calling \ref nsgif_data_complete. + */ + NSGIF_ERR_DATA_COMPLETE, + + /** + * The current frame cannot be displayed. + */ + NSGIF_ERR_FRAME_DISPLAY, + + /** + * Indicates an animation is complete, and \ref nsgif_reset must be + * called to restart the animation from the beginning. + */ + NSGIF_ERR_ANIMATION_END, +} nsgif_error; + +/** + * NSGIF \ref nsgif_bitmap_t pixel format. + * + * All pixel formats are 32 bits per pixel (bpp). The different formats + * allow control over the ordering of the colour channels. All colour + * channels are 8 bits wide. + * + * Note that the GIF file format only supports an on/off mask, so the + * alpha (A) component (opacity) will always have a value of `0` (fully + * transparent) or `255` (fully opaque). + */ +typedef enum nsgif_bitmap_fmt { + /** Bite-wise RGBA: Byte order: 0xRR, 0xGG, 0xBB, 0xAA. */ + NSGIF_BITMAP_FMT_R8G8B8A8, + + /** Bite-wise BGRA: Byte order: 0xBB, 0xGG, 0xRR, 0xAA. */ + NSGIF_BITMAP_FMT_B8G8R8A8, + + /** Bite-wise ARGB: Byte order: 0xAA, 0xRR, 0xGG, 0xBB. */ + NSGIF_BITMAP_FMT_A8R8G8B8, + + /** Bite-wise ABGR: Byte order: 0xAA, 0xBB, 0xGG, 0xRR. */ + NSGIF_BITMAP_FMT_A8B8G8R8, + + /** + * 32-bit RGBA (0xRRGGBBAA). + * + * * On little endian host, same as \ref NSGIF_BITMAP_FMT_A8B8G8R8. + * * On big endian host, same as \ref NSGIF_BITMAP_FMT_R8G8B8A8. + */ + NSGIF_BITMAP_FMT_RGBA8888, + + /** + * 32-bit BGRA (0xBBGGRRAA). + * + * * On little endian host, same as \ref NSGIF_BITMAP_FMT_A8R8G8B8. + * * On big endian host, same as \ref NSGIF_BITMAP_FMT_B8G8R8A8. + */ + NSGIF_BITMAP_FMT_BGRA8888, + + /** + * 32-bit ARGB (0xAARRGGBB). + * + * * On little endian host, same as \ref NSGIF_BITMAP_FMT_B8G8R8A8. + * * On big endian host, same as \ref NSGIF_BITMAP_FMT_A8R8G8B8. + */ + NSGIF_BITMAP_FMT_ARGB8888, + + /** + * 32-bit BGRA (0xAABBGGRR). + * + * * On little endian host, same as \ref NSGIF_BITMAP_FMT_R8G8B8A8. + * * On big endian host, same as \ref NSGIF_BITMAP_FMT_A8B8G8R8. + */ + NSGIF_BITMAP_FMT_ABGR8888, +} nsgif_bitmap_fmt_t; + +/** + * Client bitmap type. + * + * These are client-created and destroyed, via the \ref nsgif_bitmap_cb_vt + * callbacks, but they are owned by a \ref nsgif_t. + * + * See \ref nsgif_bitmap_fmt for pixel format information. + * + * The bitmap may have a row_span greater than the bitmap width, but the + * difference between row span and width must be a whole number of pixels + * (a multiple of four bytes). + */ +typedef void nsgif_bitmap_t; + +/** Bitmap callbacks function table */ +typedef struct nsgif_bitmap_cb_vt { + /** + * Callback to create a bitmap with the given dimensions. + * + * \param[in] width Required bitmap width in pixels. + * \param[in] height Required bitmap height in pixels. + * \return pointer to client's bitmap structure or NULL on error. + */ + nsgif_bitmap_t* (*create)(int width, int height); + + /** + * Callback to free a bitmap. + * + * \param[in] bitmap The bitmap to destroy. + */ + void (*destroy)(nsgif_bitmap_t *bitmap); + + /** + * Get pointer to pixel buffer in a bitmap. + * + * The pixel buffer must be `(width + N) * height * sizeof(uint32_t)`. + * Where `N` is any number greater than or equal to 0. + * Note that the returned pointer to uint8_t must be 4-byte aligned. + * + * \param[in] bitmap The bitmap. + * \return pointer to bitmap's pixel buffer. + */ + uint8_t* (*get_buffer)(nsgif_bitmap_t *bitmap); + + /* The following functions are optional. */ + + /** + * Set whether a bitmap can be plotted opaque. + * + * \param[in] bitmap The bitmap. + * \param[in] opaque Whether the current frame is opaque. + */ + void (*set_opaque)(nsgif_bitmap_t *bitmap, bool opaque); + + /** + * Tests whether a bitmap has an opaque alpha channel. + * + * \param[in] bitmap The bitmap. + * \return true if the bitmap is opaque, false otherwise. + */ + bool (*test_opaque)(nsgif_bitmap_t *bitmap); + + /** + * Bitmap modified notification. + * + * \param[in] bitmap The bitmap. + */ + void (*modified)(nsgif_bitmap_t *bitmap); + + /** + * Get row span in pixels. + * + * If this callback is not provided, LibNSGIF will use the width. + * + * If row span is greater than width, this callback must be provided. + * + * \param[in] bitmap The bitmap. + */ + uint32_t (*get_rowspan)(nsgif_bitmap_t *bitmap); +} nsgif_bitmap_cb_vt; + +/** + * Convert an error code to a string. + * + * \param[in] err The error code to convert. + * \return String representation of given error code. + */ +const char *nsgif_strerror(nsgif_error err); + +/** + * Create the NSGIF object. + * + * \param[in] bitmap_vt Bitmap operation functions v-table. + * \param[in] bitmap_fmt Bitmap pixel format specification. + * \param[out] gif_out Return \ref nsgif_t object on success. + * + * \return NSGIF_OK on success, or appropriate error otherwise. + */ +nsgif_error nsgif_create( + const nsgif_bitmap_cb_vt *bitmap_vt, + nsgif_bitmap_fmt_t bitmap_fmt, + nsgif_t **gif_out); + +/** + * Free a NSGIF object. + * + * \param[in] gif The NSGIF to free. + */ +void nsgif_destroy(nsgif_t *gif); + +/** + * Scan the source image data. + * + * This is used to feed the source data into LibNSGIF. This must be called + * before calling \ref nsgif_frame_decode. + * + * It can be called multiple times with, with increasing sizes. If it is called + * several times, as more data is available (e.g. slow network fetch) the data + * already given to \ref nsgif_data_scan must be provided each time. + * + * Once all the data has been provided, call \ref nsgif_data_complete. + * + * For example, if you call \ref nsgif_data_scan with 25 bytes of data, and then + * fetch another 10 bytes, you would need to call \ref nsgif_data_scan with a + * size of 35 bytes, and the whole 35 bytes must be contiguous memory. It is + * safe to `realloc` the source buffer between calls to \ref nsgif_data_scan. + * (The actual data pointer is allowed to be different.) + * + * If an error occurs, all previously scanned frames are retained. + * + * Note that an error returned from this function is purely informational. + * So long as at least one frame is available, you can display frames. + * + * \param[in] gif The \ref nsgif_t object. + * \param[in] size Number of bytes in data. + * \param[in] data Raw source GIF data. + * + * \return NSGIF_OK on success, or appropriate error otherwise. + */ +nsgif_error nsgif_data_scan( + nsgif_t *gif, + size_t size, + const uint8_t *data); + +/** + * Tell libnsgif that all the gif data has been provided. + * + * Call this after calling \ref nsgif_data_scan with the the entire GIF + * source data. You can call \ref nsgif_data_scan multiple times up until + * this is called, and after this is called, \ref nsgif_data_scan will + * return an error. + * + * You can decode a GIF before this is called, however, it will fail to + * decode any truncated final frame data and will not perform loops when + * driven via \ref nsgif_frame_prepare (because it doesn't know if there + * will be more frames supplied in future data). + * + * \param[in] gif The \ref nsgif_t object. + */ +void nsgif_data_complete( + nsgif_t *gif); + +/** + * Prepare to show a frame. + * + * If this is the last frame of an animation with a finite loop count, the + * returned `delay_cs` will be \ref NSGIF_INFINITE, indicating that the frame + * should be shown forever. + * + * Note that if \ref nsgif_data_complete has not been called on this gif, + * animated GIFs will not loop back to the start. Instead it will return + * \ref NSGIF_ERR_END_OF_DATA. + * + * \param[in] gif The \ref nsgif_t object. + * \param[out] area The area in pixels that must be redrawn. + * \param[out] delay_cs Time to wait after frame_new before next frame in cs. + * \param[out] frame_new The frame to decode. + * + * \return NSGIF_OK on success, or appropriate error otherwise. + */ +nsgif_error nsgif_frame_prepare( + nsgif_t *gif, + nsgif_rect_t *area, + uint32_t *delay_cs, + uint32_t *frame_new); + +/** + * Decodes a GIF frame. + * + * \param[in] gif The \ref nsgif_t object. + * \param[in] frame The frame number to decode. + * \param[out] bitmap On success, returns pointer to the client-allocated, + * nsgif-owned client bitmap structure. + * + * \return NSGIF_OK on success, or appropriate error otherwise. + */ +nsgif_error nsgif_frame_decode( + nsgif_t *gif, + uint32_t frame, + nsgif_bitmap_t **bitmap); + +/** + * Reset a GIF animation. + * + * Some animations are only meant to loop N times, and then show the + * final frame forever. This function resets the loop and frame counters, + * so that the animation can be replayed without the overhead of recreating + * the \ref nsgif_t object and rescanning the raw data. + * + * \param[in] gif A \ref nsgif_t object. + * + * \return NSGIF_OK on success, or appropriate error otherwise. + */ +nsgif_error nsgif_reset( + nsgif_t *gif); + +/** + * Information about a GIF. + */ +typedef struct nsgif_info { + /** width of GIF (may increase during decoding) */ + uint32_t width; + /** height of GIF (may increase during decoding) */ + uint32_t height; + /** number of frames decoded */ + uint32_t frame_count; + /** number of times to play animation (zero means loop forever) */ + int loop_max; + /** background colour in same pixel format as \ref nsgif_bitmap_t. */ + uint32_t background; + /** whether the GIF has a global colour table */ + bool global_palette; +} nsgif_info_t; + +/** + * Frame disposal method. + * + * Clients do not need to know about this, it is provided purely for dumping + * raw information about GIF frames. + */ +enum nsgif_disposal { + NSGIF_DISPOSAL_UNSPECIFIED, /**< No disposal method specified. */ + NSGIF_DISPOSAL_NONE, /**< Frame remains. */ + NSGIF_DISPOSAL_RESTORE_BG, /**< Clear frame to background colour. */ + NSGIF_DISPOSAL_RESTORE_PREV, /**< Restore previous frame. */ + NSGIF_DISPOSAL_RESTORE_QUIRK, /**< Alias for NSGIF_DISPOSAL_RESTORE_PREV. */ +}; + +/** + * Convert a disposal method to a string. + * + * \param[in] disposal The disposal method to convert. + * \return String representation of given disposal method. + */ +const char *nsgif_str_disposal(enum nsgif_disposal disposal); + +/** + * Information about a GIF frame. + */ +typedef struct nsgif_frame_info { + /** whether the frame should be displayed/animated */ + bool display; + /** whether the frame may have transparency */ + bool transparency; + /** whether the frame has a local colour table */ + bool local_palette; + /** whether the frame is interlaced */ + bool interlaced; + /** Disposal method for previous frame; affects plotting */ + uint8_t disposal; + /** delay (in cs) before animating the frame */ + uint32_t delay; + + /** Frame's redraw rectangle. */ + nsgif_rect_t rect; +} nsgif_frame_info_t; + +/** + * Get information about a GIF from an \ref nsgif_t object. + * + * \param[in] gif The \ref nsgif_t object to get info for. + * + * \return The gif info, or NULL on error. + */ +const nsgif_info_t *nsgif_get_info(const nsgif_t *gif); + +/** + * Get information about a GIF from an \ref nsgif_t object. + * + * \param[in] gif The \ref nsgif_t object to get frame info for. + * \param[in] frame The frame number to get info for. + * + * \return The gif frame info, or NULL on error. + */ +const nsgif_frame_info_t *nsgif_get_frame_info( + const nsgif_t *gif, + uint32_t frame); + +/** + * Get the global colour palette. + * + * If the GIF has no global colour table, this will return the default + * colour palette. + * + * Colours in same pixel format as \ref nsgif_bitmap_t. + * + * \param[in] gif The \ref nsgif_t object. + * \param[out] table Client buffer to hold the colour table. + * \param[out] entries The number of used entries in the colour table. + */ +void nsgif_global_palette( + const nsgif_t *gif, + uint32_t table[NSGIF_MAX_COLOURS], + size_t *entries); + +/** + * Get the local colour palette for a frame. + * + * Frames may have no local palette. In this case they use the global palette. + * This function returns false if the frame has no local palette. + * + * Colours in same pixel format as \ref nsgif_bitmap_t. + * + * \param[in] gif The \ref nsgif_t object. + * \param[in] frame The frame to get the palette for. + * \param[out] table Client buffer to hold the colour table. + * \param[out] entries The number of used entries in the colour table. + * \return true if a palette is returned, false otherwise. + */ +bool nsgif_local_palette( + const nsgif_t *gif, + uint32_t frame, + uint32_t table[NSGIF_MAX_COLOURS], + size_t *entries); + +/** + * Configure handling of small frame delays. + * + * Historically people created GIFs with a tiny frame delay, however the slow + * hardware of the time meant they actually played much slower. As computers + * sped up, to prevent animations playing faster than intended, decoders came + * to ignore overly small frame delays. + * + * By default a \ref nsgif_frame_prepare() managed animation will override + * frame delays of less than 2 centiseconds with a default frame delay of + * 10 centiseconds. This matches the behaviour of web browsers and other + * renderers. + * + * Both the minimum and the default values can be overridden for a given GIF + * by the client. To get frame delays exactly as specified by the GIF file, set + * `delay_min` to zero. + * + * Note that this does not affect the frame delay in the frame info + * (\ref nsgif_frame_info_t) structure, which will always contain values + * specified by the GIF. + * + * \param[in] gif The \ref nsgif_t object to configure. + * \param[in] delay_min The minimum frame delay in centiseconds. + * \param[in] delay_default The delay to use if a frame delay is less than + * `delay_min`. + */ +void nsgif_set_frame_delay_behaviour( + nsgif_t *gif, + uint16_t delay_min, + uint16_t delay_default); + +#endif