add compression support in GetMsgPackedValueAsString (#327)

adds support to retrieve a compressed version of the msgpacked value. If values are stored compressed directly uses the stored/compressed value.

Author: hendrikmuhs

.github/workflows/keyvi.yml

@@ -33,7 +33,8 @@ jobs:
           brew update
           # workaround for https://github.com/actions/setup-python/issues/577
           brew list -1 | grep python | while read formula; do brew unlink $formula; brew link --overwrite $formula; done
-          brew install zlib snappy boost
+          brew install zlib snappy boost@1.85
+          brew link boost@1.85
       - name: checkout from git
         uses: actions/checkout@v4
 

.github/workflows/python-cibuildwheel.yml

@@ -64,7 +64,8 @@ jobs:
         run: |
           brew update && \
           brew list -1 | grep python | while read formula; do brew unlink $formula; brew link --overwrite $formula; done && \
-          brew install ccache zlib snappy boost
+          brew install ccache zlib snappy boost@1.85
+          brew link boost@1.85
 
       - name: set mac deployment target X64
         if: runner.os == 'macOS' && runner.arch == 'X64'
@@ -102,7 +103,7 @@ jobs:
           CIBW_BEFORE_BUILD: pip install -r python/requirements.txt
 
           # testing
-          CIBW_TEST_REQUIRES: pytest
+          CIBW_TEST_REQUIRES: pytest python-snappy zstd
           CIBW_TEST_COMMAND: >
             python -m pytest {package}/tests &&
             python -m pytest {package}/integration-tests
@@ -139,6 +140,7 @@ jobs:
         python setup.py sdist -d wheelhouse && \
         python -m pip uninstall -y autowrap && \
         python -m pip install wheelhouse/*.tar.gz -v && \
+        python -m pip install python-snappy zstd && \
         python -m pytest tests && \
         python -m pip uninstall -y keyvi
 

CMakeLists.txt

@@ -72,7 +72,7 @@ else ()
     message(FATAL_ERROR "Can not find Boost")
 endif ()
 if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-    set(_KEYVI_LINK_LIBRARIES_STATIC "${_KEYVI_LINK_LIBRARIES_STATIC} boost_program_options boost_iostreams boost_filesystem boost_system boost_regex boost_thread")
+    set(_KEYVI_LINK_LIBRARIES_STATIC "${_KEYVI_LINK_LIBRARIES_STATIC} boost_program_options boost_iostreams boost_filesystem boost_system boost_regex boost_thread-mt")
 else ()
     set(_KEYVI_LINK_LIBRARIES_DYNAMIC "${_KEYVI_LINK_LIBRARIES_DYNAMIC} boost_program_options boost_iostreams boost_filesystem boost_system boost_regex boost_thread")
 endif ()

keyvi/bin/keyvi_c/c_api.cpp

@@ -182,6 +182,29 @@ keyvi_bytes keyvi_match_get_msgpacked_value(const struct keyvi_match* match) {
   return keyvi_bytes{data_size, static_cast<const uint8_t*>(data_ptr)};
 }
 
+keyvi_bytes keyvi_match_get_msgpacked_value_compressed(const struct keyvi_match* match,
+                                                       keyvi::compression::CompressionAlgorithm compression) {
+  const keyvi_bytes empty_keyvi_bytes{0, nullptr};
+
+  if (!match->obj_) {
+    return empty_keyvi_bytes;
+  }
+
+  const std::string compressed_value = match->obj_->GetMsgPackedValueAsString(compression);
+
+  const size_t data_size = compressed_value.size();
+  if (0 == data_size) {
+    return empty_keyvi_bytes;
+  }
+  auto* data_ptr = malloc(data_size);
+  if (nullptr == data_ptr) {
+    return empty_keyvi_bytes;
+  }
+  memcpy(data_ptr, compressed_value.c_str(), data_size);
+
+  return keyvi_bytes{data_size, static_cast<const uint8_t*>(data_ptr)};
+}
+
 char* keyvi_match_get_matched_string(const keyvi_match* match) {
   return std_2_c_string(match->obj_ ? match->obj_->GetMatchedString() : "");
 }

keyvi/include/keyvi/c_api/c_api.h

@@ -32,6 +32,8 @@ extern "C" {
 #include <stddef.h>
 #include <stdint.h>
 
+#include "keyvi/compression/compression_algorithm.h"
+
 struct keyvi_dictionary;
 struct keyvi_match;
 struct keyvi_match_iterator;
@@ -92,6 +94,9 @@ char* keyvi_match_get_value_as_string(const struct keyvi_match*);
 
 keyvi_bytes keyvi_match_get_msgpacked_value(const struct keyvi_match*);
 
+keyvi_bytes keyvi_match_get_msgpacked_value_compressed(const struct keyvi_match*,
+                                                       keyvi::compression::CompressionAlgorithm);
+
 char* keyvi_match_get_matched_string(const struct keyvi_match*);
 
 //////////////////////

keyvi/include/keyvi/compression/compression_algorithm.h

@@ -0,0 +1,34 @@
+/* * keyvi - A key value store.
+ *
+ * Copyright 2025 Hendrik Muhs<hendrik.muhs@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef KEYVI_COMPRESSION_COMPRESSION_ALGORITHM_H_
+#define KEYVI_COMPRESSION_COMPRESSION_ALGORITHM_H_
+
+namespace keyvi {
+namespace compression {
+
+enum CompressionAlgorithm {
+  NO_COMPRESSION = 0,
+  ZLIB_COMPRESSION = 1,
+  SNAPPY_COMPRESSION = 2,
+  ZSTD_COMPRESSION = 3,
+};
+
+} /* namespace compression */
+} /* namespace keyvi */
+
+#endif  // KEYVI_COMPRESSION_COMPRESSION_ALGORITHM_H_

keyvi/include/keyvi/compression/compression_selector.h

@@ -25,11 +25,13 @@
 #ifndef KEYVI_COMPRESSION_COMPRESSION_SELECTOR_H_
 #define KEYVI_COMPRESSION_COMPRESSION_SELECTOR_H_
 
+#include <memory>
 #include <string>
 
 #include <boost/algorithm/string.hpp>
 #include <boost/lexical_cast.hpp>
 
+#include "keyvi/compression/compression_algorithm.h"
 #include "keyvi/compression/compression_strategy.h"
 #include "keyvi/compression/snappy_compression_strategy.h"
 #include "keyvi/compression/zlib_compression_strategy.h"
@@ -64,8 +66,8 @@ inline CompressionStrategy* compression_strategy(const std::string& name = "") {
 typedef std::string (*decompress_func_t)(const std::string&);
 typedef void (CompressionStrategy::*compress_mem_fn_t)(buffer_t*, const char*, size_t);
 
-inline decompress_func_t decompressor_by_code(const std::string& s) {
-  switch (s[0]) {
+inline decompress_func_t decompressor_by_code(const CompressionAlgorithm algorithm) {
+  switch (algorithm) {
     case NO_COMPRESSION:
       TRACE("unpack uncompressed string");
       return RawCompressionStrategy::DoDecompress;
@@ -79,8 +81,29 @@ inline decompress_func_t decompressor_by_code(const std::string& s) {
       TRACE("unpack zstd compressed string");
       return ZstdCompressionStrategy::DoDecompress;
     default:
-      throw std::invalid_argument("Invalid compression code " +
-                                  boost::lexical_cast<std::string>(static_cast<int>(s[0])));
+      throw std::invalid_argument("Invalid compression algorithm " +
+                                  boost::lexical_cast<std::string>(static_cast<int>(algorithm)));
+  }
+}
+
+inline decompress_func_t decompressor_from_string(const std::string& s) {
+  return decompressor_by_code(static_cast<CompressionAlgorithm>(s[0]));
+}
+
+/** Returns an instance of a compression strategy by enum. */
+inline compression_strategy_t compression_strategy_by_code(const CompressionAlgorithm algorithm) {
+  switch (algorithm) {
+    case NO_COMPRESSION:
+      return std::make_unique<RawCompressionStrategy>();
+    case ZLIB_COMPRESSION:
+      return std::make_unique<ZlibCompressionStrategy>();
+    case SNAPPY_COMPRESSION:
+      return std::make_unique<SnappyCompressionStrategy>();
+    case ZSTD_COMPRESSION:
+      return std::make_unique<ZstdCompressionStrategy>();
+    default:
+      throw std::invalid_argument("Invalid compression algorithm " +
+                                  boost::lexical_cast<std::string>(static_cast<int>(algorithm)));
   }
 }
 

keyvi/include/keyvi/compression/compression_strategy.h

@@ -26,23 +26,18 @@
 #define KEYVI_COMPRESSION_COMPRESSION_STRATEGY_H_
 
 #include <cstring>
+#include <memory>
 #include <string>
 #include <vector>
 
+#include "keyvi/compression/compression_algorithm.h"
 #include "keyvi/dictionary/fsa/internal/constants.h"
 
 namespace keyvi {
 namespace compression {
 
-enum CompressionCode {
-  NO_COMPRESSION = 0,
-  ZLIB_COMPRESSION = 1,
-  SNAPPY_COMPRESSION = 2,
-  ZSTD_COMPRESSION = 3,
-};
-
 // buffer type which is realloc-able
-typedef std::vector<char> buffer_t;
+using buffer_t = std::vector<char>;
 
 /**
  * The base class of every compression strategy.
@@ -64,6 +59,12 @@ struct CompressionStrategy {
     return std::string(buf.data(), buf.size());
   }
 
+  inline std::string CompressWithoutHeader(const std::string& raw) {
+    buffer_t buf;
+    Compress(&buf, raw.data(), raw.size());
+    return std::string(buf.data() + 1, buf.size() - 1);
+  }
+
   /**
    * By the time this function is called, the length field added in Compress()
    * will have been removed.
@@ -77,6 +78,8 @@ struct CompressionStrategy {
   virtual uint64_t GetFileVersionMin() const = 0;
 };
 
+using compression_strategy_t = std::unique_ptr<CompressionStrategy>;
+
 /**
  * A compression strategy that does almost nothing; i.e. it only adds
  * the length field.
@@ -90,12 +93,6 @@ struct RawCompressionStrategy final : public CompressionStrategy {
     std::memcpy(buffer->data() + 1, raw, raw_size);
   }
 
-  static inline std::string DoCompress(const char* raw, size_t raw_size) {
-    buffer_t buf;
-    DoCompress(&buf, raw, raw_size);
-    return std::string(buf.data(), buf.size());
-  }
-
   inline std::string Decompress(const std::string& compressed) { return DoDecompress(compressed); }
 
   static inline std::string DoDecompress(const std::string& compressed) { return compressed.substr(1); }

keyvi/include/keyvi/compression/snappy_compression_strategy.h

@@ -47,12 +47,6 @@ struct SnappyCompressionStrategy final : public CompressionStrategy {
     buffer->resize(output_length + 1);
   }
 
-  static inline std::string DoCompress(const char* raw, size_t raw_size) {
-    buffer_t buf;
-    DoCompress(&buf, raw, raw_size);
-    return std::string(buf.data(), buf.size());
-  }
-
   inline std::string Decompress(const std::string& compressed) { return DoDecompress(compressed); }
 
   static std::string DoDecompress(const std::string& compressed) {

keyvi/include/keyvi/dictionary/fsa/automata.h

@@ -394,6 +394,13 @@ class Automata final {
     return value_store_reader_->GetRawValueAsString(state_value);
   }
 
+  std::string GetMsgPackedValueAsString(uint64_t state_value,
+                                        const compression::CompressionAlgorithm compression_algorithm =
+                                            compression::CompressionAlgorithm::NO_COMPRESSION) const {
+    assert(value_store_reader_);
+    return value_store_reader_->GetMsgPackedValueAsString(state_value, compression_algorithm);
+  }
+
   std::string GetStatistics() const {
     return dictionary_properties_->GetStatistics();
   }