From be833efd3d3be3c618010ab8feb1921db217b574 Mon Sep 17 00:00:00 2001
From: Dusan Klinec <dusan.klinec@gmail.com>
Date: Tue, 17 Jan 2017 14:51:57 +0100
Subject: [PATCH 1/3] copy_n: fast copy with memmove fixed

- fixed a problem in cases a < b when self == other. Source memory was overwritten.
---
 bitarray/_bitarray.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/bitarray/_bitarray.c b/bitarray/_bitarray.c
index 0add832b1..4a03ff4c9 100644
--- a/bitarray/_bitarray.c
+++ b/bitarray/_bitarray.c
@@ -254,24 +254,30 @@ copy_n(bitarrayobject *self, idx_t a,
     assert(0 <= a && a <= self->nbits - n);
     assert(0 <= b && b <= other->nbits - n);
 
-    /* XXX
     if (self->endian == other->endian && a % 8 == 0 && b % 8 == 0 && n >= 8)
     {
-        Py_ssize_t bytes;
-        idx_t bits;
+        const Py_ssize_t bytes = (Py_ssize_t) n / 8;
+        const idx_t bits = bytes * 8;
+
+        if (a <= b){
+            memmove(self->ob_item + a / 8, other->ob_item + b / 8, bytes);
+        }
+
+        if (n != bits) {
+            copy_n(self, bits + a, other, bits + b, n - bits);
+        }
+
+        if (a > b){
+            memmove(self->ob_item + a / 8, other->ob_item + b / 8, bytes);
+        }
 
-        bytes = n / 8;
-        bits = 8 * bytes;
-        copy_n(self, bits + a, other, bits + b, n - bits);
-        memmove(self->ob_item + a / 8, other->ob_item + b / 8, bytes);
         return;
     }
-    */
 
     /* the different type of looping is only relevant when other and self
        are the same object, i.e. when copying a piece of an bitarrayobject
        onto itself */
-    if (a < b) {
+    if (a <= b) {
         for (i = 0; i < n; i++)             /* loop forward (delete) */
             setbit(self, i + a, GETBIT(other, i + b));
     }

From 4e0da30bd04b178cf2545e6e8b08765f10dfa295 Mon Sep 17 00:00:00 2001
From: Dusan Klinec <dusan.klinec@gmail.com>
Date: Tue, 17 Jan 2017 14:55:33 +0100
Subject: [PATCH 2/3] copy_n: if n is null return immediately

---
 bitarray/_bitarray.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/bitarray/_bitarray.c b/bitarray/_bitarray.c
index 4a03ff4c9..eaaf0d52e 100644
--- a/bitarray/_bitarray.c
+++ b/bitarray/_bitarray.c
@@ -253,6 +253,9 @@ copy_n(bitarrayobject *self, idx_t a,
     assert(0 <= n && n <= self->nbits && n <= other->nbits);
     assert(0 <= a && a <= self->nbits - n);
     assert(0 <= b && b <= other->nbits - n);
+    if (n == 0){
+        return;
+    }
 
     if (self->endian == other->endian && a % 8 == 0 && b % 8 == 0 && n >= 8)
     {

From f6d8d8dc1e95c8451c35f0e646cd379c2c5aa4e6 Mon Sep 17 00:00:00 2001
From: Dusan Klinec <dusan.klinec@gmail.com>
Date: Tue, 17 Jan 2017 14:59:26 +0100
Subject: [PATCH 3/3] randomised tests - more rounds, helped with debugging
 fast_copy in copy_n

---
 test/test_bitarray.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/test_bitarray.py b/test/test_bitarray.py
index 4b60e3d6d..27e6ca33f 100644
--- a/test/test_bitarray.py
+++ b/test/test_bitarray.py
@@ -506,7 +506,7 @@ def test_setitem4(self):
         for a in self.randombitarrays():
             la = len(a)
             if la == 0: continue
-            for dum in range(3):
+            for dum in range(50):
                 step = self.rndsliceidx(la)
                 if step == 0: step = None
                 s = slice(self.rndsliceidx(la),
@@ -580,7 +580,7 @@ def test_delitem2(self):
         for a in self.randombitarrays():
             la = len(a)
             if la == 0: continue
-            for dum in range(10):
+            for dum in range(50):
                 step = self.rndsliceidx(la)
                 if step == 0: step = None
                 s = slice(self.rndsliceidx(la),