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Optimize function xcrush_copy_bytes()

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Use memcpy to copy the bytes when we can assure that the memory areas does not overlap.
When the areas overlap, copy the area that doesn't overlap repeatly.
With this change, the copy is ~30x faster.
This commit is contained in:
Raul Fernandes 2019-10-24 13:35:24 -03:00 committed by akallabeth
parent 2ed941f9e2
commit 54c902b3b5
1 changed files with 19 additions and 5 deletions
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24
libfreerdp/codec/xcrush.c
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@ -732,13 +732,27 @@ static int xcrush_generate_output(XCRUSH_CONTEXT* xcrush, BYTE* OutputBuffer, UI
return 1;
}
static size_t xcrush_copy_bytes(BYTE* dst, const BYTE* src, size_t num)
static INLINE size_t xcrush_copy_bytes(BYTE* dst, const BYTE* src, size_t num)
{
size_t index;
for (index = 0; index < num; index++)
size_t diff, rest, end, a;
if (src + num < dst || src > dst + num)
{
dst[index] = src[index];
memcpy(dst, src, num);
}
else
{
// src and dst overlaps
// we should copy the area that doesn't overlap repeatly
diff = (dst > src) ? dst - src : src - dst;
rest = num % diff;
end = num - rest;
for (a = 0; a < end; a += diff)
{
memcpy(&dst[a], &src[a], diff);
}
if (rest != 0)
memcpy(&dst[end], &src[end], rest);
}
return num;