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fixed overlapping count & workspace special case

dev
Yann Collet 2020-07-26 22:40:21 -07:00
parent 051232223f
commit 8b9cdd2597
1 changed files with 5 additions and 4 deletions
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9
lib/compress/hist.c
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@ -71,20 +71,21 @@ static size_t HIST_count_parallel_wksp(
{
const BYTE* ip = (const BYTE*)source;
const BYTE* const iend = ip+sourceSize;
size_t const countSize = (*maxSymbolValuePtr + 1) * sizeof(*count);
unsigned max=0;
U32* const Counting1 = workSpace;
U32* const Counting2 = Counting1 + 256;
U32* const Counting3 = Counting2 + 256;
U32* const Counting4 = Counting3 + 256;
memset(workSpace, 0, 4*256*sizeof(unsigned));
/* safety checks */
assert(*maxSymbolValuePtr <= 255);
if (!sourceSize) {
memset(count, 0, (*maxSymbolValuePtr + 1) * 4);
memset(count, 0, countSize);
*maxSymbolValuePtr = 0;
return 0;
}
memset(workSpace, 0, 4*256*sizeof(unsigned));
/* by stripes of 16 bytes */
{ U32 cached = MEM_read32(ip); ip += 4;
@ -126,7 +127,7 @@ static size_t HIST_count_parallel_wksp(
while (!Counting1[maxSymbolValue]) maxSymbolValue--;
if (check && maxSymbolValue > *maxSymbolValuePtr) return ERROR(maxSymbolValue_tooSmall);
*maxSymbolValuePtr = maxSymbolValue;
memcpy(count, Counting1, (maxSymbolValue+1) * 4);
memmove(count, Counting1, countSize); /* in case count & Counting1 are overlapping */
}
return (size_t)max;
}