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Fix UBSan error (ptr + offset overflow) #148

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Jul 27, 2022
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Fix UBSan error (ptr + offset overflow) #148

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2 changes: 1 addition & 1 deletion snappy.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -340,7 +340,7 @@ static inline bool Copy64BytesWithPatternExtension(char* dst, size_t offset) {
if (SNAPPY_PREDICT_TRUE(offset < 16)) {
if (SNAPPY_PREDICT_FALSE(offset == 0)) return false;
// Extend the pattern to the first 16 bytes.
for (int i = 0; i < 16; i++) dst[i] = dst[i - offset];
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@emkornfield emkornfield Jul 19, 2022 •
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was there s specific reason for this formulation vs pure pointer arithmetic? *(dst - offset + i)

for (int i = 0; i < 16; i++) dst[i] = (dst - offset)[i];
// Find a multiple of pattern >= 16.
static std::array<uint8_t, 16> pattern_sizes = []() {
std::array<uint8_t, 16> res;
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