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fix: concatbits erase out-of-bound

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douniwan5788 2024-10-28 16:04:44 +08:00
commit 923e7dced9
2 changed files with 19 additions and 11 deletions
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28
common/commonutil.c
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@ -544,18 +544,26 @@ void reverse_arraybytes_copy(uint8_t *arr, uint8_t *dest, size_t len) {
}
}
// TODO: consider overlap, Implement _membitmovebb
size_t concatbits(uint8_t *dst, size_t dstskip, const uint8_t *src, size_t srcstart, size_t srclen) {
// erase dstbuf bits that will be overriden
dst[dstskip / 8] &= 0xFF - ((1 << (7 - (dstskip % 8) + 1)) - 1);
for (size_t i = (dstskip / 8) + 1; i <= (dstskip + srclen) / 8; i++) {
dst[i] = 0;
// TODO: Boost performance by copying in chunks of 1, 2, or 4 bytes when feasible.
size_t concatbits(uint8_t *dest, int dest_offset, const uint8_t *src, int src_offset, size_t nbits) {
int i, end, step;
// overlap
if ((src - dest) * 8 + src_offset - dest_offset > 0) {
i = 0;
end = nbits;
step = 1;
} else {
i = nbits;
end = 0;
step = -1;
}
for (size_t i = 0; i < srclen; i++) {
// equiv of dstbufbits[dstbufskip + i] = srcbufbits[srcbufstart + i]
dst[(dstskip + i) / 8] |= ((src[(srcstart + i) / 8] >> (7 - ((srcstart + i) % 8))) & 1) << (7 - ((dstskip + i) % 8));
for (; i != end; i += step) {
// equiv of dest_bits[dest_offset + i] = src_bits[src_offset + i]
CLEAR_BIT(dest, dest_offset + i);
if (TEST_BIT(src, src_offset + i)) SET_BIT(dest, dest_offset + i);
}
return dstskip + srclen;
return dest_offset + nbits;
}