AuroraMiddleware/lz4
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lz4hc.c: change (length >> 8) to (length / 255)

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Every 0xff byte in the compressed block corresponds to a length of 255 (not 256) in the input data. For long repeating sequences, using (length >> 8) may generate bad compressed blocks.
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qiuyangs 2019-01-06 16:29:30 +08:00 committed by GitHub
parent ec735ac53e
commit 660d21272e
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 2 additions and 2 deletions
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lib/lz4hc.c
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@ -437,7 +437,7 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
/* Encode Literal length */
length = (size_t)(*ip - *anchor);
if ((limit) && ((*op + (length >> 8) + length + (2 + 1 + LASTLITERALS)) > oend)) return 1; /* Check output limit */
if ((limit) && ((*op + (length / 255) + length + (2 + 1 + LASTLITERALS)) > oend)) return 1; /* Check output limit */
if (length >= RUN_MASK) {
size_t len = length - RUN_MASK;
*token = (RUN_MASK << ML_BITS);
@ -458,7 +458,7 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
/* Encode MatchLength */
assert(matchLength >= MINMATCH);
length = (size_t)(matchLength - MINMATCH);
if ((limit) && (*op + (length >> 8) + (1 + LASTLITERALS) > oend)) return 1; /* Check output limit */
if ((limit) && (*op + (length / 255) + (1 + LASTLITERALS) > oend)) return 1; /* Check output limit */
if (length >= ML_MASK) {
*token += ML_MASK;
length -= ML_MASK;