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fixed dictCtx compression

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This commit is contained in:
Yann Collet 2018-04-16 23:59:42 -07:00
parent 444211d259
commit da3b5ba6f0
1 changed files with 12 additions and 7 deletions
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19
lib/lz4.c
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@ -602,6 +602,7 @@ LZ4_FORCE_INLINE void LZ4_prepareTable(
* currentOffset == 0 is faster still, so we preserve that case.
*/
if (cctx->currentOffset != 0 && tableType == byU32) {
DEBUGLOG(5, "LZ4_prepareTable: adding 64KB to currentOffset");
cctx->currentOffset += 64 KB;
}
@ -636,8 +637,9 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
dictDirective == usingDictCtx ? dictCtx->dictionary : cctx->dictionary;
const U32 dictSize =
dictDirective == usingDictCtx ? dictCtx->dictSize : cctx->dictSize;
const U32 dictDelta = usingDictCtx ? startIndex - dictCtx->currentOffset : 0; /* make indexes in dictCtx comparable with index in current context */
int const maybe_ext_memSegment = (dictDirective == usingExtDict) || (dictDirective == usingDictCtx);
int const maybe_extMem = (dictDirective == usingExtDict) || (dictDirective == usingDictCtx);
U32 const prefixIdxLimit = startIndex - dictSize; /* used when dictDirective == dictSmall */
const BYTE* const dictEnd = dictionary + dictSize;
const BYTE* anchor = (const BYTE*) source;
@ -648,7 +650,7 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
/* the dictCtx currentOffset is indexed on the start of the dictionary,
* while a dictionary in the current context precedes the currentOffset */
const BYTE* dictBase = dictDirective == usingDictCtx ?
dictionary + dictSize - dictCtx->currentOffset : /* is it possible that dictCtx->currentOffset != dictCtx->dictSize ? */
dictionary + dictSize - dictCtx->currentOffset : /* is it possible that dictCtx->currentOffset != dictCtx->dictSize ? Yes if the dictionary context is not reset */
dictionary + dictSize - startIndex;
BYTE* op = (BYTE*) dest;
@ -657,6 +659,7 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
U32 offset = 0;
U32 forwardH;
DEBUGLOG(5, "LZ4_compress_generic: srcSize=%i, tableType=%u", inputSize, tableType);
/* Init conditions */
if ((U32)inputSize > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported inputSize, too large (or negative) */
if (tableType==byPtr) assert(dictDirective==noDict); /* only supported use case with byPtr */
@ -731,8 +734,10 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
if (dictDirective == usingDictCtx) {
if (matchIndex < startIndex) {
/* there was no match, try the dictionary */
assert(tableType == byU32);
matchIndex = LZ4_getIndexOnHash(h, dictCtx->hashTable, byU32);
match = dictBase + matchIndex;
matchIndex += dictDelta; /* make dictCtx index comparable with current context */
lowLimit = dictionary;
} else {
match = base + matchIndex;
@ -758,7 +763,7 @@ LZ4_FORCE_INLINE int LZ4_compress_generic(
if (tableType == byU16) assert((current - matchIndex) <= MAX_DISTANCE); /* too_far presumed impossible with byU16 */
if (LZ4_read32(match) == LZ4_read32(ip)) {
if (maybe_ext_memSegment) offset = current - matchIndex;
if (maybe_extMem) offset = current - matchIndex;
break; /* match found */
}
@ -798,7 +803,7 @@ _next_match:
*/
/* Encode Offset */
if (maybe_ext_memSegment) { /* static test */
if (maybe_extMem) { /* static test */
DEBUGLOG(6, " with offset=%u (ext if > %i)", offset, (int)(ip - (const BYTE*)source));
assert(offset <= MAX_DISTANCE && offset > 0);
LZ4_writeLE16(op, (U16)offset); op+=2;
@ -878,6 +883,7 @@ _next_match:
matchIndex = LZ4_getIndexOnHash(h, dictCtx->hashTable, byU32);
match = dictBase + matchIndex;
lowLimit = dictionary; /* required for match length counter */
matchIndex += dictDelta;
} else {
match = base + matchIndex;
lowLimit = (const BYTE*)source; /* required for match length counter */
@ -899,8 +905,7 @@ _next_match:
&& (LZ4_read32(match) == LZ4_read32(ip)) ) {
token=op++;
*token=0;
if (maybe_ext_memSegment)
offset = current - matchIndex;
if (maybe_extMem) offset = current - matchIndex;
DEBUGLOG(6, "seq.start:%i, literals=%u, match.start:%i", (int)(anchor-(const BYTE*)source), 0, (int)(ip-(const BYTE*)source));
goto _next_match;
}
@ -1285,7 +1290,7 @@ int LZ4_loadDict (LZ4_stream_t* LZ4_dict, const char* dictionary, int dictSize)
const BYTE* const dictEnd = p + dictSize;
const BYTE* base;
DEBUGLOG(4, "LZ4_loadDict (%p into %p)", dictionary, LZ4_dict);
DEBUGLOG(4, "LZ4_loadDict (%i bytes from %p into %p)", dictSize, dictionary, LZ4_dict);
LZ4_prepareTable(dict, 0, tableType);