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refactored decompress (#82)

dev
Yann Collet 2015-11-30 23:13:56 +01:00
parent aead1bf86b
commit 44287a3bf4
2 changed files with 58 additions and 71 deletions
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@ -1,5 +1,5 @@
v0.4.1
Fixed : ZSTD_LEGACY=disable build mode (reported by Luben)
Fixed : ZSTD_LEGACY_SUPPORT=0 build mode (reported by Luben)
removed `zstd.c`
v0.4.0

127
lib/zstd_decompress.c
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@ -527,64 +527,64 @@ FORCE_INLINE size_t ZSTD_execSequence(BYTE* op,
*litPtr = litEnd; /* update for next sequence */
/* copy Match */
/* check */
//if (match > oLitEnd) return ERROR(corruption_detected); /* address space overflow test (is clang optimizer wrongly removing this test ?) */
if (sequence.offset > (size_t)oLitEnd) return ERROR(corruption_detected); /* address space overflow test (this test seems preserved by clang optimizer) */
/* check */
//if (match > oLitEnd) return ERROR(corruption_detected); /* address space overflow test (is clang optimizer wrongly removing this test ?) */
if (sequence.offset > (size_t)oLitEnd) return ERROR(corruption_detected); /* address space overflow test (this test seems preserved by clang optimizer) */
if (match < base)
{
/* offset beyond prefix */
if (match < vBase) return ERROR(corruption_detected);
match = dictEnd - (base-match);
if (match + sequence.matchLength <= dictEnd)
{
memcpy(oLitEnd, match, sequence.matchLength);
return sequenceLength;
}
/* span extDict & currentPrefixSegment */
{
size_t length1 = dictEnd - match;
memcpy(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
match = base;
}
}
if (match < base)
{
/* offset beyond prefix */
if (match < vBase) return ERROR(corruption_detected);
match = dictEnd - (base-match);
if (match + sequence.matchLength <= dictEnd)
{
memcpy(oLitEnd, match, sequence.matchLength);
return sequenceLength;
}
/* span extDict & currentPrefixSegment */
{
size_t length1 = dictEnd - match;
memcpy(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
match = base;
}
}
/* match within prefix */
if (sequence.offset < 8)
{
/* close range match, overlap */
const int sub2 = dec64table[sequence.offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[sequence.offset];
ZSTD_copy4(op+4, match);
match -= sub2;
}
else
{
ZSTD_copy8(op, match);
}
op += 8; match += 8;
/* match within prefix */
if (sequence.offset < 8)
{
/* close range match, overlap */
const int sub2 = dec64table[sequence.offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[sequence.offset];
ZSTD_copy4(op+4, match);
match -= sub2;
}
else
{
ZSTD_copy8(op, match);
}
op += 8; match += 8;
if (oMatchEnd > oend-12)
{
if (op < oend_8)
{
ZSTD_wildcopy(op, match, oend_8 - op);
match += oend_8 - op;
op = oend_8;
}
while (op < oMatchEnd) *op++ = *match++;
}
else
{
ZSTD_wildcopy(op, match, sequence.matchLength-8); /* works even if matchLength < 8 */
}
return sequenceLength;
if (oMatchEnd > oend-12)
{
if (op < oend_8)
{
ZSTD_wildcopy(op, match, oend_8 - op);
match += oend_8 - op;
op = oend_8;
}
while (op < oMatchEnd) *op++ = *match++;
}
else
{
ZSTD_wildcopy(op, match, sequence.matchLength-8); /* works even if matchLength < 8 */
}
return sequenceLength;
}
@ -634,20 +634,7 @@ static size_t ZSTD_decompressSequences(
FSE_initDState(&(seqState.stateOffb), &(seqState.DStream), DTableOffb);
FSE_initDState(&(seqState.stateML), &(seqState.DStream), DTableML);
for ( ; (BIT_reloadDStream(&(seqState.DStream)) < BIT_DStream_completed) ; )
{
size_t oneSeqSize;
nbSeq--;
ZSTD_decodeSequence(&sequence, &seqState);
oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litLimit_8, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
op += oneSeqSize;
}
if (nbSeq<0) return ERROR(corruption_detected); /* requested too many sequences : data is corrupted */
/* now BIT_reloadDStream(&(seqState.DStream)) >= BIT_DStream_completed) */
for ( ; (BIT_reloadDStream(&(seqState.DStream)) == BIT_DStream_completed) && nbSeq ; )
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq ; )
{
size_t oneSeqSize;
nbSeq--;
@ -658,7 +645,7 @@ static size_t ZSTD_decompressSequences(
}
/* check if reached exact end */
if ( !BIT_endOfDStream(&(seqState.DStream)) ) return ERROR(corruption_detected); /* DStream should be entirely and precisely consumed; otherwise data is corrupted */
if ( !BIT_endOfDStream(&(seqState.DStream)) ) return ERROR(corruption_detected); /* DStream should be entirely and exactly consumed; otherwise data is corrupted */
/* last literal segment */
{