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minor simplification

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This commit is contained in:
Yann Collet
2024-12-10 16:38:51 -08:00
parent f381665c6a
commit 92747abca3
3 changed files with 34 additions and 32 deletions
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27
doc/zstd_manual.html
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@@ -1376,13 +1376,14 @@ ZSTD_generateSequences(ZSTD_CCtx* zc,
</p></pre><BR>
<pre><b>ZSTDLIB_STATIC_API size_t
ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* src, size_t srcSize);
ZSTD_compressSequences(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* src, size_t srcSize);
</b><p> Compress an array of ZSTD_Sequence, associated with @src buffer, into dst.
@src contains the entire input (not just the literals).
If @srcSize > sum(sequence.length), the remaining bytes are considered all literals
If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.)
If a dictionary is included, then the cctx should reference the dict (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.).
The entire source is compressed into a single frame.
The compression behavior changes based on cctx params. In particular:
@@ -1403,23 +1404,25 @@ ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
- ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset
is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md
Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused.
Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly,
and cannot emit an RLE block that disagrees with the repcode history
Note: Repcodes are, as of now, always re-calculated within this function, ZSTD_Sequence.rep is effectively unused.
Dev Note: Once ability to ingest repcodes become available, the explicit block delims mode must respect those repcodes exactly,
and cannot emit an RLE block that disagrees with the repcode history.
@return : final compressed size, or a ZSTD error code.
</p></pre><BR>
<pre><b>ZSTDLIB_STATIC_API size_t
ZSTD_compressSequencesAndLiterals( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* literals, size_t litSize);
ZSTD_compressSequencesAndLiterals(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* literals, size_t litSize);
</b><p> This is a variant of ZSTD_compressSequences() which,
instead of receiving (src,srcSize) as input parameter, receives (literals,litSize),
aka all literals already extracted and grouped into a single continuous buffer.
aka all literals already extracted and laid out into a single continuous buffer.
This can be useful if the process generating the sequences also happens to generate the buffer of literals,
thus skipping an extraction + caching stage.
To be valid, `litSize` must be equal to the sum of all @.litLength fields in @inSeqs.
To be valid, @litSize must be equal to the sum of all @.litLength fields in @inSeqs.
Important: Employing this prototype is incompatible with frame checksum.
@return : final compressed size, or a ZSTD error code.
</p></pre><BR>

17
lib/compress/zstd_compress.c
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@@ -6887,20 +6887,17 @@ blockSize_explicitDelimiter(const ZSTD_Sequence* inSeqs, size_t inSeqsSize, ZSTD
return blockSize;
}
/* More a "target" block size */
static size_t blockSize_noDelimiter(size_t blockSize, size_t remaining)
{
int const lastBlock = (remaining <= blockSize);
return lastBlock ? remaining : blockSize;
}
static size_t determine_blockSize(ZSTD_SequenceFormat_e mode,
size_t blockSize, size_t remaining,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize, ZSTD_SequencePosition seqPos)
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
ZSTD_SequencePosition seqPos)
{
DEBUGLOG(6, "determine_blockSize : remainingSize = %zu", remaining);
if (mode == ZSTD_sf_noBlockDelimiters)
return blockSize_noDelimiter(blockSize, remaining);
if (mode == ZSTD_sf_noBlockDelimiters) {
/* Note: more a "target" block size */
return MIN(remaining, blockSize);
}
assert(mode == ZSTD_sf_explicitBlockDelimiters);
{ size_t const explicitBlockSize = blockSize_explicitDelimiter(inSeqs, inSeqsSize, seqPos);
FORWARD_IF_ERROR(explicitBlockSize, "Error while determining block size with explicit delimiters");
if (explicitBlockSize > blockSize)

22
lib/zstd.h
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@@ -1625,7 +1625,7 @@ ZSTDLIB_STATIC_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, si
* Compress an array of ZSTD_Sequence, associated with @src buffer, into dst.
* @src contains the entire input (not just the literals).
* If @srcSize > sum(sequence.length), the remaining bytes are considered all literals
* If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.)
* If a dictionary is included, then the cctx should reference the dict (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.).
* The entire source is compressed into a single frame.
*
* The compression behavior changes based on cctx params. In particular:
@@ -1646,15 +1646,16 @@ ZSTDLIB_STATIC_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, si
* - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset
* is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md
*
* Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused.
* Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly,
* and cannot emit an RLE block that disagrees with the repcode history
* Note: Repcodes are, as of now, always re-calculated within this function, ZSTD_Sequence.rep is effectively unused.
* Dev Note: Once ability to ingest repcodes become available, the explicit block delims mode must respect those repcodes exactly,
* and cannot emit an RLE block that disagrees with the repcode history.
* @return : final compressed size, or a ZSTD error code.
*/
ZSTDLIB_STATIC_API size_t
ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* src, size_t srcSize);
ZSTD_compressSequences(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* src, size_t srcSize);
/*! ZSTD_compressSequencesAndLiterals() :
@@ -1668,9 +1669,10 @@ ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
* @return : final compressed size, or a ZSTD error code.
*/
ZSTDLIB_STATIC_API size_t
ZSTD_compressSequencesAndLiterals( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* literals, size_t litSize);
ZSTD_compressSequencesAndLiterals(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* literals, size_t litSize);
/*! ZSTD_writeSkippableFrame() :