[lib] Avoid allocating the input buffer when ZSTD_c_stableInBuffer is set

We don't use it when we have a stable input buffer, so don't allocate
it. I had to slightly modify `ZSTD_copyCCtx()` by storing the
`ZSTD_buffered_policy_e` in the `ZSTD_CCtx`, since `inBuffSize > 0` is
no longer the correct signal for the buffered mode.
This commit is contained in:
Nick Terrell 2020-10-12 14:47:55 -07:00
parent 24f72789e2
commit d4e021fe35
2 changed files with 33 additions and 17 deletions

View File

@ -1351,7 +1351,9 @@ size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
{ ZSTD_compressionParameters const cParams =
ZSTD_getCParamsFromCCtxParams(params, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << cParams.windowLog);
size_t const inBuffSize = ((size_t)1 << cParams.windowLog) + blockSize;
size_t const inBuffSize = (params->inBufferMode == ZSTD_bm_buffered)
? ((size_t)1 << cParams.windowLog) + blockSize
: 0;
size_t const outBuffSize = (params->outBufferMode == ZSTD_bm_buffered)
? ZSTD_compressBound(blockSize) + 1
: 0;
@ -1463,16 +1465,6 @@ static void ZSTD_invalidateMatchState(ZSTD_matchState_t* ms)
ms->dictMatchState = NULL;
}
/**
* Indicates whether this compression proceeds directly from user-provided
* source buffer to user-provided destination buffer (ZSTDb_not_buffered), or
* whether the context needs to buffer the input/output (ZSTDb_buffered).
*/
typedef enum {
ZSTDb_not_buffered,
ZSTDb_buffered
} ZSTD_buffered_policy_e;
/**
* Controls, for this matchState reset, whether the tables need to be cleared /
* prepared for the coming compression (ZSTDcrp_makeClean), or whether the
@ -1603,7 +1595,9 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
size_t const buffOutSize = (zbuff == ZSTDb_buffered && params.outBufferMode == ZSTD_bm_buffered)
? ZSTD_compressBound(blockSize) + 1
: 0;
size_t const buffInSize = (zbuff==ZSTDb_buffered) ? windowSize + blockSize : 0;
size_t const buffInSize = (zbuff == ZSTDb_buffered && params.inBufferMode == ZSTD_bm_buffered)
? windowSize + blockSize
: 0;
size_t const maxNbLdmSeq = ZSTD_ldm_getMaxNbSeq(params.ldmParams, blockSize);
int const indexTooClose = ZSTD_indexTooCloseToMax(zc->blockState.matchState.window);
@ -1678,6 +1672,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
zc->seqStore.maxNbLit = blockSize;
/* buffers */
zc->bufferedPolicy = zbuff;
zc->inBuffSize = buffInSize;
zc->inBuff = (char*)ZSTD_cwksp_reserve_buffer(ws, buffInSize);
zc->outBuffSize = buffOutSize;
@ -1995,7 +1990,7 @@ static size_t ZSTD_copyCCtx_internal(ZSTD_CCtx* dstCCtx,
size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long long pledgedSrcSize)
{
ZSTD_frameParameters fParams = { 1 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
ZSTD_buffered_policy_e const zbuff = (ZSTD_buffered_policy_e)(srcCCtx->inBuffSize>0);
ZSTD_buffered_policy_e const zbuff = srcCCtx->bufferedPolicy;
ZSTD_STATIC_ASSERT((U32)ZSTDb_buffered==1);
if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;
fParams.contentSizeFlag = (pledgedSrcSize != ZSTD_CONTENTSIZE_UNKNOWN);
@ -4052,8 +4047,10 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
/* check expectations */
DEBUGLOG(5, "ZSTD_compressStream_generic, flush=%u", (unsigned)flushMode);
assert(zcs->inBuff != NULL);
assert(zcs->inBuffSize > 0);
if (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered) {
assert(zcs->inBuff != NULL);
assert(zcs->inBuffSize > 0);
}
if (zcs->appliedParams.outBufferMode == ZSTD_bm_buffered) {
assert(zcs->outBuff != NULL);
assert(zcs->outBuffSize > 0);
@ -4327,8 +4324,14 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
assert(cctx->appliedParams.nbWorkers == 0);
cctx->inToCompress = 0;
cctx->inBuffPos = 0;
/* for small input: avoid automatic flush on reaching end of block, since it would require to add a 3-bytes null block to end frame */
cctx->inBuffTarget = cctx->blockSize + (cctx->blockSize == pledgedSrcSize);
if (cctx->appliedParams.inBufferMode == ZSTD_bm_buffered) {
/* for small input: avoid automatic flush on reaching end of block, since
* it would require to add a 3-bytes null block to end frame
*/
cctx->inBuffTarget = cctx->blockSize + (cctx->blockSize == pledgedSrcSize);
} else {
cctx->inBuffTarget = 0;
}
cctx->outBuffContentSize = cctx->outBuffFlushedSize = 0;
cctx->streamStage = zcss_load;
cctx->frameEnded = 0;

View File

@ -249,6 +249,16 @@ struct ZSTD_CCtx_params_s {
#define COMPRESS_SEQUENCES_WORKSPACE_SIZE (sizeof(unsigned) * (MaxSeq + 2))
#define ENTROPY_WORKSPACE_SIZE (HUF_WORKSPACE_SIZE + COMPRESS_SEQUENCES_WORKSPACE_SIZE)
/**
* Indicates whether this compression proceeds directly from user-provided
* source buffer to user-provided destination buffer (ZSTDb_not_buffered), or
* whether the context needs to buffer the input/output (ZSTDb_buffered).
*/
typedef enum {
ZSTDb_not_buffered,
ZSTDb_buffered
} ZSTD_buffered_policy_e;
struct ZSTD_CCtx_s {
ZSTD_compressionStage_e stage;
int cParamsChanged; /* == 1 if cParams(except wlog) or compression level are changed in requestedParams. Triggers transmission of new params to ZSTDMT (if available) then reset to 0. */
@ -278,6 +288,9 @@ struct ZSTD_CCtx_s {
ZSTD_blockState_t blockState;
U32* entropyWorkspace; /* entropy workspace of ENTROPY_WORKSPACE_SIZE bytes */
/* Wether we are streaming or not */
ZSTD_buffered_policy_e bufferedPolicy;
/* streaming */
char* inBuff;
size_t inBuffSize;