diff --git a/doc/zstd_manual.html b/doc/zstd_manual.html
index 1058503f8..c166e7258 100644
--- a/doc/zstd_manual.html
+++ b/doc/zstd_manual.html
@@ -813,7 +813,9 @@ void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
* Special: value 0 means "do not change strategy". */
/* frame parameters */
- ZSTD_p_contentSizeFlag=200, /* Content size is written into frame header _whenever known_ (default:1) */
+ ZSTD_p_contentSizeFlag=200, /* Content size is written into frame header _whenever known_ (default:1)
+ * note that content size must be known at the beginning,
+ * it is sent using ZSTD_CCtx_setPledgedSrcSize() */
ZSTD_p_checksumFlag, /* A 32-bits checksum of content is written at end of frame (default:0) */
ZSTD_p_dictIDFlag, /* When applicable, dictID of dictionary is provided in frame header (default:1) */
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index 677e96f08..ed4b9117a 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -10,6 +10,7 @@
/* ====== Tuning parameters ====== */
#define ZSTDMT_NBTHREADS_MAX 128
+#define ZSTDMT_OVERLAPLOG_DEFAULT 6
/* ====== Compiler specifics ====== */
@@ -383,7 +384,7 @@ struct ZSTDMT_CCtx_s {
unsigned nextJobID;
unsigned frameEnded;
unsigned allJobsCompleted;
- unsigned overlapRLog;
+ unsigned overlapLog;
unsigned long long frameContentSize;
size_t sectionSize;
ZSTD_customMem cMem;
@@ -417,7 +418,7 @@ ZSTDMT_CCtx* ZSTDMT_createCCtx_advanced(unsigned nbThreads, ZSTD_customMem cMem)
mtctx->nbThreads = nbThreads;
mtctx->allJobsCompleted = 1;
mtctx->sectionSize = 0;
- mtctx->overlapRLog = 3;
+ mtctx->overlapLog = ZSTDMT_OVERLAPLOG_DEFAULT;
mtctx->factory = POOL_create(nbThreads, 1);
mtctx->jobs = ZSTDMT_allocJobsTable(&nbJobs, cMem);
mtctx->jobIDMask = nbJobs - 1;
@@ -491,7 +492,7 @@ size_t ZSTDMT_setMTCtxParameter(ZSTDMT_CCtx* mtctx, ZSDTMT_parameter parameter,
return 0;
case ZSTDMT_p_overlapSectionLog :
DEBUGLOG(5, "ZSTDMT_p_overlapSectionLog : %u", value);
- mtctx->overlapRLog = (value >= 9) ? 0 : 9 - value;
+ mtctx->overlapLog = (value >= 9) ? 9 : value;
return 0;
default :
return ERROR(compressionParameter_unsupported);
@@ -520,8 +521,9 @@ size_t ZSTDMT_compress_advanced(ZSTDMT_CCtx* mtctx,
const void* src, size_t srcSize,
const ZSTD_CDict* cdict,
ZSTD_parameters const params,
- unsigned overlapRLog)
+ unsigned overlapLog)
{
+ unsigned const overlapRLog = (overlapLog>9) ? 0 : 9-overlapLog;
size_t const overlapSize = (overlapRLog>=9) ? 0 : (size_t)1 << (params.cParams.windowLog - overlapRLog);
unsigned nbChunks = computeNbChunks(srcSize, params.cParams.windowLog, mtctx->nbThreads);
size_t const proposedChunkSize = (srcSize + (nbChunks-1)) / nbChunks;
@@ -538,7 +540,7 @@ size_t ZSTDMT_compress_advanced(ZSTDMT_CCtx* mtctx,
if (cdict) return ZSTD_compress_usingCDict_advanced(cctx, dst, dstCapacity, src, srcSize, cdict, params.fParams);
return ZSTD_compress_advanced(cctx, dst, dstCapacity, src, srcSize, NULL, 0, params);
}
- assert(avgChunkSize >= 256 KB); /* condition for ZSTD_compressBound(A) + ZSTD_compressBound(B) <= ZSTD_compressBound(A+B), which is useful to avoid allocating extra buffers */
+ assert(avgChunkSize >= 256 KB); /* condition for ZSTD_compressBound(A) + ZSTD_compressBound(B) <= ZSTD_compressBound(A+B), which is required for compressWithinDst */
ZSTDMT_setBufferSize(mtctx->bufPool, ZSTD_compressBound(avgChunkSize) );
XXH64_reset(&xxh64, 0);
@@ -642,10 +644,10 @@ size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* mtctx,
const void* src, size_t srcSize,
int compressionLevel)
{
- U32 const overlapRLog = (compressionLevel >= ZSTD_maxCLevel()) ? 0 : 3;
+ U32 const overlapLog = (compressionLevel >= ZSTD_maxCLevel()) ? 9 : ZSTDMT_OVERLAPLOG_DEFAULT;
ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, 0);
params.fParams.contentSizeFlag = 1;
- return ZSTDMT_compress_advanced(mtctx, dst, dstCapacity, src, srcSize, NULL, params, overlapRLog);
+ return ZSTDMT_compress_advanced(mtctx, dst, dstCapacity, src, srcSize, NULL, params, overlapLog);
}
@@ -710,8 +712,8 @@ size_t ZSTDMT_initCStream_internal(ZSTDMT_CCtx* zcs,
zcs->cdict = cdict;
}
- zcs->targetDictSize = (zcs->overlapRLog>=9) ? 0 : (size_t)1 << (zcs->params.cParams.windowLog - zcs->overlapRLog);
- DEBUGLOG(4, "overlapRLog : %u ", zcs->overlapRLog);
+ zcs->targetDictSize = (zcs->overlapLog==0) ? 0 : (size_t)1 << (zcs->params.cParams.windowLog - (9 - zcs->overlapLog));
+ DEBUGLOG(4, "overlapLog : %u ", zcs->overlapLog);
DEBUGLOG(4, "overlap Size : %u KB", (U32)(zcs->targetDictSize>>10));
zcs->targetSectionSize = zcs->sectionSize ? zcs->sectionSize : (size_t)1 << (zcs->params.cParams.windowLog + 2);
zcs->targetSectionSize = MAX(ZSTDMT_SECTION_SIZE_MIN, zcs->targetSectionSize);
@@ -918,7 +920,7 @@ size_t ZSTDMT_compressStream_generic(ZSTDMT_CCtx* mtctx,
size_t const cSize = ZSTDMT_compress_advanced(mtctx,
(char*)output->dst + output->pos, output->size - output->pos,
(const char*)input->src + input->pos, input->size - input->pos,
- mtctx->cdict, mtctx->params, mtctx->overlapRLog);
+ mtctx->cdict, mtctx->params, mtctx->overlapLog);
if (ZSTD_isError(cSize)) return cSize;
input->pos = input->size;
output->pos += cSize;
diff --git a/lib/compress/zstdmt_compress.h b/lib/compress/zstdmt_compress.h
index 7584007f1..843a240aa 100644
--- a/lib/compress/zstdmt_compress.h
+++ b/lib/compress/zstdmt_compress.h
@@ -68,7 +68,7 @@ ZSTDLIB_API size_t ZSTDMT_compress_advanced(ZSTDMT_CCtx* mtctx,
const void* src, size_t srcSize,
const ZSTD_CDict* cdict,
ZSTD_parameters const params,
- unsigned overlapRLog); /* overlapRLog = 9 - overlapLog */
+ unsigned overlapLog);
ZSTDLIB_API size_t ZSTDMT_initCStream_advanced(ZSTDMT_CCtx* mtctx,
const void* dict, size_t dictSize, /* dict can be released after init, a local copy is preserved within zcs */