ddidderr/zstd-rs
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adaptive mode uses default window size of 8 MB

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This commit is contained in:
Yann Collet
2018-08-13 13:13:22 -07:00
parent 33f7709c71
commit 0853f86044
2 changed files with 7 additions and 2 deletions
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programs/fileio.c
+4
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@@ -71,6 +71,7 @@
#define MB *(1<<20) #define MB *(1<<20)
#define GB *(1U<<30) #define GB *(1U<<30)
#define ADAPT_WINDOWLOG_DEFAULT 23 /* 8 MB */
#define DICTSIZE_MAX (32 MB) /* protection against large input (attack scenario) */ #define DICTSIZE_MAX (32 MB) /* protection against large input (attack scenario) */
#define FNSPACE 30 #define FNSPACE 30
@@ -427,6 +428,9 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
if (dictFileName && (dictBuffer==NULL)) if (dictFileName && (dictBuffer==NULL))
EXM_THROW(32, "allocation error : can't create dictBuffer"); EXM_THROW(32, "allocation error : can't create dictBuffer");
if (g_adaptiveMode && !g_ldmFlag && !comprParams.windowLog)
comprParams.windowLog = ADAPT_WINDOWLOG_DEFAULT;
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_contentSizeFlag, 1) ); /* always enable content size when available (note: supposed to be default) */ CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_contentSizeFlag, 1) ); /* always enable content size when available (note: supposed to be default) */
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_dictIDFlag, g_dictIDFlag) ); CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_dictIDFlag, g_dictIDFlag) );
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_checksumFlag, g_checksumFlag) ); CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_p_checksumFlag, g_checksumFlag) );
programs/zstd.1.md
+3 -2
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@@ -136,10 +136,11 @@ the last one takes effect.
Final compressed result is slightly different from `-T1`. Final compressed result is slightly different from `-T1`.
* `--adapt` : * `--adapt` :
`zstd` will dynamically adapt compression level to perceived I/O conditions. `zstd` will dynamically adapt compression level to perceived I/O conditions.
The current compression level can be observed live by using command `-v`. Compression level adaptation can be observed live by using command `-v`.
Works with multi-threading and `--long` mode. Works with multi-threading and `--long` mode.
Does not work with `--single-thread`. When not specified otherwise, uses a window size of 8 MB.
Due to the chaotic nature of dynamic adaptation, compressed result is not reproducible. Due to the chaotic nature of dynamic adaptation, compressed result is not reproducible.
Adaptation does not work with `--single-thread`.
* `-D file`: * `-D file`:
use `file` as Dictionary to compress or decompress FILE(s) use `file` as Dictionary to compress or decompress FILE(s)
* `--no-dictID`: * `--no-dictID`: