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updated documentation for v1.4.5

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API manual and man pages
This commit is contained in:
Yann Collet 2020-05-14 16:17:03 -07:00
parent 9ff4991d73
commit f22b371e31
4 changed files with 39 additions and 29 deletions
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50
doc/zstd_manual.html
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@ -1,10 +1,10 @@
<html> <html>
<head> <head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>zstd 1.4.4 Manual</title> <title>zstd 1.4.5 Manual</title>
</head> </head>
<body> <body>
<h1>zstd 1.4.4 Manual</h1> <h1>zstd 1.4.5 Manual</h1>
<hr> <hr>
<a name="Contents"></a><h2>Contents</h2> <a name="Contents"></a><h2>Contents</h2>
<ol> <ol>
@ -217,7 +217,10 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
* Default level is ZSTD_CLEVEL_DEFAULT==3. * Default level is ZSTD_CLEVEL_DEFAULT==3.
* Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT.
* Note 1 : it's possible to pass a negative compression level. * Note 1 : it's possible to pass a negative compression level.
* Note 2 : setting a level resets all other compression parameters to default */ * Note 2 : setting a level does not automatically set all other compression parameters
* to default. Setting this will however eventually dynamically impact the compression
* parameters which have not been manually set. The manually set
* ones will 'stick'. */
</b>/* Advanced compression parameters :<b> </b>/* Advanced compression parameters :<b>
* It's possible to pin down compression parameters to some specific values. * It's possible to pin down compression parameters to some specific values.
* In which case, these values are no longer dynamically selected by the compressor */ * In which case, these values are no longer dynamically selected by the compressor */
@ -451,11 +454,13 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
</b>/* note : additional experimental parameters are also available<b> </b>/* note : additional experimental parameters are also available<b>
* within the experimental section of the API. * within the experimental section of the API.
* At the time of this writing, they include : * At the time of this writing, they include :
* ZSTD_c_format * ZSTD_d_format
* ZSTD_d_stableOutBuffer
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
* note : never ever use experimentalParam? names directly * note : never ever use experimentalParam? names directly
*/ */
ZSTD_d_experimentalParam1=1000 ZSTD_d_experimentalParam1=1000,
ZSTD_d_experimentalParam2=1001
} ZSTD_dParameter; } ZSTD_dParameter;
</b></pre><BR> </b></pre><BR>
@ -1055,23 +1060,28 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params);
size_t ZSTD_estimateDCtxSize(void); size_t ZSTD_estimateDCtxSize(void);
</b><p> These functions make it possible to estimate memory usage of a future </b><p> These functions make it possible to estimate memory usage
{D,C}Ctx, before its creation. of a future {D,C}Ctx, before its creation.
ZSTD_estimateCCtxSize() will provide a budget large enough for any ZSTD_estimateCCtxSize() will provide a memory budget large enough
compression level up to selected one. Unlike ZSTD_estimateCStreamSize*(), for any compression level up to selected one.
this estimate does not include space for a window buffer, so this estimate Note : Unlike ZSTD_estimateCStreamSize*(), this estimate
is guaranteed to be enough for single-shot compressions, but not streaming does not include space for a window buffer.
compressions. It will however assume the input may be arbitrarily large, Therefore, the estimation is only guaranteed for single-shot compressions, not streaming.
which is the worst case. If srcSize is known to always be small, The estimate will assume the input may be arbitrarily large,
ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation. which is the worst case.
ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with
ZSTD_getCParams() to create cParams from compressionLevel.
ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with
ZSTD_CCtxParams_setParameter().
Note: only single-threaded compression is supported. This function will When srcSize can be bound by a known and rather "small" value,
return an error code if ZSTD_c_nbWorkers is >= 1. this fact can be used to provide a tighter estimation
because the CCtx compression context will need less memory.
This tighter estimation can be provided by more advanced functions
ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(),
and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter().
Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits.
Note 2 : only single-threaded compression is supported.
ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
</p></pre><BR> </p></pre><BR>
<pre><b>size_t ZSTD_estimateCStreamSize(int compressionLevel); <pre><b>size_t ZSTD_estimateCStreamSize(int compressionLevel);

14
programs/zstd.1
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@ -1,5 +1,5 @@
. .
.TH "ZSTD" "1" "February 2020" "zstd 1.4.5" "User Commands" .TH "ZSTD" "1" "May 2020" "zstd 1.4.5" "User Commands"
. .
.SH "NAME" .SH "NAME"
\fBzstd\fR \- zstd, zstdmt, unzstd, zstdcat \- Compress or decompress \.zst files \fBzstd\fR \- zstd, zstdmt, unzstd, zstdcat \- Compress or decompress \.zst files
@ -114,7 +114,7 @@ Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \
\fB\-\-patch\-from=FILE\fR: Specify the file to be used as a reference point for zstd\'s diff engine\. This is effectively dictionary compression with some convenient parameter selection, namely that windowSize > srcSize\. \fB\-\-patch\-from=FILE\fR: Specify the file to be used as a reference point for zstd\'s diff engine\. This is effectively dictionary compression with some convenient parameter selection, namely that windowSize > srcSize\.
. .
.IP .IP
Note: cannot use both this and \-D together Note: cannot use both this and \-D together Note: \fB\-\-long\fR mode will be automatically activated if chainLog < fileLog (fileLog being the windowLog requried to cover the whole file)\. You can also manually force it\. Node: for all levels, you can use \-\-patch\-from in \-\-single\-thread mode to improve compression ratio at the cost of speed Note: for level 19, you can get increased compression ratio at the cost of speed by specifying \fB\-\-zstd=targetLength=\fR to be something large (i\.e 4096), and by setting a large \fB\-\-zstd=chainLog=\fR
. .
.IP "\(bu" 4 .IP "\(bu" 4
\fB\-M#\fR, \fB\-\-memory=#\fR: Set a memory usage limit\. By default, Zstandard uses 128 MB for decompression as the maximum amount of memory the decompressor is allowed to use, but you can override this manually if need be in either direction (ie\. you can increase or decrease it)\. \fB\-M#\fR, \fB\-\-memory=#\fR: Set a memory usage limit\. By default, Zstandard uses 128 MB for decompression as the maximum amount of memory the decompressor is allowed to use, but you can override this manually if need be in either direction (ie\. you can increase or decrease it)\.
@ -159,6 +159,9 @@ This is also used during compression when using with \-\-patch\-from=\. In this
\fB\-\-[no\-]sparse\fR: enable / disable sparse FS support, to make files with many zeroes smaller on disk\. Creating sparse files may save disk space and speed up decompression by reducing the amount of disk I/O\. default: enabled when output is into a file, and disabled when output is stdout\. This setting overrides default and can force sparse mode over stdout\. \fB\-\-[no\-]sparse\fR: enable / disable sparse FS support, to make files with many zeroes smaller on disk\. Creating sparse files may save disk space and speed up decompression by reducing the amount of disk I/O\. default: enabled when output is into a file, and disabled when output is stdout\. This setting overrides default and can force sparse mode over stdout\.
. .
.IP "\(bu" 4 .IP "\(bu" 4
\fB\-\-[no\-]content\-size\fR: enable / disable whether or not the original size of the file is placed in the header of the compressed file\. The default option is \-\-content\-size (meaning that the original size will be placed in the header)\.
.
.IP "\(bu" 4
\fB\-\-rm\fR: remove source file(s) after successful compression or decompression \fB\-\-rm\fR: remove source file(s) after successful compression or decompression
. .
.IP "\(bu" 4 .IP "\(bu" 4
@ -386,14 +389,11 @@ Larger search lengths usually decrease compression ratio but improve decompressi
The minimum \fImml\fR is 3 and the maximum is 7\. The minimum \fImml\fR is 3 and the maximum is 7\.
. .
.TP .TP
\fBtargetLen\fR=\fItlen\fR, \fBtlen\fR=\fItlen\fR \fBtargetLength\fR=\fItlen\fR, \fBtlen\fR=\fItlen\fR
The impact of this field vary depending on selected strategy\. The impact of this field vary depending on selected strategy\.
. .
.IP .IP
For ZSTD_btopt, ZSTD_btultra and ZSTD_btultra2, it specifies the minimum match length that causes match finder to stop searching\. A larger \fBtargetLen\fR usually improves compression ratio but decreases compression speed\. For ZSTD_btopt, ZSTD_btultra and ZSTD_btultra2, it specifies the minimum match length that causes match finder to stop searching\. A larger \fBtargetLength\fR usually improves compression ratio but decreases compression speed\. t For ZSTD_fast, it triggers ultra\-fast mode when > 0\. The value represents the amount of data skipped between match sampling\. Impact is reversed : a larger \fBtargetLength\fR increases compression speed but decreases compression ratio\.
.
.IP
For ZSTD_fast, it triggers ultra\-fast mode when > 0\. The value represents the amount of data skipped between match sampling\. Impact is reversed : a larger \fBtargetLen\fR increases compression speed but decreases compression ratio\.
. .
.IP .IP
For all other strategies, this field has no impact\. For all other strategies, this field has no impact\.

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programs/zstdgrep.1
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. .
.TH "ZSTDGREP" "1" "February 2020" "zstd 1.4.5" "User Commands" .TH "ZSTDGREP" "1" "May 2020" "zstd 1.4.5" "User Commands"
. .
.SH "NAME" .SH "NAME"
\fBzstdgrep\fR \- print lines matching a pattern in zstandard\-compressed files \fBzstdgrep\fR \- print lines matching a pattern in zstandard\-compressed files

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programs/zstdless.1
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@ -1,5 +1,5 @@
. .
.TH "ZSTDLESS" "1" "February 2020" "zstd 1.4.5" "User Commands" .TH "ZSTDLESS" "1" "May 2020" "zstd 1.4.5" "User Commands"
. .
.SH "NAME" .SH "NAME"
\fBzstdless\fR \- view zstandard\-compressed files \fBzstdless\fR \- view zstandard\-compressed files