vendor/zstd/1.3.2

1 files changed, 74 insertions, 4 deletions

diff --git a/programs/zstd.1 b/programs/zstd.1
index 5a91eea281f4..8187c7403509 100644
--- a/programs/zstd.1
+++ b/programs/zstd.1
@@ -1,5 +1,5 @@
 .
-.TH "ZSTD" "1" "August 2017" "zstd 1.3.1" "User Commands"
+.TH "ZSTD" "1" "September 2017" "zstd 1.3.1" "User Commands"
 .
 .SH "NAME"
 \fBzstd\fR \- zstd, zstdmt, unzstd, zstdcat \- Compress or decompress \.zst files
@@ -60,11 +60,11 @@ In most places where an integer argument is expected, an optional suffix is supp
 .
 .TP
 \fBKiB\fR
-Multiply the integer by 1,024 (2^10)\. \fBKi\fR, \fBK\fR, and \fBKB\fR are accepted as synonyms for \fBKiB\fR\.
+Multiply the integer by 1,024 (2\e \fBKi\fR, \fBK\fR, and \fBKB\fR are accepted as synonyms for \fBKiB\fR\.
 .
 .TP
 \fBMiB\fR
-Multiply the integer by 1,048,576 (2^20)\. \fBMi\fR, \fBM\fR, and \fBMB\fR are accepted as synonyms for \fBMiB\fR\.
+Multiply the integer by 1,048,576 (2\e \fBMi\fR, \fBM\fR, and \fBMB\fR are accepted as synonyms for \fBMiB\fR\.
 .
 .SS "Operation mode"
 If multiple operation mode options are given, the last one takes effect\.
@@ -104,6 +104,13 @@ Display information related to a zstd compressed file, such as size, ratio, and
 unlocks high compression levels 20+ (maximum 22), using a lot more memory\. Note that decompression will also require more memory when using these levels\.
 .
 .TP
+\fB\-\-long[=#]\fR
+enables long distance matching with \fB#\fR \fBwindowLog\fR, if not \fB#\fR is not present it defaults to \fB27\fR\. This increases the window size (\fBwindowLog\fR) and memory usage for both the compressor and decompressor\. This setting is designed to improve the compression ratio for files with long matches at a large distance\.
+.
+.IP
+Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \fB\-\-memory=windowSize\fR needs to be passed to the decompressor\.
+.
+.TP
 \fB\-T#\fR, \fB\-\-threads=#\fR
 Compress using \fB#\fR threads (default: 1)\. If \fB#\fR is 0, attempt to detect and use the number of physical CPU cores\. In all cases, the nb of threads is capped to ZSTDMT_NBTHREADS_MAX==256\. This modifier does nothing if \fBzstd\fR is compiled without multithread support\.
 .
@@ -144,6 +151,10 @@ keep source file(s) after successful compression or decompression\. This is the
 operate recursively on dictionaries
 .
 .TP
+\fB\-\-format=FORMAT\fR
+compress and decompress in other formats\. If compiled with support, zstd can compress to or decompress from other compression algorithm formats\. Possibly available options are \fBgzip\fR, \fBxz\fR, \fBlzma\fR, and \fBlz4\fR\.
+.
+.TP
 \fB\-h\fR/\fB\-H\fR, \fB\-\-help\fR
 display help/long help and exit
 .
@@ -186,6 +197,10 @@ Dictionary saved into \fBfile\fR (default name: dictionary)\.
 Limit dictionary to specified size (default: 112640)\.
 .
 .TP
+\fB\-B#\fR
+Split input files in blocks of size # (default: no split)
+.
+.TP
 \fB\-\-dictID=#\fR
 A dictionary ID is a locally unique ID that a decoder can use to verify it is using the right dictionary\. By default, zstd will create a 4\-bytes random number ID\. It\'s possible to give a precise number instead\. Short numbers have an advantage : an ID < 256 will only need 1 byte in the compressed frame header, and an ID < 65536 will only need 2 bytes\. This compares favorably to 4 bytes default\. However, it\'s up to the dictionary manager to not assign twice the same ID to 2 different dictionaries\.
 .
@@ -263,7 +278,10 @@ There are 8 strategies numbered from 1 to 8, from faster to stronger: 1=ZSTD_fas
 Specify the maximum number of bits for a match distance\.
 .
 .IP
-The higher number of increases the chance to find a match which usually improves compression ratio\. It also increases memory requirements for the compressor and decompressor\. The minimum \fIwlog\fR is 10 (1 KiB) and the maximum is 27 (128 MiB)\.
+The higher number of increases the chance to find a match which usually improves compression ratio\. It also increases memory requirements for the compressor and decompressor\. The minimum \fIwlog\fR is 10 (1 KiB) and the maximum is 30 (1 GiB) on 32\-bit platforms and 31 (2 GiB) on 64\-bit platforms\.
+.
+.IP
+Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \fB\-\-memory=windowSize\fR needs to be passed to the decompressor\.
 .
 .TP
 \fBhashLog\fR=\fIhlog\fR, \fBhlog\fR=\fIhlog\fR
@@ -322,6 +340,58 @@ Determine \fBoverlapSize\fR, amount of data reloaded from previous job\. This pa
 .IP
 The minimum \fIovlog\fR is 0, and the maximum is 9\. 0 means "no overlap", hence completely independent jobs\. 9 means "full overlap", meaning up to \fBwindowSize\fR is reloaded from previous job\. Reducing \fIovlog\fR by 1 reduces the amount of reload by a factor 2\. Default \fIovlog\fR is 6, which means "reload \fBwindowSize / 8\fR"\. Exception : the maximum compression level (22) has a default \fIovlog\fR of 9\.
 .
+.TP
+\fBldmHashLog\fR=\fIldmhlog\fR, \fBldmhlog\fR=\fIldmhlog\fR
+Specify the maximum size for a hash table used for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Bigger hash tables usually improve compression ratio at the expense of more memory during compression and a decrease in compression speed\.
+.
+.IP
+The minimum \fIldmhlog\fR is 6 and the maximum is 26 (default: 20)\.
+.
+.TP
+\fBldmSearchLength\fR=\fIldmslen\fR, \fBldmslen\fR=\fIldmslen\fR
+Specify the minimum searched length of a match for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger/very small values usually decrease compression ratio\.
+.
+.IP
+The minumum \fIldmslen\fR is 4 and the maximum is 4096 (default: 64)\.
+.
+.TP
+\fBldmBucketSizeLog\fR=\fIldmblog\fR, \fBldmblog\fR=\fIldmblog\fR
+Specify the size of each bucket for the hash table used for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger bucket sizes improve collision resolution but decrease compression speed\.
+.
+.IP
+The minimum \fIldmblog\fR is 0 and the maximum is 8 (default: 3)\.
+.
+.TP
+\fBldmHashEveryLog\fR=\fIldmhevery\fR, \fBldmhevery\fR=\fIldmhevery\fR
+Specify the frequency of inserting entries into the long distance matching hash table\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger values will improve compression speed\. Deviating far from the default value will likely result in a decrease in compression ratio\.
+.
+.IP
+The default value is \fBwlog \- ldmhlog\fR\.
+.
 .SS "\-B#:"
 Select the size of each compression job\. This parameter is available only when multi\-threading is enabled\. Default value is \fB4 * windowSize\fR, which means it varies depending on compression level\. \fB\-B#\fR makes it possible to select a custom value\. Note that job size must respect a minimum value which is enforced transparently\. This minimum is either 1 MB, or \fBoverlapSize\fR, whichever is largest\.
 .