diff options
Diffstat (limited to 'doc/zlib.n')
| -rw-r--r-- | doc/zlib.n | 22 |
1 files changed, 14 insertions, 8 deletions
@@ -3,7 +3,7 @@ '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. -'\" +'\" .TH zlib n 8.6 Tcl "Tcl Built-In Commands" .so man.macros .BS @@ -81,7 +81,7 @@ named by the \fBfilename\fR field was modified. Suitable for use with The type of the uncompressed data (\fBbinary\fR or \fBtext\fR) if known. .RE .TP -\fBzlib gzip\fI string\fR ?\fB\-level \fIlevel\fR? ?\fB\-header \fIdict\fR? +\fBzlib gzip\fI string\fR ?\fB\-level \fIlevel\fR? ?\fB\-header \fIdict\fR? . Return the compressed contents of binary string \fIstring\fR in gzip format. If \fB\-level\fR is given, \fIlevel\fR gives the compression level to use @@ -174,7 +174,11 @@ to the \fBzlib push\fR command: .VS "TIP 400" Sets the compression dictionary to use when working with compressing or decompressing the data to be \fIbinData\fR. Not valid for transformations that -work with gzip-format data. +work with gzip-format data. The dictionary should consist of strings (byte +sequences) that are likely to be encountered later in the data to be compressed, +with the most commonly used strings preferably put towards the end of the +dictionary. Tcl provides no mechanism for choosing a good such dictionary for +a particular data sequence. .VE .TP \fB\-header\fI dictionary\fR @@ -207,11 +211,13 @@ compression algorithm depends on what format is being produced or consumed. .TP \fB\-dictionary\fI binData\fR .VS "TIP 400" -This read-write options gets or sets the compression dictionary to use when -working with compressing or decompressing the data to be \fIbinData\fR. It is -not valid for transformations that work with gzip-format data, and should not -normally be set on compressing transformations other than at the point where -the transformation is stacked. +This read-write options gets or sets the initial compression dictionary to use +when working with compressing or decompressing the data to be \fIbinData\fR. +It is not valid for transformations that work with gzip-format data, and should +not normally be set on compressing transformations other than at the point where +the transformation is stacked. Note that this cannot be used to get the +current active compression dictionary mid-stream, as that information is not +exposed by the underlying library. .VE .TP \fB\-flush\fI type\fR |