Compressing and decompressing channel transformation support.

Note that there may be "quality-of-implementation" issues left...

1 files changed, 41 insertions, 4 deletions

diff --git a/doc/zlib.n b/doc/zlib.n
index b010eb4..45bfd1d 100644
--- a/doc/zlib.n
+++ b/doc/zlib.n
@@ -4,7 +4,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: zlib.n,v 1.4 2008/12/13 17:36:34 dkf Exp $
+'\" RCS: @(#) $Id: zlib.n,v 1.5 2008/12/18 10:37:43 dkf Exp $
 '\" 
 .so man.macros
 .TH zlib n 8.6 Tcl "Tcl Built-In Commands"
@@ -165,7 +165,45 @@ gzip-format data on \fIchannel\fR, which must be writable.
 The transformation will be a decompressing transformation that reads raw
 compressed data from \fIchannel\R, which must be readable.
 .PP
-\fITODO: not yet implemented!\fR
+The following options may be set when creating a transformation:
+.TP
+\fB\-header\fI dictionary\fR
+.
+Passes a description of the gzip header to create, in the same format that
+\fBzlib gzip\fR understands.
+.TP
+\fB\-level\fI compressionLevel\fR
+.
+How hard to compress the data. Must be an integer from 0 (uncompressed) to 9
+(maximally compressed).
+'\".TP
+'\"\fB\-limit\fI readaheadLimit\fR
+'\".
+'\"The maximum number of bytes ahead to read.
+'\"\fITODO: not yet implemented!\fR
+.PP
+Both compressing and decompressing channel transformations add extra options
+that may be accessed through \fBchan configure\fR. These are:
+.TP
+\fB\-flush\fI type\fR
+.
+This write-only operation flushes the current state of the compressor to the
+underlying channel. It is only valid for compressing transformations. The
+\fItype\fR must be either \fBsync\fR or \fBfull\fR for a normal flush or an
+expensive flush respectively. Note that flushing degrades compression.
+.TP
+\fB\-checksum\fR
+.
+This read-only option, valid for both compressing and decompressing
+transforms, gets the current checksum for the uncompressed data that the
+compression engine has seen so far. The compression algorithm depends on what
+format is being produced or consumed.
+.TP
+\fB\-header\fR
+.
+This read-only option, only valid for decompressing transforms that are
+processing gzip-format data, returns the dictionary describing the header read
+off the data stream.
 .RE
 .TP
 \fBzlib stream\fI mode\fR ?\fIlevel\fR?
@@ -238,9 +276,8 @@ A short-cut for
 followed by
 .QW "\fIstream \fBget\fR" .
 .TP
-\fIstream \fBadler32\fR
+\fIstream \fBchecksum\fR
 .
-'\" Change name?
 Returns the checksum of the uncompressed data seen so far by this stream.
 .TP
 \fIstream \fBclose\fR