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authordkf <donal.k.fellows@manchester.ac.uk>2012-06-24 15:15:36 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2012-06-24 15:15:36 (GMT)
commit4eb006ef70aa3737a687697eb03ba83b080e1a1a (patch)
tree093ebe74c606b2474b6405ec12a0aaa470fd9f71 /doc/zlib.n
parent5aa79e6ffa7474ff3409dd9e018c6ad41c307efb (diff)
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add configurability of readahead limit
Diffstat (limited to 'doc/zlib.n')
-rw-r--r--doc/zlib.n41
1 files changed, 25 insertions, 16 deletions
diff --git a/doc/zlib.n b/doc/zlib.n
index a78e8e3..0233ba8 100644
--- a/doc/zlib.n
+++ b/doc/zlib.n
@@ -179,15 +179,24 @@ Passes a description of the gzip header to create, in the same format that
.
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
+.TP
+\fB\-limit\fI readaheadLimit\fR
+.
+The maximum number of bytes ahead to read when decompressing. This defaults to
+1, which ensures that data is always decompressed correctly, but may be
+increased to improve performance. This is more useful when the channel is
+non-blocking.
.PP
Both compressing and decompressing channel transformations add extra
-configuration options that may be accessed through \fBchan configure\fR. Each
-option is either a read-only or a write-only option. The options are:
+configuration options that may be accessed through \fBchan configure\fR. The
+options are:
+.TP
+\fB\-checksum\fI checksum\fR
+.
+This read-only option gets the current checksum for the uncompressed data that
+the compression engine has seen so far. It is valid for both compressing and
+decompressing transforms, but not for the raw inflate and deflate formats. The
+compression algorithm depends on what format is being produced or consumed.
.TP
\fB\-flush\fI type\fR
.
@@ -198,19 +207,19 @@ expensive flush respectively. Flushing degrades the compression ratio, but
makes it easier for a decompressor to recover more of the file in the case of
data corruption.
.TP
-\fB\-checksum\fR
-.
-This read-only option gets the current checksum for the uncompressed data
-that the compression engine has seen so far. It is valid for both
-compressing and decompressing transforms, but not for the raw inflate
-and deflate formats. The compression algorithm depends on what
-format is being produced or consumed.
-.TP
-\fB\-header\fR
+\fB\-header\fI dictionary\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.
+.TP
+\fB\-limit\fI readaheadLimit\fR
+.
+This read-write option is used by decompressing channels to control the
+maximum number of bytes ahead to read from the underlying data source. This
+defaults to 1, which ensures that data is always decompressed correctly, but
+may be increased to improve performance. This is more useful when the channel
+is non-blocking.
.RE
.SS "STREAMING SUBCOMMAND"
.TP