add configurability of readahead limit

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