diff options
Diffstat (limited to 'doc/binary.n')
| -rw-r--r-- | doc/binary.n | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/doc/binary.n b/doc/binary.n index a40afe6..cbbebd1 100644 --- a/doc/binary.n +++ b/doc/binary.n @@ -36,6 +36,13 @@ The \fBbinary encode\fR and \fBbinary decode\fR subcommands convert binary data to or from string encodings such as base64 (used in MIME messages for example). .VE 8.6 +.PP +Note that other operations on binary data, such as taking a subsequence of it, +getting its length, or reinterpreting it as a string in some encoding, are +done by other Tcl commands (respectively \fBstring range\fR, +\fBstring length\fR and \fBencoding convertfrom\fR in the example cases). A +binary string in Tcl is merely one where all the characters it contains are in +the range \eu0000\-\eu00FF. .SH "BINARY ENCODE AND DECODE" .VS 8.6 .PP @@ -95,13 +102,14 @@ between Unix systems and on USENET, but is less common these days, having been largely superseded by the \fBbase64\fR binary encoding. .RS .PP -During encoding, the following options are supported: -'\" This is wrong! The uuencode format had more complexity than this! +During encoding, the following options are supported (though changing them may +produce files that other implementations of decoders cannot process): .TP \fB\-maxlen \fIlength\fR . Indicates that the output should be split into lines of no more than -\fIlength\fR characters. By default, lines are not split. +\fIlength\fR characters. By default, lines are split every 61 characters, and +this must be in the range 3 to 85 due to limitations in the encoding. .TP \fB\-wrapchar \fIcharacter\fR . @@ -114,7 +122,11 @@ During decoding, the following options are supported: .TP \fB\-strict\fR . -Instructs the decoder to throw an error if it encounters whitespace characters. Otherwise it ignores them. +Instructs the decoder to throw an error if it encounters unexpected whitespace +characters. Otherwise it ignores them. +.PP +Note that neither the encoder nor the decoder handle the header and footer of +the uuencode format. .RE .VE 8.6 .SH "BINARY FORMAT" @@ -855,6 +867,7 @@ architectures, use their textual representation (as produced by .PP This is a procedure to write a Tcl string to a binary-encoded channel as UTF-8 data preceded by a length word: +.PP .CS proc \fIwriteString\fR {channel string} { set data [encoding convertto utf-8 $string] @@ -865,6 +878,7 @@ proc \fIwriteString\fR {channel string} { .PP This procedure reads a string from a channel that was written by the previously presented \fIwriteString\fR procedure: +.PP .CS proc \fIreadString\fR {channel} { if {![\fBbinary scan\fR [read $channel 4] I length]} { @@ -877,6 +891,7 @@ proc \fIreadString\fR {channel} { .PP This converts the contents of a file (named in the variable \fIfilename\fR) to base64 and prints them: +.PP .CS set f [open $filename rb] set data [read $f] @@ -884,9 +899,10 @@ close $f puts [\fBbinary encode\fR base64 \-maxlen 64 $data] .CE .SH "SEE ALSO" -format(n), scan(n), tcl_platform(n) +encoding(n), format(n), scan(n), string(n), tcl_platform(n) .SH KEYWORDS binary, format, scan '\" Local Variables: '\" mode: nroff +'\" fill-column: 78 '\" End: |