mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-27 11:55:06 +00:00
fbc400a67a
track.
The $Id$ line is normally at the bottom of the main comment block in the
man page, separated from the rest of the manpage by an empty comment,
like so;
.\" $Id$
.\"
If the immediately preceding comment is a @(#) format ID marker than the
the $Id$ will line up underneath it with no intervening blank lines.
Otherwise, an additional blank line is inserted.
Approved by: bde
165 lines
5.0 KiB
Groff
165 lines
5.0 KiB
Groff
.\" Copyright (c) 1989, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)unvis.3 8.2 (Berkeley) 12/11/93
|
|
.\" $Id$
|
|
.\"
|
|
.Dd December 11, 1993
|
|
.Dt UNVIS 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm unvis ,
|
|
.Nm strunvis
|
|
.Nd decode a visual representation of characters
|
|
.Sh SYNOPSIS
|
|
.Fd #include <vis.h>
|
|
.Ft int
|
|
.Fn unvis "char *cp" "int c" "int *astate" "int flag"
|
|
.Ft int
|
|
.Fn strunvis "char *dst" "const char *src"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn unvis
|
|
and
|
|
.Fn strunvis
|
|
functions
|
|
are used to decode a visual representation of characters, as produced
|
|
by the
|
|
.Xr vis 3
|
|
function, back into
|
|
the original form. Unvis is called with successive characters in
|
|
.Ar c
|
|
until a valid
|
|
sequence is recognized, at which time the decoded character is
|
|
available at the character pointed to by
|
|
.Ar cp .
|
|
Strunvis decodes the
|
|
characters pointed to by
|
|
.Ar src
|
|
into the buffer pointed to by
|
|
.Ar dst .
|
|
.Pp
|
|
The
|
|
.Fn strunvis
|
|
function
|
|
simply copies
|
|
.Ar src
|
|
to
|
|
.Ar dst ,
|
|
decoding any escape sequences along the way,
|
|
and returns the number of characters placed into
|
|
.Ar dst ,
|
|
or \-1 if an
|
|
invalid escape sequence was detected. The size of
|
|
.Ar dst
|
|
should be
|
|
equal to the size of
|
|
.Ar src
|
|
(that is, no expansion takes place during
|
|
decoding).
|
|
.Pp
|
|
The
|
|
.Fn unvis
|
|
function
|
|
implements a state machine that can be used to decode an arbitrary
|
|
stream of bytes. All state associated with the bytes being decoded
|
|
is stored outside the
|
|
.Fn unvis
|
|
function (that is, a pointer to the state is passed in), so
|
|
calls decoding different streams can be freely intermixed. To
|
|
start decoding a stream of bytes, first initialize an integer
|
|
to zero. Call
|
|
.Fn unvis
|
|
with each successive byte, along with a pointer
|
|
to this integer, and a pointer to a destination character.
|
|
The
|
|
.Fn unvis
|
|
function
|
|
has several return codes that must be handled properly. They are:
|
|
.Bl -tag -width UNVIS_VALIDPUSH
|
|
.It Li \&0 (zero)
|
|
Another character is necessary; nothing has been recognized yet.
|
|
.It Dv UNVIS_VALID
|
|
A valid character has been recognized and is available at the location
|
|
pointed to by cp.
|
|
.It Dv UNVIS_VALIDPUSH
|
|
A valid character has been recognized and is available at the location
|
|
pointed to by cp; however, the character currently passed in should
|
|
be passed in again.
|
|
.It Dv UNVIS_NOCHAR
|
|
A valid sequence was detected, but no character was produced. This
|
|
return code is necessary to indicate a logical break between characters.
|
|
.It Dv UNVIS_SYNBAD
|
|
An invalid escape sequence was detected, or the decoder is in an
|
|
unknown state. The decoder is placed into the starting state.
|
|
.El
|
|
.Pp
|
|
When all bytes in the stream have been processed, call
|
|
.Fn unvis
|
|
one more time with flag set to
|
|
.Dv UNVIS_END
|
|
to extract any remaining character (the character passed in is ignored).
|
|
.Pp
|
|
The following code fragment illustrates a proper use of
|
|
.Fn unvis .
|
|
.Bd -literal -offset indent
|
|
int state = 0;
|
|
char out;
|
|
|
|
while ((ch = getchar()) != EOF) {
|
|
again:
|
|
switch(unvis(&out, ch, &state, 0)) {
|
|
case 0:
|
|
case UNVIS_NOCHAR:
|
|
break;
|
|
case UNVIS_VALID:
|
|
(void) putchar(out);
|
|
break;
|
|
case UNVIS_VALIDPUSH:
|
|
(void) putchar(out);
|
|
goto again;
|
|
case UNVIS_SYNBAD:
|
|
(void)fprintf(stderr, "bad sequence!\n");
|
|
exit(1);
|
|
}
|
|
}
|
|
if (unvis(&out, (char)0, &state, UNVIS_END) == UNVIS_VALID)
|
|
(void) putchar(out);
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr vis 1
|
|
.Sh HISTORY
|
|
The
|
|
.Nm unvis
|
|
function
|
|
first appeared in
|
|
.Bx 4.4 .
|