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diff --git a/static/openbsd/man3/unvis.3 b/static/openbsd/man3/unvis.3 new file mode 100644 index 00000000..c9bdfa67 --- /dev/null +++ b/static/openbsd/man3/unvis.3 @@ -0,0 +1,195 @@ +.\" $OpenBSD: unvis.3,v 1.19 2022/07/30 07:19:30 jsg Exp $ +.\" +.\" 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. 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. +.\" +.Dd $Mdocdate: July 30 2022 $ +.Dt UNVIS 3 +.Os +.Sh NAME +.Nm unvis , +.Nm strunvis , +.Nm strnunvis +.Nd decode a visual representation of characters +.Sh SYNOPSIS +.In vis.h +.Ft int +.Fn unvis "char *cp" "char c" "int *astate" "int flag" +.Ft int +.Fn strunvis "char *dst" "const char *src" +.Ft ssize_t +.Fn strnunvis "char *dst" "const char *src" "size_t size" +.Sh DESCRIPTION +The +.Fn unvis , +.Fn strunvis +and +.Fn strnunvis +functions are used to decode a visual representation of characters, +as produced by the +.Xr vis 3 +function, back into the original form. +.Fn unvis +is called with successive characters in +.Fa c +until a valid +sequence is recognized, at which time the decoded character is +available at the character pointed to by +.Fa cp . +.Pp +.Fn strunvis +decodes the characters pointed to by +.Fa src +into the buffer pointed to by +.Fa dst . +.Pp +.Fn strnunvis +decodes the characters pointed to by +.Fa src +into the buffer pointed to by +.Fa dst , +writing a maximum of +.Fa size +bytes. +The +.Fn strunvis +function simply copies +.Fa src +to +.Fa dst , +decoding any escape sequences along the way, +and returns the number of characters placed into +.Fa dst , +or \-1 if an +invalid escape sequence was detected. +The size of +.Fa dst +should be +equal to the size of +.Fa src +(that is, no expansion takes place during decoding). +.Fn strunvis +terminates the destination string with a trailing NUL byte; +.Fn strnunvis +does so if +.Fa size +is larger than 0. +.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. +.Sh RETURN VALUES +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 +.Fa cp . +.It Dv UNVIS_VALIDPUSH +A valid character has been recognized and is available at the location +pointed to by +.Fa 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 +.Fa flag +set to +.Dv UNVIS_END +to extract any remaining character (the character passed in is ignored). +.Pp +The +.Fn strunvis +function returns the number of bytes written (not counting +the trailing NUL byte) or \-1 if an error occurred. +.Pp +The +.Fn strnunvis +function returns the number of bytes (not counting the trailing NUL byte) +that would be needed to fully convert the input string, or \-1 if an +error occurred. +.Sh EXAMPLES +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!\en"); + exit(1); + } +} +if (unvis(&out, (char)0, &state, UNVIS_END) == UNVIS_VALID) + (void) putchar(out); +.Ed +.Sh SEE ALSO +.Xr unvis 1 , +.Xr vis 1 , +.Xr vis 3 +.Sh HISTORY +The +.Fn unvis +function first appeared in +.Bx 4.3 Reno . |