+.\" $NetBSD: unvis.3,v 1.27 2012/12/15 07:34:36 wiz Exp $
+.\" $FreeBSD$
+.\"
.\" Copyright (c) 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" 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.
-.\" 4. Neither the name of the University nor the names of its contributors
+.\" 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.
.\"
.\" SUCH DAMAGE.
.\"
.\" @(#)unvis.3 8.2 (Berkeley) 12/11/93
-.\" $FreeBSD: src/lib/libc/gen/unvis.3,v 1.18 2007/01/09 00:27:56 imp Exp $
.\"
-.Dd December 11, 1993
+.Dd March 12, 2011
.Dt UNVIS 3
.Os
.Sh NAME
.Ft int
.Fn strunvis "char *dst" "const char *src"
.Ft int
+.Fn strnunvis "char *dst" "size_t dlen" "const char *src"
+.Ft int
.Fn strunvisx "char *dst" "const char *src" "int flag"
+.Ft int
+.Fn strnunvisx "char *dst" "size_t dlen" "const char *src" "int flag"
.Sh DESCRIPTION
The
.Fn unvis ,
.Xr vis 3
function, back into
the original form.
-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 .
-Strunvis decodes the
-characters pointed to by
-.Fa src
-into the buffer pointed to by
-.Fa dst .
+.Pp
+The
+.Fn unvis
+function 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 .
.Pp
The
.Fn strunvis
-function
-simply copies
-.Fa src
+function decodes the characters pointed to by
+.Ar src
+into the buffer pointed to by
+.Ar dst .
+The
+.Fn strunvis
+function simply copies
+.Ar src
to
-.Fa dst ,
+.Ar dst ,
decoding any escape sequences along the way,
and returns the number of characters placed into
-.Fa dst ,
+.Ar 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).
+.Ar dst
+should be equal to the size of
+.Ar src
+(that is, no expansion takes place during decoding).
.Pp
The
.Fn strunvisx
.Fn strunvis
function,
but it allows you to add a flag that specifies the style the string
-.Fa src
+.Ar src
is encoded with.
-Currently, the only supported flag is
-.Dv VIS_HTTPSTYLE .
+Currently, the supported flags are:
+.Dv VIS_HTTPSTYLE
+and
+.Dv VIS_MIMESTYLE .
.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
+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.
+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.
+function has several return codes that must be handled properly.
They are:
.Bl -tag -width UNVIS_VALIDPUSH
-.It Li \&0 (zero)
+.It Li \&0 No (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.
+pointed to by
+.Fa 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.
+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.
+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.
+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
+one more time with flag set to
.Dv UNVIS_END
to extract any remaining character (the character passed in is ignored).
.Pp
.Fa flag
argument is also used to specify the encoding style of the source.
If set to
-.Dv VIS_HTTPSTYLE ,
+.Dv VIS_HTTPSTYLE
+or
+.Dv VIS_HTTP1808 ,
.Fn unvis
will decode URI strings as specified in RFC 1808.
+If set to
+.Dv VIS_HTTP1866 ,
+.Fn unvis
+will decode entity references and numeric character references
+as specified in RFC 1866.
+If set to
+.Dv VIS_MIMESTYLE ,
+.Fn unvis
+will decode MIME Quoted-Printable strings as specified in RFC 2045.
+If set to
+.Dv VIS_NOESCAPE ,
+.Fn unvis
+will not decode
+.Ql \e
+quoted characters.
.Pp
The following code fragment illustrates a proper use of
.Fn unvis .
while ((ch = getchar()) != EOF) {
again:
- switch(unvis(&out, ch, &state, 0)) {
+ switch(unvis(\*[Am]out, ch, \*[Am]state, 0)) {
case 0:
case UNVIS_NOCHAR:
break;
case UNVIS_VALID:
- (void) putchar(out);
+ (void)putchar(out);
break;
case UNVIS_VALIDPUSH:
- (void) putchar(out);
+ (void)putchar(out);
goto again;
case UNVIS_SYNBAD:
- (void)fprintf(stderr, "bad sequence!\en");
- exit(1);
+ errx(EXIT_FAILURE, "Bad character sequence!");
}
}
-if (unvis(&out, (char)0, &state, UNVIS_END) == UNVIS_VALID)
- (void) putchar(out);
+if (unvis(\*[Am]out, '\e0', \*[Am]state, UNVIS_END) == UNVIS_VALID)
+ (void)putchar(out);
.Ed
+.Sh ERRORS
+The functions
+.Fn strunvis ,
+.Fn strnunvis ,
+.Fn strunvisx ,
+and
+.Fn strnunvisx
+will return \-1 on error and set
+.Va errno
+to:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+An invalid escape sequence was detected, or the decoder is in an unknown state.
+.El
+.Pp
+In addition the functions
+.Fn strnunvis
+and
+.Fn strnunvisx
+will can also set
+.Va errno
+on error to:
+.Bl -tag -width Er
+.It Bq Er ENOSPC
+Not enough space to perform the conversion.
+.El
.Sh SEE ALSO
+.Xr unvis 1 ,
.Xr vis 1 ,
.Xr vis 3
.Rs
function
first appeared in
.Bx 4.4 .
+The
+.Fn strnunvis
+and
+.Fn strnunvisx
+functions appeared in OS X 10.12.
+.Sh BUGS
+The names
+.Dv VIS_HTTP1808
+and
+.Dv VIS_HTTP1866
+are wrong.
+Percent-encoding was defined in RFC 1738, the original RFC for URL.
+RFC 1866 defines HTML 2.0, an application of SGML, from which it
+inherits concepts of numeric character references and entity
+references.
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