/*      $NetBSD: vis.c,v 1.88 2024/03/17 21:48:02 andvar Exp $  */

/*-
* Copyright (c) 1989, 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.
*/

/*-
* Copyright (c) 1999, 2005 The NetBSD Foundation, Inc.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: vis.c,v 1.88 2024/03/17 21:48:02 andvar Exp $");
#endif /* LIBC_SCCS and not lint */
#ifdef __FBSDID
__FBSDID("$FreeBSD$");
#define _DIAGASSERT(x)  assert(x)
#endif

#include "namespace.h"

#include <sys/param.h>
#include <sys/types.h>

#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <vis.h>
#include <wchar.h>
#include <wctype.h>

#ifdef __weak_alias
__weak_alias(strvisx,_strvisx)
#endif

#if !HAVE_VIS || !HAVE_SVIS
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>

/*
* The reason for going through the trouble to deal with character encodings
* in vis(3), is that we use this to safe encode output of commands. This
* safe encoding varies depending on the character set. For example if we
* display ps output in French, we don't want to display French characters
* as M-foo.
*/

static wchar_t *do_svis(wchar_t *, wint_t, int, wint_t, const wchar_t *);

#undef BELL
#define BELL L'\a'

#if defined(LC_C_LOCALE)
#define iscgraph(c)      isgraph_l(c, LC_C_LOCALE)
#else
/* Keep it simple for now, no locale stuff */
#define iscgraph(c)     isgraph(c)
#ifdef notyet
#include <locale.h>
static int
iscgraph(int c) {
       int rv;
       char *ol;

       ol = setlocale(LC_CTYPE, "C");
       rv = isgraph(c);
       if (ol)
               setlocale(LC_CTYPE, ol);
       return rv;
}
#endif
#endif

#define ISGRAPH(flags, c) \
   (((flags) & VIS_NOLOCALE) ? iscgraph(c) : iswgraph(c))

#define iswoctal(c)     (((u_char)(c)) >= L'0' && ((u_char)(c)) <= L'7')
#define iswwhite(c)     (c == L' ' || c == L'\t' || c == L'\n')
#define iswsafe(c)      (c == L'\b' || c == BELL || c == L'\r')
#define xtoa(c)         L"0123456789abcdef"[c]
#define XTOA(c)         L"0123456789ABCDEF"[c]

#define MAXEXTRAS       30

static const wchar_t char_shell[] = L"'`\";&<>()|{}]\\$!^~";
static const wchar_t char_glob[] = L"*?[#";

#if !HAVE_NBTOOL_CONFIG_H
#ifndef __NetBSD__
/*
* On NetBSD MB_LEN_MAX is currently 32 which does not fit on any integer
* integral type and it is probably wrong, since currently the maximum
* number of bytes and character needs is 6. Until this is fixed, the
* loops below are using sizeof(uint64_t) - 1 instead of MB_LEN_MAX, and
* the assertion is commented out.
*/
#ifdef __FreeBSD__
/*
* On FreeBSD including <sys/systm.h> for CTASSERT only works in kernel
* mode.
*/
#ifndef CTASSERT
#define CTASSERT(x)             _CTASSERT(x, __LINE__)
#define _CTASSERT(x, y)         __CTASSERT(x, y)
#define __CTASSERT(x, y)        typedef char __assert ## y[(x) ? 1 : -1]
#endif
#endif /* __FreeBSD__ */
CTASSERT(MB_LEN_MAX <= sizeof(uint64_t));
#endif /* !__NetBSD__ */
#endif

/*
* This is do_hvis, for HTTP style (RFC 1808)
*/
static wchar_t *
do_hvis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
{
       if (iswalnum(c)
           /* safe */
           || c == L'$' || c == L'-' || c == L'_' || c == L'.' || c == L'+'
           /* extra */
           || c == L'!' || c == L'*' || c == L'\'' || c == L'(' || c == L')'
           || c == L',')
               dst = do_svis(dst, c, flags, nextc, extra);
       else {
               *dst++ = L'%';
               *dst++ = xtoa(((unsigned int)c >> 4) & 0xf);
               *dst++ = xtoa((unsigned int)c & 0xf);
       }

       return dst;
}

/*
* This is do_mvis, for Quoted-Printable MIME (RFC 2045)
* NB: No handling of long lines or CRLF.
*/
static wchar_t *
do_mvis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
{
       if ((c != L'\n') &&
           /* Space at the end of the line */
           ((iswspace(c) && (nextc == L'\r' || nextc == L'\n')) ||
           /* Out of range */
           (!iswspace(c) && (c < 33 || (c > 60 && c < 62) || c > 126)) ||
           /* Specific char to be escaped */
           wcschr(L"#$@[\\]^`{|}~", c) != NULL)) {
               *dst++ = L'=';
               *dst++ = XTOA(((unsigned int)c >> 4) & 0xf);
               *dst++ = XTOA((unsigned int)c & 0xf);
       } else
               dst = do_svis(dst, c, flags, nextc, extra);
       return dst;
}

/*
* Output single byte of multibyte character.
*/
static wchar_t *
do_mbyte(wchar_t *dst, wint_t c, int flags, wint_t nextc, int iswextra)
{
       if (flags & VIS_CSTYLE) {
               switch (c) {
               case L'\n':
                       *dst++ = L'\\'; *dst++ = L'n';
                       return dst;
               case L'\r':
                       *dst++ = L'\\'; *dst++ = L'r';
                       return dst;
               case L'\b':
                       *dst++ = L'\\'; *dst++ = L'b';
                       return dst;
               case BELL:
                       *dst++ = L'\\'; *dst++ = L'a';
                       return dst;
               case L'\v':
                       *dst++ = L'\\'; *dst++ = L'v';
                       return dst;
               case L'\t':
                       *dst++ = L'\\'; *dst++ = L't';
                       return dst;
               case L'\f':
                       *dst++ = L'\\'; *dst++ = L'f';
                       return dst;
               case L' ':
                       *dst++ = L'\\'; *dst++ = L's';
                       return dst;
               case L'\0':
                       *dst++ = L'\\'; *dst++ = L'0';
                       if (iswoctal(nextc)) {
                               *dst++ = L'0';
                               *dst++ = L'0';
                       }
                       return dst;
               /* We cannot encode these characters in VIS_CSTYLE
                * because they special meaning */
               case L'n':
               case L'r':
               case L'b':
               case L'a':
               case L'v':
               case L't':
               case L'f':
               case L's':
               case L'0':
               case L'M':
               case L'^':
               case L'$': /* vis(1) -l */
                       break;
               default:
                       if (ISGRAPH(flags, c) && !iswoctal(c)) {
                               *dst++ = L'\\';
                               *dst++ = c;
                               return dst;
                       }
               }
       }
       if (iswextra || ((c & 0177) == L' ') || (flags & VIS_OCTAL)) {
               *dst++ = L'\\';
               *dst++ = (u_char)(((u_int32_t)(u_char)c >> 6) & 03) + L'0';
               *dst++ = (u_char)(((u_int32_t)(u_char)c >> 3) & 07) + L'0';
               *dst++ =                             (c       & 07) + L'0';
       } else {
               if ((flags & VIS_NOSLASH) == 0)
                       *dst++ = L'\\';

               if (c & 0200) {
                       c &= 0177;
                       *dst++ = L'M';
               }

               if (iswcntrl(c)) {
                       *dst++ = L'^';
                       if (c == 0177)
                               *dst++ = L'?';
                       else
                               *dst++ = c + L'@';
               } else {
                       *dst++ = L'-';
                       *dst++ = c;
               }
       }

       return dst;
}

/*
* This is do_vis, the central code of vis.
* dst:       Pointer to the destination buffer
* c:         Character to encode
* flags:     Flags word
* nextc:     The character following 'c'
* extra:     Pointer to the list of extra characters to be
*            backslash-protected.
*/
static wchar_t *
do_svis(wchar_t *dst, wint_t c, int flags, wint_t nextc, const wchar_t *extra)
{
       int iswextra, i, shft;
       uint64_t bmsk, wmsk;

       iswextra = wcschr(extra, c) != NULL;
       if (!iswextra && (ISGRAPH(flags, c) || iswwhite(c) ||
           ((flags & VIS_SAFE) && iswsafe(c)))) {
               *dst++ = c;
               return dst;
       }

       /* See comment in istrsenvisx() output loop, below. */
       wmsk = 0;
       for (i = sizeof(wmsk) - 1; i >= 0; i--) {
               shft = i * NBBY;
               bmsk = (uint64_t)0xffLL << shft;
               wmsk |= bmsk;
               if ((c & wmsk) || i == 0)
                       dst = do_mbyte(dst, (wint_t)(
                           (uint64_t)(c & bmsk) >> shft),
                           flags, nextc, iswextra);
       }

       return dst;
}

typedef wchar_t *(*visfun_t)(wchar_t *, wint_t, int, wint_t, const wchar_t *);

/*
* Return the appropriate encoding function depending on the flags given.
*/
static visfun_t
getvisfun(int flags)
{
       if (flags & VIS_HTTPSTYLE)
               return do_hvis;
       if (flags & VIS_MIMESTYLE)
               return do_mvis;
       return do_svis;
}

/*
* Expand list of extra characters to not visually encode.
*/
static wchar_t *
makeextralist(int flags, const char *src)
{
       wchar_t *dst, *d;
       size_t len;
       const wchar_t *s;
       mbstate_t mbstate;

       len = strlen(src);
       if ((dst = calloc(len + MAXEXTRAS, sizeof(*dst))) == NULL)
               return NULL;

       memset(&mbstate, 0, sizeof(mbstate));
       if ((flags & VIS_NOLOCALE)
           || mbsrtowcs(dst, &src, len, &mbstate) == (size_t)-1) {
               size_t i;
               for (i = 0; i < len; i++)
                       dst[i] = (wchar_t)(u_char)src[i];
               d = dst + len;
       } else
               d = dst + wcslen(dst);

       if (flags & VIS_GLOB)
               for (s = char_glob; *s; *d++ = *s++)
                       continue;

       if (flags & VIS_SHELL)
               for (s = char_shell; *s; *d++ = *s++)
                       continue;

       if (flags & VIS_SP) *d++ = L' ';
       if (flags & VIS_TAB) *d++ = L'\t';
       if (flags & VIS_NL) *d++ = L'\n';
       if (flags & VIS_DQ) *d++ = L'"';
       if ((flags & VIS_NOSLASH) == 0) *d++ = L'\\';
       *d = L'\0';

       return dst;
}

/*
* istrsenvisx()
*      The main internal function.
*      All user-visible functions call this one.
*/
static int
istrsenvisx(char **mbdstp, size_t *dlen, const char *mbsrc, size_t mblength,
   int flags, const char *mbextra, int *cerr_ptr)
{
       char mbbuf[MB_LEN_MAX];
       wchar_t *dst, *src, *pdst, *psrc, *start, *extra;
       size_t len, olen;
       uint64_t bmsk, wmsk;
       wint_t c;
       visfun_t f;
       int cerr, error = -1, i, shft;
       ssize_t clen = 0;
       char *mbdst, *mbwrite, *mdst;
       size_t mbslength;
       size_t maxolen;
       mbstate_t mbstate;

       _DIAGASSERT(mbdstp != NULL);
       _DIAGASSERT(mbsrc != NULL || mblength == 0);
       _DIAGASSERT(mbextra != NULL);

       mbslength = mblength;
       /*
        * When inputing a single character, must also read in the
        * next character for nextc, the look-ahead character.
        */
       if (mbslength == 1)
               mbslength++;

       /*
        * Input (mbsrc) is a char string considered to be multibyte
        * characters.  The input loop will read this string pulling
        * one character, possibly multiple bytes, from mbsrc and
        * converting each to wchar_t in src.
        *
        * The vis conversion will be done using the wide char
        * wchar_t string.
        *
        * This will then be converted back to a multibyte string to
        * return to the caller.
        */

       /*
        * Guarantee the arithmetic on input to calloc won't overflow.
        */
       if (mbslength > (SIZE_MAX - 1)/16) {
               errno = ENOMEM;
               return -1;
       }

       /* Allocate space for the wide char strings */
       psrc = pdst = extra = NULL;
       mdst = NULL;
       if ((psrc = calloc(mbslength + 1, sizeof(*psrc))) == NULL)
               return -1;
       if ((pdst = calloc((16 * mbslength) + 1, sizeof(*pdst))) == NULL)
               goto out;
       if (*mbdstp == NULL) {
               if ((mdst = calloc((16 * mbslength) + 1, sizeof(*mdst))) == NULL)
                       goto out;
               *mbdstp = mdst;
       }

       mbdst = *mbdstp;
       dst = pdst;
       src = psrc;

       if (flags & VIS_NOLOCALE) {
               /* Do one byte at a time conversion */
               cerr = 1;
       } else {
               /* Use caller's multibyte conversion error flag. */
               cerr = cerr_ptr ? *cerr_ptr : 0;
       }

       /*
        * Input loop.
        * Handle up to mblength characters (not bytes).  We do not
        * stop at NULs because we may be processing a block of data
        * that includes NULs.
        */
       memset(&mbstate, 0, sizeof(mbstate));
       while (mbslength > 0) {
               /* Convert one multibyte character to wchar_t. */
               if (!cerr) {
                       clen = (ssize_t)mbrtowc(src, mbsrc,
                           (mbslength < MB_LEN_MAX
                               ? mbslength
                               : MB_LEN_MAX),
                           &mbstate);
                       assert(clen < 0 || (size_t)clen <= mbslength);
                       assert(clen <= MB_LEN_MAX);
               }
               if (cerr || clen < 0) {
                       /* Conversion error, process as a byte instead. */
                       *src = (wint_t)(u_char)*mbsrc;
                       clen = 1;
                       cerr = 1;
               }
               if (clen == 0) {
                       /*
                        * NUL in input gives 0 return value. process
                        * as single NUL byte and keep going.
                        */
                       clen = 1;
               }
               /*
                * Let n := MIN(mbslength, MB_LEN_MAX).  We have:
                *
                *      mbslength >= 1
                *      mbrtowc(..., n, &mbstate) <= n,
                *              by the contract of mbrtowc
                *
                *  clen is either
                *  (a) mbrtowc(..., n, &mbstate), in which case
                *      clen <= n <= mbslength; or
                *  (b) 1, in which case clen = 1 <= mbslength.
                */
               assert(clen > 0);
               assert((size_t)clen <= mbslength);
               /* Advance buffer character pointer. */
               src++;
               /* Advance input pointer by number of bytes read. */
               mbsrc += clen;
               /* Decrement input byte count. */
               mbslength -= clen;
       }
       len = src - psrc;
       src = psrc;

       /*
        * In the single character input case, we will have actually
        * processed two characters, c and nextc.  Reset len back to
        * just a single character.
        */
       if (mblength < len)
               len = mblength;

       /* Convert extra argument to list of characters for this mode. */
       extra = makeextralist(flags, mbextra);
       if (!extra) {
               if (dlen && *dlen == 0) {
                       errno = ENOSPC;
                       goto out;
               }
               *mbdst = '\0';  /* can't create extra, return "" */
               error = 0;
               goto out;
       }

       /* Look up which processing function to call. */
       f = getvisfun(flags);

       /*
        * Main processing loop.
        * Call do_Xvis processing function one character at a time
        * with next character available for look-ahead.
        */
       for (start = dst; len > 0; len--) {
               c = *src++;
               dst = (*f)(dst, c, flags, len >= 1 ? *src : L'\0', extra);
               if (dst == NULL) {
                       errno = ENOSPC;
                       goto out;
               }
       }

       /* Terminate the string in the buffer. */
       *dst = L'\0';

       /*
        * Output loop.
        * Convert wchar_t string back to multibyte output string.
        * If we have hit a multi-byte conversion error on input,
        * output byte-by-byte here.  Else use wctomb().
        */
       len = wcslen(start);
       if (dlen) {
               maxolen = *dlen;
               if (maxolen == 0) {
                       errno = ENOSPC;
                       goto out;
               }
       } else {
               if (len > (SIZE_MAX - 1)/MB_LEN_MAX) {
                       errno = ENOSPC;
                       goto out;
               }
               maxolen = len*MB_LEN_MAX + 1;
       }
       olen = 0;
       memset(&mbstate, 0, sizeof(mbstate));
       for (dst = start; len > 0; len--) {
               if (!cerr) {
                       /*
                        * If we have at least MB_CUR_MAX bytes in the buffer,
                        * we'll just do the conversion in-place into mbdst.  We
                        * need to be a little more conservative when we get to
                        * the end of the buffer, as we may not have MB_CUR_MAX
                        * bytes but we may not need it.
                        */
                       if (maxolen - olen > MB_CUR_MAX)
                               mbwrite = mbdst;
                       else
                               mbwrite = mbbuf;
                       clen = (ssize_t)wcrtomb(mbwrite, *dst, &mbstate);
                       if (clen > 0 && mbwrite != mbdst) {
                               /*
                                * Don't break past our output limit, noting
                                * that maxolen includes the nul terminator so
                                * we can't write past maxolen - 1 here.
                                */
                               if (olen + clen >= maxolen) {
                                       errno = ENOSPC;
                                       goto out;
                               }

                               memcpy(mbdst, mbwrite, clen);
                       }
               }
               if (cerr || clen < 0) {
                       /*
                        * Conversion error, process as a byte(s) instead.
                        * Examine each byte and higher-order bytes for
                        * data.  E.g.,
                        *      0x000000000000a264 -> a2 64
                        *      0x000000001f00a264 -> 1f 00 a2 64
                        */
                       clen = 0;
                       wmsk = 0;
                       for (i = sizeof(wmsk) - 1; i >= 0; i--) {
                               shft = i * NBBY;
                               bmsk = (uint64_t)0xffLL << shft;
                               wmsk |= bmsk;
                               if ((*dst & wmsk) || i == 0) {
                                       if (olen + clen + 1 >= maxolen) {
                                               errno = ENOSPC;
                                               goto out;
                                       }

                                       mbdst[clen++] = (char)(
                                           (uint64_t)(*dst & bmsk) >>
                                           shft);
                               }
                       }
                       cerr = 1;
               }

               /*
                * We'll be dereferencing mbdst[clen] after this to write the
                * nul terminator; the above paths should have checked for a
                * possible overflow already.
                */
               assert(olen + clen < maxolen);

               /* Advance output pointer by number of bytes written. */
               mbdst += clen;
               /* Advance buffer character pointer. */
               dst++;
               /* Increment output character count. */
               olen += clen;
       }

       /* Terminate the output string. */
       assert(olen < maxolen);
       *mbdst = '\0';

       if (flags & VIS_NOLOCALE) {
               /* Pass conversion error flag out. */
               if (cerr_ptr)
                       *cerr_ptr = cerr;
       }

       free(extra);
       free(pdst);
       free(psrc);

       return (int)olen;
out:
       free(extra);
       free(pdst);
       free(psrc);
       free(mdst);
       return error;
}

static int
istrsenvisxl(char **mbdstp, size_t *dlen, const char *mbsrc,
   int flags, const char *mbextra, int *cerr_ptr)
{
       return istrsenvisx(mbdstp, dlen, mbsrc,
           mbsrc != NULL ? strlen(mbsrc) : 0, flags, mbextra, cerr_ptr);
}

#endif

#if !HAVE_SVIS
/*
*      The "svis" variants all take an "extra" arg that is a pointer
*      to a NUL-terminated list of characters to be encoded, too.
*      These functions are useful e. g. to encode strings in such a
*      way so that they are not interpreted by a shell.
*/

char *
svis(char *mbdst, int c, int flags, int nextc, const char *mbextra)
{
       char cc[2];
       int ret;

       cc[0] = c;
       cc[1] = nextc;

       ret = istrsenvisx(&mbdst, NULL, cc, 1, flags, mbextra, NULL);
       if (ret < 0)
               return NULL;
       return mbdst + ret;
}

char *
snvis(char *mbdst, size_t dlen, int c, int flags, int nextc, const char *mbextra)
{
       char cc[2];
       int ret;

       cc[0] = c;
       cc[1] = nextc;

       ret = istrsenvisx(&mbdst, &dlen, cc, 1, flags, mbextra, NULL);
       if (ret < 0)
               return NULL;
       return mbdst + ret;
}

int
strsvis(char *mbdst, const char *mbsrc, int flags, const char *mbextra)
{
       return istrsenvisxl(&mbdst, NULL, mbsrc, flags, mbextra, NULL);
}

int
strsnvis(char *mbdst, size_t dlen, const char *mbsrc, int flags, const char *mbextra)
{
       return istrsenvisxl(&mbdst, &dlen, mbsrc, flags, mbextra, NULL);
}

int
strsvisx(char *mbdst, const char *mbsrc, size_t len, int flags, const char *mbextra)
{
       return istrsenvisx(&mbdst, NULL, mbsrc, len, flags, mbextra, NULL);
}

int
strsnvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
   const char *mbextra)
{
       return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, mbextra, NULL);
}

int
strsenvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
   const char *mbextra, int *cerr_ptr)
{
       return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, mbextra, cerr_ptr);
}
#endif

#if !HAVE_VIS
/*
* vis - visually encode characters
*/
char *
vis(char *mbdst, int c, int flags, int nextc)
{
       char cc[2];
       int ret;

       cc[0] = c;
       cc[1] = nextc;

       ret = istrsenvisx(&mbdst, NULL, cc, 1, flags, "", NULL);
       if (ret < 0)
               return NULL;
       return mbdst + ret;
}

char *
nvis(char *mbdst, size_t dlen, int c, int flags, int nextc)
{
       char cc[2];
       int ret;

       cc[0] = c;
       cc[1] = nextc;

       ret = istrsenvisx(&mbdst, &dlen, cc, 1, flags, "", NULL);
       if (ret < 0)
               return NULL;
       return mbdst + ret;
}

/*
* strvis - visually encode characters from src into dst
*
*      Dst must be 4 times the size of src to account for possible
*      expansion.  The length of dst, not including the trailing NULL,
*      is returned.
*/

int
strvis(char *mbdst, const char *mbsrc, int flags)
{
       return istrsenvisxl(&mbdst, NULL, mbsrc, flags, "", NULL);
}

int
strnvis(char *mbdst, size_t dlen, const char *mbsrc, int flags)
{
       return istrsenvisxl(&mbdst, &dlen, mbsrc, flags, "", NULL);
}

int
stravis(char **mbdstp, const char *mbsrc, int flags)
{
       *mbdstp = NULL;
       return istrsenvisxl(mbdstp, NULL, mbsrc, flags, "", NULL);
}

/*
* strvisx - visually encode characters from src into dst
*
*      Dst must be 4 times the size of src to account for possible
*      expansion.  The length of dst, not including the trailing NULL,
*      is returned.
*
*      Strvisx encodes exactly len characters from src into dst.
*      This is useful for encoding a block of data.
*/

int
strvisx(char *mbdst, const char *mbsrc, size_t len, int flags)
{
       return istrsenvisx(&mbdst, NULL, mbsrc, len, flags, "", NULL);
}

int
strnvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags)
{
       return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, "", NULL);
}

int
strenvisx(char *mbdst, size_t dlen, const char *mbsrc, size_t len, int flags,
   int *cerr_ptr)
{
       return istrsenvisx(&mbdst, &dlen, mbsrc, len, flags, "", cerr_ptr);
}
#endif