/*  $OpenBSD: vis.c,v 1.26 2022/05/04 18:57:50 deraadt 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.

 */

/* OPENBSD ORIGINAL: lib/libc/gen/vis.c */

#if !defined(HAVE_STRNVIS)

#include <sys/types.h>

#include <errno.h>

#include <ctype.h>

#include <limits.h>

#include <string.h>

#include <stdlib.h>

#include <vis.h>

static int

isoctal(int c)

{

  u_char uc = c;

  return uc >= '0' && uc <= '7';

}

static int

isvisible(int c, int flag)

{

  int vis_sp = flag & VIS_SP;

  int vis_tab = flag & VIS_TAB;

  int vis_nl = flag & VIS_NL;

  int vis_safe = flag & VIS_SAFE;

  int vis_glob = flag & VIS_GLOB;

  int vis_all = flag & VIS_ALL;

  u_char uc = c;

  if (c == '\\' || !vis_all) {

    if ((u_int)c <= UCHAR_MAX && isascii(uc) &&

        ((c != '*' && c != '?' && c != '[' && c != '#') || !vis_glob) &&

        isgraph(uc))

      return 1;

    if (!vis_sp && c == ' ')

      return 1;

    if (!vis_tab && c == '\t')

      return 1;

    if (!vis_nl && c == '\n')

      return 1;

    if (vis_safe && (c == '\b' || c == '\007' || c == '\r' || isgraph(uc)))

      return 1;

  }

  return 0;

}

/*

 * vis - visually encode characters

 */

char *

vis(char *dst, int c, int flag, int nextc)

{

  int vis_dq = flag & VIS_DQ;

  int vis_noslash = flag & VIS_NOSLASH;

  int vis_cstyle = flag & VIS_CSTYLE;

  int vis_octal = flag & VIS_OCTAL;

  int vis_glob = flag & VIS_GLOB;

  if (isvisible(c, flag)) {

    if ((c == '"' && vis_dq) ||

        (c == '\\' && !vis_noslash))

      *dst++ = '\\';

    *dst++ = c;

    *dst = '\0';

    return (dst);

  }

  if (vis_cstyle) {

    switch (c) {

    case '\n':

      *dst++ = '\\';

      *dst++ = 'n';

      goto done;

    case '\r':

      *dst++ = '\\';

      *dst++ = 'r';

      goto done;

    case '\b':

      *dst++ = '\\';

      *dst++ = 'b';

      goto done;

    case '\a':

      *dst++ = '\\';

      *dst++ = 'a';

      goto done;

    case '\v':

      *dst++ = '\\';

      *dst++ = 'v';

      goto done;

    case '\t':

      *dst++ = '\\';

      *dst++ = 't';

      goto done;

    case '\f':

      *dst++ = '\\';

      *dst++ = 'f';

      goto done;

    case ' ':

      *dst++ = '\\';

      *dst++ = 's';

      goto done;

    case '\0':

      *dst++ = '\\';

      *dst++ = '0';

      if (isoctal(nextc)) {

        *dst++ = '0';

        *dst++ = '0';

      }

      goto done;

    }

  }

  if (((c & 0177) == ' ') || vis_octal ||

      (vis_glob && (c == '*' || c == '?' || c == '[' || c == '#'))) {

    *dst++ = '\\';

    *dst++ = ((u_char)c >> 6 & 07) + '0';

    *dst++ = ((u_char)c >> 3 & 07) + '0';

    *dst++ = ((u_char)c & 07) + '0';

    goto done;

  }

  if (!vis_noslash)

    *dst++ = '\\';

  if (c & 0200) {

    c &= 0177;

    *dst++ = 'M';

  }

  if (iscntrl((u_char)c)) {

    *dst++ = '^';

    if (c == 0177)

      *dst++ = '?';

    else

      *dst++ = c + '@';

  } else {

    *dst++ = '-';

    *dst++ = c;

  }

done:

  *dst = '\0';

  return (dst);

}

/*

 * strvis, strnvis, 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. 

 *

 *  Strnvis will write no more than siz-1 bytes (and will NULL terminate).

 *  The number of bytes needed to fully encode the string is returned.

 *

 *  Strvisx encodes exactly len bytes from src into dst.

 *  This is useful for encoding a block of data.

 */

int

strvis(char *dst, const char *src, int flag)

{

  char c;

  char *start;

  for (start = dst; (c = *src);)

    dst = vis(dst, c, flag, *++src);

  *dst = '\0';

  return (dst - start);

}

int

strnvis(char *dst, const char *src, size_t siz, int flag)

{

  int vis_dq = flag & VIS_DQ;

  int vis_noslash = flag & VIS_NOSLASH;

  char *start, *end;

  char tbuf[5];

  int c, i;

  i = 0;

  for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {

    if (isvisible(c, flag)) {

      if ((c == '"' && vis_dq) ||

          (c == '\\' && !vis_noslash)) {

        /* need space for the extra '\\' */

        if (dst + 1 >= end) {

          i = 2;

          break;

        }

        *dst++ = '\\';

      }

      i = 1;

      *dst++ = c;

      src++;

    } else {

      i = vis(tbuf, c, flag, *++src) - tbuf;

      if (dst + i <= end) {

        memcpy(dst, tbuf, i);

        dst += i;

      } else {

        src--;

        break;

      }

    }

  }

  if (siz > 0)

    *dst = '\0';

  if (dst + i > end) {

    /* adjust return value for truncation */

    while ((c = *src))

      dst += vis(tbuf, c, flag, *++src) - tbuf;

  }

  return (dst - start);

}

int

stravis(char **outp, const char *src, int flag)

{

  char *buf;

  int len, serrno;

  buf = reallocarray(NULL, 4, strlen(src) + 1);

  if (buf == NULL)

    return -1;

  len = strvis(buf, src, flag);

  serrno = errno;

  *outp = realloc(buf, len + 1);

  if (*outp == NULL) {

    *outp = buf;

    errno = serrno;

  }

  return (len);

}

int

strvisx(char *dst, const char *src, size_t len, int flag)

{

  char c;

  char *start;

  for (start = dst; len > 1; len--) {

    c = *src;

    dst = vis(dst, c, flag, *++src);

  }

  if (len)

    dst = vis(dst, *src, flag, '\0');

  *dst = '\0';

  return (dst - start);

}

#endif