/* Determine the number of screen columns needed for a string.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <haible@clisp.cons.org>.  */

#include <config.h>

/* Specification.  */

#include "mbswidth.h"

/* Get MB_CUR_MAX.  */

#include <stdlib.h>

#include <string.h>

/* Get isprint().  */

#include <ctype.h>

/* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth().  */

#include <wchar.h>

/* Get iswcntrl().  */

#include <wctype.h>

/* Get INT_MAX.  */

#include <limits.h>

/* Returns the number of columns needed to represent the multibyte

   character string pointed to by STRING.  If a non-printable character

   occurs, and MBSW_REJECT_UNPRINTABLE is specified, -1 is returned.

   With flags = MBSW_REJECT_INVALID | MBSW_REJECT_UNPRINTABLE, this is

   the multibyte analogue of the wcswidth function.  */

int

mbswidth (const char *string, int flags)

{

  return mbsnwidth (string, strlen (string), flags);

}

/* Returns the number of columns needed to represent the multibyte

   character string pointed to by STRING of length NBYTES.  If a

   non-printable character occurs, and MBSW_REJECT_UNPRINTABLE is

   specified, -1 is returned.  */

int

mbsnwidth (const char *string, size_t nbytes, int flags)

{

  const char *p = string;

  const char *plimit = p + nbytes;

  int width;

  width = 0;

  if (MB_CUR_MAX > 1)

    {

      while (p < plimit)

        switch (*p)

          {

            case ' ': case '!': case '"': case '#': case '%':

            case '&': case '\'': case '(': case ')': case '*':

            case '+': case ',': case '-': case '.': case '/':

            case '0': case '1': case '2': case '3': case '4':

            case '5': case '6': case '7': case '8': case '9':

            case ':': case ';': case '<': case '=': case '>':

            case '?':

            case 'A': case 'B': case 'C': case 'D': case 'E':

            case 'F': case 'G': case 'H': case 'I': case 'J':

            case 'K': case 'L': case 'M': case 'N': case 'O':

            case 'P': case 'Q': case 'R': case 'S': case 'T':

            case 'U': case 'V': case 'W': case 'X': case 'Y':

            case 'Z':

            case '[': case '\\': case ']': case '^': case '_':

            case 'a': case 'b': case 'c': case 'd': case 'e':

            case 'f': case 'g': case 'h': case 'i': case 'j':

            case 'k': case 'l': case 'm': case 'n': case 'o':

            case 'p': case 'q': case 'r': case 's': case 't':

            case 'u': case 'v': case 'w': case 'x': case 'y':

            case 'z': case '{': case '|': case '}': case '~':

              /* These characters are printable ASCII characters.  */

              p++;

              width++;

              break;

            default:

              /* If we have a multibyte sequence, scan it up to its end.  */

              {

                mbstate_t mbstate;

                memset (&mbstate, 0, sizeof mbstate);

                do

                  {

                    wchar_t wc;

                    size_t bytes;

                    int w;

                    bytes = mbrtowc (&wc, p, plimit - p, &mbstate);

                    if (bytes == (size_t) -1)

                      /* An invalid multibyte sequence was encountered.  */

                      {

                        if (!(flags & MBSW_REJECT_INVALID))

                          {

                            p++;

                            width++;

                            break;

                          }

                        else

                          return -1;

                      }

                    if (bytes == (size_t) -2)

                      /* An incomplete multibyte character at the end.  */

                      {

                        if (!(flags & MBSW_REJECT_INVALID))

                          {

                            p = plimit;

                            width++;

                            break;

                          }

                        else

                          return -1;

                      }

                    if (bytes == 0)

                      /* A null wide character was encountered.  */

                      bytes = 1;

                    w = wcwidth (wc);

                    if (w >= 0)

                      /* A printable multibyte character.  */

                      {

                        if (w > INT_MAX - width)

                          goto overflow;

                        width += w;

                      }

                    else

                      /* An unprintable multibyte character.  */

                      if (!(flags & MBSW_REJECT_UNPRINTABLE))

                        {

                          if (!iswcntrl (wc))

                            {

                              if (width == INT_MAX)

                                goto overflow;

                              width++;

                            }

                        }

                      else

                        return -1;

                    p += bytes;

                  }

                while (! mbsinit (&mbstate));

              }

              break;

          }

      return width;

    }

  while (p < plimit)

    {

      unsigned char c = (unsigned char) *p++;

      if (isprint (c))

        {

          if (width == INT_MAX)

            goto overflow;

          width++;

        }

      else if (!(flags & MBSW_REJECT_UNPRINTABLE))

        {

          if (!iscntrl (c))

            {

              if (width == INT_MAX)

                goto overflow;

              width++;

            }

        }

      else

        return -1;

    }

  return width;

 overflow:

  return INT_MAX;

}