/* $Id: $ */

#include "pg_mb_utf8.h"

/*
 * This is an implementation of wcwidth() and wcswidth() as defined in
 * "The Single UNIX Specification, Version 2, The Open Group, 1997"
 * <http://www.UNIX-systems.org/online.html>
 *
 * Markus Kuhn -- 2001-09-08 -- public domain
 *
 * customised to PostgreSQL by Patrice Hede
 * - removed dependency to wchar,
 * - modified and renamed wcswidth to take utf8 strings.
 *
 * original available at : http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
 */

struct pg_mbinterval {
  unsigned short first;
  unsigned short last;
};

/* auxiliary function for binary search in interval table */
static int
pg_mbbisearch(pg_wchar ucs, const struct pg_mbinterval *table, int max)
{
  int min = 0;
  int mid;

  if (ucs < table[0].first || ucs > table[max].last)
    return 0;
  while (max >= min) {
    mid = (min + max) / 2;
    if (ucs > table[mid].last)
      min = mid + 1;
    else if (ucs < table[mid].first)
      max = mid - 1;
    else
      return 1;
  }

  return 0;
}


/* The following functions define the column width of an ISO 10646
 * character as follows:
 *
 *    - The null character (U+0000) has a column width of 0.
 *
 *    - Other C0/C1 control characters and DEL will lead to a return
 *      value of -1.
 *
 *    - Non-spacing and enclosing combining characters (general
 *      category code Mn or Me in the Unicode database) have a
 *      column width of 0.
 *
 *    - Other format characters (general category code Cf in the Unicode
 *      database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
 *
 *    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
 *      have a column width of 0.
 *
 *    - Spacing characters in the East Asian Wide (W) or East Asian
 *      FullWidth (F) category as defined in Unicode Technical
 *      Report #11 have a column width of 2.
 *
 *    - All remaining characters (including all printable
 *      ISO 8859-1 and WGL4 characters, Unicode control characters,
 *      etc.) have a column width of 1.
 *
 * This implementation assumes that wchar_t characters are encoded
 * in ISO 10646.
 */

int pg_mb_wcwidth(pg_wchar ucs)
{
  /* sorted list of non-overlapping intervals of non-spacing characters */
  static const struct pg_mbinterval combining[] = {
    { 0x0300, 0x034E }, { 0x0360, 0x0362 }, { 0x0483, 0x0486 },
    { 0x0488, 0x0489 }, { 0x0591, 0x05A1 }, { 0x05A3, 0x05B9 },
    { 0x05BB, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
    { 0x05C4, 0x05C4 }, { 0x064B, 0x0655 }, { 0x0670, 0x0670 },
    { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
    { 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
    { 0x07A6, 0x07B0 }, { 0x0901, 0x0902 }, { 0x093C, 0x093C },
    { 0x0941, 0x0948 }, { 0x094D, 0x094D }, { 0x0951, 0x0954 },
    { 0x0962, 0x0963 }, { 0x0981, 0x0981 }, { 0x09BC, 0x09BC },
    { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 },
    { 0x0A02, 0x0A02 }, { 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 },
    { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D }, { 0x0A70, 0x0A71 },
    { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC }, { 0x0AC1, 0x0AC5 },
    { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD }, { 0x0B01, 0x0B01 },
    { 0x0B3C, 0x0B3C }, { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 },
    { 0x0B4D, 0x0B4D }, { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 },
    { 0x0BC0, 0x0BC0 }, { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 },
    { 0x0C46, 0x0C48 }, { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 },
    { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
    { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D }, { 0x0DCA, 0x0DCA },
    { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 }, { 0x0E31, 0x0E31 },
    { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E }, { 0x0EB1, 0x0EB1 },
    { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC }, { 0x0EC8, 0x0ECD },
    { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 }, { 0x0F37, 0x0F37 },
    { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E }, { 0x0F80, 0x0F84 },
    { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 }, { 0x0F99, 0x0FBC },
    { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 }, { 0x1032, 0x1032 },
    { 0x1036, 0x1037 }, { 0x1039, 0x1039 }, { 0x1058, 0x1059 },
    { 0x1160, 0x11FF }, { 0x17B7, 0x17BD }, { 0x17C6, 0x17C6 },
    { 0x17C9, 0x17D3 }, { 0x180B, 0x180E }, { 0x18A9, 0x18A9 },
    { 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x206A, 0x206F },
    { 0x20D0, 0x20E3 }, { 0x302A, 0x302F }, { 0x3099, 0x309A },
    { 0xFB1E, 0xFB1E }, { 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF },
    { 0xFFF9, 0xFFFB }
  };

  /* test for 8-bit control characters */
  if (ucs == 0) {
    return 0;
  }

  if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0) ||
      ucs > 0x0010ffff) {
    return -1;
  }

  /* binary search in table of non-spacing characters */
  if (pg_mbbisearch(ucs, combining,
		    sizeof(combining) / sizeof(struct pg_mbinterval) - 1)) {
    return 0;
  }

  /* if we arrive here, ucs is not a combining or C0/C1 control character */

  return 1 + 
    (ucs >= 0x1100 &&
     (ucs <= 0x115f ||                    /* Hangul Jamo init. consonants */
      (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a &&
       ucs != 0x303f) ||                  /* CJK ... Yi */
      (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */
      (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */
      (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
      (ucs >= 0xff00 && ucs <= 0xff5f) || /* Fullwidth Forms */
      (ucs >= 0xffe0 && ucs <= 0xffe6) ||
      (ucs >= 0x20000 && ucs <= 0x2ffff)));
}

pg_wchar pg_mb_utf_ucs(const unsigned char *c, int *l)
{
  /* returns a pg_wchar containing the character, as well as the size to skip */
  pg_wchar u = 0;

  *l = 1;

  if (!(*c & 0x80)) {
    return *c;
  }
  if (!(*c & 0x40)) {
    /* will generate a fault as soon as it reaches pg_wcwidth as
     * the last valid unicode char is 0x10ffff.
     */
    return PG_MB_UTF_INVALID;
  }
  switch (*c & 0x30) {
  case 0x30:
    if (*c & 0x08) {
      return PG_MB_UTF_INVALID;
    }
    (*l)++;
    u = (*(c++) & 0x07) << 6;

    if ((*c & 0xc0) != 0x80) {
      return PG_MB_UTF_INVALID;
    }
    /* no break */

  case 0x20:
    (*l)++;
    u = (u | (*(c++) & 0x3f)) << 6;

    if ((*c & 0xc0) != 0x80) {
      return PG_MB_UTF_INVALID;
    }
    /* no break */

  default:
    (*l)++;
    u = (u | (*(c++) & 0x3f)) << 6;
  }
  if ((*c & 0xc0) != 0x80) {
    return PG_MB_UTF_INVALID;
  }
  u |= *c & 0x3f;

  if (*l == 3) {
    u &= 0xffff;
  }

  return u;
}

/* pwcs : utf8 string to mesure
 * truncate : in case the utf-8 is not legal :
 * 0 : return -1 (invalid), 1 : truncate the string at the invalid character
 */
int pg_mb_utfs_width(unsigned char *pwcs, int truncate)
{
  int w, l = 0;
  int width = 0;

  for (;*pwcs; pwcs+=l)
  {
    if ((w = pg_mb_wcwidth(pg_mb_utf_ucs(pwcs,&l))) < 0) {
      if(truncate) {
	*pwcs = '\0';
	return width;
      }
      else {
	return -1;
      }
    }

    width += w;
  }
  return width;
}