/* Association between Unicode characters and their names.
   Copyright (C) 2000-2002, 2005-2007, 2009-2018 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.
   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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "uniname.h"

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))


/* Table of Unicode character names, derived from UnicodeData.txt.
   This table is generated in a way to minimize the memory footprint:
     1. its compiled size is small (less than 350 KB),
     2. it resides entirely in the text or read-only data segment of the
        executable or shared library: the table contains only immediate
        integers, no pointers, and the functions don't do heap allocation.
 */
#include "uninames.h"
/* It contains:
  static const char unicode_name_words[36303] = ...;
  #define UNICODE_CHARNAME_NUM_WORDS 6260
  static const struct { uint16_t extra_offset; uint16_t ind_offset; } unicode_name_by_length[26] = ...;
  #define UNICODE_CHARNAME_WORD_HANGUL 3902
  #define UNICODE_CHARNAME_WORD_SYLLABLE 4978
  #define UNICODE_CHARNAME_WORD_CJK 417
  #define UNICODE_CHARNAME_WORD_COMPATIBILITY 6107
  static const uint16_t unicode_names[68940] = ...;
  static const struct { uint16_t index; uint32_t name:24; } unicode_name_to_index[16626] = ...;
  static const struct { uint16_t index; uint32_t name:24; } unicode_index_to_name[16626] = ...;
  #define UNICODE_CHARNAME_MAX_LENGTH 83
  #define UNICODE_CHARNAME_MAX_WORDS 13
  static const struct { uint32_t index; uint32_t gap; uint16_t length; } unicode_ranges[401] = ...;
*/

/* Returns the word with a given index.  */
static const char *
unicode_name_word (unsigned int index, unsigned int *lengthp)
{
  unsigned int i1;
  unsigned int i2;
  unsigned int i;

  assert (index < UNICODE_CHARNAME_NUM_WORDS);

  /* Binary search for i with
       unicode_name_by_length[i].ind_offset <= index
     and
       index < unicode_name_by_length[i+1].ind_offset
   */

  i1 = 0;
  i2 = SIZEOF (unicode_name_by_length) - 1;
  while (i2 - i1 > 1)
    {
      unsigned int i = (i1 + i2) >> 1;
      if (unicode_name_by_length[i].ind_offset <= index)
        i1 = i;
      else
        i2 = i;
    }
  i = i1;
  assert (unicode_name_by_length[i].ind_offset <= index
          && index < unicode_name_by_length[i+1].ind_offset);
  *lengthp = i;
  return &unicode_name_words[unicode_name_by_length[i].extra_offset
                             + (index-unicode_name_by_length[i].ind_offset)*i];
}

/* Looks up the index of a word.  */
static int
unicode_name_word_lookup (const char *word, unsigned int length)
{
  if (length > 0 && length < SIZEOF (unicode_name_by_length) - 1)
    {
      /* Binary search among the words of given length.  */
      unsigned int extra_offset = unicode_name_by_length[length].extra_offset;
      unsigned int i0 = unicode_name_by_length[length].ind_offset;
      unsigned int i1 = i0;
      unsigned int i2 = unicode_name_by_length[length+1].ind_offset;
      while (i2 - i1 > 0)
        {
          unsigned int i = (i1 + i2) >> 1;
          const char *p = &unicode_name_words[extra_offset + (i-i0)*length];
          const char *w = word;
          unsigned int n = length;
          for (;;)
            {
              if (*p < *w)
                {
                  if (i1 == i)
                    return -1;
                  /* Note here: i1 < i < i2.  */
                  i1 = i;
                  break;
                }
              if (*p > *w)
                {
                  /* Note here: i1 <= i < i2.  */
                  i2 = i;
                  break;
                }
              p++; w++; n--;
              if (n == 0)
                return i;
            }
        }
    }
  return -1;
}

#define UNINAME_INVALID_INDEX UINT16_MAX

/* Looks up the internal index of a Unicode character.  */
static uint16_t
unicode_code_to_index (ucs4_t c)
{
  /* Binary search in unicode_ranges.  */
  unsigned int i1 = 0;
  unsigned int i2 = SIZEOF (unicode_ranges);

  for (;;)
    {
      unsigned int i = (i1 + i2) >> 1;
      ucs4_t start_code =
        unicode_ranges[i].index + unicode_ranges[i].gap;
      ucs4_t end_code =
        start_code + unicode_ranges[i].length - 1;

      if (start_code <= c && c <= end_code)
        return c - unicode_ranges[i].gap;

      if (end_code < c)
        {
          if (i1 == i)
            break;
          /* Note here: i1 < i < i2.  */
          i1 = i;
        }
      else if (c < start_code)
        {
          if (i2 == i)
            break;
          /* Note here: i1 <= i < i2.  */
          i2 = i;
        }
    }
  return UNINAME_INVALID_INDEX;
}

/* Looks up the codepoint of a Unicode character, from the given
   internal index.  */
static ucs4_t
unicode_index_to_code (uint16_t index)
{
  /* Binary search in unicode_ranges.  */
  unsigned int i1 = 0;
  unsigned int i2 = SIZEOF (unicode_ranges);

  for (;;)
    {
      unsigned int i = (i1 + i2) >> 1;
      uint16_t start_index = unicode_ranges[i].index;
      uint16_t end_index = start_index + unicode_ranges[i].length - 1;

      if (start_index <= index && index <= end_index)
        return index + unicode_ranges[i].gap;

      if (end_index < index)
        {
          if (i1 == i)
            break;
          /* Note here: i1 < i < i2.  */
          i1 = i;
        }
      else if (index < start_index)
        {
          if (i2 == i)
            break;
          /* Note here: i1 <= i < i2.  */
          i2 = i;
        }
    }
  return UNINAME_INVALID;
}


/* Auxiliary tables for Hangul syllable names, see the Unicode 3.0 book,
   sections 3.11 and 4.4.  */
static const char jamo_initial_short_name[19][3] =
{
  "G", "GG", "N", "D", "DD", "R", "M", "B", "BB", "S", "SS", "", "J", "JJ",
  "C", "K", "T", "P", "H"
};
static const char jamo_medial_short_name[21][4] =
{
  "A", "AE", "YA", "YAE", "EO", "E", "YEO", "YE", "O", "WA", "WAE", "OE", "YO",
  "U", "WEO", "WE", "WI", "YU", "EU", "YI", "I"
};
static const char jamo_final_short_name[28][3] =
{
  "", "G", "GG", "GS", "N", "NI", "NH", "D", "L", "LG", "LM", "LB", "LS", "LT",
  "LP", "LH", "M", "B", "BS", "S", "SS", "NG", "J", "C", "K", "T", "P", "H"
};

/* Looks up the name of a Unicode character, in uppercase ASCII.
   Returns the filled buf, or NULL if the character does not have a name.  */
char *
unicode_character_name (ucs4_t c, char *buf)
{
  if (c >= 0xAC00 && c <= 0xD7A3)
    {
      /* Special case for Hangul syllables. Keeps the tables small.  */
      char *ptr;
      unsigned int tmp;
      unsigned int index1;
      unsigned int index2;
      unsigned int index3;
      const char *q;

      /* buf needs to have at least 16 + 7 bytes here.  */
      memcpy (buf, "HANGUL SYLLABLE ", 16);
      ptr = buf + 16;

      tmp = c - 0xAC00;
      index3 = tmp % 28; tmp = tmp / 28;
      index2 = tmp % 21; tmp = tmp / 21;
      index1 = tmp;

      q = jamo_initial_short_name[index1];
      while (*q != '\0')
        *ptr++ = *q++;
      q = jamo_medial_short_name[index2];
      while (*q != '\0')
        *ptr++ = *q++;
      q = jamo_final_short_name[index3];
      while (*q != '\0')
        *ptr++ = *q++;
      *ptr = '\0';
      return buf;
    }
  else if ((c >= 0xF900 && c <= 0xFA2D) || (c >= 0xFA30 && c <= 0xFA6A)
           || (c >= 0xFA70 && c <= 0xFAD9) || (c >= 0x2F800 && c <= 0x2FA1D))
    {
      /* Special case for CJK compatibility ideographs. Keeps the tables
         small.  */
      char *ptr;
      int i;

      /* buf needs to have at least 28 + 5 bytes here.  */
      memcpy (buf, "CJK COMPATIBILITY IDEOGRAPH-", 28);
      ptr = buf + 28;

      for (i = (c < 0x10000 ? 12 : 16); i >= 0; i -= 4)
        {
          unsigned int x = (c >> i) & 0xf;
          *ptr++ = (x < 10 ? '0' : 'A' - 10) + x;
        }
      *ptr = '\0';
      return buf;
    }
  else if ((c >= 0xFE00 && c <= 0xFE0F) || (c >= 0xE0100 && c <= 0xE01EF))
    {
      /* Special case for variation selectors. Keeps the tables
         small.  */

      /* buf needs to have at least 19 + 3 bytes here.  */
      sprintf (buf, "VARIATION SELECTOR-%d",
               c <= 0xFE0F ? c - 0xFE00 + 1 : c - 0xE0100 + 17);
      return buf;
    }
  else
    {
      uint16_t index = unicode_code_to_index (c);
      const uint16_t *words = NULL;

      if (index != UNINAME_INVALID_INDEX)
        {
          /* Binary search in unicode_code_to_name.  */
          unsigned int i1 = 0;
          unsigned int i2 = SIZEOF (unicode_index_to_name);
          for (;;)
            {
              unsigned int i = (i1 + i2) >> 1;
              if (unicode_index_to_name[i].index == index)
                {
                  words = &unicode_names[unicode_index_to_name[i].name];
                  break;
                }
              else if (unicode_index_to_name[i].index < index)
                {
                  if (i1 == i)
                    {
                      words = NULL;
                      break;
                    }
                  /* Note here: i1 < i < i2.  */
                  i1 = i;
                }
              else if (unicode_index_to_name[i].index > index)
                {
                  if (i2 == i)
                    {
                      words = NULL;
                      break;
                    }
                  /* Note here: i1 <= i < i2.  */
                  i2 = i;
                }
            }
        }
      if (words != NULL)
        {
          /* Found it in unicode_index_to_name. Now concatenate the words.  */
          /* buf needs to have at least UNICODE_CHARNAME_MAX_LENGTH bytes.  */
          char *ptr = buf;
          for (;;)
            {
              unsigned int wordlen;
              const char *word = unicode_name_word (*words>>1, &wordlen);
              do
                *ptr++ = *word++;
              while (--wordlen > 0);
              if ((*words & 1) == 0)
                break;
              *ptr++ = ' ';
              words++;
            }
          *ptr = '\0';
          return buf;
        }
      return NULL;
    }
}

/* Looks up the Unicode character with a given name, in upper- or lowercase
   ASCII.  Returns the character if found, or UNINAME_INVALID if not found.  */
ucs4_t
unicode_name_character (const char *name)
{
  unsigned int len = strlen (name);
  if (len > 1 && len <= UNICODE_CHARNAME_MAX_LENGTH)
    {
      /* Test for "word1 word2 ..." syntax.  */
      char buf[UNICODE_CHARNAME_MAX_LENGTH];
      char *ptr = buf;
      for (;;)
        {
          char c = *name++;
          if (!(c >= ' ' && c <= '~'))
            break;
          *ptr++ = (c >= 'a' && c <= 'z' ? c - 'a' + 'A' : c);
          if (--len == 0)
            goto filled_buf;
        }
      if (false)
      filled_buf:
        {
          {
            /* Special case for variation selector aliases. Keeps the
               tables small.  */
            const char *p1 = buf;
            if (ptr >= buf + 3 && *p1++ == 'V')
              {
                if (*p1++ == 'S')
                  {
                    if (*p1 != '0')
                      {
                        unsigned int c = 0;
                        for (;;)
                          {
                            if (*p1 >= '0' && *p1 <= '9')
                              c += (*p1 - '0');
                            p1++;
                            if (p1 == ptr)
                              {
                                if (c >= 1 && c <= 16)
                                  return c - 1 + 0xFE00;
                                else if (c >= 17 && c <= 256)
                                  return c - 17 + 0xE0100;
                                else
                                  break;
                              }
                            c = c * 10;
                          }
                      }
                  }
              }
          }
          {
            /* Convert the constituents to uint16_t words.  */
            uint16_t words[UNICODE_CHARNAME_MAX_WORDS];
            uint16_t *wordptr = words;
            {
              const char *p1 = buf;
              for (;;)
                {
                  {
                    int word;
                    const char *p2 = p1;
                    while (p2 < ptr && *p2 != ' ')
                      p2++;
                    word = unicode_name_word_lookup (p1, p2 - p1);
                    if (word < 0)
                      break;
                    if (wordptr == &words[UNICODE_CHARNAME_MAX_WORDS])
                      break;
                    *wordptr++ = word;
                    if (p2 == ptr)
                      goto filled_words;
                    p1 = p2 + 1;
                  }
                  /* Special case for Hangul syllables. Keeps the tables small. */
                  if (wordptr == &words[2]
                      && words[0] == UNICODE_CHARNAME_WORD_HANGUL
                      && words[1] == UNICODE_CHARNAME_WORD_SYLLABLE)
                    {
                      /* Split the last word [p1..ptr) into three parts:
                           1) [BCDGHJKMNPRST]
                           2) [AEIOUWY]
                           3) [BCDGHIJKLMNPST]
                       */
                      const char *p2;
                      const char *p3;
                      const char *p4;

                      p2 = p1;
                      while (p2 < ptr
                             && (*p2 == 'B' || *p2 == 'C' || *p2 == 'D'
                                 || *p2 == 'G' || *p2 == 'H' || *p2 == 'J'
                                 || *p2 == 'K' || *p2 == 'M' || *p2 == 'N'
                                 || *p2 == 'P' || *p2 == 'R' || *p2 == 'S'
                                 || *p2 == 'T'))
                        p2++;
                      p3 = p2;
                      while (p3 < ptr
                             && (*p3 == 'A' || *p3 == 'E' || *p3 == 'I'
                                 || *p3 == 'O' || *p3 == 'U' || *p3 == 'W'
                                 || *p3 == 'Y'))
                        p3++;
                      p4 = p3;
                      while (p4 < ptr
                             && (*p4 == 'B' || *p4 == 'C' || *p4 == 'D'
                                 || *p4 == 'G' || *p4 == 'H' || *p4 == 'I'
                                 || *p4 == 'J' || *p4 == 'K' || *p4 == 'L'
                                 || *p4 == 'M' || *p4 == 'N' || *p4 == 'P'
                                 || *p4 == 'S' || *p4 == 'T'))
                        p4++;
                      if (p4 == ptr)
                        {
                          unsigned int n1 = p2 - p1;
                          unsigned int n2 = p3 - p2;
                          unsigned int n3 = p4 - p3;

                          if (n1 <= 2 && (n2 >= 1 && n2 <= 3) && n3 <= 2)
                            {
                              unsigned int index1;

                              for (index1 = 0; index1 < 19; index1++)
                                if (memcmp (jamo_initial_short_name[index1], p1, n1) == 0
                                    && jamo_initial_short_name[index1][n1] == '\0')
                                  {
                                    unsigned int index2;

                                    for (index2 = 0; index2 < 21; index2++)
                                      if (memcmp (jamo_medial_short_name[index2], p2, n2) == 0
                                          && jamo_medial_short_name[index2][n2] == '\0')
                                        {
                                          unsigned int index3;

                                          for (index3 = 0; index3 < 28; index3++)
                                            if (memcmp (jamo_final_short_name[index3], p3, n3) == 0
                                                && jamo_final_short_name[index3][n3] == '\0')
                                              {
                                                return 0xAC00 + (index1 * 21 + index2) * 28 + index3;
                                              }
                                          break;
                                        }
                                    break;
                                  }
                            }
                        }
                    }
                  /* Special case for CJK compatibility ideographs. Keeps the
                     tables small.  */
                  if (wordptr == &words[2]
                      && words[0] == UNICODE_CHARNAME_WORD_CJK
                      && words[1] == UNICODE_CHARNAME_WORD_COMPATIBILITY
                      && p1 + 14 <= ptr
                      && p1 + 15 >= ptr
                      && memcmp (p1, "IDEOGRAPH-", 10) == 0)
                    {
                      const char *p2 = p1 + 10;

                      if (*p2 != '0')
                        {
                          unsigned int c = 0;

                          for (;;)
                            {
                              if (*p2 >= '0' && *p2 <= '9')
                                c += (*p2 - '0');
                              else if (*p2 >= 'A' && *p2 <= 'F')
                                c += (*p2 - 'A' + 10);
                              else
                                break;
                              p2++;
                              if (p2 == ptr)
                                {
                                  if ((c >= 0xF900 && c <= 0xFA2D)
                                      || (c >= 0xFA30 && c <= 0xFA6A)
                                      || (c >= 0xFA70 && c <= 0xFAD9)
                                      || (c >= 0x2F800 && c <= 0x2FA1D))
                                    return c;
                                  else
                                    break;
                                }
                              c = c << 4;
                            }
                        }
                    }
                  /* Special case for variation selectors. Keeps the
                     tables small.  */
                  if (wordptr == &words[1]
                      && words[0] == UNICODE_CHARNAME_WORD_VARIATION
                      && p1 + 10 <= ptr
                      && p1 + 12 >= ptr
                      && memcmp (p1, "SELECTOR-", 9) == 0)
                    {
                      const char *p2 = p1 + 9;

                      if (*p2 != '0')
                        {
                          unsigned int c = 0;

                          for (;;)
                            {
                              if (*p2 >= '0' && *p2 <= '9')
                                c += (*p2 - '0');
                              p2++;
                              if (p2 == ptr)
                                {
                                  if (c >= 1 && c <= 16)
                                    return c - 1 + 0xFE00;
                                  else if (c >= 17 && c <= 256)
                                    return c - 17 + 0xE0100;
                                  else
                                    break;
                                }
                              c = c * 10;
                            }
                        }
                    }
                }
            }
            if (false)
            filled_words:
              {
                /* Multiply by 2, to simplify later comparisons.  */
                unsigned int words_length = wordptr - words;
                {
                  int i = words_length - 1;
                  words[i] = 2 * words[i];
                  for (; --i >= 0; )
                    words[i] = 2 * words[i] + 1;
                }
                /* Binary search in unicode_name_to_index.  */
                {
                  unsigned int i1 = 0;
                  unsigned int i2 = SIZEOF (unicode_name_to_index);
                  for (;;)
                    {
                      unsigned int i = (i1 + i2) >> 1;
                      const uint16_t *w = words;
                      const uint16_t *p = &unicode_names[unicode_name_to_index[i].name];
                      unsigned int n = words_length;
                      for (;;)
                        {
                          if (*p < *w)
                            {
                              if (i1 == i)
                                goto name_not_found;
                              /* Note here: i1 < i < i2.  */
                              i1 = i;
                              break;
                            }
                          else if (*p > *w)
                            {
                              if (i2 == i)
                                goto name_not_found;
                              /* Note here: i1 <= i < i2.  */
                              i2 = i;
                              break;
                            }
                          p++; w++; n--;
                          if (n == 0)
                            return unicode_index_to_code (unicode_name_to_index[i].index);
                        }
                    }
                }
              name_not_found: ;
              }
          }
        }
    }
  return UNINAME_INVALID;
}
