/* decomp.c - Character decomposition.

 *

 *  Copyright (C) 1999, 2000 Tom Tromey

 *  Copyright 2000 Red Hat, Inc.

 * Portions copyright (c) 2006-2009 Nokia Corporation.  All rights reserved.

 *

 * The Gnome Library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2 of the

 * License, or (at your option) any later version.

 *

 * The Gnome Library 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 the Gnome Library; see the file COPYING.LIB.  If not,

 * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 *   Boston, MA 02111-1307, USA.

 */

#include "config.h"

#include <stdlib.h>

#include "glib.h"

#include "gunidecomp.h"

#include "gunicomp.h"

#include "gunicodeprivate.h"

#include "galias.h"

#define CC_PART1(Page, Char) \

  ((combining_class_table_part1[Page] >= G_UNICODE_MAX_TABLE_INDEX) \

   ? (combining_class_table_part1[Page] - G_UNICODE_MAX_TABLE_INDEX) \

   : (cclass_data[combining_class_table_part1[Page]][Char]))

#define CC_PART2(Page, Char) \

  ((combining_class_table_part2[Page] >= G_UNICODE_MAX_TABLE_INDEX) \

   ? (combining_class_table_part2[Page] - G_UNICODE_MAX_TABLE_INDEX) \

   : (cclass_data[combining_class_table_part2[Page]][Char]))

#define COMBINING_CLASS(Char) \

  (((Char) <= G_UNICODE_LAST_CHAR_PART1) \

   ? CC_PART1 ((Char) >> 8, (Char) & 0xff) \

   : (((Char) >= 0xe0000 && (Char) <= G_UNICODE_LAST_CHAR) \

      ? CC_PART2 (((Char) - 0xe0000) >> 8, (Char) & 0xff) \

      : 0))

/**

 * g_unichar_combining_class:

 * @uc: a Unicode character

 * 

 * Determines the canonical combining class of a Unicode character.

 * 

 * Return value: the combining class of the character

 *

 * Since: 2.14

 **/

EXPORT_C gint

g_unichar_combining_class (gunichar uc)

{

  return COMBINING_CLASS (uc);

}

/* constants for hangul syllable [de]composition */

#define SBase 0xAC00 

#define LBase 0x1100 

#define VBase 0x1161 

#define TBase 0x11A7

#define LCount 19 

#define VCount 21

#define TCount 28

#define NCount (VCount * TCount)

#define SCount (LCount * NCount)

/**

 * g_unicode_canonical_ordering:

 * @string: a UCS-4 encoded string.

 * @len: the maximum length of @string to use.

 *

 * Computes the canonical ordering of a string in-place.  

 * This rearranges decomposed characters in the string 

 * according to their combining classes.  See the Unicode 

 * manual for more information. 

 **/

EXPORT_C void

g_unicode_canonical_ordering (gunichar *string,

			      gsize     len)

{

  gsize i;

  int swap = 1;

  while (swap)

    {

      int last;

      swap = 0;

      last = COMBINING_CLASS (string[0]);

      for (i = 0; i < len - 1; ++i)

	{

	  int next = COMBINING_CLASS (string[i + 1]);

	  if (next != 0 && last > next)

	    {

	      gsize j;

	      /* Percolate item leftward through string.  */

	      for (j = i + 1; j > 0; --j)

		{

		  gunichar t;

		  if (COMBINING_CLASS (string[j - 1]) <= next)

		    break;

		  t = string[j];

		  string[j] = string[j - 1];

		  string[j - 1] = t;

		  swap = 1;

		}

	      /* We're re-entering the loop looking at the old

		 character again.  */

	      next = last;

	    }

	  last = next;

	}

    }

}

/* http://www.unicode.org/unicode/reports/tr15/#Hangul

 * r should be null or have sufficient space. Calling with r == NULL will

 * only calculate the result_len; however, a buffer with space for three

 * characters will always be big enough. */

static void

decompose_hangul (gunichar s, 

                  gunichar *r,

                  gsize *result_len)

{

  gint SIndex = s - SBase;

  /* not a hangul syllable */

  if (SIndex < 0 || SIndex >= SCount)

    {

      if (r)

        r[0] = s;

      *result_len = 1;

    }

  else

    {

      gunichar L = LBase + SIndex / NCount;

      gunichar V = VBase + (SIndex % NCount) / TCount;

      gunichar T = TBase + SIndex % TCount;

      if (r)

        {

          r[0] = L;

          r[1] = V;

        }

      if (T != TBase) 

        {

          if (r)

            r[2] = T;

          *result_len = 3;

        }

      else

        *result_len = 2;

    }

}

/* returns a pointer to a null-terminated UTF-8 string */

static const gchar *

find_decomposition (gunichar ch,

		    gboolean compat)

{

  int start = 0;

  int end = G_N_ELEMENTS (decomp_table);

  if (ch >= decomp_table[start].ch &&

      ch <= decomp_table[end - 1].ch)

    {

      while (TRUE)

	{

	  int half = (start + end) / 2;

	  if (ch == decomp_table[half].ch)

	    {

	      int offset;

	      if (compat)

		{

		  offset = decomp_table[half].compat_offset;

		  if (offset == G_UNICODE_NOT_PRESENT_OFFSET)

		    offset = decomp_table[half].canon_offset;

		}

	      else

		{

		  offset = decomp_table[half].canon_offset;

		  if (offset == G_UNICODE_NOT_PRESENT_OFFSET)

		    return NULL;

		}

	      return &(decomp_expansion_string[offset]);

	    }

	  else if (half == start)

	    break;

	  else if (ch > decomp_table[half].ch)

	    start = half;

	  else

	    end = half;

	}

    }

  return NULL;

}

/**

 * g_unicode_canonical_decomposition:

 * @ch: a Unicode character.

 * @result_len: location to store the length of the return value.

 *

 * Computes the canonical decomposition of a Unicode character.  

 * 

 * Return value: a newly allocated string of Unicode characters.

 *   @result_len is set to the resulting length of the string.

 **/

EXPORT_C gunichar *

g_unicode_canonical_decomposition (gunichar ch,

				   gsize   *result_len)

{

  const gchar *decomp;

  const gchar *p;

  gunichar *r;

  /* Hangul syllable */

  if (ch >= 0xac00 && ch <= 0xd7a3)

    {

      decompose_hangul (ch, NULL, result_len);

      r = g_malloc (*result_len * sizeof (gunichar));

      decompose_hangul (ch, r, result_len);

    }

  else if ((decomp = find_decomposition (ch, FALSE)) != NULL)

    {

      /* Found it.  */

      int i;

      *result_len = g_utf8_strlen (decomp, -1);

      r = g_malloc (*result_len * sizeof (gunichar));

      for (p = decomp, i = 0; *p != '\0'; p = g_utf8_next_char (p), i++)

        r[i] = g_utf8_get_char (p);

    }

  else

    {

      /* Not in our table.  */

      r = g_malloc (sizeof (gunichar));

      *r = ch;

      *result_len = 1;

    }

  /* Supposedly following the Unicode 2.1.9 table means that the

     decompositions come out in canonical order.  I haven't tested

     this, but we rely on it here.  */

  return r;

}

/* L,V => LV and LV,T => LVT  */

static gboolean

combine_hangul (gunichar a,

                gunichar b,

                gunichar *result)

{

  gint LIndex = a - LBase;

  gint SIndex = a - SBase;

  gint VIndex = b - VBase;

  gint TIndex = b - TBase;

  if (0 <= LIndex && LIndex < LCount

      && 0 <= VIndex && VIndex < VCount)

    {

      *result = SBase + (LIndex * VCount + VIndex) * TCount;

      return TRUE;

    }

  else if (0 <= SIndex && SIndex < SCount && (SIndex % TCount) == 0

           && 0 < TIndex && TIndex < TCount)

    {

      *result = a + TIndex;

      return TRUE;

    }

  return FALSE;

}

#define CI(Page, Char) \

  ((compose_table[Page] >= G_UNICODE_MAX_TABLE_INDEX) \

   ? (compose_table[Page] - G_UNICODE_MAX_TABLE_INDEX) \

   : (compose_data[compose_table[Page]][Char]))

#define COMPOSE_INDEX(Char) \

     (((Char >> 8) > (COMPOSE_TABLE_LAST)) ? 0 : CI((Char) >> 8, (Char) & 0xff))

static gboolean

combine (gunichar  a,

	 gunichar  b,

	 gunichar *result)

{

  gushort index_a, index_b;

  if (combine_hangul (a, b, result))

    return TRUE;

  index_a = COMPOSE_INDEX(a);

  if (index_a >= COMPOSE_FIRST_SINGLE_START && index_a < COMPOSE_SECOND_START)

    {

      if (b == compose_first_single[index_a - COMPOSE_FIRST_SINGLE_START][0])

	{

	  *result = compose_first_single[index_a - COMPOSE_FIRST_SINGLE_START][1];

	  return TRUE;

	}

      else

        return FALSE;

    }

  index_b = COMPOSE_INDEX(b);

  if (index_b >= COMPOSE_SECOND_SINGLE_START)

    {

      if (a == compose_second_single[index_b - COMPOSE_SECOND_SINGLE_START][0])

	{

	  *result = compose_second_single[index_b - COMPOSE_SECOND_SINGLE_START][1];

	  return TRUE;

	}

      else

        return FALSE;

    }

  if (index_a >= COMPOSE_FIRST_START && index_a < COMPOSE_FIRST_SINGLE_START &&

      index_b >= COMPOSE_SECOND_START && index_b < COMPOSE_SECOND_SINGLE_START)

    {

      gunichar res = compose_array[index_a - COMPOSE_FIRST_START][index_b - COMPOSE_SECOND_START];

      if (res)

	{

	  *result = res;

	  return TRUE;

	}

    }

  return FALSE;

}

gunichar *

_g_utf8_normalize_wc (const gchar    *str,

		      gssize          max_len,

		      GNormalizeMode  mode)

{

  gsize n_wc;

  gunichar *wc_buffer;

  const char *p;

  gsize last_start;

  gboolean do_compat = (mode == G_NORMALIZE_NFKC ||

			mode == G_NORMALIZE_NFKD);

  gboolean do_compose = (mode == G_NORMALIZE_NFC ||

			 mode == G_NORMALIZE_NFKC);

  n_wc = 0;

  p = str;

  while ((max_len < 0 || p < str + max_len) && *p)

    {

      const gchar *decomp;

      gunichar wc = g_utf8_get_char (p);

      if (wc >= 0xac00 && wc <= 0xd7a3)

        {

          gsize result_len;

          decompose_hangul (wc, NULL, &result_len);

          n_wc += result_len;

        }

      else 

        {

          decomp = find_decomposition (wc, do_compat);

          if (decomp)

            n_wc += g_utf8_strlen (decomp, -1);

          else

            n_wc++;

        }

      p = g_utf8_next_char (p);

    }

  wc_buffer = g_new (gunichar, n_wc + 1);

  last_start = 0;

  n_wc = 0;

  p = str;

  while ((max_len < 0 || p < str + max_len) && *p)

    {

      gunichar wc = g_utf8_get_char (p);

      const gchar *decomp;

      int cc;

      gsize old_n_wc = n_wc;

      if (wc >= 0xac00 && wc <= 0xd7a3)

        {

          gsize result_len;

          decompose_hangul (wc, wc_buffer + n_wc, &result_len);

          n_wc += result_len;

        }

      else

        {

          decomp = find_decomposition (wc, do_compat);

          if (decomp)

            {

              const char *pd;

              for (pd = decomp; *pd != '\0'; pd = g_utf8_next_char (pd))

                wc_buffer[n_wc++] = g_utf8_get_char (pd);

            }

          else

            wc_buffer[n_wc++] = wc;

        }

      if (n_wc > 0)

	{

	  cc = COMBINING_CLASS (wc_buffer[old_n_wc]);

	  if (cc == 0)

	    {

	      g_unicode_canonical_ordering (wc_buffer + last_start, n_wc - last_start);

	      last_start = old_n_wc;

	    }

	}

      p = g_utf8_next_char (p);

    }

  if (n_wc > 0)

    {

      g_unicode_canonical_ordering (wc_buffer + last_start, n_wc - last_start);

      last_start = n_wc;

    }

  wc_buffer[n_wc] = 0;

  /* All decomposed and reordered */ 

  if (do_compose && n_wc > 0)

    {

      gsize i, j;

      int last_cc = 0;

      last_start = 0;

      for (i = 0; i < n_wc; i++)

	{

	  int cc = COMBINING_CLASS (wc_buffer[i]);

	  if (i > 0 &&

	      (last_cc == 0 || last_cc < cc) &&

	      combine (wc_buffer[last_start], wc_buffer[i],

		       &wc_buffer[last_start]))

	    {

	      for (j = i + 1; j < n_wc; j++)

		wc_buffer[j-1] = wc_buffer[j];

	      n_wc--;

	      i--;

	      if (i == last_start)

		last_cc = 0;

	      else

		last_cc = COMBINING_CLASS (wc_buffer[i-1]);

	      continue;

	    }

	  if (cc == 0)

	    last_start = i;

	  last_cc = cc;

	}

    }

  wc_buffer[n_wc] = 0;

  return wc_buffer;

}

/**

 * g_utf8_normalize:

 * @str: a UTF-8 encoded string.

 * @len: length of @str, in bytes, or -1 if @str is nul-terminated.

 * @mode: the type of normalization to perform.

 *

 * Converts a string into canonical form, standardizing

 * such issues as whether a character with an accent

 * is represented as a base character and combining

 * accent or as a single precomposed character. The

 * string has to be valid UTF-8, otherwise %NULL is

 * returned. You should generally call g_utf8_normalize()

 * before comparing two Unicode strings.

 *

 * The normalization mode %G_NORMALIZE_DEFAULT only

 * standardizes differences that do not affect the

 * text content, such as the above-mentioned accent

 * representation. %G_NORMALIZE_ALL also standardizes

 * the "compatibility" characters in Unicode, such

 * as SUPERSCRIPT THREE to the standard forms

 * (in this case DIGIT THREE). Formatting information

 * may be lost but for most text operations such

 * characters should be considered the same.

 *

 * %G_NORMALIZE_DEFAULT_COMPOSE and %G_NORMALIZE_ALL_COMPOSE

 * are like %G_NORMALIZE_DEFAULT and %G_NORMALIZE_ALL,

 * but returned a result with composed forms rather

 * than a maximally decomposed form. This is often

 * useful if you intend to convert the string to

 * a legacy encoding or pass it to a system with

 * less capable Unicode handling.

 *

 * Return value: a newly allocated string, that is the

 *   normalized form of @str, or %NULL if @str is not

 *   valid UTF-8.

 **/

EXPORT_C gchar *

g_utf8_normalize (const gchar    *str,

		  gssize          len,

		  GNormalizeMode  mode)

{

  gunichar *result_wc = _g_utf8_normalize_wc (str, len, mode);

  gchar *result;