/*
 * Copyright (C) 2003 Red Hat Software
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * This 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 2.1 of the License, or (at your option) any later version.
 *
 * This 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 this library; if not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include <glib.h>
#include <glib-object.h>
#include <pango2/pango.h>

G_BEGIN_DECLS


/* String interning for static strings */
#define I_(string) g_intern_static_string (string)

/* We define these functions static here because we don't want to add public API
 * for them (if anything, it belongs to glib, but glib found it trivial enough
 * not to add API for).  At some point metrics calculations will be
 * centralized and this mess can be minimized.  Or so I hope.
 */

static inline G_GNUC_UNUSED int
pango2_unichar_width (gunichar c)
{
  return G_UNLIKELY (g_unichar_iszerowidth (c)) ? 0 :
           G_UNLIKELY (g_unichar_iswide (c)) ? 2 : 1;
}

static G_GNUC_UNUSED glong
pango2_utf8_strwidth (const char *p)
{
  glong len = 0;
  g_return_val_if_fail (p != NULL, 0);

  while (*p)
    {
      len += pango2_unichar_width (g_utf8_get_char (p));
      p = g_utf8_next_char (p);
    }

  return len;
}

/* Glib's g_utf8_strlen() is broken and stops at embedded NUL's.
 * Wrap it here. */
static G_GNUC_UNUSED glong
pango2_utf8_strlen (const char *p,
                    gssize      max)
{
  glong len = 0;
  const char *start = p;
  g_return_val_if_fail (p != NULL || max == 0, 0);

  if (max <= 0)
    return g_utf8_strlen (p, max);

  p = g_utf8_next_char (p);
  while (p - start < max)
    {
      ++len;
      p = g_utf8_next_char (p);
    }

  /* only do the last len increment if we got a complete
   * char (don't count partial chars)
   */
  if (p - start <= max)
    ++len;

  return len;
}


/* To be made public at some point */

static G_GNUC_UNUSED void
pango2_glyph_string_reverse_range (Pango2GlyphString *glyphs,
                                   int                start,
                                   int                end)
{
  int i, j;

  for (i = start, j = end - 1; i < j; i++, j--)
    {
      Pango2GlyphInfo glyph_info;
      int log_cluster;

      glyph_info = glyphs->glyphs[i];
      glyphs->glyphs[i] = glyphs->glyphs[j];
      glyphs->glyphs[j] = glyph_info;

      log_cluster = glyphs->log_clusters[i];
      glyphs->log_clusters[i] = glyphs->log_clusters[j];
      glyphs->log_clusters[j] = log_cluster;
    }
}

static inline gboolean
pango2_is_default_ignorable (gunichar ch)
{
  int plane = ch >> 16;

  if (G_LIKELY (plane == 0))
    {
      int page = ch >> 8;
      switch (page)
        {
        case 0x00: return ch == 0x00ad;
        case 0x03: return ch == 0x034f;
        case 0x06: return ch == 0x061c;
        case 0x17: return (0x17b4 <= ch && ch <= 0x17b5);
        case 0x18: return (0x180b <= ch && ch <= 0x180e);
        case 0x20: return (0x200b <= ch && ch <= 0x200f) ||
                          (0x202a <= ch && ch <= 0x202e) ||
                          (0x2060 <= ch && ch <= 0x206f);
        case 0xfe: return (0xfe00 <= ch && ch <= 0xfe0f) || ch == 0xfeff;
        case 0xff: return (0xfff0 <= ch && ch <= 0xfff8);
        default: return FALSE;
      }
    }
  else
    {
      /* Other planes */
      switch (plane)
        {
        case 0x01: return (0x1d173 <= ch && ch <= 0x1d17a);
        case 0x0e: return (0xe0000 <= ch && ch <= 0xe0fff);
        default: return FALSE;
        }
    }
}

/* These are the default ignorables that we render as hexboxes
 * with nicks if PANGO2_SHOW_IGNORABLES is used.
 *
 * The cairo hexbox drawing code assumes that these nicks are
 * 1-6 ASCII chars
 */
static struct {
  gunichar ch;
  const char *nick;
} ignorables[] = {
  { 0x00ad, "SHY"   }, /* SOFT HYPHEN */
  { 0x034f, "CGJ"   }, /* COMBINING GRAPHEME JOINER */
  { 0x061c, "ALM"   }, /* ARABIC LETTER MARK */
  { 0x200b, "ZWS"   }, /* ZERO WIDTH SPACE */
  { 0x200c, "ZWNJ"  }, /* ZERO WIDTH NON-JOINER */
  { 0x200d, "ZWJ"   }, /* ZERO WIDTH JOINER */
  { 0x200e, "LRM"   }, /* LEFT-TO-RIGHT MARK */
  { 0x200f, "RLM"   }, /* RIGHT-TO-LEFT MARK */
  { 0x2028, "LS"    }, /* LINE SEPARATOR */
  { 0x2029, "PS"    }, /* PARAGRAPH SEPARATOR */
  { 0x202a, "LRE"   }, /* LEFT-TO-RIGHT EMBEDDING */
  { 0x202b, "RLE"   }, /* RIGHT-TO-LEFT EMBEDDING */
  { 0x202c, "PDF"   }, /* POP DIRECTIONAL FORMATTING */
  { 0x202d, "LRO"   }, /* LEFT-TO-RIGHT OVERRIDE */
  { 0x202e, "RLO"   }, /* RIGHT-TO-LEFT OVERRIDE */
  { 0x2060, "WJ"    }, /* WORD JOINER */
  { 0x2061, "FA"    }, /* FUNCTION APPLICATION */
  { 0x2062, "IT"    }, /* INVISIBLE TIMES */
  { 0x2063, "IS"    }, /* INVISIBLE SEPARATOR */
  { 0x2066, "LRI"   }, /* LEFT-TO-RIGHT ISOLATE */
  { 0x2067, "RLI"   }, /* RIGHT-TO-LEFT ISOLATE */
  { 0x2068, "FSI"   }, /* FIRST STRONG ISOLATE */
  { 0x2069, "PDI"   }, /* POP DIRECTIONAL ISOLATE */
  { 0xfeff, "ZWNBS" }, /* ZERO WIDTH NO-BREAK SPACE */
};

static inline G_GNUC_UNUSED const char *
pango2_get_ignorable (gunichar ch)
{
  for (guint i = 0; i < G_N_ELEMENTS (ignorables); i++)
    {
      if (ch < ignorables[i].ch)
        return NULL;

      if (ch == ignorables[i].ch)
        return ignorables[i].nick;
    }

  return NULL;
}

static inline G_GNUC_UNUSED const char *
pango2_get_ignorable_size (gunichar  ch,
                           int      *rows,
                           int      *cols)
{
  const char *nick;
  int len;

  nick = pango2_get_ignorable (ch);
  if (nick)
    {
      len = strlen (nick);
      if (len < 4)
        {
          *rows = 1;
          *cols = len;
        }
      else if (len > 4)
        {
          *rows = 2;
          *cols = 3;
         }
       else
        {
          *rows = 2;
          *cols = 2;
        }
    }

  return nick;
}

/* Backward compatibility shim, to avoid bumping up the minimum
 * required version of GLib; most of our uses of g_memdup() are
 * safe, and those that aren't have been fixed
 */
#if !GLIB_CHECK_VERSION (2, 67, 3)
# define g_memdup2(mem,size)    g_memdup((mem),(size))
#endif

G_END_DECLS