/*

 * Copyright © 1998-2004  David Turner and Werner Lemberg

 * Copyright © 2004,2007,2009,2010  Red Hat, Inc.

 * Copyright © 2011,2012  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Red Hat Author(s): Owen Taylor, Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#include "hb-buffer-private.hh"

#include "hb-utf-private.hh"

#ifndef HB_DEBUG_BUFFER

#define HB_DEBUG_BUFFER (HB_DEBUG+0)

#endif

/**

 * SECTION: hb-buffer

 * @title: Buffers

 * @short_description: Input and output buffers

 * @include: hb.h

 *

 * Buffers serve dual role in HarfBuzz; they hold the input characters that are

 * passed hb_shape(), and after shaping they hold the output glyphs.

 **/

/**

 * hb_segment_properties_equal:

 * @a: first #hb_segment_properties_t to compare.

 * @b: second #hb_segment_properties_t to compare.

 *

 * Checks the equality of two #hb_segment_properties_t's.

 *

 * Return value:

 * %true if all properties of @a equal those of @b, false otherwise.

 *

 * Since: 0.9.7

 **/

hb_bool_t

hb_segment_properties_equal (const hb_segment_properties_t *a,

                             const hb_segment_properties_t *b)

{

  return a->direction == b->direction &&

         a->script    == b->script    &&

         a->language  == b->language  &&

         a->reserved1 == b->reserved1 &&

         a->reserved2 == b->reserved2;

}

/**

 * hb_segment_properties_hash:

 * @p: #hb_segment_properties_t to hash.

 *

 * Creates a hash representing @p.

 *

 * Return value:

 * A hash of @p.

 *

 * Since: 0.9.7

 **/

unsigned int

hb_segment_properties_hash (const hb_segment_properties_t *p)

{

  return (unsigned int) p->direction ^

         (unsigned int) p->script ^

         (intptr_t) (p->language);

}

/* Here is how the buffer works internally:

 *

 * There are two info pointers: info and out_info.  They always have

 * the same allocated size, but different lengths.

 *

 * As an optimization, both info and out_info may point to the

 * same piece of memory, which is owned by info.  This remains the

 * case as long as out_len doesn't exceed i at any time.

 * In that case, swap_buffers() is no-op and the glyph operations operate

 * mostly in-place.

 *

 * As soon as out_info gets longer than info, out_info is moved over

 * to an alternate buffer (which we reuse the pos buffer for!), and its

 * current contents (out_len entries) are copied to the new place.

 * This should all remain transparent to the user.  swap_buffers() then

 * switches info and out_info.

 */

/* Internal API */

bool

hb_buffer_t::enlarge (unsigned int size)

{

  if (unlikely (in_error))

    return false;

  if (unlikely (size > max_len))

  {

    in_error = true;

    return false;

  }

  unsigned int new_allocated = allocated;

  hb_glyph_position_t *new_pos = NULL;

  hb_glyph_info_t *new_info = NULL;

  bool separate_out = out_info != info;

  if (unlikely (_hb_unsigned_int_mul_overflows (size, sizeof (info[0]))))

    goto done;

  while (size >= new_allocated)

    new_allocated += (new_allocated >> 1) + 32;

  ASSERT_STATIC (sizeof (info[0]) == sizeof (pos[0]));

  if (unlikely (_hb_unsigned_int_mul_overflows (new_allocated, sizeof (info[0]))))

    goto done;

  new_pos = (hb_glyph_position_t *) realloc (pos, new_allocated * sizeof (pos[0]));

  new_info = (hb_glyph_info_t *) realloc (info, new_allocated * sizeof (info[0]));

done:

  if (unlikely (!new_pos || !new_info))

    in_error = true;

  if (likely (new_pos))

    pos = new_pos;

  if (likely (new_info))

    info = new_info;

  out_info = separate_out ? (hb_glyph_info_t *) pos : info;

  if (likely (!in_error))

    allocated = new_allocated;

  return likely (!in_error);

}

bool

hb_buffer_t::make_room_for (unsigned int num_in,

                            unsigned int num_out)

{

  if (unlikely (!ensure (out_len + num_out))) return false;

  if (out_info == info &&

      out_len + num_out > idx + num_in)

  {

    assert (have_output);

    out_info = (hb_glyph_info_t *) pos;

    memcpy (out_info, info, out_len * sizeof (out_info[0]));

  }

  return true;

}

bool

hb_buffer_t::shift_forward (unsigned int count)

{

  assert (have_output);

  if (unlikely (!ensure (len + count))) return false;

  memmove (info + idx + count, info + idx, (len - idx) * sizeof (info[0]));

  if (idx + count > len)

  {

    /* Under memory failure we might expose this area.  At least

     * clean it up.  Oh well... */

    memset (info + len, 0, (idx + count - len) * sizeof (info[0]));

  }

  len += count;

  idx += count;

  return true;

}

hb_buffer_t::scratch_buffer_t *

hb_buffer_t::get_scratch_buffer (unsigned int *size)

{

  have_output = false;

  have_positions = false;

  out_len = 0;

  out_info = info;

  assert ((uintptr_t) pos % sizeof (scratch_buffer_t) == 0);

  *size = allocated * sizeof (pos[0]) / sizeof (scratch_buffer_t);

  return (scratch_buffer_t *) (void *) pos;

}

/* HarfBuzz-Internal API */

void

hb_buffer_t::reset (void)

{

  if (unlikely (hb_object_is_inert (this)))

    return;

  hb_unicode_funcs_destroy (unicode);

  unicode = hb_unicode_funcs_get_default ();

  flags = HB_BUFFER_FLAG_DEFAULT;

  replacement = HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT;

  clear ();

}

void

hb_buffer_t::clear (void)

{

  if (unlikely (hb_object_is_inert (this)))

    return;

  hb_segment_properties_t default_props = HB_SEGMENT_PROPERTIES_DEFAULT;

  props = default_props;

  scratch_flags = HB_BUFFER_SCRATCH_FLAG_DEFAULT;

  content_type = HB_BUFFER_CONTENT_TYPE_INVALID;

  in_error = false;

  have_output = false;

  have_positions = false;

  idx = 0;

  len = 0;

  out_len = 0;

  out_info = info;

  serial = 0;

  memset (context, 0, sizeof context);

  memset (context_len, 0, sizeof context_len);

  deallocate_var_all ();

}

void

hb_buffer_t::add (hb_codepoint_t  codepoint,

                  unsigned int    cluster)

{

  hb_glyph_info_t *glyph;

  if (unlikely (!ensure (len + 1))) return;

  glyph = &info[len];

  memset (glyph, 0, sizeof (*glyph));

  glyph->codepoint = codepoint;

  glyph->mask = 1;

  glyph->cluster = cluster;

  len++;

}

void

hb_buffer_t::add_info (const hb_glyph_info_t &glyph_info)

{

  if (unlikely (!ensure (len + 1))) return;

  info[len] = glyph_info;

  len++;

}

void

hb_buffer_t::remove_output (void)

{

  if (unlikely (hb_object_is_inert (this)))

    return;

  have_output = false;

  have_positions = false;

  out_len = 0;

  out_info = info;

}

void

hb_buffer_t::clear_output (void)

{

  if (unlikely (hb_object_is_inert (this)))

    return;

  have_output = true;

  have_positions = false;

  out_len = 0;

  out_info = info;

}

void

hb_buffer_t::clear_positions (void)

{

  if (unlikely (hb_object_is_inert (this)))

    return;

  have_output = false;

  have_positions = true;

  out_len = 0;

  out_info = info;

  memset (pos, 0, sizeof (pos[0]) * len);

}

void

hb_buffer_t::swap_buffers (void)

{

  if (unlikely (in_error)) return;

  assert (have_output);

  have_output = false;

  if (out_info != info)

  {

    hb_glyph_info_t *tmp_string;

    tmp_string = info;

    info = out_info;

    out_info = tmp_string;

    pos = (hb_glyph_position_t *) out_info;

  }

  unsigned int tmp;

  tmp = len;

  len = out_len;

  out_len = tmp;

  idx = 0;

}

void

hb_buffer_t::replace_glyphs (unsigned int num_in,

                             unsigned int num_out,

                             const uint32_t *glyph_data)

{

  if (unlikely (!make_room_for (num_in, num_out))) return;

  merge_clusters (idx, idx + num_in);

  hb_glyph_info_t orig_info = info[idx];

  hb_glyph_info_t *pinfo = &out_info[out_len];

  for (unsigned int i = 0; i < num_out; i++)

  {

    *pinfo = orig_info;

    pinfo->codepoint = glyph_data[i];

    pinfo++;

  }

  idx  += num_in;

  out_len += num_out;

}

void

hb_buffer_t::output_glyph (hb_codepoint_t glyph_index)

{

  if (unlikely (!make_room_for (0, 1))) return;

  out_info[out_len] = info[idx];

  out_info[out_len].codepoint = glyph_index;

  out_len++;

}

void

hb_buffer_t::output_info (const hb_glyph_info_t &glyph_info)

{

  if (unlikely (!make_room_for (0, 1))) return;

  out_info[out_len] = glyph_info;

  out_len++;

}

void

hb_buffer_t::copy_glyph (void)

{

  if (unlikely (!make_room_for (0, 1))) return;

  out_info[out_len] = info[idx];

  out_len++;

}

bool

hb_buffer_t::move_to (unsigned int i)

{

  if (!have_output)

  {

    assert (i <= len);

    idx = i;

    return true;

  }

  if (unlikely (in_error))

    return false;

  assert (i <= out_len + (len - idx));

  if (out_len < i)

  {

    unsigned int count = i - out_len;

    if (unlikely (!make_room_for (count, count))) return false;

    memmove (out_info + out_len, info + idx, count * sizeof (out_info[0]));

    idx += count;

    out_len += count;

  }

  else if (out_len > i)

  {

    /* Tricky part: rewinding... */

    unsigned int count = out_len - i;

    /* This will blow in our face if memory allocation fails later

     * in this same lookup... */

    if (unlikely (idx < count && !shift_forward (count + 32))) return false;

    assert (idx >= count);

    idx -= count;

    out_len -= count;

    memmove (info + idx, out_info + out_len, count * sizeof (out_info[0]));

  }

  return true;

}

void

hb_buffer_t::replace_glyph (hb_codepoint_t glyph_index)

{

  if (unlikely (out_info != info || out_len != idx)) {

    if (unlikely (!make_room_for (1, 1))) return;

    out_info[out_len] = info[idx];

  }

  out_info[out_len].codepoint = glyph_index;

  idx++;

  out_len++;

}

void

hb_buffer_t::set_masks (hb_mask_t    value,

                        hb_mask_t    mask,

                        unsigned int cluster_start,

                        unsigned int cluster_end)

{

  hb_mask_t not_mask = ~mask;

  value &= mask;

  if (!mask)

    return;

  if (cluster_start == 0 && cluster_end == (unsigned int)-1) {

    unsigned int count = len;

    for (unsigned int i = 0; i < count; i++)

      info[i].mask = (info[i].mask & not_mask) | value;

    return;

  }

  unsigned int count = len;

  for (unsigned int i = 0; i < count; i++)

    if (cluster_start <= info[i].cluster && info[i].cluster < cluster_end)

      info[i].mask = (info[i].mask & not_mask) | value;

}

void

hb_buffer_t::reverse_range (unsigned int start,

                            unsigned int end)

{

  unsigned int i, j;

  if (end - start < 2)

    return;

  for (i = start, j = end - 1; i < j; i++, j--) {

    hb_glyph_info_t t;

    t = info[i];

    info[i] = info[j];

    info[j] = t;

  }

  if (have_positions) {

    for (i = start, j = end - 1; i < j; i++, j--) {

      hb_glyph_position_t t;

      t = pos[i];

      pos[i] = pos[j];

      pos[j] = t;

    }

  }

}

void

hb_buffer_t::reverse (void)

{

  if (unlikely (!len))

    return;

  reverse_range (0, len);

}

void