/*

 * 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

hb_buffer_t::reverse_clusters (void)

{

  unsigned int i, start, count, last_cluster;

  if (unlikely (!len))

    return;

  reverse ();

  count = len;

  start = 0;

  last_cluster = info[0].cluster;

  for (i = 1; i < count; i++) {

    if (last_cluster != info[i].cluster) {

      reverse_range (start, i);

      start = i;

      last_cluster = info[i].cluster;

    }

  }

  reverse_range (start, i);

}

void

hb_buffer_t::merge_clusters_impl (unsigned int start,

				  unsigned int end)

{

  if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_CHARACTERS)

    return;

  uint32_t cluster = info[start].cluster;

  for (unsigned int i = start + 1; i < end; i++)

    cluster = MIN (cluster, info[i].cluster);

  /* Extend end */

  while (end < len && info[end - 1].cluster == info[end].cluster)

    end++;

  /* Extend start */

  while (idx < start && info[start - 1].cluster == info[start].cluster)

    start--;

  /* If we hit the start of buffer, continue in out-buffer. */

  if (idx == start)

    for (unsigned int i = out_len; i && out_info[i - 1].cluster == info[start].cluster; i--)

      out_info[i - 1].cluster = cluster;

  for (unsigned int i = start; i < end; i++)

    info[i].cluster = cluster;

}

void

hb_buffer_t::merge_out_clusters (unsigned int start,

				 unsigned int end)

{

  if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_CHARACTERS)

    return;

  if (unlikely (end - start < 2))

    return;

  uint32_t cluster = out_info[start].cluster;

  for (unsigned int i = start + 1; i < end; i++)

    cluster = MIN (cluster, out_info[i].cluster);

  /* Extend start */

  while (start && out_info[start - 1].cluster == out_info[start].cluster)

    start--;

  /* Extend end */

  while (end < out_len && out_info[end - 1].cluster == out_info[end].cluster)

    end++;

  /* If we hit the end of out-buffer, continue in buffer. */

  if (end == out_len)

    for (unsigned int i = idx; i < len && info[i].cluster == out_info[end - 1].cluster; i++)

      info[i].cluster = cluster;

  for (unsigned int i = start; i < end; i++)

    out_info[i].cluster = cluster;

}

void

hb_buffer_t::delete_glyph ()

{

  unsigned int cluster = info[idx].cluster;

  if (idx + 1 < len && cluster == info[idx + 1].cluster)

  {

    /* Cluster survives; do nothing. */

    goto done;

  }

  if (out_len)

  {

    /* Merge cluster backward. */

    if (cluster < out_info[out_len - 1].cluster)

    {

      unsigned int old_cluster = out_info[out_len - 1].cluster;

      for (unsigned i = out_len; i && out_info[i - 1].cluster == old_cluster; i--)

	out_info[i - 1].cluster = cluster;

    }

    goto done;

  }

  if (idx + 1 < len)

  {

    /* Merge cluster forward. */

    merge_clusters (idx, idx + 2);

    goto done;

  }

done:

  skip_glyph ();

}

void

hb_buffer_t::guess_segment_properties (void)

{

  assert (content_type == HB_BUFFER_CONTENT_TYPE_UNICODE ||

	  (!len && content_type == HB_BUFFER_CONTENT_TYPE_INVALID));

  /* If script is set to INVALID, guess from buffer contents */

  if (props.script == HB_SCRIPT_INVALID) {

    for (unsigned int i = 0; i < len; i++) {

      hb_script_t script = unicode->script (info[i].codepoint);

      if (likely (script != HB_SCRIPT_COMMON &&

		  script != HB_SCRIPT_INHERITED &&

		  script != HB_SCRIPT_UNKNOWN)) {

        props.script = script;

        break;

      }

    }

  }

  /* If direction is set to INVALID, guess from script */

  if (props.direction == HB_DIRECTION_INVALID) {

    props.direction = hb_script_get_horizontal_direction (props.script);

  }

  /* If language is not set, use default language from locale */

  if (props.language == HB_LANGUAGE_INVALID) {

    /* TODO get_default_for_script? using $LANGUAGE */

    props.language = hb_language_get_default ();

  }

}

/* Public API */

/**

 * hb_buffer_create: (Xconstructor)

 *

 * Creates a new #hb_buffer_t with all properties to defaults.

 *

 * Return value: (transfer full):

 * A newly allocated #hb_buffer_t with a reference count of 1. The initial

 * reference count should be released with hb_buffer_destroy() when you are done

 * using the #hb_buffer_t. This function never returns %NULL. If memory cannot

 * be allocated, a special #hb_buffer_t object will be returned on which

 * hb_buffer_allocation_successful() returns %false.

 *

 * Since: 0.9.2

 **/

hb_buffer_t *

hb_buffer_create (void)

{

  hb_buffer_t *buffer;

  if (!(buffer = hb_object_create<hb_buffer_t> ()))

    return hb_buffer_get_empty ();

  buffer->max_len = HB_BUFFER_MAX_LEN_DEFAULT;

  buffer->reset ();

  return buffer;

}

/**

 * hb_buffer_get_empty:

 *

 * 

 *

 * Return value: (transfer full):

 *

 * Since: 0.9.2

 **/

hb_buffer_t *

hb_buffer_get_empty (void)

{

  static const hb_buffer_t _hb_buffer_nil = {

    HB_OBJECT_HEADER_STATIC,

    const_cast<hb_unicode_funcs_t *> (&_hb_unicode_funcs_nil),

    HB_BUFFER_FLAG_DEFAULT,

    HB_BUFFER_CLUSTER_LEVEL_DEFAULT,

    HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT,

    HB_BUFFER_SCRATCH_FLAG_DEFAULT,

    HB_BUFFER_MAX_LEN_DEFAULT,

    HB_BUFFER_CONTENT_TYPE_INVALID,

    HB_SEGMENT_PROPERTIES_DEFAULT,

    true, /* in_error */

    true, /* have_output */

    true  /* have_positions */

    /* Zero is good enough for everything else. */

  };

  return const_cast<hb_buffer_t *> (&_hb_buffer_nil);

}

/**

 * hb_buffer_reference: (skip)

 * @buffer: an #hb_buffer_t.

 *

 * Increases the reference count on @buffer by one. This prevents @buffer from

 * being destroyed until a matching call to hb_buffer_destroy() is made.

 *

 * Return value: (transfer full):

 * The referenced #hb_buffer_t.

 *

 * Since: 0.9.2

 **/

hb_buffer_t *

hb_buffer_reference (hb_buffer_t *buffer)

{

  return hb_object_reference (buffer);

}

/**

 * hb_buffer_destroy: (skip)

 * @buffer: an #hb_buffer_t.

 *

 * Deallocate the @buffer.

 * Decreases the reference count on @buffer by one. If the result is zero, then

 * @buffer and all associated resources are freed. See hb_buffer_reference().

 *

 * Since: 0.9.2

 **/

void

hb_buffer_destroy (hb_buffer_t *buffer)

{

  if (!hb_object_destroy (buffer)) return;

  hb_unicode_funcs_destroy (buffer->unicode);

  free (buffer->info);

  free (buffer->pos);

  if (buffer->message_destroy)

    buffer->message_destroy (buffer->message_data);

  free (buffer);

}

/**

 * hb_buffer_set_user_data: (skip)

 * @buffer: an #hb_buffer_t.

 * @key: 

 * @data: 

 * @destroy: 

 * @replace: 

 *

 * 

 *

 * Return value: 

 *

 * Since: 0.9.2

 **/

hb_bool_t

hb_buffer_set_user_data (hb_buffer_t        *buffer,

			 hb_user_data_key_t *key,

			 void *              data,

			 hb_destroy_func_t   destroy,

			 hb_bool_t           replace)

{

  return hb_object_set_user_data (buffer, key, data, destroy, replace);

}

/**

 * hb_buffer_get_user_data: (skip)

 * @buffer: an #hb_buffer_t.

 * @key: 

 *

 * 

 *

 * Return value: 

 *

 * Since: 0.9.2

 **/

void *

hb_buffer_get_user_data (hb_buffer_t        *buffer,

			 hb_user_data_key_t *key)

{

  return hb_object_get_user_data (buffer, key);

}

/**

 * hb_buffer_set_content_type:

 * @buffer: an #hb_buffer_t.

 * @content_type: the type of buffer contents to set

 *

 * Sets the type of @buffer contents, buffers are either empty, contain

 * characters (before shaping) or glyphs (the result of shaping).

 *

 * Since: 0.9.5

 **/

void

hb_buffer_set_content_type (hb_buffer_t              *buffer,

			    hb_buffer_content_type_t  content_type)

{

  buffer->content_type = content_type;

}

/**

 * hb_buffer_get_content_type:

 * @buffer: an #hb_buffer_t.

 *

 * see hb_buffer_set_content_type().

 *

 * Return value:

 * The type of @buffer contents.

 *

 * Since: 0.9.5

 **/

hb_buffer_content_type_t

hb_buffer_get_content_type (hb_buffer_t *buffer)

{

  return buffer->content_type;

}

/**

 * hb_buffer_set_unicode_funcs:

 * @buffer: an #hb_buffer_t.

 * @unicode_funcs: 

 *

 * 

 *

 * Since: 0.9.2

 **/

void

hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,

			     hb_unicode_funcs_t *unicode_funcs)

{

  if (unlikely (hb_object_is_inert (buffer)))

    return;

  if (!unicode_funcs)

    unicode_funcs = hb_unicode_funcs_get_default ();

  hb_unicode_funcs_reference (unicode_funcs);

  hb_unicode_funcs_destroy (buffer->unicode);

  buffer->unicode = unicode_funcs;