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 /*

  * 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

 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;

 }

 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;

   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]));

   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 ();

   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;

   flags = HB_BUFFER_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 (allocated_var_bytes, 0, sizeof allocated_var_bytes);

   memset (allocated_var_owner, 0, sizeof allocated_var_owner);

   memset (context, 0, sizeof context);

   memset (context_len, 0, sizeof context_len);

 }

 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;

   }

   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;

     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 (start == end - 1)

     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 (pos) {

     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 (unsigned int start,

 			     unsigned int end)

 {

   if (unlikely (end - start < 2))

     return;

   unsigned int 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 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 (unlikely (end - start < 2))

     return;

   unsigned int 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 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::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 ();

   }

 }

 static inline void

 dump_var_allocation (const hb_buffer_t *buffer)

 {

   char buf[80];

   for (unsigned int i = 0; i < 8; i++)

     buf[i] = '0' + buffer->allocated_var_bytes[7 - i];

   buf[8] = '\0';

   DEBUG_MSG (BUFFER, buffer,

 	     "Current var allocation: %s",

 	     buf);

 }

 void hb_buffer_t::allocate_var (unsigned int byte_i, unsigned int count, const char *owner)

 {

   assert (byte_i < 8 && byte_i + count <= 8);

   if (DEBUG_ENABLED (BUFFER))

     dump_var_allocation (this);

   DEBUG_MSG (BUFFER, this,

 	     "Allocating var bytes %d..%d for %s",

 	     byte_i, byte_i + count - 1, owner);

   for (unsigned int i = byte_i; i < byte_i + count; i++) {

     assert (!allocated_var_bytes[i]);

     allocated_var_bytes[i]++;

     allocated_var_owner[i] = owner;

   }

 }

 void hb_buffer_t::deallocate_var (unsigned int byte_i, unsigned int count, const char *owner)

 {

   if (DEBUG_ENABLED (BUFFER))

     dump_var_allocation (this);

   DEBUG_MSG (BUFFER, this,

 	     "Deallocating var bytes %d..%d for %s",

 	     byte_i, byte_i + count - 1, owner);

   assert (byte_i < 8 && byte_i + count <= 8);

   for (unsigned int i = byte_i; i < byte_i + count; i++) {

     assert (allocated_var_bytes[i]);

     assert (0 == strcmp (allocated_var_owner[i], owner));

     allocated_var_bytes[i]--;

   }

 }

 void hb_buffer_t::assert_var (unsigned int byte_i, unsigned int count, const char *owner)

 {

   if (DEBUG_ENABLED (BUFFER))

     dump_var_allocation (this);

   DEBUG_MSG (BUFFER, this,

 	     "Asserting var bytes %d..%d for %s",

 	     byte_i, byte_i + count - 1, owner);

   assert (byte_i < 8 && byte_i + count <= 8);

   for (unsigned int i = byte_i; i < byte_i + count; i++) {

     assert (allocated_var_bytes[i]);

     assert (0 == strcmp (allocated_var_owner[i], owner));

   }

 }

 void hb_buffer_t::deallocate_var_all (void)

 {

   memset (allocated_var_bytes, 0, sizeof (allocated_var_bytes));

   memset (allocated_var_owner, 0, sizeof (allocated_var_owner));

 }

 /* Public API */

 /**

  * hb_buffer_create: (Xconstructor)

  *

  * 

  *

  * Return value: (transfer full)

  *

  * Since: 1.0

  **/

 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->reset ();

   return buffer;

 }

 /**

  * hb_buffer_get_empty:

  *

  * 

  *

  * Return value: (transfer full):

  *

  * Since: 1.0

  **/

 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_SEGMENT_PROPERTIES_DEFAULT,

     HB_BUFFER_FLAG_DEFAULT,

     HB_BUFFER_CONTENT_TYPE_INVALID,

     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: a buffer.

  *

  * 

  *

  * Return value: (transfer full):

  *

  * Since: 1.0

  **/

 hb_buffer_t *

 hb_buffer_reference (hb_buffer_t *buffer)

 {

   return hb_object_reference (buffer);

 }

 /**

  * hb_buffer_destroy: (skip)

  * @buffer: a buffer.

  *

  * 

  *

  * Since: 1.0

  **/

 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);

   free (buffer);

 }

 /**

  * hb_buffer_set_user_data: (skip)

  * @buffer: a buffer.

  * @key: 

  * @data: 

  * @destroy: 

  * @replace: 

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 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: a buffer.

  * @key: 

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 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: a buffer.

  * @content_type: 

  *

  * 

  *

  * Since: 1.0

  **/

 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: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_buffer_content_type_t

 hb_buffer_get_content_type (hb_buffer_t *buffer)

 {

   return buffer->content_type;

 }

 /**

  * hb_buffer_set_unicode_funcs:

  * @buffer: a buffer.

  * @unicode_funcs: 

  *

  * 

  *

  * Since: 1.0

  **/

 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;

 }

 /**

  * hb_buffer_get_unicode_funcs:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_unicode_funcs_t *

 hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer)

 {

   return buffer->unicode;

 }

 /**

  * hb_buffer_set_direction:

  * @buffer: a buffer.

  * @direction: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_set_direction (hb_buffer_t    *buffer,

 			 hb_direction_t  direction)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   buffer->props.direction = direction;

 }

 /**

  * hb_buffer_get_direction:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_direction_t

 hb_buffer_get_direction (hb_buffer_t    *buffer)

 {

   return buffer->props.direction;

 }

 /**

  * hb_buffer_set_script:

  * @buffer: a buffer.

  * @script: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_set_script (hb_buffer_t *buffer,

 		      hb_script_t  script)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   buffer->props.script = script;

 }

 /**

  * hb_buffer_get_script:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_script_t

 hb_buffer_get_script (hb_buffer_t *buffer)

 {

   return buffer->props.script;

 }

 /**

  * hb_buffer_set_language:

  * @buffer: a buffer.

  * @language: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_set_language (hb_buffer_t   *buffer,

 			hb_language_t  language)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   buffer->props.language = language;

 }

 /**

  * hb_buffer_get_language:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_language_t

 hb_buffer_get_language (hb_buffer_t *buffer)

 {

   return buffer->props.language;

 }

 /**

  * hb_buffer_set_segment_properties:

  * @buffer: a buffer.

  * @props: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_set_segment_properties (hb_buffer_t *buffer,

 				  const hb_segment_properties_t *props)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   buffer->props = *props;

 }

 /**

  * hb_buffer_get_segment_properties:

  * @buffer: a buffer.

  * @props: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_get_segment_properties (hb_buffer_t *buffer,

 				  hb_segment_properties_t *props)

 {

   *props = buffer->props;

 }

 /**

  * hb_buffer_set_flags:

  * @buffer: a buffer.

  * @flags: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_set_flags (hb_buffer_t       *buffer,

 		     hb_buffer_flags_t  flags)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   buffer->flags = flags;

 }

 /**

  * hb_buffer_get_flags:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_buffer_flags_t

 hb_buffer_get_flags (hb_buffer_t *buffer)

 {

   return buffer->flags;

 }

 /**

  * hb_buffer_reset:

  * @buffer: a buffer.

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_reset (hb_buffer_t *buffer)

 {

   buffer->reset ();

 }

 /**

  * hb_buffer_clear_contents:

  * @buffer: a buffer.

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_clear_contents (hb_buffer_t *buffer)

 {

   buffer->clear ();

 }

 /**

  * hb_buffer_pre_allocate:

  * @buffer: a buffer.

  * @size: 

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_bool_t

 hb_buffer_pre_allocate (hb_buffer_t *buffer, unsigned int size)

 {

   return buffer->ensure (size);

 }

 /**

  * hb_buffer_allocation_successful:

  * @buffer: a buffer.

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_bool_t

 hb_buffer_allocation_successful (hb_buffer_t  *buffer)

 {

   return !buffer->in_error;

 }

 /**

  * hb_buffer_add:

  * @buffer: a buffer.

  * @codepoint: 

  * @cluster: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_add (hb_buffer_t    *buffer,

 	       hb_codepoint_t  codepoint,

 	       unsigned int    cluster)

 {

   buffer->add (codepoint, cluster);

   buffer->clear_context (1);

 }

 /**

  * hb_buffer_set_length:

  * @buffer: a buffer.

  * @length: 

  *

  * 

  *

  * Return value: 

  *

  * Since: 1.0

  **/

 hb_bool_t

 hb_buffer_set_length (hb_buffer_t  *buffer,

 		      unsigned int  length)

 {

   if (unlikely (hb_object_is_inert (buffer)))

     return length == 0;

   if (!buffer->ensure (length))

     return false;

   /* Wipe the new space */

   if (length > buffer->len) {

     memset (buffer->info + buffer->len, 0, sizeof (buffer->info[0]) * (length - buffer->len));

     if (buffer->have_positions)

       memset (buffer->pos + buffer->len, 0, sizeof (buffer->pos[0]) * (length - buffer->len));

   }

   buffer->len = length;

   if (!length)

   {

     buffer->content_type = HB_BUFFER_CONTENT_TYPE_INVALID;

     buffer->clear_context (0);

   }

   buffer->clear_context (1);

   return true;

 }

 /**

  * hb_buffer_get_length:

  * @buffer: a buffer.

  *

  * Returns the number of items in the buffer.

  *

  * Return value: buffer length.

  *

  * Since: 1.0

  **/

 unsigned int

 hb_buffer_get_length (hb_buffer_t *buffer)

 {

   return buffer->len;

 }

 /**

  * hb_buffer_get_glyph_infos:

  * @buffer: a buffer.

  * @length: (out): output array length.

  *

  * Returns buffer glyph information array.  Returned pointer

  * is valid as long as buffer contents are not modified.

  *

  * Return value: (transfer none) (array length=length): buffer glyph information array.

  *

  * Since: 1.0

  **/

 hb_glyph_info_t *

 hb_buffer_get_glyph_infos (hb_buffer_t  *buffer,

                            unsigned int *length)

 {

   if (length)

     *length = buffer->len;

   return (hb_glyph_info_t *) buffer->info;

 }

 /**

  * hb_buffer_get_glyph_positions:

  * @buffer: a buffer.

  * @length: (out): output length.

  *

  * Returns buffer glyph position array.  Returned pointer

  * is valid as long as buffer contents are not modified.

  *

  * Return value: (transfer none) (array length=length): buffer glyph position array.

  *

  * Since: 1.0

  **/

 hb_glyph_position_t *

 hb_buffer_get_glyph_positions (hb_buffer_t  *buffer,

                                unsigned int *length)

 {

   if (!buffer->have_positions)

     buffer->clear_positions ();

   if (length)

     *length = buffer->len;

   return (hb_glyph_position_t *) buffer->pos;

 }

 /**

  * hb_buffer_reverse:

  * @buffer: a buffer.

  *

  * Reverses buffer contents.

  *

  * Since: 1.0

  **/

 void

 hb_buffer_reverse (hb_buffer_t *buffer)

 {

   buffer->reverse ();

 }

 /**

  * hb_buffer_reverse_clusters:

  * @buffer: a buffer.

  *

  * Reverses buffer clusters.  That is, the buffer contents are

  * reversed, then each cluster (consecutive items having the

  * same cluster number) are reversed again.

  *

  * Since: 1.0

  **/

 void

 hb_buffer_reverse_clusters (hb_buffer_t *buffer)

 {

   buffer->reverse_clusters ();

 }

 /**

  * hb_buffer_guess_segment_properties:

  * @buffer: a buffer.

  *

  * Sets unset buffer segment properties based on buffer Unicode

  * contents.  If buffer is not empty, it must have content type

  * %HB_BUFFER_CONTENT_TYPE_UNICODE.

  *

  * If buffer script is not set (ie. is %HB_SCRIPT_INVALID), it

  * will be set to the Unicode script of the first character in

  * the buffer that has a script other than %HB_SCRIPT_COMMON,

  * %HB_SCRIPT_INHERITED, and %HB_SCRIPT_UNKNOWN.

  *

  * Next, if buffer direction is not set (ie. is %HB_DIRECTION_INVALID),

  * it will be set to the natural horizontal direction of the

  * buffer script as returned by hb_script_get_horizontal_direction().

  *

  * Finally, if buffer language is not set (ie. is %HB_LANGUAGE_INVALID),

  * it will be set to the process's default language as returned by

  * hb_language_get_default().  This may change in the future by

  * taking buffer script into consideration when choosing a language.

  *

  * Since: 1.0

  **/

 void

 hb_buffer_guess_segment_properties (hb_buffer_t *buffer)

 {

   buffer->guess_segment_properties ();

 }

 template <typename T>

 static inline void

 hb_buffer_add_utf (hb_buffer_t  *buffer,

 		   const T      *text,

 		   int           text_length,

 		   unsigned int  item_offset,

 		   int           item_length)

 {

   assert (buffer->content_type == HB_BUFFER_CONTENT_TYPE_UNICODE ||

 	  (!buffer->len && buffer->content_type == HB_BUFFER_CONTENT_TYPE_INVALID));

   if (unlikely (hb_object_is_inert (buffer)))

     return;

   if (text_length == -1)

     text_length = hb_utf_strlen (text);

   if (item_length == -1)

     item_length = text_length - item_offset;

   buffer->ensure (buffer->len + item_length * sizeof (T) / 4);

   /* If buffer is empty and pre-context provided, install it.

    * This check is written this way, to make sure people can

    * provide pre-context in one add_utf() call, then provide

    * text in a follow-up call.  See:

    *

    * https://bugzilla.mozilla.org/show_bug.cgi?id=801410#c13

    */

   if (!buffer->len && item_offset > 0)

   {

     /* Add pre-context */

     buffer->clear_context (0);

     const T *prev = text + item_offset;

     const T *start = text;

     while (start < prev && buffer->context_len[0] < buffer->CONTEXT_LENGTH)

     {

       hb_codepoint_t u;

       prev = hb_utf_prev (prev, start, &u);

       buffer->context[0][buffer->context_len[0]++] = u;

     }

   }

   const T *next = text + item_offset;

   const T *end = next + item_length;

   while (next < end)

   {

     hb_codepoint_t u;

     const T *old_next = next;

     next = hb_utf_next (next, end, &u);

     buffer->add (u, old_next - (const T *) text);

   }

   /* Add post-context */

   buffer->clear_context (1);

   end = text + text_length;

   while (next < end && buffer->context_len[1] < buffer->CONTEXT_LENGTH)

   {

     hb_codepoint_t u;

     next = hb_utf_next (next, end, &u);

     buffer->context[1][buffer->context_len[1]++] = u;

   }

   buffer->content_type = HB_BUFFER_CONTENT_TYPE_UNICODE;

 }

 /**

  * hb_buffer_add_utf8:

  * @buffer: a buffer.

  * @text: (array length=text_length):

  * @text_length: 

  * @item_offset: 

  * @item_length: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_add_utf8 (hb_buffer_t  *buffer,

 		    const char   *text,

 		    int           text_length,

 		    unsigned int  item_offset,

 		    int           item_length)

 {

   hb_buffer_add_utf (buffer, (const uint8_t *) text, text_length, item_offset, item_length);

 }

 /**

  * hb_buffer_add_utf16:

  * @buffer: a buffer.

  * @text: (array length=text_length):

  * @text_length: 

  * @item_offset: 

  * @item_length: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_add_utf16 (hb_buffer_t    *buffer,

 		     const uint16_t *text,

 		     int             text_length,

 		     unsigned int    item_offset,

 		     int             item_length)

 {

   hb_buffer_add_utf (buffer, text, text_length, item_offset, item_length);

 }

 /**

  * hb_buffer_add_utf32:

  * @buffer: a buffer.

  * @text: (array length=text_length):

  * @text_length: 

  * @item_offset: 

  * @item_length: 

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_add_utf32 (hb_buffer_t    *buffer,

 		     const uint32_t *text,

 		     int             text_length,

 		     unsigned int    item_offset,

 		     int             item_length)

 {

   hb_buffer_add_utf (buffer, text, text_length, item_offset, item_length);

 }

 static int

 compare_info_codepoint (const hb_glyph_info_t *pa,

 			const hb_glyph_info_t *pb)

 {

   return (int) pb->codepoint - (int) pa->codepoint;

 }

 static inline void

 normalize_glyphs_cluster (hb_buffer_t *buffer,

 			  unsigned int start,

 			  unsigned int end,

 			  bool backward)

 {

   hb_glyph_position_t *pos = buffer->pos;

   /* Total cluster advance */

   hb_position_t total_x_advance = 0, total_y_advance = 0;

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

   {

     total_x_advance += pos[i].x_advance;

     total_y_advance += pos[i].y_advance;

   }

   hb_position_t x_advance = 0, y_advance = 0;

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

   {

     pos[i].x_offset += x_advance;

     pos[i].y_offset += y_advance;

     x_advance += pos[i].x_advance;

     y_advance += pos[i].y_advance;

     pos[i].x_advance = 0;

     pos[i].y_advance = 0;

   }

   if (backward)

   {

     /* Transfer all cluster advance to the last glyph. */

     pos[end - 1].x_advance = total_x_advance;

     pos[end - 1].y_advance = total_y_advance;

     hb_bubble_sort (buffer->info + start, end - start - 1, compare_info_codepoint, buffer->pos + start);

   } else {

     /* Transfer all cluster advance to the first glyph. */

     pos[start].x_advance += total_x_advance;

     pos[start].y_advance += total_y_advance;

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

       pos[i].x_offset -= total_x_advance;

       pos[i].y_offset -= total_y_advance;

     }

     hb_bubble_sort (buffer->info + start + 1, end - start - 1, compare_info_codepoint, buffer->pos + start + 1);

   }

 }

 /**

  * hb_buffer_normalize_glyphs:

  * @buffer: a buffer.

  *

  * 

  *

  * Since: 1.0

  **/

 void

 hb_buffer_normalize_glyphs (hb_buffer_t *buffer)

 {

   assert (buffer->have_positions);

   assert (buffer->content_type == HB_BUFFER_CONTENT_TYPE_GLYPHS);

   bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);

   unsigned int count = buffer->len;

   if (unlikely (!count)) return;

   hb_glyph_info_t *info = buffer->info;

   unsigned int start = 0;

   unsigned int end;

   for (end = start + 1; end < count; end++)

     if (info[start].cluster != info[end].cluster) {

       normalize_glyphs_cluster (buffer, start, end, backward);

       start = end;

     }

   normalize_glyphs_cluster (buffer, start, end, backward);

 }