src/hb-buffer.c - third_party/harfbuzz - Git at Google

 /*
  * Copyright (C) 1998-2004  David Turner and Werner Lemberg
  * Copyright (C) 2004,2007  Red Hat, Inc.
  *
  * This is part of HarfBuzz, an OpenType Layout engine 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
  */

 #include "hb-buffer-private.h"

 #include <string.h>


 static hb_buffer_t _hb_buffer_nil = {
   HB_REFERENCE_COUNT_INVALID /* ref_count */
 };

 /* Here is how the buffer works internally:
  *
  * There are two string pointers: in_string and out_string.  They
  * always have same allocated size, but different length and positions.
  *
  * As an optimization, both in_string and out_string may point to the
  * same piece of memory, which is owned by in_string.  This remains the
  * case as long as out_length doesn't exceed in_length at any time.
  * In that case, swap() is no-op and the glyph operations operate mostly
  * in-place.
  *
  * As soon as out_string gets longer than in_string, out_string is moved over
  * to an alternate buffer (which we reuse the positions buffer for!), and its
  * current contents (out_length entries) are copied to the alt buffer.
  * This should all remain transparent to the user.  swap() then switches
  * in_string and out_string.
  */

 /* XXX err handling */

 /* Internal API */

 static void
 hb_buffer_ensure_separate (hb_buffer_t *buffer, unsigned int size)
 {
   hb_buffer_ensure (buffer, size);
   if (buffer->out_string == buffer->in_string)
   {
     assert (buffer->have_output);
     if (!buffer->positions)
       buffer->positions = calloc (buffer->allocated, sizeof (buffer->positions[0]));

     buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
     memcpy (buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]));
   }
 }

 /* Public API */

 hb_buffer_t *
 hb_buffer_create (unsigned int pre_alloc_size)
 {
   hb_buffer_t *buffer;

   if (!HB_OBJECT_DO_CREATE (hb_buffer_t, buffer))
     return &_hb_buffer_nil;

   if (pre_alloc_size)
     hb_buffer_ensure(buffer, pre_alloc_size);

   return buffer;
 }

 hb_buffer_t *
 hb_buffer_reference (hb_buffer_t *buffer)
 {
   HB_OBJECT_DO_REFERENCE (buffer);
 }

 unsigned int
 hb_buffer_get_reference_count (hb_buffer_t *buffer)
 {
   HB_OBJECT_DO_GET_REFERENCE_COUNT (buffer);
 }

 void
 hb_buffer_destroy (hb_buffer_t *buffer)
 {
   HB_OBJECT_DO_DESTROY (buffer);

   free (buffer->in_string);
   free (buffer->positions);

   free (buffer);
 }

 void
 hb_buffer_clear (hb_buffer_t *buffer)
 {
   buffer->have_output = FALSE;
   buffer->in_length = 0;
   buffer->out_length = 0;
   buffer->in_pos = 0;
   buffer->out_pos = 0;
   buffer->out_string = buffer->in_string;
   buffer->max_lig_id = 0;
 }

 void
 hb_buffer_ensure (hb_buffer_t *buffer, unsigned int size)
 {
   unsigned int new_allocated = buffer->allocated;

   if (size > new_allocated)
   {
     while (size > new_allocated)
       new_allocated += (new_allocated >> 1) + 8;

     if (buffer->positions)
       buffer->positions = realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));

     if (buffer->out_string != buffer->in_string)
     {
       buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
       buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
     }
     else
     {
       buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
       buffer->out_string = buffer->in_string;
     }

     buffer->allocated = new_allocated;
   }
 }

 void
 hb_buffer_add_glyph (hb_buffer_t    *buffer,
 		     hb_codepoint_t  codepoint,
 		     hb_mask_t       mask,
 		     unsigned int    cluster)
 {
   hb_internal_glyph_info_t *glyph;

   hb_buffer_ensure (buffer, buffer->in_length + 1);

   glyph = &buffer->in_string[buffer->in_length];
   glyph->codepoint = codepoint;
   glyph->mask = mask;
   glyph->cluster = cluster;
   glyph->component = 0;
   glyph->lig_id = 0;
   glyph->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;

   buffer->in_length++;
 }

 void
 hb_buffer_set_direction (hb_buffer_t    *buffer,
 			 hb_direction_t  direction)

 {
   buffer->direction = direction;
 }


 /* HarfBuzz-Internal API */

 void
 _hb_buffer_clear_output (hb_buffer_t *buffer)
 {
   buffer->have_output = TRUE;
   buffer->out_length = 0;
   buffer->out_pos = 0;
   buffer->out_string = buffer->in_string;
 }

 void
 hb_buffer_clear_positions (hb_buffer_t *buffer)
 {
   _hb_buffer_clear_output (buffer);
   buffer->have_output = FALSE;

   if (HB_UNLIKELY (!buffer->positions))
   {
     buffer->positions = calloc (buffer->allocated, sizeof (buffer->positions[0]));
     return;
   }

   memset (buffer->positions, 0, sizeof (buffer->positions[0]) * buffer->in_length);
 }

 void
 _hb_buffer_swap (hb_buffer_t *buffer)
 {
   unsigned int tmp;

   assert (buffer->have_output);

   if (buffer->out_string != buffer->in_string)
   {
     hb_internal_glyph_info_t *tmp_string;
     tmp_string = buffer->in_string;
     buffer->in_string = buffer->out_string;
     buffer->out_string = tmp_string;
     buffer->positions = (hb_internal_glyph_position_t *) buffer->out_string;
   }

   tmp = buffer->in_length;
   buffer->in_length = buffer->out_length;
   buffer->out_length = tmp;

   tmp = buffer->in_pos;
   buffer->in_pos = buffer->out_pos;
   buffer->out_pos = tmp;
 }

 /* The following function copies `num_out' elements from `glyph_data'
    to `buffer->out_string', advancing the in array pointer in the structure
    by `num_in' elements, and the out array pointer by `num_out' elements.
    Finally, it sets the `length' field of `out' equal to
    `pos' of the `out' structure.

    If `component' is 0xFFFF, the component value from buffer->in_pos
    will copied `num_out' times, otherwise `component' itself will
    be used to fill the `component' fields.

    If `lig_id' is 0xFFFF, the lig_id value from buffer->in_pos
    will copied `num_out' times, otherwise `lig_id' itself will
    be used to fill the `lig_id' fields.

    The mask for all replacement glyphs are taken
    from the glyph at position `buffer->in_pos'.

    The cluster value for the glyph at position buffer->in_pos is used
    for all replacement glyphs */
 void
 _hb_buffer_add_output_glyphs (hb_buffer_t *buffer,
 			      unsigned int num_in,
 			      unsigned int num_out,
 			      const uint16_t *glyph_data_be,
 			      unsigned short component,
 			      unsigned short lig_id)
 {
   unsigned int i;
   unsigned int mask;
   unsigned int cluster;

   if (buffer->out_string != buffer->in_string ||
       buffer->out_pos + num_out > buffer->in_pos + num_in)
   {
     hb_buffer_ensure_separate (buffer, buffer->out_pos + num_out);
   }

   mask = buffer->in_string[buffer->in_pos].mask;
   cluster = buffer->in_string[buffer->in_pos].cluster;
   if (component == 0xFFFF)
     component = buffer->in_string[buffer->in_pos].component;
   if (lig_id == 0xFFFF)
     lig_id = buffer->in_string[buffer->in_pos].lig_id;

   for (i = 0; i < num_out; i++)
   {
     hb_internal_glyph_info_t *info = &buffer->out_string[buffer->out_pos + i];
     info->codepoint = hb_be_uint16 (glyph_data_be[i]);
     info->mask = mask;
     info->cluster = cluster;
     info->component = component;
     info->lig_id = lig_id;
     info->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;
   }

   buffer->in_pos  += num_in;
   buffer->out_pos += num_out;
   buffer->out_length = buffer->out_pos;
 }


 void
 _hb_buffer_add_output_glyph (hb_buffer_t *buffer,
 			     hb_codepoint_t glyph_index,
 			     unsigned short component,
 			     unsigned short lig_id)
 {
   hb_internal_glyph_info_t *info;

   if (buffer->out_string != buffer->in_string)
   {
     hb_buffer_ensure (buffer, buffer->out_pos + 1);
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
   }
   else if (buffer->out_pos != buffer->in_pos)
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];

   info = &buffer->out_string[buffer->out_pos];
   info->codepoint = glyph_index;
   if (component != 0xFFFF)
     info->component = component;
   if (lig_id != 0xFFFF)
     info->lig_id = lig_id;
   info->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;

   buffer->in_pos++;
   buffer->out_pos++;
   buffer->out_length = buffer->out_pos;
 }

 void
 _hb_buffer_next_glyph (hb_buffer_t *buffer)
 {
   if (!buffer->have_output)
   {
     buffer->in_pos++;
     return;
   }

   if (buffer->out_string != buffer->in_string)
   {
     hb_buffer_ensure (buffer, buffer->out_pos + 1);
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
   }
   else if (buffer->out_pos != buffer->in_pos)
     buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];

   buffer->in_pos++;
   buffer->out_pos++;
   buffer->out_length = buffer->out_pos;
 }

 void
 _hb_buffer_replace_glyph (hb_buffer_t *buffer,
 			  hb_codepoint_t glyph_index)
 {
   _hb_buffer_add_output_glyph (buffer, glyph_index, 0xFFFF, 0xFFFF);
 }

 unsigned short
 _hb_buffer_allocate_lig_id (hb_buffer_t *buffer)
 {
   return ++buffer->max_lig_id;
 }


 unsigned int
 hb_buffer_get_len (hb_buffer_t *buffer)
 {
   return buffer->in_length;
 }

 /* Return value valid as long as buffer not modified */
 hb_glyph_info_t *
 hb_buffer_get_glyph_infos (hb_buffer_t *buffer)
 {
   return (hb_glyph_info_t *) buffer->in_string;
 }

 /* Return value valid as long as buffer not modified */
 hb_glyph_position_t *
 hb_buffer_get_glyph_positions (hb_buffer_t *buffer)
 {
   if (buffer->have_output || (buffer->in_length && !buffer->positions))
     hb_buffer_clear_positions (buffer);

   return (hb_glyph_position_t *) buffer->positions;
 }


 void
 hb_buffer_reverse (hb_buffer_t *buffer)
 {
   unsigned int i, j;

   for (i = 0, j = buffer->in_length - 1; i < buffer->in_length / 2; i++, j--) {
     hb_internal_glyph_info_t t;

     t = buffer->in_string[i];
     buffer->in_string[i] = buffer->in_string[j];
     buffer->in_string[j] = t;
   }

   if (buffer->positions) {
     for (i = 0, j = buffer->in_length - 1; i < buffer->in_length / 2; i++, j--) {
       hb_internal_glyph_position_t t;

       t = buffer->positions[i];
       buffer->positions[i] = buffer->positions[j];
       buffer->positions[j] = t;
     }
   }
 }


 #define ADD_UTF(T) \
 	HB_STMT_START { \
 	  const T *next = (const T *) text + item_offset; \
 	  const T *end = next + item_length; \
 	  while (next < end) { \
 	    hb_codepoint_t u; \
 	    const T *old_next = next; \
 	    next = UTF_NEXT (next, end, u); \
 	    hb_buffer_add_glyph (buffer, u, 0,  old_next - (const T *) text); \
 	  } \
 	} HB_STMT_END


 #define UTF8_COMPUTE(Char, Mask, Len) \
   if (Char < 128) { Len = 1; Mask = 0x7f; } \
   else if ((Char & 0xe0) == 0xc0) { Len = 2; Mask = 0x1f; } \
   else if ((Char & 0xf0) == 0xe0) { Len = 3; Mask = 0x0f; } \
   else if ((Char & 0xf8) == 0xf0) { Len = 4; Mask = 0x07; } \
   else Len = 0;

 static inline const uint8_t *
 hb_utf8_next (const uint8_t *text,
 	      const uint8_t *end,
 	      hb_codepoint_t *unicode)
 {
   uint8_t c = *text;
   unsigned int mask, len;

   UTF8_COMPUTE (c, mask, len);
   if (HB_UNLIKELY (!len || (unsigned int) (end - text) < len)) {
     *unicode = -1;
     return text + 1;
   } else {
     hb_codepoint_t result;
     unsigned int i;
     result = c & mask;
     for (i = 1; i < len; i++)
       {
 	if (HB_UNLIKELY ((text[i] & 0xc0) != 0x80))
 	  {
 	    *unicode = -1;
 	    return text + 1;
 	  }
 	result <<= 6;
 	result |= (text[i] & 0x3f);
       }
     *unicode = result;
     return text + len;
   }
 }

 void
 hb_buffer_add_utf8 (hb_buffer_t  *buffer,
 		    const char   *text,
 		    unsigned int  text_length,
 		    unsigned int  item_offset,
 		    unsigned int  item_length)
 {
 #define UTF_NEXT(S, E, U)	hb_utf8_next (S, E, &(U))
   ADD_UTF (uint8_t);
 #undef UTF_NEXT
 }

 static inline const uint16_t *
 hb_utf16_next (const uint16_t *text,
 	       const uint16_t *end,
 	       hb_codepoint_t *unicode)
 {
   uint16_t c = *text++;

   if (HB_UNLIKELY (c >= 0xd800 && c < 0xdc00)) {
     /* high surrogate */
     uint16_t l;
     if (text < end && ((l = *text), HB_UNLIKELY (l >= 0xdc00 && l < 0xe000))) {
       /* low surrogate */
       *unicode = ((hb_codepoint_t) ((c) - 0xd800) * 0x400 + (l) - 0xdc00 + 0x10000);
        text++;
     } else
       *unicode = -1;
   } else
     *unicode = c;

   return text;
 }

 void
 hb_buffer_add_utf16 (hb_buffer_t    *buffer,
 		     const uint16_t *text,
 		     unsigned int    text_length,
 		     unsigned int    item_offset,
 		     unsigned int    item_length)
 {
 #define UTF_NEXT(S, E, U)	hb_utf16_next (S, E, &(U))
   ADD_UTF (uint16_t);
 #undef UTF_NEXT
 }

 void
 hb_buffer_add_utf32 (hb_buffer_t    *buffer,
 		     const uint32_t *text,
 		     unsigned int    text_length,
 		     unsigned int    item_offset,
 		     unsigned int    item_length)
 {
 #define UTF_NEXT(S, E, U)	((U) = *(S), (S)+1)
   ADD_UTF (uint32_t);
 #undef UTF_NEXT
 }
	/*
	* Copyright (C) 1998-2004 David Turner and Werner Lemberg
	* Copyright (C) 2004,2007 Red Hat, Inc.
	*
	* This is part of HarfBuzz, an OpenType Layout engine 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
	*/

	#include "hb-buffer-private.h"

	#include <string.h>


	static hb_buffer_t _hb_buffer_nil = {
	HB_REFERENCE_COUNT_INVALID /* ref_count */
	};

	/* Here is how the buffer works internally:
	*
	* There are two string pointers: in_string and out_string. They
	* always have same allocated size, but different length and positions.
	*
	* As an optimization, both in_string and out_string may point to the
	* same piece of memory, which is owned by in_string. This remains the
	* case as long as out_length doesn't exceed in_length at any time.
	* In that case, swap() is no-op and the glyph operations operate mostly
	* in-place.
	*
	* As soon as out_string gets longer than in_string, out_string is moved over
	* to an alternate buffer (which we reuse the positions buffer for!), and its
	* current contents (out_length entries) are copied to the alt buffer.
	* This should all remain transparent to the user. swap() then switches
	* in_string and out_string.
	*/

	/* XXX err handling */

	/* Internal API */

	static void
	hb_buffer_ensure_separate (hb_buffer_t *buffer, unsigned int size)
	{
	hb_buffer_ensure (buffer, size);
	if (buffer->out_string == buffer->in_string)
	{
	assert (buffer->have_output);
	if (!buffer->positions)
	buffer->positions = calloc (buffer->allocated, sizeof (buffer->positions[0]));

	buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
	memcpy (buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]));
	}
	}

	/* Public API */

	hb_buffer_t *
	hb_buffer_create (unsigned int pre_alloc_size)
	{
	hb_buffer_t *buffer;

	if (!HB_OBJECT_DO_CREATE (hb_buffer_t, buffer))
	return &_hb_buffer_nil;

	if (pre_alloc_size)
	hb_buffer_ensure(buffer, pre_alloc_size);

	return buffer;
	}

	hb_buffer_t *
	hb_buffer_reference (hb_buffer_t *buffer)
	{
	HB_OBJECT_DO_REFERENCE (buffer);
	}

	unsigned int
	hb_buffer_get_reference_count (hb_buffer_t *buffer)
	{
	HB_OBJECT_DO_GET_REFERENCE_COUNT (buffer);
	}

	void
	hb_buffer_destroy (hb_buffer_t *buffer)
	{
	HB_OBJECT_DO_DESTROY (buffer);

	free (buffer->in_string);
	free (buffer->positions);

	free (buffer);
	}

	void
	hb_buffer_clear (hb_buffer_t *buffer)
	{
	buffer->have_output = FALSE;
	buffer->in_length = 0;
	buffer->out_length = 0;
	buffer->in_pos = 0;
	buffer->out_pos = 0;
	buffer->out_string = buffer->in_string;
	buffer->max_lig_id = 0;
	}

	void
	hb_buffer_ensure (hb_buffer_t *buffer, unsigned int size)
	{
	unsigned int new_allocated = buffer->allocated;

	if (size > new_allocated)
	{
	while (size > new_allocated)
	new_allocated += (new_allocated >> 1) + 8;

	if (buffer->positions)
	buffer->positions = realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));

	if (buffer->out_string != buffer->in_string)
	{
	buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
	buffer->out_string = (hb_internal_glyph_info_t *) buffer->positions;
	}
	else
	{
	buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
	buffer->out_string = buffer->in_string;
	}

	buffer->allocated = new_allocated;
	}
	}

	void
	hb_buffer_add_glyph (hb_buffer_t *buffer,
	hb_codepoint_t codepoint,
	hb_mask_t mask,
	unsigned int cluster)
	{
	hb_internal_glyph_info_t *glyph;

	hb_buffer_ensure (buffer, buffer->in_length + 1);

	glyph = &buffer->in_string[buffer->in_length];
	glyph->codepoint = codepoint;
	glyph->mask = mask;
	glyph->cluster = cluster;
	glyph->component = 0;
	glyph->lig_id = 0;
	glyph->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;

	buffer->in_length++;
	}

	void
	hb_buffer_set_direction (hb_buffer_t *buffer,
	hb_direction_t direction)

	{
	buffer->direction = direction;
	}


	/* HarfBuzz-Internal API */

	void
	_hb_buffer_clear_output (hb_buffer_t *buffer)
	{
	buffer->have_output = TRUE;
	buffer->out_length = 0;
	buffer->out_pos = 0;
	buffer->out_string = buffer->in_string;
	}

	void
	hb_buffer_clear_positions (hb_buffer_t *buffer)
	{
	_hb_buffer_clear_output (buffer);
	buffer->have_output = FALSE;

	if (HB_UNLIKELY (!buffer->positions))
	{
	buffer->positions = calloc (buffer->allocated, sizeof (buffer->positions[0]));
	return;
	}

	memset (buffer->positions, 0, sizeof (buffer->positions[0]) * buffer->in_length);
	}

	void
	_hb_buffer_swap (hb_buffer_t *buffer)
	{
	unsigned int tmp;

	assert (buffer->have_output);

	if (buffer->out_string != buffer->in_string)
	{
	hb_internal_glyph_info_t *tmp_string;
	tmp_string = buffer->in_string;
	buffer->in_string = buffer->out_string;
	buffer->out_string = tmp_string;
	buffer->positions = (hb_internal_glyph_position_t *) buffer->out_string;
	}

	tmp = buffer->in_length;
	buffer->in_length = buffer->out_length;
	buffer->out_length = tmp;

	tmp = buffer->in_pos;
	buffer->in_pos = buffer->out_pos;
	buffer->out_pos = tmp;
	}

	/* The following function copies `num_out' elements from `glyph_data'
	to `buffer->out_string', advancing the in array pointer in the structure
	by `num_in' elements, and the out array pointer by `num_out' elements.
	Finally, it sets the `length' field of `out' equal to
	`pos' of the `out' structure.

	If `component' is 0xFFFF, the component value from buffer->in_pos
	will copied `num_out' times, otherwise `component' itself will
	be used to fill the `component' fields.

	If `lig_id' is 0xFFFF, the lig_id value from buffer->in_pos
	will copied `num_out' times, otherwise `lig_id' itself will
	be used to fill the `lig_id' fields.

	The mask for all replacement glyphs are taken
	from the glyph at position `buffer->in_pos'.

	The cluster value for the glyph at position buffer->in_pos is used
	for all replacement glyphs */
	void
	_hb_buffer_add_output_glyphs (hb_buffer_t *buffer,
	unsigned int num_in,
	unsigned int num_out,
	const uint16_t *glyph_data_be,
	unsigned short component,
	unsigned short lig_id)
	{
	unsigned int i;
	unsigned int mask;
	unsigned int cluster;

	if (buffer->out_string != buffer->in_string \|\|
	buffer->out_pos + num_out > buffer->in_pos + num_in)
	{
	hb_buffer_ensure_separate (buffer, buffer->out_pos + num_out);
	}

	mask = buffer->in_string[buffer->in_pos].mask;
	cluster = buffer->in_string[buffer->in_pos].cluster;
	if (component == 0xFFFF)
	component = buffer->in_string[buffer->in_pos].component;
	if (lig_id == 0xFFFF)
	lig_id = buffer->in_string[buffer->in_pos].lig_id;

	for (i = 0; i < num_out; i++)
	{
	hb_internal_glyph_info_t *info = &buffer->out_string[buffer->out_pos + i];
	info->codepoint = hb_be_uint16 (glyph_data_be[i]);
	info->mask = mask;
	info->cluster = cluster;
	info->component = component;
	info->lig_id = lig_id;
	info->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;
	}

	buffer->in_pos += num_in;
	buffer->out_pos += num_out;
	buffer->out_length = buffer->out_pos;
	}


	void
	_hb_buffer_add_output_glyph (hb_buffer_t *buffer,
	hb_codepoint_t glyph_index,
	unsigned short component,
	unsigned short lig_id)
	{
	hb_internal_glyph_info_t *info;

	if (buffer->out_string != buffer->in_string)
	{
	hb_buffer_ensure (buffer, buffer->out_pos + 1);
	buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
	}
	else if (buffer->out_pos != buffer->in_pos)
	buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];

	info = &buffer->out_string[buffer->out_pos];
	info->codepoint = glyph_index;
	if (component != 0xFFFF)
	info->component = component;
	if (lig_id != 0xFFFF)
	info->lig_id = lig_id;
	info->gproperty = HB_BUFFER_GLYPH_PROPERTIES_UNKNOWN;

	buffer->in_pos++;
	buffer->out_pos++;
	buffer->out_length = buffer->out_pos;
	}

	void
	_hb_buffer_next_glyph (hb_buffer_t *buffer)
	{
	if (!buffer->have_output)
	{
	buffer->in_pos++;
	return;
	}

	if (buffer->out_string != buffer->in_string)
	{
	hb_buffer_ensure (buffer, buffer->out_pos + 1);
	buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
	}
	else if (buffer->out_pos != buffer->in_pos)
	buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];

	buffer->in_pos++;
	buffer->out_pos++;
	buffer->out_length = buffer->out_pos;
	}

	void
	_hb_buffer_replace_glyph (hb_buffer_t *buffer,
	hb_codepoint_t glyph_index)
	{
	_hb_buffer_add_output_glyph (buffer, glyph_index, 0xFFFF, 0xFFFF);
	}

	unsigned short
	_hb_buffer_allocate_lig_id (hb_buffer_t *buffer)
	{
	return ++buffer->max_lig_id;
	}


	unsigned int
	hb_buffer_get_len (hb_buffer_t *buffer)
	{
	return buffer->in_length;
	}

	/* Return value valid as long as buffer not modified */
	hb_glyph_info_t *
	hb_buffer_get_glyph_infos (hb_buffer_t *buffer)
	{
	return (hb_glyph_info_t *) buffer->in_string;
	}

	/* Return value valid as long as buffer not modified */
	hb_glyph_position_t *
	hb_buffer_get_glyph_positions (hb_buffer_t *buffer)
	{
	if (buffer->have_output \|\| (buffer->in_length && !buffer->positions))
	hb_buffer_clear_positions (buffer);

	return (hb_glyph_position_t *) buffer->positions;
	}


	void
	hb_buffer_reverse (hb_buffer_t *buffer)
	{
	unsigned int i, j;

	for (i = 0, j = buffer->in_length - 1; i < buffer->in_length / 2; i++, j--) {
	hb_internal_glyph_info_t t;

	t = buffer->in_string[i];
	buffer->in_string[i] = buffer->in_string[j];
	buffer->in_string[j] = t;
	}

	if (buffer->positions) {
	for (i = 0, j = buffer->in_length - 1; i < buffer->in_length / 2; i++, j--) {
	hb_internal_glyph_position_t t;

	t = buffer->positions[i];
	buffer->positions[i] = buffer->positions[j];
	buffer->positions[j] = t;
	}
	}
	}


	#define ADD_UTF(T) \
	HB_STMT_START { \
	const T next = (const T ) text + item_offset; \
	const T *end = next + item_length; \
	while (next < end) { \
	hb_codepoint_t u; \
	const T *old_next = next; \
	next = UTF_NEXT (next, end, u); \
	hb_buffer_add_glyph (buffer, u, 0, old_next - (const T *) text); \
	} \
	} HB_STMT_END


	#define UTF8_COMPUTE(Char, Mask, Len) \
	if (Char < 128) { Len = 1; Mask = 0x7f; } \
	else if ((Char & 0xe0) == 0xc0) { Len = 2; Mask = 0x1f; } \
	else if ((Char & 0xf0) == 0xe0) { Len = 3; Mask = 0x0f; } \
	else if ((Char & 0xf8) == 0xf0) { Len = 4; Mask = 0x07; } \
	else Len = 0;

	static inline const uint8_t *
	hb_utf8_next (const uint8_t *text,
	const uint8_t *end,
	hb_codepoint_t *unicode)
	{
	uint8_t c = *text;
	unsigned int mask, len;

	UTF8_COMPUTE (c, mask, len);
	if (HB_UNLIKELY (!len \|\| (unsigned int) (end - text) < len)) {
	*unicode = -1;
	return text + 1;
	} else {
	hb_codepoint_t result;
	unsigned int i;
	result = c & mask;
	for (i = 1; i < len; i++)
	{
	if (HB_UNLIKELY ((text[i] & 0xc0) != 0x80))
	{
	*unicode = -1;
	return text + 1;
	}
	result <<= 6;
	result \|= (text[i] & 0x3f);
	}
	*unicode = result;
	return text + len;
	}
	}

	void
	hb_buffer_add_utf8 (hb_buffer_t *buffer,
	const char *text,
	unsigned int text_length,
	unsigned int item_offset,
	unsigned int item_length)
	{
	#define UTF_NEXT(S, E, U) hb_utf8_next (S, E, &(U))
	ADD_UTF (uint8_t);
	#undef UTF_NEXT
	}

	static inline const uint16_t *
	hb_utf16_next (const uint16_t *text,
	const uint16_t *end,
	hb_codepoint_t *unicode)
	{
	uint16_t c = *text++;

	if (HB_UNLIKELY (c >= 0xd800 && c < 0xdc00)) {
	/* high surrogate */
	uint16_t l;
	if (text < end && ((l = *text), HB_UNLIKELY (l >= 0xdc00 && l < 0xe000))) {
	/* low surrogate */
	unicode = ((hb_codepoint_t) ((c) - 0xd800) 0x400 + (l) - 0xdc00 + 0x10000);
	text++;
	} else
	*unicode = -1;
	} else
	*unicode = c;

	return text;
	}

	void
	hb_buffer_add_utf16 (hb_buffer_t *buffer,
	const uint16_t *text,
	unsigned int text_length,
	unsigned int item_offset,
	unsigned int item_length)
	{
	#define UTF_NEXT(S, E, U) hb_utf16_next (S, E, &(U))
	ADD_UTF (uint16_t);
	#undef UTF_NEXT
	}

	void
	hb_buffer_add_utf32 (hb_buffer_t *buffer,
	const uint32_t *text,
	unsigned int text_length,
	unsigned int item_offset,
	unsigned int item_length)
	{
	#define UTF_NEXT(S, E, U) ((U) = *(S), (S)+1)
	ADD_UTF (uint32_t);
	#undef UTF_NEXT
	}