Add m-esr52 at 52.6.0

1 files changed, 1818 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-buffer.cc b/gfx/harfbuzz/src/hb-buffer.cc
new file mode 100644
index 000000000..3940a3dbf
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-buffer.cc
@@ -0,0 +1,1818 @@
+/*
+ * 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;
+
+  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 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;
+
+  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 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;
+}
+
+/**
+ * hb_buffer_get_unicode_funcs:
+ * @buffer: an #hb_buffer_t.
+ *
+ * 
+ *
+ * Return value: 
+ *
+ * Since: 0.9.2
+ **/
+hb_unicode_funcs_t *
+hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer)
+{
+  return buffer->unicode;
+}
+
+/**
+ * hb_buffer_set_direction:
+ * @buffer: an #hb_buffer_t.
+ * @direction: the #hb_direction_t of the @buffer
+ *
+ * Set the text flow direction of the buffer. No shaping can happen without
+ * setting @buffer direction, and it controls the visual direction for the
+ * output glyphs; for RTL direction the glyphs will be reversed. Many layout
+ * features depend on the proper setting of the direction, for example,
+ * reversing RTL text before shaping, then shaping with LTR direction is not
+ * the same as keeping the text in logical order and shaping with RTL
+ * direction.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ *
+ * See hb_buffer_set_direction()
+ *
+ * Return value:
+ * The direction of the @buffer.
+ *
+ * Since: 0.9.2
+ **/
+hb_direction_t
+hb_buffer_get_direction (hb_buffer_t    *buffer)
+{
+  return buffer->props.direction;
+}
+
+/**
+ * hb_buffer_set_script:
+ * @buffer: an #hb_buffer_t.
+ * @script: an #hb_script_t to set.
+ *
+ * Sets the script of @buffer to @script.
+ *
+ * Script is crucial for choosing the proper shaping behaviour for scripts that
+ * require it (e.g. Arabic) and the which OpenType features defined in the font
+ * to be applied.
+ *
+ * You can pass one of the predefined #hb_script_t values, or use
+ * hb_script_from_string() or hb_script_from_iso15924_tag() to get the
+ * corresponding script from an ISO 15924 script tag.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ *
+ * See hb_buffer_set_script().
+ *
+ * Return value:
+ * The #hb_script_t of the @buffer.
+ *
+ * Since: 0.9.2
+ **/
+hb_script_t
+hb_buffer_get_script (hb_buffer_t *buffer)
+{
+  return buffer->props.script;
+}
+
+/**
+ * hb_buffer_set_language:
+ * @buffer: an #hb_buffer_t.
+ * @language: an hb_language_t to set.
+ *
+ * Sets the language of @buffer to @language.
+ *
+ * Languages are crucial for selecting which OpenType feature to apply to the
+ * buffer which can result in applying language-specific behaviour. Languages
+ * are orthogonal to the scripts, and though they are related, they are
+ * different concepts and should not be confused with each other.
+ *
+ * Use hb_language_from_string() to convert from ISO 639 language codes to
+ * #hb_language_t.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ *
+ * See hb_buffer_set_language().
+ *
+ * Return value: (transfer none):
+ * The #hb_language_t of the buffer. Must not be freed by the caller.
+ *
+ * Since: 0.9.2
+ **/
+hb_language_t
+hb_buffer_get_language (hb_buffer_t *buffer)
+{
+  return buffer->props.language;
+}
+
+/**
+ * hb_buffer_set_segment_properties:
+ * @buffer: an #hb_buffer_t.
+ * @props: an #hb_segment_properties_t to use.
+ *
+ * Sets the segment properties of the buffer, a shortcut for calling
+ * hb_buffer_set_direction(), hb_buffer_set_script() and
+ * hb_buffer_set_language() individually.
+ *
+ * Since: 0.9.7
+ **/
+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: an #hb_buffer_t.
+ * @props: (out): the output #hb_segment_properties_t.
+ *
+ * Sets @props to the #hb_segment_properties_t of @buffer.
+ *
+ * Since: 0.9.7
+ **/
+void
+hb_buffer_get_segment_properties (hb_buffer_t *buffer,
+				  hb_segment_properties_t *props)
+{
+  *props = buffer->props;
+}
+
+
+/**
+ * hb_buffer_set_flags:
+ * @buffer: an #hb_buffer_t.
+ * @flags: the buffer flags to set.
+ *
+ * Sets @buffer flags to @flags. See #hb_buffer_flags_t.
+ *
+ * Since: 0.9.7
+ **/
+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: an #hb_buffer_t.
+ *
+ * See hb_buffer_set_flags().
+ *
+ * Return value: 
+ * The @buffer flags.
+ *
+ * Since: 0.9.7
+ **/
+hb_buffer_flags_t
+hb_buffer_get_flags (hb_buffer_t *buffer)
+{
+  return buffer->flags;
+}
+
+/**
+ * hb_buffer_set_cluster_level:
+ * @buffer: an #hb_buffer_t.
+ * @cluster_level: 
+ *
+ * 
+ *
+ * Since: 0.9.42
+ **/
+void
+hb_buffer_set_cluster_level (hb_buffer_t       *buffer,
+		     hb_buffer_cluster_level_t  cluster_level)
+{
+  if (unlikely (hb_object_is_inert (buffer)))
+    return;
+
+  buffer->cluster_level = cluster_level;
+}
+
+/**
+ * hb_buffer_get_cluster_level:
+ * @buffer: an #hb_buffer_t.
+ *
+ * 
+ *
+ * Return value: 
+ *
+ * Since: 0.9.42
+ **/
+hb_buffer_cluster_level_t
+hb_buffer_get_cluster_level (hb_buffer_t *buffer)
+{
+  return buffer->cluster_level;
+}
+
+
+/**
+ * hb_buffer_set_replacement_codepoint:
+ * @buffer: an #hb_buffer_t.
+ * @replacement: the replacement #hb_codepoint_t
+ *
+ * Sets the #hb_codepoint_t that replaces invalid entries for a given encoding
+ * when adding text to @buffer.
+ *
+ * Default is %HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT.
+ *
+ * Since: 0.9.31
+ **/
+void
+hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
+				     hb_codepoint_t  replacement)
+{
+  if (unlikely (hb_object_is_inert (buffer)))
+    return;
+
+  buffer->replacement = replacement;
+}
+
+/**
+ * hb_buffer_get_replacement_codepoint:
+ * @buffer: an #hb_buffer_t.
+ *
+ * See hb_buffer_set_replacement_codepoint().
+ *
+ * Return value: 
+ * The @buffer replacement #hb_codepoint_t.
+ *
+ * Since: 0.9.31
+ **/
+hb_codepoint_t
+hb_buffer_get_replacement_codepoint (hb_buffer_t    *buffer)
+{
+  return buffer->replacement;
+}
+
+
+/**
+ * hb_buffer_reset:
+ * @buffer: an #hb_buffer_t.
+ *
+ * Resets the buffer to its initial status, as if it was just newly created
+ * with hb_buffer_create().
+ *
+ * Since: 0.9.2
+ **/
+void
+hb_buffer_reset (hb_buffer_t *buffer)
+{
+  buffer->reset ();
+}
+
+/**
+ * hb_buffer_clear_contents:
+ * @buffer: an #hb_buffer_t.
+ *
+ * Similar to hb_buffer_reset(), but does not clear the Unicode functions and
+ * the replacement code point.
+ *
+ * Since: 0.9.11
+ **/
+void
+hb_buffer_clear_contents (hb_buffer_t *buffer)
+{
+  buffer->clear ();
+}
+
+/**
+ * hb_buffer_pre_allocate:
+ * @buffer: an #hb_buffer_t.
+ * @size: number of items to pre allocate.
+ *
+ * Pre allocates memory for @buffer to fit at least @size number of items.
+ *
+ * Return value:
+ * %true if @buffer memory allocation succeeded, %false otherwise.
+ *
+ * Since: 0.9.2
+ **/
+hb_bool_t
+hb_buffer_pre_allocate (hb_buffer_t *buffer, unsigned int size)
+{
+  return buffer->ensure (size);
+}
+
+/**
+ * hb_buffer_allocation_successful:
+ * @buffer: an #hb_buffer_t.
+ *
+ * Check if allocating memory for the buffer succeeded.
+ *
+ * Return value:
+ * %true if @buffer memory allocation succeeded, %false otherwise.
+ *
+ * Since: 0.9.2
+ **/
+hb_bool_t
+hb_buffer_allocation_successful (hb_buffer_t  *buffer)
+{
+  return !buffer->in_error;
+}
+
+/**
+ * hb_buffer_add:
+ * @buffer: an #hb_buffer_t.
+ * @codepoint: a Unicode code point.
+ * @cluster: the cluster value of @codepoint.
+ *
+ * Appends a character with the Unicode value of @codepoint to @buffer, and
+ * gives it the initial cluster value of @cluster. Clusters can be any thing
+ * the client wants, they are usually used to refer to the index of the
+ * character in the input text stream and are output in
+ * #hb_glyph_info_t.cluster field.
+ *
+ * This function does not check the validity of @codepoint, it is up to the
+ * caller to ensure it is a valid Unicode code point.
+ *
+ * Since: 0.9.7
+ **/
+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: an #hb_buffer_t.
+ * @length: the new length of @buffer.
+ *
+ * Similar to hb_buffer_pre_allocate(), but clears any new items added at the
+ * end.
+ *
+ * Return value: 
+ * %true if @buffer memory allocation succeeded, %false otherwise.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ *
+ * Returns the number of items in the buffer.
+ *
+ * Return value:
+ * The @buffer length.
+ * The value valid as long as buffer has not been modified.
+ *
+ * Since: 0.9.2
+ **/
+unsigned int
+hb_buffer_get_length (hb_buffer_t *buffer)
+{
+  return buffer->len;
+}
+
+/**
+ * hb_buffer_get_glyph_infos:
+ * @buffer: an #hb_buffer_t.
+ * @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):
+ * The @buffer glyph information array.
+ * The value valid as long as buffer has not been modified.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ * @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):
+ * The @buffer glyph position array.
+ * The value valid as long as buffer has not been modified.
+ *
+ * Since: 0.9.2
+ **/
+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: an #hb_buffer_t.
+ *
+ * Reverses buffer contents.
+ *
+ * Since: 0.9.2
+ **/
+void
+hb_buffer_reverse (hb_buffer_t *buffer)
+{
+  buffer->reverse ();
+}
+
+/**
+ * hb_buffer_reverse_range:
+ * @buffer: an #hb_buffer_t.
+ * @start: start index.
+ * @end: end index.
+ *
+ * Reverses buffer contents between start to end.
+ *
+ * Since: 0.9.41
+ **/
+void
+hb_buffer_reverse_range (hb_buffer_t *buffer,
+			 unsigned int start, unsigned int end)
+{
+  buffer->reverse_range (start, end);
+}
+
+/**
+ * hb_buffer_reverse_clusters:
+ * @buffer: an #hb_buffer_t.
+ *
+ * Reverses buffer clusters.  That is, the buffer contents are
+ * reversed, then each cluster (consecutive items having the
+ * same cluster number) are reversed again.
+ *
+ * Since: 0.9.2
+ **/
+void
+hb_buffer_reverse_clusters (hb_buffer_t *buffer)
+{
+  buffer->reverse_clusters ();
+}
+
+/**
+ * hb_buffer_guess_segment_properties:
+ * @buffer: an #hb_buffer_t.
+ *
+ * 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: 0.9.7
+ **/
+void
+hb_buffer_guess_segment_properties (hb_buffer_t *buffer)
+{
+  buffer->guess_segment_properties ();
+}
+
+template <typename utf_t>
+static inline void
+hb_buffer_add_utf (hb_buffer_t  *buffer,
+		   const typename utf_t::codepoint_t *text,
+		   int           text_length,
+		   unsigned int  item_offset,
+		   int           item_length)
+{
+  typedef typename utf_t::codepoint_t T;
+  const hb_codepoint_t replacement = buffer->replacement;
+
+  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 = utf_t::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 = utf_t::prev (prev, start, &u, replacement);
+      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 = utf_t::next (next, end, &u, replacement);
+    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 = utf_t::next (next, end, &u, replacement);
+    buffer->context[1][buffer->context_len[1]++] = u;
+  }
+
+  buffer->content_type = HB_BUFFER_CONTENT_TYPE_UNICODE;
+}
+
+/**
+ * hb_buffer_add_utf8:
+ * @buffer: an #hb_buffer_t.
+ * @text: (array length=text_length) (element-type uint8_t): an array of UTF-8
+ *               characters to append.
+ * @text_length: the length of the @text, or -1 if it is %NULL terminated.
+ * @item_offset: the offset of the first character to add to the @buffer.
+ * @item_length: the number of characters to add to the @buffer, or -1 for the
+ *               end of @text (assuming it is %NULL terminated).
+ *
+ * See hb_buffer_add_codepoints().
+ *
+ * Replaces invalid UTF-8 characters with the @buffer replacement code point,
+ * see hb_buffer_set_replacement_codepoint().
+ *
+ * Since: 0.9.2
+ **/
+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<hb_utf8_t> (buffer, (const uint8_t *) text, text_length, item_offset, item_length);
+}
+
+/**
+ * hb_buffer_add_utf16:
+ * @buffer: an #hb_buffer_t.
+ * @text: (array length=text_length): an array of UTF-16 characters to append.
+ * @text_length: the length of the @text, or -1 if it is %NULL terminated.
+ * @item_offset: the offset of the first character to add to the @buffer.
+ * @item_length: the number of characters to add to the @buffer, or -1 for the
+ *               end of @text (assuming it is %NULL terminated).
+ *
+ * See hb_buffer_add_codepoints().
+ *
+ * Replaces invalid UTF-16 characters with the @buffer replacement code point,
+ * see hb_buffer_set_replacement_codepoint().
+ *
+ * Since: 0.9.2
+ **/
+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<hb_utf16_t> (buffer, text, text_length, item_offset, item_length);
+}
+
+/**
+ * hb_buffer_add_utf32:
+ * @buffer: an #hb_buffer_t.
+ * @text: (array length=text_length): an array of UTF-32 characters to append.
+ * @text_length: the length of the @text, or -1 if it is %NULL terminated.
+ * @item_offset: the offset of the first character to add to the @buffer.
+ * @item_length: the number of characters to add to the @buffer, or -1 for the
+ *               end of @text (assuming it is %NULL terminated).
+ *
+ * See hb_buffer_add_codepoints().
+ *
+ * Replaces invalid UTF-32 characters with the @buffer replacement code point,
+ * see hb_buffer_set_replacement_codepoint().
+ *
+ * Since: 0.9.2
+ **/
+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<hb_utf32_t<> > (buffer, text, text_length, item_offset, item_length);
+}
+
+/**
+ * hb_buffer_add_latin1:
+ * @buffer: an #hb_buffer_t.
+ * @text: (array length=text_length) (element-type uint8_t): an array of UTF-8
+ *               characters to append.
+ * @text_length: the length of the @text, or -1 if it is %NULL terminated.
+ * @item_offset: the offset of the first character to add to the @buffer.
+ * @item_length: the number of characters to add to the @buffer, or -1 for the
+ *               end of @text (assuming it is %NULL terminated).
+ *
+ * Similar to hb_buffer_add_codepoints(), but allows only access to first 256
+ * Unicode code points that can fit in 8-bit strings.
+ *
+ * <note>Has nothing to do with non-Unicode Latin-1 encoding.</note>
+ *
+ * Since: 0.9.39
+ **/
+void
+hb_buffer_add_latin1 (hb_buffer_t   *buffer,
+		      const uint8_t *text,
+		      int            text_length,
+		      unsigned int   item_offset,
+		      int            item_length)
+{
+  hb_buffer_add_utf<hb_latin1_t> (buffer, text, text_length, item_offset, item_length);
+}
+
+/**
+ * hb_buffer_add_codepoints:
+ * @buffer: a #hb_buffer_t to append characters to.
+ * @text: (array length=text_length): an array of Unicode code points to append.
+ * @text_length: the length of the @text, or -1 if it is %NULL terminated.
+ * @item_offset: the offset of the first code point to add to the @buffer.
+ * @item_length: the number of code points to add to the @buffer, or -1 for the
+ *               end of @text (assuming it is %NULL terminated).
+ *
+ * Appends characters from @text array to @buffer. The @item_offset is the
+ * position of the first character from @text that will be appended, and
+ * @item_length is the number of character. When shaping part of a larger text
+ * (e.g. a run of text from a paragraph), instead of passing just the substring
+ * corresponding to the run, it is preferable to pass the whole
+ * paragraph and specify the run start and length as @item_offset and
+ * @item_length, respectively, to give HarfBuzz the full context to be able,
+ * for example, to do cross-run Arabic shaping or properly handle combining
+ * marks at stat of run.
+ *
+ * This function does not check the validity of @text, it is up to the caller
+ * to ensure it contains a valid Unicode code points.
+ *
+ * Since: 0.9.31
+ **/
+void
+hb_buffer_add_codepoints (hb_buffer_t          *buffer,
+			  const hb_codepoint_t *text,
+			  int                   text_length,
+			  unsigned int          item_offset,
+			  int                   item_length)
+{
+  hb_buffer_add_utf<hb_utf32_t<false> > (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_stable_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_stable_sort (buffer->info + start + 1, end - start - 1, compare_info_codepoint, buffer->pos + start + 1);
+  }
+}
+
+/**
+ * hb_buffer_normalize_glyphs:
+ * @buffer: an #hb_buffer_t.
+ *
+ * Reorders a glyph buffer to have canonical in-cluster glyph order / position.
+ * The resulting clusters should behave identical to pre-reordering clusters.
+ *
+ * <note>This has nothing to do with Unicode normalization.</note>
+ *
+ * Since: 0.9.2
+ **/
+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);
+}
+
+void
+hb_buffer_t::sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *))
+{
+  assert (!have_positions);
+  for (unsigned int i = start + 1; i < end; i++)
+  {
+    unsigned int j = i;
+    while (j > start && compar (&info[j - 1], &info[i]) > 0)
+      j--;
+    if (i == j)
+      continue;
+    /* Move item i to occupy place for item j, shift what's in between. */
+    merge_clusters (j, i + 1);
+    {
+      hb_glyph_info_t t = info[i];
+      memmove (&info[j + 1], &info[j], (i - j) * sizeof (hb_glyph_info_t));
+      info[j] = t;
+    }
+  }
+}
+
+/*
+ * Debugging.
+ */
+
+/**
+ * hb_buffer_set_message_func:
+ * @buffer: an #hb_buffer_t.
+ * @func: (closure user_data) (destroy destroy) (scope notified):
+ * @user_data:
+ * @destroy:
+ *
+ * 
+ *
+ * Since: 1.1.3
+ **/
+void
+hb_buffer_set_message_func (hb_buffer_t *buffer,
+			    hb_buffer_message_func_t func,
+			    void *user_data, hb_destroy_func_t destroy)
+{
+  if (buffer->message_destroy)
+    buffer->message_destroy (buffer->message_data);
+
+  if (func) {
+    buffer->message_func = func;
+    buffer->message_data = user_data;
+    buffer->message_destroy = destroy;
+  } else {
+    buffer->message_func = NULL;
+    buffer->message_data = NULL;
+    buffer->message_destroy = NULL;
+  }
+}
+
+bool
+hb_buffer_t::message_impl (hb_font_t *font, const char *fmt, va_list ap)
+{
+  char buf[100];
+  vsnprintf (buf, sizeof (buf),  fmt, ap);
+  return (bool) this->message_func (this, font, buf, this->message_data);
+}