Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 681 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-buffer.hh b/gfx/harfbuzz/src/hb-buffer.hh
new file mode 100644
index 0000000000..f04ad58f11
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-buffer.hh
@@ -0,0 +1,681 @@
+/*
+ * 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
+ */
+
+#ifndef HB_BUFFER_HH
+#define HB_BUFFER_HH
+
+#include "hb.hh"
+#include "hb-unicode.hh"
+#include "hb-set-digest.hh"
+
+
+static_assert ((sizeof (hb_glyph_info_t) == 20), "");
+static_assert ((sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t)), "");
+
+HB_MARK_AS_FLAG_T (hb_glyph_flags_t);
+HB_MARK_AS_FLAG_T (hb_buffer_flags_t);
+HB_MARK_AS_FLAG_T (hb_buffer_serialize_flags_t);
+HB_MARK_AS_FLAG_T (hb_buffer_diff_flags_t);
+
+enum hb_buffer_scratch_flags_t {
+  HB_BUFFER_SCRATCH_FLAG_DEFAULT			= 0x00000000u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII			= 0x00000001u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES		= 0x00000002u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_SPACE_FALLBACK		= 0x00000004u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT		= 0x00000008u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_CGJ			= 0x00000010u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_GLYPH_FLAGS		= 0x00000020u,
+  HB_BUFFER_SCRATCH_FLAG_HAS_BROKEN_SYLLABLE		= 0x00000040u,
+
+  /* Reserved for shapers' internal use. */
+  HB_BUFFER_SCRATCH_FLAG_SHAPER0			= 0x01000000u,
+  HB_BUFFER_SCRATCH_FLAG_SHAPER1			= 0x02000000u,
+  HB_BUFFER_SCRATCH_FLAG_SHAPER2			= 0x04000000u,
+  HB_BUFFER_SCRATCH_FLAG_SHAPER3			= 0x08000000u,
+};
+HB_MARK_AS_FLAG_T (hb_buffer_scratch_flags_t);
+
+
+/*
+ * hb_buffer_t
+ */
+
+struct hb_buffer_t
+{
+  hb_object_header_t header;
+
+  /*
+   * Information about how the text in the buffer should be treated.
+   */
+
+  hb_unicode_funcs_t *unicode; /* Unicode functions */
+  hb_buffer_flags_t flags; /* BOT / EOT / etc. */
+  hb_buffer_cluster_level_t cluster_level;
+  hb_codepoint_t replacement; /* U+FFFD or something else. */
+  hb_codepoint_t invisible; /* 0 or something else. */
+  hb_codepoint_t not_found; /* 0 or something else. */
+
+  /*
+   * Buffer contents
+   */
+
+  hb_buffer_content_type_t content_type;
+  hb_segment_properties_t props; /* Script, language, direction */
+
+  bool successful; /* Allocations successful */
+  bool shaping_failed; /* Shaping failure */
+  bool have_output; /* Whether we have an output buffer going on */
+  bool have_positions; /* Whether we have positions */
+
+  unsigned int idx; /* Cursor into ->info and ->pos arrays */
+  unsigned int len; /* Length of ->info and ->pos arrays */
+  unsigned int out_len; /* Length of ->out_info array if have_output */
+
+  unsigned int allocated; /* Length of allocated arrays */
+  hb_glyph_info_t     *info;
+  hb_glyph_info_t     *out_info;
+  hb_glyph_position_t *pos;
+
+  /* Text before / after the main buffer contents.
+   * Always in Unicode, and ordered outward.
+   * Index 0 is for "pre-context", 1 for "post-context". */
+  static constexpr unsigned CONTEXT_LENGTH = 5u;
+  hb_codepoint_t context[2][CONTEXT_LENGTH];
+  unsigned int context_len[2];
+
+
+  /*
+   * Managed by enter / leave
+   */
+
+  uint8_t allocated_var_bits;
+  uint8_t serial;
+  hb_buffer_scratch_flags_t scratch_flags; /* Have space-fallback, etc. */
+  unsigned int max_len; /* Maximum allowed len. */
+  int max_ops; /* Maximum allowed operations. */
+  /* The bits here reflect current allocations of the bytes in glyph_info_t's var1 and var2. */
+
+
+  /*
+   * Messaging callback
+   */
+
+#ifndef HB_NO_BUFFER_MESSAGE
+  hb_buffer_message_func_t message_func;
+  void *message_data;
+  hb_destroy_func_t message_destroy;
+  unsigned message_depth; /* How deeply are we inside a message callback? */
+#else
+  static constexpr unsigned message_depth = 0u;
+#endif
+
+
+
+  /* Methods */
+
+  HB_NODISCARD bool in_error () const { return !successful; }
+
+  void allocate_var (unsigned int start, unsigned int count)
+  {
+    unsigned int end = start + count;
+    assert (end <= 8);
+    unsigned int bits = (1u<<end) - (1u<<start);
+    assert (0 == (allocated_var_bits & bits));
+    allocated_var_bits |= bits;
+  }
+  bool try_allocate_var (unsigned int start, unsigned int count)
+  {
+    unsigned int end = start + count;
+    assert (end <= 8);
+    unsigned int bits = (1u<<end) - (1u<<start);
+    if (allocated_var_bits & bits)
+      return false;
+    allocated_var_bits |= bits;
+    return true;
+  }
+  void deallocate_var (unsigned int start, unsigned int count)
+  {
+    unsigned int end = start + count;
+    assert (end <= 8);
+    unsigned int bits = (1u<<end) - (1u<<start);
+    assert (bits == (allocated_var_bits & bits));
+    allocated_var_bits &= ~bits;
+  }
+  void assert_var (unsigned int start, unsigned int count)
+  {
+    unsigned int end = start + count;
+    assert (end <= 8);
+    HB_UNUSED unsigned int bits = (1u<<end) - (1u<<start);
+    assert (bits == (allocated_var_bits & bits));
+  }
+  void deallocate_var_all ()
+  {
+    allocated_var_bits = 0;
+  }
+
+  hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }
+  hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }
+
+  hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }
+  hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }
+
+  hb_glyph_info_t &prev ()      { return out_info[out_len ? out_len - 1 : 0]; }
+  hb_glyph_info_t prev () const { return out_info[out_len ? out_len - 1 : 0]; }
+
+  hb_set_digest_t digest () const
+  {
+    hb_set_digest_t d;
+    d.init ();
+    d.add_array (&info[0].codepoint, len, sizeof (info[0]));
+    return d;
+  }
+
+  HB_INTERNAL void similar (const hb_buffer_t &src);
+  HB_INTERNAL void reset ();
+  HB_INTERNAL void clear ();
+
+  /* Called around shape() */
+  HB_INTERNAL void enter ();
+  HB_INTERNAL void leave ();
+
+#ifndef HB_NO_BUFFER_VERIFY
+  HB_INTERNAL
+#endif
+  bool verify (hb_buffer_t        *text_buffer,
+	       hb_font_t          *font,
+	       const hb_feature_t *features,
+	       unsigned int        num_features,
+	       const char * const *shapers)
+#ifndef HB_NO_BUFFER_VERIFY
+  ;
+#else
+  { return true; }
+#endif
+
+  unsigned int backtrack_len () const { return have_output ? out_len : idx; }
+  unsigned int lookahead_len () const { return len - idx; }
+  uint8_t next_serial () { return ++serial ? serial : ++serial; }
+
+  HB_INTERNAL void add (hb_codepoint_t  codepoint,
+			unsigned int    cluster);
+  HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);
+
+  void reverse_range (unsigned start, unsigned end)
+  {
+    hb_array_t<hb_glyph_info_t> (info, len).reverse (start, end);
+    if (have_positions)
+      hb_array_t<hb_glyph_position_t> (pos, len).reverse (start, end);
+  }
+  void reverse () { reverse_range (0, len); }
+
+  template <typename FuncType>
+  void reverse_groups (const FuncType& group,
+		       bool merge_clusters = false)
+  {
+    if (unlikely (!len))
+      return;
+
+    unsigned start = 0;
+    unsigned i;
+    for (i = 1; i < len; i++)
+    {
+      if (!group (info[i - 1], info[i]))
+      {
+	if (merge_clusters)
+	  this->merge_clusters (start, i);
+	reverse_range (start, i);
+	start = i;
+      }
+    }
+    if (merge_clusters)
+      this->merge_clusters (start, i);
+    reverse_range (start, i);
+
+    reverse ();
+  }
+
+  template <typename FuncType>
+  unsigned group_end (unsigned start, const FuncType& group) const
+  {
+    while (++start < len && group (info[start - 1], info[start]))
+      ;
+
+    return start;
+  }
+
+  static bool _cluster_group_func (const hb_glyph_info_t& a,
+				   const hb_glyph_info_t& b)
+  { return a.cluster == b.cluster; }
+
+  void reverse_clusters () { reverse_groups (_cluster_group_func); }
+
+  HB_INTERNAL void guess_segment_properties ();
+
+  HB_INTERNAL bool sync ();
+  HB_INTERNAL int sync_so_far ();
+  HB_INTERNAL void clear_output ();
+  HB_INTERNAL void clear_positions ();
+
+  template <typename T>
+  HB_NODISCARD bool replace_glyphs (unsigned int num_in,
+				    unsigned int num_out,
+				    const T *glyph_data)
+  {
+    if (unlikely (!make_room_for (num_in, num_out))) return false;
+
+    assert (idx + num_in <= len);
+
+    merge_clusters (idx, idx + num_in);
+
+    hb_glyph_info_t &orig_info = idx < len ? cur() : prev();
+
+    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;
+    return true;
+  }
+
+  HB_NODISCARD bool replace_glyph (hb_codepoint_t glyph_index)
+  { return replace_glyphs (1, 1, &glyph_index); }
+
+  /* Makes a copy of the glyph at idx to output and replace glyph_index */
+  HB_NODISCARD bool output_glyph (hb_codepoint_t glyph_index)
+  { return replace_glyphs (0, 1, &glyph_index); }
+
+  HB_NODISCARD bool output_info (const hb_glyph_info_t &glyph_info)
+  {
+    if (unlikely (!make_room_for (0, 1))) return false;
+
+    out_info[out_len] = glyph_info;
+
+    out_len++;
+    return true;
+  }
+  /* Copies glyph at idx to output but doesn't advance idx */
+  HB_NODISCARD bool copy_glyph ()
+  {
+    /* Extra copy because cur()'s return can be freed within
+     * output_info() call if buffer reallocates. */
+    return output_info (hb_glyph_info_t (cur()));
+  }
+
+  /* Copies glyph at idx to output and advance idx.
+   * If there's no output, just advance idx. */
+  HB_NODISCARD bool next_glyph ()
+  {
+    if (have_output)
+    {
+      if (out_info != info || out_len != idx)
+      {
+	if (unlikely (!make_room_for (1, 1))) return false;
+	out_info[out_len] = info[idx];
+      }
+      out_len++;
+    }
+
+    idx++;
+    return true;
+  }
+  /* Copies n glyphs at idx to output and advance idx.
+   * If there's no output, just advance idx. */
+  HB_NODISCARD bool next_glyphs (unsigned int n)
+  {
+    if (have_output)
+    {
+      if (out_info != info || out_len != idx)
+      {
+	if (unlikely (!make_room_for (n, n))) return false;
+	memmove (out_info + out_len, info + idx, n * sizeof (out_info[0]));
+      }
+      out_len += n;
+    }
+
+    idx += n;
+    return true;
+  }
+  /* Advance idx without copying to output. */
+  void skip_glyph () { idx++; }
+  void reset_masks (hb_mask_t mask)
+  {
+    for (unsigned int j = 0; j < len; j++)
+      info[j].mask = mask;
+  }
+  void add_masks (hb_mask_t mask)
+  {
+    for (unsigned int j = 0; j < len; j++)
+      info[j].mask |= mask;
+  }
+  HB_INTERNAL void set_masks (hb_mask_t value, hb_mask_t mask,
+			      unsigned int cluster_start, unsigned int cluster_end);
+
+  void merge_clusters (unsigned int start, unsigned int end)
+  {
+    if (end - start < 2)
+      return;
+    merge_clusters_impl (start, end);
+  }
+  HB_INTERNAL void merge_clusters_impl (unsigned int start, unsigned int end);
+  HB_INTERNAL void merge_out_clusters (unsigned int start, unsigned int end);
+  /* Merge clusters for deleting current glyph, and skip it. */
+  HB_INTERNAL void delete_glyph ();
+  HB_INTERNAL void delete_glyphs_inplace (bool (*filter) (const hb_glyph_info_t *info));
+
+
+
+  /* Adds glyph flags in mask to infos with clusters between start and end.
+   * The start index will be from out-buffer if from_out_buffer is true.
+   * If interior is true, then the cluster having the minimum value is skipped. */
+  void _set_glyph_flags (hb_mask_t mask,
+			 unsigned start = 0,
+			 unsigned end = (unsigned) -1,
+			 bool interior = false,
+			 bool from_out_buffer = false)
+  {
+    end = hb_min (end, len);
+
+    if (interior && !from_out_buffer && end - start < 2)
+      return;
+
+    scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GLYPH_FLAGS;
+
+    if (!from_out_buffer || !have_output)
+    {
+      if (!interior)
+      {
+	for (unsigned i = start; i < end; i++)
+	  info[i].mask |= mask;
+      }
+      else
+      {
+	unsigned cluster = _infos_find_min_cluster (info, start, end);
+	_infos_set_glyph_flags (info, start, end, cluster, mask);
+      }
+    }
+    else
+    {
+      assert (start <= out_len);
+      assert (idx <= end);
+
+      if (!interior)
+      {
+	for (unsigned i = start; i < out_len; i++)
+	  out_info[i].mask |= mask;
+	for (unsigned i = idx; i < end; i++)
+	  info[i].mask |= mask;
+      }
+      else
+      {
+	unsigned cluster = _infos_find_min_cluster (info, idx, end);
+	cluster = _infos_find_min_cluster (out_info, start, out_len, cluster);
+
+	_infos_set_glyph_flags (out_info, start, out_len, cluster, mask);
+	_infos_set_glyph_flags (info, idx, end, cluster, mask);
+      }
+    }
+  }
+
+  void unsafe_to_break (unsigned int start = 0, unsigned int end = -1)
+  {
+    _set_glyph_flags (HB_GLYPH_FLAG_UNSAFE_TO_BREAK | HB_GLYPH_FLAG_UNSAFE_TO_CONCAT,
+		      start, end,
+		      true);
+  }
+  void safe_to_insert_tatweel (unsigned int start = 0, unsigned int end = -1)
+  {
+    if ((flags & HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL) == 0)
+    {
+      unsafe_to_break (start, end);
+      return;
+    }
+    _set_glyph_flags (HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL,
+		      start, end,
+		      true);
+  }
+#ifndef HB_OPTIMIZE_SIZE
+  HB_ALWAYS_INLINE
+#endif
+  void unsafe_to_concat (unsigned int start = 0, unsigned int end = -1)
+  {
+    if (likely ((flags & HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT) == 0))
+      return;
+    _set_glyph_flags (HB_GLYPH_FLAG_UNSAFE_TO_CONCAT,
+		      start, end,
+		      false);
+  }
+  void unsafe_to_break_from_outbuffer (unsigned int start = 0, unsigned int end = -1)
+  {
+    _set_glyph_flags (HB_GLYPH_FLAG_UNSAFE_TO_BREAK | HB_GLYPH_FLAG_UNSAFE_TO_CONCAT,
+		      start, end,
+		      true, true);
+  }
+#ifndef HB_OPTIMIZE_SIZE
+  HB_ALWAYS_INLINE
+#endif
+  void unsafe_to_concat_from_outbuffer (unsigned int start = 0, unsigned int end = -1)
+  {
+    if (likely ((flags & HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT) == 0))
+      return;
+    _set_glyph_flags (HB_GLYPH_FLAG_UNSAFE_TO_CONCAT,
+		      start, end,
+		      false, true);
+  }
+
+
+  /* Internal methods */
+  HB_NODISCARD HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */
+
+  HB_NODISCARD HB_INTERNAL bool enlarge (unsigned int size);
+
+  HB_NODISCARD bool resize (unsigned length)
+  {
+    assert (!have_output);
+    if (unlikely (!ensure (length))) return false;
+    len = length;
+    return true;
+  }
+  HB_NODISCARD bool ensure (unsigned int size)
+  { return likely (!size || size < allocated) ? true : enlarge (size); }
+
+  HB_NODISCARD bool ensure_inplace (unsigned int size)
+  { return likely (!size || size < allocated); }
+
+  void assert_glyphs ()
+  {
+    assert ((content_type == HB_BUFFER_CONTENT_TYPE_GLYPHS) ||
+	    (!len && (content_type == HB_BUFFER_CONTENT_TYPE_INVALID)));
+  }
+  void assert_unicode ()
+  {
+    assert ((content_type == HB_BUFFER_CONTENT_TYPE_UNICODE) ||
+	    (!len && (content_type == HB_BUFFER_CONTENT_TYPE_INVALID)));
+  }
+  HB_NODISCARD bool ensure_glyphs ()
+  {
+    if (unlikely (content_type != HB_BUFFER_CONTENT_TYPE_GLYPHS))
+    {
+      if (content_type != HB_BUFFER_CONTENT_TYPE_INVALID)
+	return false;
+      assert (len == 0);
+      content_type = HB_BUFFER_CONTENT_TYPE_GLYPHS;
+    }
+    return true;
+  }
+  HB_NODISCARD bool ensure_unicode ()
+  {
+    if (unlikely (content_type != HB_BUFFER_CONTENT_TYPE_UNICODE))
+    {
+      if (content_type != HB_BUFFER_CONTENT_TYPE_INVALID)
+	return false;
+      assert (len == 0);
+      content_type = HB_BUFFER_CONTENT_TYPE_UNICODE;
+    }
+    return true;
+  }
+
+  HB_NODISCARD HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);
+  HB_NODISCARD HB_INTERNAL bool shift_forward (unsigned int count);
+
+  typedef long scratch_buffer_t;
+  HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);
+
+  void clear_context (unsigned int side) { context_len[side] = 0; }
+
+  HB_INTERNAL void sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *));
+
+  bool messaging ()
+  {
+#ifdef HB_NO_BUFFER_MESSAGE
+    return false;
+#else
+    return unlikely (message_func);
+#endif
+  }
+  bool message (hb_font_t *font, const char *fmt, ...) HB_PRINTF_FUNC(3, 4)
+  {
+#ifdef HB_NO_BUFFER_MESSAGE
+    return true;
+#else
+    if (likely (!messaging ()))
+      return true;
+
+    va_list ap;
+    va_start (ap, fmt);
+    bool ret = message_impl (font, fmt, ap);
+    va_end (ap);
+
+    return ret;
+#endif
+  }
+  HB_INTERNAL bool message_impl (hb_font_t *font, const char *fmt, va_list ap) HB_PRINTF_FUNC(3, 0);
+
+  static void
+  set_cluster (hb_glyph_info_t &inf, unsigned int cluster, unsigned int mask = 0)
+  {
+    if (inf.cluster != cluster)
+      inf.mask = (inf.mask & ~HB_GLYPH_FLAG_DEFINED) | (mask & HB_GLYPH_FLAG_DEFINED);
+    inf.cluster = cluster;
+  }
+  void
+  _infos_set_glyph_flags (hb_glyph_info_t *infos,
+			  unsigned int start, unsigned int end,
+			  unsigned int cluster,
+			  hb_mask_t mask)
+  {
+    if (unlikely (start == end))
+      return;
+
+    unsigned cluster_first = infos[start].cluster;
+    unsigned cluster_last = infos[end - 1].cluster;
+
+    if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_CHARACTERS ||
+	(cluster != cluster_first && cluster != cluster_last))
+    {
+      for (unsigned int i = start; i < end; i++)
+	if (cluster != infos[i].cluster)
+	{
+	  scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GLYPH_FLAGS;
+	  infos[i].mask |= mask;
+	}
+      return;
+    }
+
+    /* Monotone clusters */
+
+    if (cluster == cluster_first)
+    {
+      for (unsigned int i = end; start < i && infos[i - 1].cluster != cluster_first; i--)
+      {
+	scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GLYPH_FLAGS;
+	infos[i - 1].mask |= mask;
+      }
+    }
+    else /* cluster == cluster_last */
+    {
+      for (unsigned int i = start; i < end && infos[i].cluster != cluster_last; i++)
+      {
+	scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GLYPH_FLAGS;
+	infos[i].mask |= mask;
+      }
+    }
+  }
+  unsigned
+  _infos_find_min_cluster (const hb_glyph_info_t *infos,
+			   unsigned start, unsigned end,
+			   unsigned cluster = UINT_MAX)
+  {
+    if (unlikely (start == end))
+      return cluster;
+
+    if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_CHARACTERS)
+    {
+      for (unsigned int i = start; i < end; i++)
+	cluster = hb_min (cluster, infos[i].cluster);
+      return cluster;
+    }
+
+    return hb_min (cluster, hb_min (infos[start].cluster, infos[end - 1].cluster));
+  }
+
+  void clear_glyph_flags (hb_mask_t mask = 0)
+  {
+    for (unsigned int i = 0; i < len; i++)
+      info[i].mask = (info[i].mask & ~HB_GLYPH_FLAG_DEFINED) | (mask & HB_GLYPH_FLAG_DEFINED);
+  }
+};
+DECLARE_NULL_INSTANCE (hb_buffer_t);
+
+
+#define foreach_group(buffer, start, end, group_func) \
+  for (unsigned int \
+       _count = buffer->len, \
+       start = 0, end = _count ? buffer->group_end (0, group_func) : 0; \
+       start < _count; \
+       start = end, end = buffer->group_end (start, group_func))
+
+#define foreach_cluster(buffer, start, end) \
+	foreach_group (buffer, start, end, hb_buffer_t::_cluster_group_func)
+
+
+#define HB_BUFFER_XALLOCATE_VAR(b, func, var) \
+  b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
+	   sizeof (b->info[0].var))
+#define HB_BUFFER_ALLOCATE_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, allocate_var,     var ())
+#define HB_BUFFER_TRY_ALLOCATE_VAR(b, var)	HB_BUFFER_XALLOCATE_VAR (b, try_allocate_var, var ())
+#define HB_BUFFER_DEALLOCATE_VAR(b, var)	HB_BUFFER_XALLOCATE_VAR (b, deallocate_var,   var ())
+#define HB_BUFFER_ASSERT_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, assert_var,       var ())
+
+
+#endif /* HB_BUFFER_HH */