diff --git a/src/hb-buffer.cc b/src/hb-buffer.cc
new file mode 100644
index 0000000..9588d5e
--- /dev/null
+++ b/src/hb-buffer.cc
@@ -0,0 +1,650 @@
+/*
+ * Copyright (C) 1998-2004  David Turner and Werner Lemberg
+ * Copyright (C) 2004,2007,2009,2010  Red Hat, 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
+ */
+
+#include "hb-buffer-private.hh"
+
+#include <string.h>
+
+
+static hb_buffer_t _hb_buffer_nil = {
+  HB_REFERENCE_COUNT_INVALID, /* ref_count */
+
+  &_hb_unicode_funcs_nil  /* unicode */
+};
+
+/* 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 = (hb_internal_glyph_position_t *) 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);
+
+  buffer->unicode = &_hb_unicode_funcs_nil;
+
+  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);
+
+  hb_unicode_funcs_destroy (buffer->unicode);
+
+  free (buffer->in_string);
+  free (buffer->positions);
+
+  free (buffer);
+}
+
+
+void
+hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
+			     hb_unicode_funcs_t *unicode)
+{
+  if (!unicode)
+    unicode = &_hb_unicode_funcs_nil;
+
+  hb_unicode_funcs_reference (unicode);
+  hb_unicode_funcs_destroy (buffer->unicode);
+  buffer->unicode = unicode;
+}
+
+hb_unicode_funcs_t *
+hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer)
+{
+  return buffer->unicode;
+}
+
+void
+hb_buffer_set_direction (hb_buffer_t    *buffer,
+			 hb_direction_t  direction)
+
+{
+  buffer->direction = direction;
+}
+
+hb_direction_t
+hb_buffer_get_direction (hb_buffer_t    *buffer)
+{
+  return buffer->direction;
+}
+
+void
+hb_buffer_set_script (hb_buffer_t *buffer,
+		      hb_script_t  script)
+{
+  buffer->script = script;
+}
+
+hb_script_t
+hb_buffer_get_script (hb_buffer_t *buffer)
+{
+  return buffer->script;
+}
+
+void
+hb_buffer_set_language (hb_buffer_t   *buffer,
+			hb_language_t  language)
+{
+  buffer->language = language;
+}
+
+hb_language_t
+hb_buffer_get_language (hb_buffer_t *buffer)
+{
+  return buffer->language;
+}
+
+
+void
+hb_buffer_clear (hb_buffer_t *buffer)
+{
+  buffer->have_output = FALSE;
+  buffer->have_positions = 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 = (hb_internal_glyph_position_t *) realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));
+
+    if (buffer->out_string != buffer->in_string)
+    {
+      buffer->in_string = (hb_internal_glyph_info_t *) 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 = (hb_internal_glyph_info_t *) 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++;
+}
+
+
+/* HarfBuzz-Internal API */
+
+void
+_hb_buffer_clear_output (hb_buffer_t *buffer)
+{
+  buffer->have_output = TRUE;
+  buffer->have_positions = FALSE;
+  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;
+  buffer->have_positions = TRUE;
+
+  if (unlikely (!buffer->positions))
+  {
+    buffer->positions = (hb_internal_glyph_position_t *) 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 hb_codepoint_t *glyph_data,
+			      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 = glyph_data[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_glyphs_be16 (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)
+  {
+    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->out_pos++;
+    buffer->out_length = buffer->out_pos;
+  }
+
+  buffer->in_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_length (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_positions)
+    hb_buffer_clear_positions (buffer);
+
+  return (hb_glyph_position_t *) buffer->positions;
+}
+
+
+static void
+reverse_range (hb_buffer_t *buffer,
+	       unsigned int start,
+	       unsigned int end)
+{
+  unsigned int i, j;
+
+  for (i = start, j = end - 1; i < j; 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 = end - 1; i < j; i++, j--) {
+      hb_internal_glyph_position_t t;
+
+      t = buffer->positions[i];
+      buffer->positions[i] = buffer->positions[j];
+      buffer->positions[j] = t;
+    }
+  }
+}
+
+void
+hb_buffer_reverse (hb_buffer_t *buffer)
+{
+  if (unlikely (!buffer->in_length))
+    return;
+
+  reverse_range (buffer, 0, buffer->in_length);
+}
+
+void
+hb_buffer_reverse_clusters (hb_buffer_t *buffer)
+{
+  unsigned int i, start, count, last_cluster;
+
+  if (unlikely (!buffer->in_length))
+    return;
+
+  hb_buffer_reverse (buffer);
+
+  count = buffer->in_length;
+  start = 0;
+  last_cluster = buffer->in_string[0].cluster;
+  for (i = 1; i < count; i++) {
+    if (last_cluster != buffer->in_string[i].cluster) {
+      reverse_range (buffer, start, i);
+      start = i;
+      last_cluster = buffer->in_string[i].cluster;
+    }
+  }
+  reverse_range (buffer, start, i);
+}
+
+
+#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 (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 (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 HB_UNUSED,
+		    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 (unlikely (c >= 0xd800 && c < 0xdc00)) {
+    /* high surrogate */
+    uint16_t l;
+    if (text < end && ((l = *text), 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 HB_UNUSED,
+		     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 HB_UNUSED,
+		     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
+}