unicode: Cleanup implementation
diff --git a/src/hb-unicode.cc b/src/hb-unicode.cc
new file mode 100644
index 0000000..ddad884
--- /dev/null
+++ b/src/hb-unicode.cc
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2009  Red Hat, Inc.
+ * Copyright © 2011 Codethink Limited
+ * Copyright (C) 2010  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): Behdad Esfahbod
+ * Codethink Author(s): Ryan Lortie
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb-private.h"
+
+#include "hb-unicode-private.hh"
+
+HB_BEGIN_DECLS
+
+
+/*
+ * hb_unicode_funcs_t
+ */
+
+static unsigned int
+hb_unicode_get_combining_class_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
+				    hb_codepoint_t      unicode   HB_UNUSED,
+				    void               *user_data HB_UNUSED)
+{
+  return 0;
+}
+
+static unsigned int
+hb_unicode_get_eastasian_width_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
+				    hb_codepoint_t      unicode   HB_UNUSED,
+				    void               *user_data HB_UNUSED)
+{
+  return 1;
+}
+
+static hb_unicode_general_category_t
+hb_unicode_get_general_category_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
+				     hb_codepoint_t      unicode   HB_UNUSED,
+				     void               *user_data HB_UNUSED)
+{
+  return HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER;
+}
+
+static hb_codepoint_t
+hb_unicode_get_mirroring_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
+			      hb_codepoint_t      unicode   HB_UNUSED,
+			      void               *user_data HB_UNUSED)
+{
+  return unicode;
+}
+
+static hb_script_t
+hb_unicode_get_script_nil (hb_unicode_funcs_t *ufuncs    HB_UNUSED,
+			   hb_codepoint_t      unicode   HB_UNUSED,
+			   void               *user_data HB_UNUSED)
+{
+  return HB_SCRIPT_UNKNOWN;
+}
+
+
+hb_unicode_funcs_t _hb_unicode_funcs_nil = {
+  HB_REFERENCE_COUNT_INVALID, /* ref_count */
+  NULL, /* parent */
+  TRUE, /* immutable */
+  {
+    hb_unicode_get_combining_class_nil,
+    hb_unicode_get_eastasian_width_nil,
+    hb_unicode_get_general_category_nil,
+    hb_unicode_get_mirroring_nil,
+    hb_unicode_get_script_nil,
+  }
+};
+
+
+hb_unicode_funcs_t *
+hb_unicode_funcs_create (hb_unicode_funcs_t *parent)
+{
+  hb_unicode_funcs_t *ufuncs;
+
+  if (!HB_OBJECT_DO_CREATE (hb_unicode_funcs_t, ufuncs))
+    return &_hb_unicode_funcs_nil;
+
+  if (parent != NULL)
+  {
+    hb_unicode_funcs_make_immutable (parent);
+    ufuncs->parent = hb_unicode_funcs_reference (parent);
+
+    ufuncs->get = parent->get;
+
+    /* We can safely copy user_data from parent since we hold a reference
+     * onto it and it's immutable.  We should not copy the destroy notifiers
+     * though. */
+    ufuncs->user_data = parent->user_data;
+  }
+  else
+  {
+    ufuncs->get = _hb_unicode_funcs_nil.get;
+  }
+
+  return ufuncs;
+}
+
+hb_unicode_funcs_t *
+hb_unicode_funcs_reference (hb_unicode_funcs_t *ufuncs)
+{
+  HB_OBJECT_DO_REFERENCE (ufuncs);
+}
+
+unsigned int
+hb_unicode_funcs_get_reference_count (hb_unicode_funcs_t *ufuncs)
+{
+  HB_OBJECT_DO_GET_REFERENCE_COUNT (ufuncs);
+}
+
+void
+hb_unicode_funcs_destroy (hb_unicode_funcs_t *ufuncs)
+{
+  HB_OBJECT_DO_DESTROY (ufuncs);
+
+#define DESTROY(name) if (ufuncs->destroy.name) ufuncs->destroy.name (ufuncs->user_data.name)
+  DESTROY (combining_class);
+  DESTROY (eastasian_width);
+  DESTROY (general_category);
+  DESTROY (mirroring);
+  DESTROY (script);
+#undef DESTROY
+
+  if (ufuncs->parent != NULL)
+    hb_unicode_funcs_destroy (ufuncs->parent);
+
+  free (ufuncs);
+}
+
+void
+hb_unicode_funcs_make_immutable (hb_unicode_funcs_t *ufuncs)
+{
+  if (HB_OBJECT_IS_INERT (ufuncs))
+    return;
+
+  ufuncs->immutable = TRUE;
+}
+
+hb_bool_t
+hb_unicode_funcs_is_immutable (hb_unicode_funcs_t *ufuncs)
+{
+  return ufuncs->immutable;
+}
+
+hb_unicode_funcs_t *
+hb_unicode_funcs_get_parent (hb_unicode_funcs_t *ufuncs)
+{
+  return ufuncs->parent;
+}
+
+
+#define IMPLEMENT(return_type, name)                                           \
+                                                                               \
+void                                                                           \
+hb_unicode_funcs_set_##name##_func (hb_unicode_funcs_t             *ufuncs,    \
+                                    hb_unicode_get_##name##_func_t  func,      \
+                                    void                           *user_data, \
+                                    hb_destroy_func_t               destroy)   \
+{                                                                              \
+  if (ufuncs->immutable)                                                       \
+    return;                                                                    \
+                                                                               \
+  if (ufuncs->destroy.name)                                                    \
+    ufuncs->destroy.name (ufuncs->user_data.name);                             \
+                                                                               \
+  if (func) {                                                                  \
+    ufuncs->get.name = func;                                                   \
+    ufuncs->user_data.name = user_data;                                        \
+    ufuncs->destroy.name = destroy;                                            \
+  } else if (ufuncs->parent != NULL) {                                         \
+    ufuncs->get.name = ufuncs->parent->get.name;                               \
+    ufuncs->user_data.name = ufuncs->parent->user_data.name;                   \
+    ufuncs->destroy.name = NULL;                                               \
+  } else {                                                                     \
+    ufuncs->get.name = hb_unicode_get_##name##_nil;                            \
+    ufuncs->user_data.name = NULL;                                             \
+    ufuncs->destroy.name = NULL;                                               \
+  }                                                                            \
+}                                                                              \
+                                                                               \
+return_type                                                                    \
+hb_unicode_get_##name (hb_unicode_funcs_t *ufuncs,                             \
+		       hb_codepoint_t      unicode)                            \
+{                                                                              \
+  return ufuncs->get.name (ufuncs, unicode, ufuncs->user_data.name);           \
+}
+
+IMPLEMENT (unsigned int, combining_class)
+IMPLEMENT (unsigned int, eastasian_width)
+IMPLEMENT (hb_unicode_general_category_t, general_category)
+IMPLEMENT (hb_codepoint_t, mirroring)
+IMPLEMENT (hb_script_t, script)
+
+#undef IMPLEMENT
+
+
+HB_END_DECLS