[USE] Start putting together the shaper body

src/hb-ot-shape-complex-use-private.hh

@@ -131,7 +131,7 @@ enum indic_syllabic_category_t
 };
 
 /* Categories used in IndicPositionalCategory.txt from UCD */
-enum indic_matra_category_t {
+enum indic_positional_category_t {
   INDIC_POSITIONAL_CATEGORY_BOTTOM,
   INDIC_POSITIONAL_CATEGORY_BOTTOM_AND_RIGHT,
   INDIC_POSITIONAL_CATEGORY_LEFT,

src/hb-ot-shape-complex-use.cc

+/*
+ * Copyright © 2015  Mozilla Foundation.
+ * Copyright © 2015  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.
+ *
+ * Mozilla Author(s): Jonathan Kew
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb-ot-shape-complex-use-private.hh"
+
+/* buffer var allocations */
+#define use_category() complex_var_u8_0()
+
+
+/*
+ * Universal Shaping Engine.
+ * https://www.microsoft.com/typography/OpenTypeDev/USE/intro.htm
+ */
+
+static const hb_tag_t
+basic_features[] =
+{
+  /*
+   * Basic features.
+   * These features are applied in order, one at a time, after initial_reordering.
+   */
+  HB_TAG('p','r','e','f'),
+  HB_TAG('a','b','v','f'),
+  HB_TAG('b','l','w','f'),
+  HB_TAG('p','s','t','f'),
+};
+static const hb_tag_t
+other_features[] =
+{
+  /*
+   * Other features.
+   * These features are applied all at once, after final_reordering.
+   */
+  HB_TAG('p','r','e','s'),
+  HB_TAG('a','b','v','s'),
+  HB_TAG('b','l','w','s'),
+  HB_TAG('p','s','t','s'),
+  /* Positioning features, though we don't care about the types. */
+  HB_TAG('d','i','s','t'),
+};
+
+static void
+setup_syllables (const hb_ot_shape_plan_t *plan,
+		 hb_font_t *font,
+		 hb_buffer_t *buffer);
+static void
+reordering (const hb_ot_shape_plan_t *plan,
+	    hb_font_t *font,
+	    hb_buffer_t *buffer);
+
+static void
+collect_features_use (hb_ot_shape_planner_t *plan)
+{
+  hb_ot_map_builder_t *map = &plan->map;
+
+  /* Do this before any lookups have been applied. */
+  map->add_gsub_pause (setup_syllables);
+
+  map->add_global_bool_feature (HB_TAG('l','o','c','l'));
+  /* The Indic specs do not require ccmp, but we apply it here since if
+   * there is a use of it, it's typically at the beginning. */
+  map->add_global_bool_feature (HB_TAG('c','c','m','p'));
+
+  for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
+  {
+    map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
+    map->add_gsub_pause (NULL);
+  }
+  map->add_gsub_pause (reordering);
+  for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
+    map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
+}
+
+static void
+override_features_use (hb_ot_shape_planner_t *plan)
+{
+  plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
+}
+
+
+enum syllable_type_t {
+  independent_cluster,
+  virama_terminated_cluster,
+  consonant_cluster,
+  vowel_cluster,
+  number_joiner_terminated_cluster,
+  numeral_cluster,
+  symbol_cluster,
+};
+
+#include "hb-ot-shape-complex-use-machine.hh"
+
+
+static inline void
+set_use_properties (hb_glyph_info_t &info)
+{
+  hb_codepoint_t u = info.codepoint;
+  unsigned int type = hb_use_get_categories (u);
+  indic_syllabic_category_t cat = (indic_syllabic_category_t) (type & 0x7Fu);
+  indic_positional_category_t pos = (indic_positional_category_t) (type >> 8);
+  use_category_t use = USE_O;
+
+  switch (cat)
+  {
+    /* TODO */
+  }
+
+  info.use_category() = use;
+}
+
+
+static void
+setup_masks_use (const hb_ot_shape_plan_t *plan HB_UNUSED,
+		 hb_buffer_t              *buffer,
+		 hb_font_t                *font HB_UNUSED)
+{
+  HB_BUFFER_ALLOCATE_VAR (buffer, use_category);
+
+  /* We cannot setup masks here.  We save information about characters
+   * and setup masks later on in a pause-callback. */
+
+  unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
+  for (unsigned int i = 0; i < count; i++)
+    set_use_properties (info[i]);
+}
+
+static void
+setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
+		 hb_font_t *font HB_UNUSED,
+		 hb_buffer_t *buffer)
+{
+  find_syllables (buffer);
+}
+
+
+static void
+reorder_virama_terminated_cluster (const hb_ot_shape_plan_t *plan,
+				   hb_face_t *face,
+				   hb_buffer_t *buffer,
+				   unsigned int start, unsigned int end)
+{
+}
+
+static void
+reorder_consonant_cluster (const hb_ot_shape_plan_t *plan,
+			   hb_face_t *face,
+			   hb_buffer_t *buffer,
+			   unsigned int start, unsigned int end)
+{
+  hb_glyph_info_t *info = buffer->info;
+
+  /* Reorder! */
+#if 0
+  unsigned int i = start;
+  for (; i < base; i++)
+    info[i].use_position() = POS_PRE_C;
+  if (i < end)
+  {
+    info[i].use_position() = POS_BASE_C;
+    i++;
+  }
+  for (; i < end; i++)
+  {
+    if (info[i].use_category() == OT_MR) /* Pre-base reordering */
+    {
+      info[i].use_position() = POS_PRE_C;
+      continue;
+    }
+    if (info[i].use_category() == OT_VPre) /* Left matra */
+    {
+      info[i].use_position() = POS_PRE_M;
+      continue;
+    }
+
+    info[i].use_position() = POS_AFTER_MAIN;
+  }
+
+  buffer->merge_clusters (start, end);
+  /* Sit tight, rock 'n roll! */
+  hb_bubble_sort (info + start, end - start, compare_use_order);
+#endif
+}
+
+static void
+reorder_vowel_cluster (const hb_ot_shape_plan_t *plan,
+		       hb_face_t *face,
+		       hb_buffer_t *buffer,
+		       unsigned int start, unsigned int end)
+{
+  reorder_consonant_cluster (plan, face, buffer, start, end);
+}
+
+static void
+reorder_syllable (const hb_ot_shape_plan_t *plan,
+		  hb_face_t *face,
+		  hb_buffer_t *buffer,
+		  unsigned int start, unsigned int end)
+{
+  syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
+  switch (syllable_type) {
+#define HANDLE(X) case X: reorder_##X (plan, face, buffer, start, end); return
+    HANDLE (virama_terminated_cluster);
+    HANDLE (consonant_cluster);
+    HANDLE (vowel_cluster);
+#undef HANDLE
+#define HANDLE(X) case X: return
+    HANDLE (number_joiner_terminated_cluster);
+    HANDLE (numeral_cluster);
+    HANDLE (symbol_cluster);
+    HANDLE (independent_cluster);
+#undef HANDLE
+  }
+}
+
+static inline void
+insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
+		       hb_font_t *font,
+		       hb_buffer_t *buffer)
+{
+#if 0
+  /* Note: This loop is extra overhead, but should not be measurable. */
+  bool has_broken_syllables = false;
+  unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
+  for (unsigned int i = 0; i < count; i++)
+    if ((info[i].syllable() & 0x0F) == broken_cluster)
+    {
+      has_broken_syllables = true;
+      break;
+    }
+  if (likely (!has_broken_syllables))
+    return;
+
+
+  hb_codepoint_t dottedcircle_glyph;
+  if (!font->get_glyph (0x25CCu, 0, &dottedcircle_glyph))
+    return;
+
+  hb_glyph_info_t dottedcircle = {0};
+  dottedcircle.codepoint = 0x25CCu;
+  set_use_properties (dottedcircle);
+  dottedcircle.codepoint = dottedcircle_glyph;
+
+  buffer->clear_output ();
+
+  buffer->idx = 0;
+  unsigned int last_syllable = 0;
+  while (buffer->idx < buffer->len)
+  {
+    unsigned int syllable = buffer->cur().syllable();
+    syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
+    if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
+    {
+      last_syllable = syllable;
+
+      hb_glyph_info_t info = dottedcircle;
+      info.cluster = buffer->cur().cluster;
+      info.mask = buffer->cur().mask;
+      info.syllable() = buffer->cur().syllable();
+
+      buffer->output_info (info);
+    }
+    else
+      buffer->next_glyph ();
+  }
+
+  buffer->swap_buffers ();
+#endif
+}
+
+static void
+reordering (const hb_ot_shape_plan_t *plan,
+	    hb_font_t *font,
+	    hb_buffer_t *buffer)
+{
+  insert_dotted_circles (plan, font, buffer);
+
+  hb_glyph_info_t *info = buffer->info;
+  unsigned int count = buffer->len;
+  if (unlikely (!count)) return;
+  unsigned int last = 0;
+  unsigned int last_syllable = info[0].syllable();
+  for (unsigned int i = 1; i < count; i++)
+    if (last_syllable != info[i].syllable()) {
+      reorder_syllable (plan, font->face, buffer, last, i);
+      last = i;
+      last_syllable = info[last].syllable();
+    }
+  reorder_syllable (plan, font->face, buffer, last, count);
+
+  /* Zero syllables now... */
+  for (unsigned int i = 0; i < count; i++)
+    info[i].syllable() = 0;
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);
+}
+
+
+const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
+{
+  "use",
+  collect_features_use,
+  override_features_use,
+  NULL, /* data_create */
+  NULL, /* data_destroy */
+  NULL, /* preprocess_text */
+  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
+  NULL, /* decompose */
+  NULL, /* compose */
+  setup_masks_use,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
+  false, /* fallback_position */
+};