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+/*
+ * 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.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
+#include "hb-ot-shape-complex-khmer.hh"
+#include "hb-ot-shape-complex-khmer-machine.hh"
+#include "hb-ot-layout.hh"
+
+
+/*
+ * Khmer shaper.
+ */
+
+static const hb_ot_map_feature_t
+khmer_features[] =
+{
+ /*
+ * Basic features.
+ * These features are applied in order, one at a time, after reordering.
+ */
+ {HB_TAG('p','r','e','f'), F_MANUAL_JOINERS},
+ {HB_TAG('b','l','w','f'), F_MANUAL_JOINERS},
+ {HB_TAG('a','b','v','f'), F_MANUAL_JOINERS},
+ {HB_TAG('p','s','t','f'), F_MANUAL_JOINERS},
+ {HB_TAG('c','f','a','r'), F_MANUAL_JOINERS},
+ /*
+ * Other features.
+ * These features are applied all at once after clearing syllables.
+ */
+ {HB_TAG('p','r','e','s'), F_GLOBAL_MANUAL_JOINERS},
+ {HB_TAG('a','b','v','s'), F_GLOBAL_MANUAL_JOINERS},
+ {HB_TAG('b','l','w','s'), F_GLOBAL_MANUAL_JOINERS},
+ {HB_TAG('p','s','t','s'), F_GLOBAL_MANUAL_JOINERS},
+};
+
+/*
+ * Must be in the same order as the khmer_features array.
+ */
+enum {
+ KHMER_PREF,
+ KHMER_BLWF,
+ KHMER_ABVF,
+ KHMER_PSTF,
+ KHMER_CFAR,
+
+ _KHMER_PRES,
+ _KHMER_ABVS,
+ _KHMER_BLWS,
+ _KHMER_PSTS,
+
+ KHMER_NUM_FEATURES,
+ KHMER_BASIC_FEATURES = _KHMER_PRES, /* Don't forget to update this! */
+};
+
+static void
+setup_syllables_khmer (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer);
+static void
+reorder_khmer (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer);
+
+static void
+collect_features_khmer (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_khmer);
+ map->add_gsub_pause (reorder_khmer);
+
+ /* Testing suggests that Uniscribe does NOT pause between basic
+ * features. Test with KhmerUI.ttf and the following three
+ * sequences:
+ *
+ * U+1789,U+17BC
+ * U+1789,U+17D2,U+1789
+ * U+1789,U+17D2,U+1789,U+17BC
+ *
+ * https://github.com/harfbuzz/harfbuzz/issues/974
+ */
+ map->enable_feature (HB_TAG('l','o','c','l'));
+ map->enable_feature (HB_TAG('c','c','m','p'));
+
+ unsigned int i = 0;
+ for (; i < KHMER_BASIC_FEATURES; i++)
+ map->add_feature (khmer_features[i]);
+
+ map->add_gsub_pause (_hb_clear_syllables);
+
+ for (; i < KHMER_NUM_FEATURES; i++)
+ map->add_feature (khmer_features[i]);
+}
+
+static void
+override_features_khmer (hb_ot_shape_planner_t *plan)
+{
+ hb_ot_map_builder_t *map = &plan->map;
+
+ /* Khmer spec has 'clig' as part of required shaping features:
+ * "Apply feature 'clig' to form ligatures that are desired for
+ * typographical correctness.", hence in overrides... */
+ map->enable_feature (HB_TAG('c','l','i','g'));
+
+ /* Uniscribe does not apply 'kern' in Khmer. */
+ if (hb_options ().uniscribe_bug_compatible)
+ {
+ map->disable_feature (HB_TAG('k','e','r','n'));
+ }
+
+ map->disable_feature (HB_TAG('l','i','g','a'));
+}
+
+
+struct khmer_shape_plan_t
+{
+ hb_mask_t mask_array[KHMER_NUM_FEATURES];
+};
+
+static void *
+data_create_khmer (const hb_ot_shape_plan_t *plan)
+{
+ khmer_shape_plan_t *khmer_plan = (khmer_shape_plan_t *) calloc (1, sizeof (khmer_shape_plan_t));
+ if (unlikely (!khmer_plan))
+ return nullptr;
+
+ for (unsigned int i = 0; i < ARRAY_LENGTH (khmer_plan->mask_array); i++)
+ khmer_plan->mask_array[i] = (khmer_features[i].flags & F_GLOBAL) ?
+ 0 : plan->map.get_1_mask (khmer_features[i].tag);
+
+ return khmer_plan;
+}
+
+static void
+data_destroy_khmer (void *data)
+{
+ free (data);
+}
+
+static void
+setup_masks_khmer (const hb_ot_shape_plan_t *plan HB_UNUSED,
+ hb_buffer_t *buffer,
+ hb_font_t *font HB_UNUSED)
+{
+ HB_BUFFER_ALLOCATE_VAR (buffer, khmer_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_khmer_properties (info[i]);
+}
+
+static void
+setup_syllables_khmer (const hb_ot_shape_plan_t *plan HB_UNUSED,
+ hb_font_t *font HB_UNUSED,
+ hb_buffer_t *buffer)
+{
+ find_syllables_khmer (buffer);
+ foreach_syllable (buffer, start, end)
+ buffer->unsafe_to_break (start, end);
+}
+
+
+/* Rules from:
+ * https://docs.microsoft.com/en-us/typography/script-development/devanagari */
+
+static void
+reorder_consonant_syllable (const hb_ot_shape_plan_t *plan,
+ hb_face_t *face HB_UNUSED,
+ hb_buffer_t *buffer,
+ unsigned int start, unsigned int end)
+{
+ const khmer_shape_plan_t *khmer_plan = (const khmer_shape_plan_t *) plan->data;
+ hb_glyph_info_t *info = buffer->info;
+
+ /* Setup masks. */
+ {
+ /* Post-base */
+ hb_mask_t mask = khmer_plan->mask_array[KHMER_BLWF] |
+ khmer_plan->mask_array[KHMER_ABVF] |
+ khmer_plan->mask_array[KHMER_PSTF];
+ for (unsigned int i = start + 1; i < end; i++)
+ info[i].mask |= mask;
+ }
+
+ unsigned int num_coengs = 0;
+ for (unsigned int i = start + 1; i < end; i++)
+ {
+ /* """
+ * When a COENG + (Cons | IndV) combination are found (and subscript count
+ * is less than two) the character combination is handled according to the
+ * subscript type of the character following the COENG.
+ *
+ * ...
+ *
+ * Subscript Type 2 - The COENG + RO characters are reordered to immediately
+ * before the base glyph. Then the COENG + RO characters are assigned to have
+ * the 'pref' OpenType feature applied to them.
+ * """
+ */
+ if (info[i].khmer_category() == OT_Coeng && num_coengs <= 2 && i + 1 < end)
+ {
+ num_coengs++;
+
+ if (info[i + 1].khmer_category() == OT_Ra)
+ {
+ for (unsigned int j = 0; j < 2; j++)
+ info[i + j].mask |= khmer_plan->mask_array[KHMER_PREF];
+
+ /* Move the Coeng,Ro sequence to the start. */
+ buffer->merge_clusters (start, i + 2);
+ hb_glyph_info_t t0 = info[i];
+ hb_glyph_info_t t1 = info[i + 1];
+ memmove (&info[start + 2], &info[start], (i - start) * sizeof (info[0]));
+ info[start] = t0;
+ info[start + 1] = t1;
+
+ /* Mark the subsequent stuff with 'cfar'. Used in Khmer.
+ * Read the feature spec.
+ * This allows distinguishing the following cases with MS Khmer fonts:
+ * U+1784,U+17D2,U+179A,U+17D2,U+1782
+ * U+1784,U+17D2,U+1782,U+17D2,U+179A
+ */
+ if (khmer_plan->mask_array[KHMER_CFAR])
+ for (unsigned int j = i + 2; j < end; j++)
+ info[j].mask |= khmer_plan->mask_array[KHMER_CFAR];
+
+ num_coengs = 2; /* Done. */
+ }
+ }
+
+ /* Reorder left matra piece. */
+ else if (info[i].khmer_category() == OT_VPre)
+ {
+ /* Move to the start. */
+ buffer->merge_clusters (start, i + 1);
+ hb_glyph_info_t t = info[i];
+ memmove (&info[start + 1], &info[start], (i - start) * sizeof (info[0]));
+ info[start] = t;
+ }
+ }
+}
+
+static void
+reorder_syllable_khmer (const hb_ot_shape_plan_t *plan,
+ hb_face_t *face,
+ hb_buffer_t *buffer,
+ unsigned int start, unsigned int end)
+{
+ khmer_syllable_type_t syllable_type = (khmer_syllable_type_t) (buffer->info[start].syllable() & 0x0F);
+ switch (syllable_type)
+ {
+ case khmer_broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */
+ case khmer_consonant_syllable:
+ reorder_consonant_syllable (plan, face, buffer, start, end);
+ break;
+
+ case khmer_non_khmer_cluster:
+ break;
+ }
+}
+
+static void
+reorder_khmer (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer)
+{
+ if (buffer->message (font, "start reordering khmer"))
+ {
+ hb_syllabic_insert_dotted_circles (font, buffer,
+ khmer_broken_cluster,
+ OT_DOTTEDCIRCLE,
+ OT_Repha);
+
+ foreach_syllable (buffer, start, end)
+ reorder_syllable_khmer (plan, font->face, buffer, start, end);
+ (void) buffer->message (font, "end reordering khmer");
+ }
+ HB_BUFFER_DEALLOCATE_VAR (buffer, khmer_category);
+}
+
+
+static bool
+decompose_khmer (const hb_ot_shape_normalize_context_t *c,
+ hb_codepoint_t ab,
+ hb_codepoint_t *a,
+ hb_codepoint_t *b)
+{
+ switch (ab)
+ {
+ /*
+ * Decompose split matras that don't have Unicode decompositions.
+ */
+
+ /* Khmer */
+ case 0x17BEu : *a = 0x17C1u; *b= 0x17BEu; return true;
+ case 0x17BFu : *a = 0x17C1u; *b= 0x17BFu; return true;
+ case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true;
+ case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true;
+ case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true;
+ }
+
+ return (bool) c->unicode->decompose (ab, a, b);
+}
+
+static bool
+compose_khmer (const hb_ot_shape_normalize_context_t *c,
+ hb_codepoint_t a,
+ hb_codepoint_t b,
+ hb_codepoint_t *ab)
+{
+ /* Avoid recomposing split matras. */
+ if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
+ return false;
+
+ return (bool) c->unicode->compose (a, b, ab);
+}
+
+
+const hb_ot_complex_shaper_t _hb_ot_complex_shaper_khmer =
+{
+ collect_features_khmer,
+ override_features_khmer,
+ data_create_khmer,
+ data_destroy_khmer,
+ nullptr, /* preprocess_text */
+ nullptr, /* postprocess_glyphs */
+ HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
+ decompose_khmer,
+ compose_khmer,
+ setup_masks_khmer,
+ HB_TAG_NONE, /* gpos_tag */
+ nullptr, /* reorder_marks */
+ HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
+ false, /* fallback_position */
+};
+
+
+#endif
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