--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/hb-ot-shaper-use.cc	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,511 @@
+/*
+ * 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.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
+#include "hb-ot-shaper-use-machine.hh"
+#include "hb-ot-shaper-use-table.hh"
+#include "hb-ot-shaper-arabic.hh"
+#include "hb-ot-shaper-arabic-joining-list.hh"
+#include "hb-ot-shaper-vowel-constraints.hh"
+
+
+/*
+ * Universal Shaping Engine.
+ * https://docs.microsoft.com/en-us/typography/script-development/use
+ */
+
+static const hb_tag_t
+use_basic_features[] =
+{
+  /*
+   * Basic features.
+   * These features are applied all at once, before reordering, constrained
+   * to the syllable.
+   */
+  HB_TAG('r','k','r','f'),
+  HB_TAG('a','b','v','f'),
+  HB_TAG('b','l','w','f'),
+  HB_TAG('h','a','l','f'),
+  HB_TAG('p','s','t','f'),
+  HB_TAG('v','a','t','u'),
+  HB_TAG('c','j','c','t'),
+};
+static const hb_tag_t
+use_topographical_features[] =
+{
+  HB_TAG('i','s','o','l'),
+  HB_TAG('i','n','i','t'),
+  HB_TAG('m','e','d','i'),
+  HB_TAG('f','i','n','a'),
+};
+/* Same order as use_topographical_features. */
+enum joining_form_t {
+  JOINING_FORM_ISOL,
+  JOINING_FORM_INIT,
+  JOINING_FORM_MEDI,
+  JOINING_FORM_FINA,
+  _JOINING_FORM_NONE
+};
+static const hb_tag_t
+use_other_features[] =
+{
+  /*
+   * Other features.
+   * These features are applied all at once, after reordering and
+   * clearing syllables.
+   */
+  HB_TAG('a','b','v','s'),
+  HB_TAG('b','l','w','s'),
+  HB_TAG('h','a','l','n'),
+  HB_TAG('p','r','e','s'),
+  HB_TAG('p','s','t','s'),
+};
+
+static bool
+setup_syllables_use (const hb_ot_shape_plan_t *plan,
+		     hb_font_t *font,
+		     hb_buffer_t *buffer);
+static bool
+record_rphf_use (const hb_ot_shape_plan_t *plan,
+		 hb_font_t *font,
+		 hb_buffer_t *buffer);
+static bool
+record_pref_use (const hb_ot_shape_plan_t *plan,
+		 hb_font_t *font,
+		 hb_buffer_t *buffer);
+static bool
+reorder_use (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_use);
+
+  /* "Default glyph pre-processing group" */
+  map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE);
+  map->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE);
+  map->enable_feature (HB_TAG('n','u','k','t'), F_PER_SYLLABLE);
+  map->enable_feature (HB_TAG('a','k','h','n'), F_MANUAL_ZWJ | F_PER_SYLLABLE);
+
+  /* "Reordering group" */
+  map->add_gsub_pause (_hb_clear_substitution_flags);
+  map->add_feature (HB_TAG('r','p','h','f'), F_MANUAL_ZWJ | F_PER_SYLLABLE);
+  map->add_gsub_pause (record_rphf_use);
+  map->add_gsub_pause (_hb_clear_substitution_flags);
+  map->enable_feature (HB_TAG('p','r','e','f'), F_MANUAL_ZWJ | F_PER_SYLLABLE);
+  map->add_gsub_pause (record_pref_use);
+
+  /* "Orthographic unit shaping group" */
+  for (unsigned int i = 0; i < ARRAY_LENGTH (use_basic_features); i++)
+    map->enable_feature (use_basic_features[i], F_MANUAL_ZWJ | F_PER_SYLLABLE);
+
+  map->add_gsub_pause (reorder_use);
+  map->add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var
+
+  /* "Topographical features" */
+  for (unsigned int i = 0; i < ARRAY_LENGTH (use_topographical_features); i++)
+    map->add_feature (use_topographical_features[i]);
+  map->add_gsub_pause (nullptr);
+
+  /* "Standard typographic presentation" */
+  for (unsigned int i = 0; i < ARRAY_LENGTH (use_other_features); i++)
+    map->enable_feature (use_other_features[i], F_MANUAL_ZWJ);
+}
+
+struct use_shape_plan_t
+{
+  hb_mask_t rphf_mask;
+
+  arabic_shape_plan_t *arabic_plan;
+};
+
+static void *
+data_create_use (const hb_ot_shape_plan_t *plan)
+{
+  use_shape_plan_t *use_plan = (use_shape_plan_t *) hb_calloc (1, sizeof (use_shape_plan_t));
+  if (unlikely (!use_plan))
+    return nullptr;
+
+  use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f'));
+
+  if (has_arabic_joining (plan->props.script))
+  {
+    use_plan->arabic_plan = (arabic_shape_plan_t *) data_create_arabic (plan);
+    if (unlikely (!use_plan->arabic_plan))
+    {
+      hb_free (use_plan);
+      return nullptr;
+    }
+  }
+
+  return use_plan;
+}
+
+static void
+data_destroy_use (void *data)
+{
+  use_shape_plan_t *use_plan = (use_shape_plan_t *) data;
+
+  if (use_plan->arabic_plan)
+    data_destroy_arabic (use_plan->arabic_plan);
+
+  hb_free (data);
+}
+
+static void
+setup_masks_use (const hb_ot_shape_plan_t *plan,
+		 hb_buffer_t              *buffer,
+		 hb_font_t                *font HB_UNUSED)
+{
+  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
+
+  /* Do this before allocating use_category(). */
+  if (use_plan->arabic_plan)
+  {
+    setup_masks_arabic_plan (use_plan->arabic_plan, buffer, plan->props.script);
+  }
+
+  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++)
+    info[i].use_category() = hb_use_get_category (info[i].codepoint);
+}
+
+static void
+setup_rphf_mask (const hb_ot_shape_plan_t *plan,
+		 hb_buffer_t *buffer)
+{
+  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
+
+  hb_mask_t mask = use_plan->rphf_mask;
+  if (!mask) return;
+
+  hb_glyph_info_t *info = buffer->info;
+
+  foreach_syllable (buffer, start, end)
+  {
+    unsigned int limit = info[start].use_category() == USE(R) ? 1 : hb_min (3u, end - start);
+    for (unsigned int i = start; i < start + limit; i++)
+      info[i].mask |= mask;
+  }
+}
+
+static void
+setup_topographical_masks (const hb_ot_shape_plan_t *plan,
+			   hb_buffer_t *buffer)
+{
+  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
+  if (use_plan->arabic_plan)
+    return;
+
+  static_assert ((JOINING_FORM_INIT < 4 && JOINING_FORM_ISOL < 4 && JOINING_FORM_MEDI < 4 && JOINING_FORM_FINA < 4), "");
+  hb_mask_t masks[4], all_masks = 0;
+  for (unsigned int i = 0; i < 4; i++)
+  {
+    masks[i] = plan->map.get_1_mask (use_topographical_features[i]);
+    if (masks[i] == plan->map.get_global_mask ())
+      masks[i] = 0;
+    all_masks |= masks[i];
+  }
+  if (!all_masks)
+    return;
+  hb_mask_t other_masks = ~all_masks;
+
+  unsigned int last_start = 0;
+  joining_form_t last_form = _JOINING_FORM_NONE;
+  hb_glyph_info_t *info = buffer->info;
+  foreach_syllable (buffer, start, end)
+  {
+    use_syllable_type_t syllable_type = (use_syllable_type_t) (info[start].syllable() & 0x0F);
+    switch (syllable_type)
+    {
+      case use_hieroglyph_cluster:
+      case use_non_cluster:
+	/* These don't join.  Nothing to do. */
+	last_form = _JOINING_FORM_NONE;
+	break;
+
+      case use_virama_terminated_cluster:
+      case use_sakot_terminated_cluster:
+      case use_standard_cluster:
+      case use_number_joiner_terminated_cluster:
+      case use_numeral_cluster:
+      case use_symbol_cluster:
+      case use_broken_cluster:
+
+	bool join = last_form == JOINING_FORM_FINA || last_form == JOINING_FORM_ISOL;
+
+	if (join)
+	{
+	  /* Fixup previous syllable's form. */
+	  last_form = last_form == JOINING_FORM_FINA ? JOINING_FORM_MEDI : JOINING_FORM_INIT;
+	  for (unsigned int i = last_start; i < start; i++)
+	    info[i].mask = (info[i].mask & other_masks) | masks[last_form];
+	}
+
+	/* Form for this syllable. */
+	last_form = join ? JOINING_FORM_FINA : JOINING_FORM_ISOL;
+	for (unsigned int i = start; i < end; i++)
+	  info[i].mask = (info[i].mask & other_masks) | masks[last_form];
+
+	break;
+    }
+
+    last_start = start;
+  }
+}
+
+static bool
+setup_syllables_use (const hb_ot_shape_plan_t *plan,
+		     hb_font_t *font HB_UNUSED,
+		     hb_buffer_t *buffer)
+{
+  HB_BUFFER_ALLOCATE_VAR (buffer, syllable);
+  find_syllables_use (buffer);
+  foreach_syllable (buffer, start, end)
+    buffer->unsafe_to_break (start, end);
+  setup_rphf_mask (plan, buffer);
+  setup_topographical_masks (plan, buffer);
+  return false;
+}
+
+static bool
+record_rphf_use (const hb_ot_shape_plan_t *plan,
+		 hb_font_t *font HB_UNUSED,
+		 hb_buffer_t *buffer)
+{
+  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
+
+  hb_mask_t mask = use_plan->rphf_mask;
+  if (!mask) return false;
+  hb_glyph_info_t *info = buffer->info;
+
+  foreach_syllable (buffer, start, end)
+  {
+    /* Mark a substituted repha as USE(R). */
+    for (unsigned int i = start; i < end && (info[i].mask & mask); i++)
+      if (_hb_glyph_info_substituted (&info[i]))
+      {
+	info[i].use_category() = USE(R);
+	break;
+      }
+  }
+  return false;
+}
+
+static bool
+record_pref_use (const hb_ot_shape_plan_t *plan HB_UNUSED,
+		 hb_font_t *font HB_UNUSED,
+		 hb_buffer_t *buffer)
+{
+  hb_glyph_info_t *info = buffer->info;
+
+  foreach_syllable (buffer, start, end)
+  {
+    /* Mark a substituted pref as VPre, as they behave the same way. */
+    for (unsigned int i = start; i < end; i++)
+      if (_hb_glyph_info_substituted (&info[i]))
+      {
+	info[i].use_category() = USE(VPre);
+	break;
+      }
+  }
+  return false;
+}
+
+static inline bool
+is_halant_use (const hb_glyph_info_t &info)
+{
+  return (info.use_category() == USE(H) || info.use_category() == USE(HVM) || info.use_category() == USE(IS)) &&
+	 !_hb_glyph_info_ligated (&info);
+}
+
+static void
+reorder_syllable_use (hb_buffer_t *buffer, unsigned int start, unsigned int end)
+{
+  use_syllable_type_t syllable_type = (use_syllable_type_t) (buffer->info[start].syllable() & 0x0F);
+  /* Only a few syllable types need reordering. */
+  if (unlikely (!(FLAG_UNSAFE (syllable_type) &
+		  (FLAG (use_virama_terminated_cluster) |
+		   FLAG (use_sakot_terminated_cluster) |
+		   FLAG (use_standard_cluster) |
+		   FLAG (use_symbol_cluster) |
+		   FLAG (use_broken_cluster) |
+		   0))))
+    return;
+
+  hb_glyph_info_t *info = buffer->info;
+
+#define POST_BASE_FLAGS64 (FLAG64 (USE(FAbv)) | \
+			   FLAG64 (USE(FBlw)) | \
+			   FLAG64 (USE(FPst)) | \
+			   FLAG64 (USE(MAbv)) | \
+			   FLAG64 (USE(MBlw)) | \
+			   FLAG64 (USE(MPst)) | \
+			   FLAG64 (USE(MPre)) | \
+			   FLAG64 (USE(VAbv)) | \
+			   FLAG64 (USE(VBlw)) | \
+			   FLAG64 (USE(VPst)) | \
+			   FLAG64 (USE(VPre)) | \
+			   FLAG64 (USE(VMAbv)) | \
+			   FLAG64 (USE(VMBlw)) | \
+			   FLAG64 (USE(VMPst)) | \
+			   FLAG64 (USE(VMPre)))
+
+  /* Move things forward. */
+  if (info[start].use_category() == USE(R) && end - start > 1)
+  {
+    /* Got a repha.  Reorder it towards the end, but before the first post-base
+     * glyph. */
+    for (unsigned int i = start + 1; i < end; i++)
+    {
+      bool is_post_base_glyph = (FLAG64_UNSAFE (info[i].use_category()) & POST_BASE_FLAGS64) ||
+				is_halant_use (info[i]);
+      if (is_post_base_glyph || i == end - 1)
+      {
+	/* If we hit a post-base glyph, move before it; otherwise move to the
+	 * end. Shift things in between backward. */
+
+	if (is_post_base_glyph)
+	  i--;
+
+	buffer->merge_clusters (start, i + 1);
+	hb_glyph_info_t t = info[start];
+	memmove (&info[start], &info[start + 1], (i - start) * sizeof (info[0]));
+	info[i] = t;
+
+	break;
+      }
+    }
+  }
+
+  /* Move things back. */
+  unsigned int j = start;
+  for (unsigned int i = start; i < end; i++)
+  {
+    uint32_t flag = FLAG_UNSAFE (info[i].use_category());
+    if (is_halant_use (info[i]))
+    {
+      /* If we hit a halant, move after it; otherwise move to the beginning, and
+       * shift things in between forward. */
+      j = i + 1;
+    }
+    else if (((flag) & (FLAG (USE(VPre)) | FLAG (USE(VMPre)))) &&
+	     /* Only move the first component of a MultipleSubst. */
+	     0 == _hb_glyph_info_get_lig_comp (&info[i]) &&
+	     j < i)
+    {
+      buffer->merge_clusters (j, i + 1);
+      hb_glyph_info_t t = info[i];
+      memmove (&info[j + 1], &info[j], (i - j) * sizeof (info[0]));
+      info[j] = t;
+    }
+  }
+}
+
+static bool
+reorder_use (const hb_ot_shape_plan_t *plan,
+	     hb_font_t *font,
+	     hb_buffer_t *buffer)
+{
+  bool ret = false;
+  if (buffer->message (font, "start reordering USE"))
+  {
+    if (hb_syllabic_insert_dotted_circles (font, buffer,
+					   use_broken_cluster,
+					   USE(B),
+					   USE(R)))
+      ret = true;
+
+    foreach_syllable (buffer, start, end)
+      reorder_syllable_use (buffer, start, end);
+
+    (void) buffer->message (font, "end reordering USE");
+  }
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);
+
+  return ret;
+}
+
+
+static void
+preprocess_text_use (const hb_ot_shape_plan_t *plan,
+		     hb_buffer_t              *buffer,
+		     hb_font_t                *font)
+{
+  _hb_preprocess_text_vowel_constraints (plan, buffer, font);
+}
+
+static bool
+compose_use (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_shaper_t _hb_ot_shaper_use =
+{
+  collect_features_use,
+  nullptr, /* override_features */
+  data_create_use,
+  data_destroy_use,
+  preprocess_text_use,
+  nullptr, /* postprocess_glyphs */
+  nullptr, /* decompose */
+  compose_use,
+  setup_masks_use,
+  nullptr, /* reorder_marks */
+  HB_TAG_NONE, /* gpos_tag */
+  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
+  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
+  false, /* fallback_position */
+};
+
+
+#endif