The Tor Browser: comparison gfx/harfbuzz/src/hb-ot-shape-complex-hangul.cc

--1:000000000000
+:27e805599337
+/*
+* Copyright © 2013  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-ot-shape-complex-private.hh"
+/* Hangul shaper */
+/* Same order as the feature array below */
+enum {
+NONE,
+LJMO,
+VJMO,
+TJMO,
+FIRST_HANGUL_FEATURE = LJMO,
+HANGUL_FEATURE_COUNT = TJMO + 1
+};
+static const hb_tag_t hangul_features[HANGUL_FEATURE_COUNT] =
+{
+HB_TAG_NONE,
+HB_TAG('l','j','m','o'),
+HB_TAG('v','j','m','o'),
+HB_TAG('t','j','m','o')
+};
+static void
+collect_features_hangul (hb_ot_shape_planner_t *plan)
+{
+hb_ot_map_builder_t *map = &plan->map;
+for (unsigned int i = FIRST_HANGUL_FEATURE; i < HANGUL_FEATURE_COUNT; i++)
+map->add_feature (hangul_features[i], 1, F_NONE);
+}
+struct hangul_shape_plan_t
+{
+ASSERT_POD ();
+hb_mask_t mask_array[HANGUL_FEATURE_COUNT];
+};
+static void *
+data_create_hangul (const hb_ot_shape_plan_t *plan)
+{
+hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) calloc (1, sizeof (hangul_shape_plan_t));
+if (unlikely (!hangul_plan))
+return NULL;
+for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
+hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
+return hangul_plan;
+}
+static void
+data_destroy_hangul (void *data)
+{
+free (data);
+}
+/* Constants for algorithmic hangul syllable [de]composition. */
+#define LBase 0x1100
+#define VBase 0x1161
+#define TBase 0x11A7
+#define LCount 19
+#define VCount 21
+#define TCount 28
+#define SBase 0xAC00
+#define NCount (VCount * TCount)
+#define SCount (LCount * NCount)
+#define isCombiningL(u) (hb_in_range<hb_codepoint_t> ((u), LBase, LBase+LCount-1))
+#define isCombiningV(u) (hb_in_range<hb_codepoint_t> ((u), VBase, VBase+VCount-1))
+#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
+#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
+#define isL(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1100, 0x115F, 0xA960, 0xA97C))
+#define isV(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1160, 0x11A7, 0xD7B0, 0xD7C6))
+#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8, 0x11FF, 0xD7CB, 0xD7FB))
+#define isHangulTone(u) (hb_in_range<hb_codepoint_t> ((u), 0x302e, 0x302f))
+/* buffer var allocations */
+#define hangul_shaping_feature() complex_var_u8_0() /* hangul jamo shaping feature */
+static bool
+is_zero_width_char (hb_font_t *font,
+		    hb_codepoint_t unicode)
+{
+hb_codepoint_t glyph;
+return hb_font_get_glyph (font, unicode, 0, &glyph) && hb_font_get_glyph_h_advance (font, glyph) == 0;
+}
+static void
+preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
+			hb_buffer_t              *buffer,
+			hb_font_t                *font)
+{
+HB_BUFFER_ALLOCATE_VAR (buffer, hangul_shaping_feature);
+/* Hangul syllables come in two shapes: LV, and LVT.  Of those:
+*
+*   - LV can be precomposed, or decomposed.  Lets call those
+*     <LV> and <L,V>,
+*   - LVT can be fully precomposed, partically precomposed, or
+*     fully decomposed.  Ie. <LVT>, <LV,T>, or <L,V,T>.
+*
+* The composition / decomposition is mechanical.  However, not
+* all <L,V> sequences compose, and not all <LV,T> sequences
+* compose.
+*
+* Here are the specifics:
+*
+*   - <L>: U+1100..115F, U+A960..A97F
+*   - <V>: U+1160..11A7, U+D7B0..D7C7
+*   - <T>: U+11A8..11FF, U+D7CB..D7FB
+*
+*   - Only the <L,V> sequences for the 11xx ranges combine.
+*   - Only <LV,T> sequences for T in U+11A8..11C3 combine.
+*
+* Here is what we want to accomplish in this shaper:
+*
+*   - If the whole syllable can be precomposed, do that,
+*   - Otherwise, fully decompose and apply ljmo/vjmo/tjmo features.
+*   - If a valid syllable is followed by a Hangul tone mark, reorder the tone
+*     mark to precede the whole syllable - unless it is a zero-width glyph, in
+*     which case we leave it untouched, assuming it's designed to overstrike.
+*
+* That is, of the different possible syllables:
+*
+*   <L>
+*   <L,V>
+*   <L,V,T>
+*   <LV>
+*   <LVT>
+*   <LV, T>
+*
+* - <L> needs no work.
+*
+* - <LV> and <LVT> can stay the way they are if the font supports them, otherwise we
+*   should fully decompose them if font supports.
+*
+* - <L,V> and <L,V,T> we should compose if the whole thing can be composed.
+*
+* - <LV,T> we should compose if the whole thing can be composed, otherwise we should
+*   decompose.
+*/
+buffer->clear_output ();
+unsigned int start = 0, end = 0; /* Extent of most recently seen syllable;
+				    * valid only if start < end
+				    */
+unsigned int count = buffer->len;
+for (buffer->idx = 0; buffer->idx < count;)
+{
+hb_codepoint_t u = buffer->cur().codepoint;
+if (isHangulTone (u))
+{
+/*
+* We could cache the width of the tone marks and the existence of dotted-circle,
+* but the use of the Hangul tone mark characters seems to be rare enough that
+* I didn't bother for now.
+*/
+if (start < end && end == buffer->out_len)
+{
+	/* Tone mark follows a valid syllable; move it in front, unless it's zero width. */
+	buffer->next_glyph ();
+	if (!is_zero_width_char (font, u))
+	{
+	  hb_glyph_info_t *info = buffer->out_info;
+	  hb_glyph_info_t tone = info[end];
+	  memmove (&info[start + 1], &info[start], (end - start) * sizeof (hb_glyph_info_t));
+	  info[start] = tone;
+	}
+	/* Merge clusters across the (possibly reordered) syllable+tone.
+	 * We want to merge even in the zero-width tone mark case here,
+	 * so that clustering behavior isn't dependent on how the tone mark
+	 * is handled by the font.
+	 */
+	buffer->merge_out_clusters (start, end + 1);
+}
+else
+{
+	/* No valid syllable as base for tone mark; try to insert dotted circle. */
+	if (font->has_glyph (0x25cc))
+	{
+	  hb_codepoint_t chars[2];
+	  if (!is_zero_width_char (font, u)) {
+	    chars[0] = u;
+	    chars[1] = 0x25cc;
+	  } else {
+	    chars[0] = 0x25cc;
+	    chars[1] = u;
+	  }
+	  buffer->replace_glyphs (1, 2, chars);
+	}
+	else
+	{
+	  /* No dotted circle available in the font; just leave tone mark untouched. */
+	  buffer->next_glyph ();
+	}
+}
+start = end = buffer->out_len;
+continue;
+}
+start = buffer->out_len; /* Remember current position as a potential syllable start;
+			      * will only be used if we set end to a later position.
+			      */
+if (isL (u) && buffer->idx + 1 < count)
+{
+hb_codepoint_t l = u;
+hb_codepoint_t v = buffer->cur(+1).codepoint;
+if (isV (v))
+{
+	/* Have <L,V> or <L,V,T>. */
+	hb_codepoint_t t = 0;
+	unsigned int tindex = 0;
+	if (buffer->idx + 2 < count)
+	{
+	  t = buffer->cur(+2).codepoint;
+	  if (isT (t))
+	    tindex = t - TBase; /* Only used if isCombiningT (t); otherwise invalid. */
+	  else
+	    t = 0; /* The next character was not a trailing jamo. */
+	}
+	/* We've got a syllable <L,V,T?>; see if it can potentially be composed. */
+	if (isCombiningL (l) && isCombiningV (v) && (t == 0 || isCombiningT (t)))
+	{
+	  /* Try to compose; if this succeeds, end is set to start+1. */
+	  hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
+	  if (font->has_glyph (s))
+	  {
+	    buffer->replace_glyphs (t ? 3 : 2, 1, &s);
+	    if (unlikely (buffer->in_error))
+	      return;
+	    end = start + 1;
+	    continue;
+	  }
+	}
+	/* We didn't compose, either because it's an Old Hangul syllable without a
+	 * precomposed character in Unicode, or because the font didn't support the
+	 * necessary precomposed glyph.
+	 * Set jamo features on the individual glyphs, and advance past them.
+	 */
+	buffer->cur().hangul_shaping_feature() = LJMO;
+	buffer->next_glyph ();
+	buffer->cur().hangul_shaping_feature() = VJMO;
+	buffer->next_glyph ();
+	if (t)
+	{
+	  buffer->cur().hangul_shaping_feature() = TJMO;
+	  buffer->next_glyph ();
+	  end = start + 3;
+	}
+	else
+	  end = start + 2;
+	buffer->merge_out_clusters (start, end);
+	continue;
+}
+}
+else if (isCombinedS (u))
+{
+/* Have <LV>, <LVT>, or <LV,T> */
+hb_codepoint_t s = u;
+bool has_glyph = font->has_glyph (s);
+unsigned int lindex = (s - SBase) / NCount;
+unsigned int nindex = (s - SBase) % NCount;
+unsigned int vindex = nindex / TCount;
+unsigned int tindex = nindex % TCount;
+if (!tindex &&
+	  buffer->idx + 1 < count &&
+	  isCombiningT (buffer->cur(+1).codepoint))
+{
+	/* <LV,T>, try to combine. */
+	unsigned int new_tindex = buffer->cur(+1).codepoint - TBase;
+	hb_codepoint_t new_s = s + new_tindex;
+	if (font->has_glyph (new_s))
+	{
+	  buffer->replace_glyphs (2, 1, &new_s);
+	  if (unlikely (buffer->in_error))
+	    return;
+	  end = start + 1;
+	  continue;
+	}
+}
+/* Otherwise, decompose if font doesn't support <LV> or <LVT>,
+* or if having non-combining <LV,T>.  Note that we already handled
+* combining <LV,T> above. */
+if (!has_glyph ||
+	  (!tindex &&
+	   buffer->idx + 1 < count &&
+	   isT (buffer->cur(+1).codepoint)))
+{
+	hb_codepoint_t decomposed[3] = {LBase + lindex,
+					VBase + vindex,
+					TBase + tindex};
+	if (font->has_glyph (decomposed[0]) &&
+	    font->has_glyph (decomposed[1]) &&
+	    (!tindex || font->has_glyph (decomposed[2])))
+	{
+	  unsigned int s_len = tindex ? 3 : 2;
+	  buffer->replace_glyphs (1, s_len, decomposed);
+	  if (unlikely (buffer->in_error))
+	    return;
+	  /* We decomposed S: apply jamo features to the individual glyphs
+	   * that are now in buffer->out_info.
+	   */
+	  hb_glyph_info_t *info = buffer->out_info;
+	  /* If we decomposed an LV because of a non-combining T following,
+	   * we want to include this T in the syllable.
+	   */
+	  if (has_glyph && !tindex)
+	  {
+buffer->next_glyph ();
+s_len++;
+}
+end = start + s_len;
+	  unsigned int i = start;
+	  info[i++].hangul_shaping_feature() = LJMO;
+	  info[i++].hangul_shaping_feature() = VJMO;
+	  if (i < end)
+	    info[i++].hangul_shaping_feature() = TJMO;
+	  buffer->merge_out_clusters (start, end);
+	  continue;
+	}
+}
+if (has_glyph)
+{
+/* We didn't decompose the S, so just advance past it. */
+	end = start + 1;
+	buffer->next_glyph ();
+	continue;
+}
+}
+/* Didn't find a recognizable syllable, so we leave end <= start;
+* this will prevent tone-mark reordering happening.
+*/
+buffer->next_glyph ();
+}
+buffer->swap_buffers ();
+}
+static void
+setup_masks_hangul (const hb_ot_shape_plan_t *plan,
+		    hb_buffer_t              *buffer,
+		    hb_font_t                *font HB_UNUSED)
+{
+const hangul_shape_plan_t *hangul_plan = (const hangul_shape_plan_t *) plan->data;
+if (likely (hangul_plan))
+{
+unsigned int count = buffer->len;
+hb_glyph_info_t *info = buffer->info;
+for (unsigned int i = 0; i < count; i++, info++)
+info->mask |= hangul_plan->mask_array[info->hangul_shaping_feature()];
+}
+HB_BUFFER_DEALLOCATE_VAR (buffer, hangul_shaping_feature);
+}
+const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
+{
+"hangul",
+collect_features_hangul,
+NULL, /* override_features */
+data_create_hangul, /* data_create */
+data_destroy_hangul, /* data_destroy */
+preprocess_text_hangul,
+HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
+NULL, /* decompose */
+NULL, /* compose */
+setup_masks_hangul, /* setup_masks */
+HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
+false, /* fallback_position */
+};

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comparison: gfx/harfbuzz/src/hb-ot-shape-complex-hangul.cc

gfx/harfbuzz/src/hb-ot-shape-complex-hangul.cc