[glyf] Move padding removal logic to GlyphHeader
This commit is contained in:
Ebrahim Byagowi
parent
1ab8f9aa7a
commit
cbefbb2439
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@ -290,6 +290,70 @@ struct glyf
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*len = instruction_len;
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return true;
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}
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enum simple_glyph_flag_t
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{
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FLAG_ON_CURVE = 0x01,
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FLAG_X_SHORT = 0x02,
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FLAG_Y_SHORT = 0x04,
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FLAG_REPEAT = 0x08,
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FLAG_X_SAME = 0x10,
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FLAG_Y_SAME = 0x20,
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FLAG_RESERVED1 = 0x40,
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FLAG_RESERVED2 = 0x80
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};
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hb_bytes_t bytes_without_padding (hb_bytes_t glyph_bytes) const
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{
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unsigned int end_offset = glyph_bytes.length;
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/* based on FontTools _g_l_y_f.py::trim */
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const char *glyph = glyph_bytes.arrayZ;
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const char *glyph_end = glyph + glyph_bytes.length;
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/* simple glyph w/contours, possibly trimmable */
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glyph += instruction_len_offset ();
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if (unlikely (glyph + 2 >= glyph_end)) return hb_bytes_t ();
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unsigned int nCoordinates = StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;
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unsigned int nInstructions = StructAtOffset<HBUINT16> (glyph, 0);
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glyph += 2 + nInstructions;
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if (unlikely (glyph + 2 >= glyph_end)) return hb_bytes_t ();
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unsigned int coordBytes = 0;
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unsigned int coordsWithFlags = 0;
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while (glyph < glyph_end)
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{
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uint8_t flag = *glyph;
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glyph++;
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unsigned int repeat = 1;
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if (flag & FLAG_REPEAT)
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{
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if (unlikely (glyph >= glyph_end)) return hb_bytes_t ();
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repeat = *glyph + 1;
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glyph++;
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}
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unsigned int xBytes, yBytes;
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xBytes = yBytes = 0;
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if (flag & FLAG_X_SHORT) xBytes = 1;
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else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;
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if (flag & FLAG_Y_SHORT) yBytes = 1;
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else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;
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coordBytes += (xBytes + yBytes) * repeat;
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coordsWithFlags += repeat;
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if (coordsWithFlags >= nCoordinates) break;
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}
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if (unlikely (coordsWithFlags != nCoordinates)) return hb_bytes_t ();
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glyph += coordBytes;
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if (glyph < glyph_end)
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end_offset -= glyph_end - glyph;
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return glyph_bytes.sub_array (0, end_offset);
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}
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};
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struct CompositeHeader
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@ -312,6 +376,11 @@ struct glyf
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*length = end - start;
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return true;
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}
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/* Trimming for composites not implemented.
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* If removing hints it falls out of that. */
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hb_bytes_t bytes_without_padding (hb_bytes_t glyph_bytes) const
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{ return glyph_bytes; }
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};
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const SimpleHeader as_simple () const { return SimpleHeader (*this); }
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@ -337,6 +406,17 @@ struct glyf
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}
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}
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hb_bytes_t bytes_without_padding (hb_bytes_t glyph_bytes) const
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{
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switch (get_type ())
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{
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case COMPOSITE: return as_composite ().bytes_without_padding (glyph_bytes);
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case SIMPLE: return as_simple ().bytes_without_padding (glyph_bytes);
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default:
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case EMPTY: return glyph_bytes;
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}
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}
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bool has_data () const { return numberOfContours; }
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bool is_simple_glyph () const { return numberOfContours > 0; }
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bool is_composite_glyph () const { return numberOfContours < 0; }
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@ -656,10 +736,7 @@ struct glyf
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else if (glyph_header.is_simple_glyph ())
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{
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const HBUINT16 *end_pts = &StructAfter<HBUINT16, GlyphHeader> (glyph_header);
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unsigned int start_offset, end_offset;
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if (unlikely (!get_offsets (glyph, &start_offset, &end_offset))) return false;
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range_checker_t checker (glyf_table, start_offset, end_offset);
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range_checker_t checker (bytes.arrayZ, 0, bytes.length);
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num_points = 0;
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int num_contours = glyph_header.numberOfContours;
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if (unlikely (!checker.in_range (&end_pts[num_contours + 1]))) return false;
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@ -854,105 +931,6 @@ struct glyf
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#endif
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public:
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/* based on FontTools _g_l_y_f.py::trim */
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bool remove_padding (unsigned int start_offset,
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unsigned int *end_offset) const
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{
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unsigned int glyph_length = *end_offset - start_offset;
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const char *glyph = ((const char *) glyf_table) + start_offset;
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const GlyphHeader &glyph_header = *hb_bytes_t (glyph, glyph_length).as<GlyphHeader> ();
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if (!glyph_header.has_data ()) return true;
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const char *glyph_end = glyph + glyph_length;
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if (glyph_header.is_composite_glyph ())
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/* Trimming for composites not implemented.
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* If removing hints it falls out of that. */
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return true;
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else
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{
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/* simple glyph w/contours, possibly trimmable */
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glyph += glyph_header.as_simple ().instruction_len_offset ();
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if (unlikely (glyph + 2 >= glyph_end)) return false;
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uint16_t nCoordinates = (uint16_t) StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;
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uint16_t nInstructions = (uint16_t) StructAtOffset<HBUINT16> (glyph, 0);
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glyph += 2 + nInstructions;
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if (unlikely (glyph + 2 >= glyph_end)) return false;
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unsigned int coordBytes = 0;
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unsigned int coordsWithFlags = 0;
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while (glyph < glyph_end)
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{
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uint8_t flag = (uint8_t) *glyph;
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glyph++;
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unsigned int repeat = 1;
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if (flag & FLAG_REPEAT)
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{
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if (glyph >= glyph_end)
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{
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DEBUG_MSG (SUBSET, nullptr, "Bad flag");
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return false;
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}
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repeat = ((uint8_t) *glyph) + 1;
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glyph++;
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}
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unsigned int xBytes, yBytes;
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xBytes = yBytes = 0;
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if (flag & FLAG_X_SHORT) xBytes = 1;
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else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;
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if (flag & FLAG_Y_SHORT) yBytes = 1;
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else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;
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coordBytes += (xBytes + yBytes) * repeat;
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coordsWithFlags += repeat;
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if (coordsWithFlags >= nCoordinates)
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break;
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}
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if (coordsWithFlags != nCoordinates)
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{
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DEBUG_MSG (SUBSET, nullptr, "Expect %d coords to have flags, got flags for %d",
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nCoordinates, coordsWithFlags);
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return false;
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}
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glyph += coordBytes;
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if (glyph < glyph_end)
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*end_offset -= glyph_end - glyph;
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}
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return true;
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}
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bool get_offsets (hb_codepoint_t glyph,
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unsigned int *start_offset /* OUT */,
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unsigned int *end_offset /* OUT */) const
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{
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if (unlikely (glyph >= num_glyphs)) return false;
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if (short_offset)
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{
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const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ;
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*start_offset = 2 * offsets[glyph];
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*end_offset = 2 * offsets[glyph + 1];
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}
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else
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{
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const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ;
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*start_offset = offsets[glyph];
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*end_offset = offsets[glyph + 1];
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}
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if (*start_offset > *end_offset || *end_offset > glyf_table.get_length ())
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return false;
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return true;
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}
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#ifndef HB_NO_VAR
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unsigned int get_advance_var (hb_font_t *font, hb_codepoint_t glyph,
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bool is_vertical) const
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@ -1015,22 +993,35 @@ struct glyf
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bool needs_padding_removal = false) const
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{
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unsigned int start_offset, end_offset;
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if (unlikely (!get_offsets (gid, &start_offset, &end_offset)))
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if (unlikely (gid >= num_glyphs)) return hb_bytes_t ();
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if (short_offset)
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{
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const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ;
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start_offset = 2 * offsets[gid];
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end_offset = 2 * offsets[gid + 1];
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}
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else
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{
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const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ;
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start_offset = offsets[gid];
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end_offset = offsets[gid + 1];
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}
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if (unlikely (start_offset > end_offset || end_offset > glyf_table.get_length ()))
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return hb_bytes_t ();
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/* Remove padding, needed for subset */
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if (needs_padding_removal)
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if (unlikely (!remove_padding (start_offset, &end_offset)))
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return hb_bytes_t ();
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hb_bytes_t glyph_bytes = hb_bytes_t ((const char *) this->glyf_table + start_offset,
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hb_bytes_t glyph_bytes ((const char *) this->glyf_table + start_offset,
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end_offset - start_offset);
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/* Glyph size smaller than minimum header */
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if (!glyph_bytes.as<GlyphHeader> ()->has_data ())
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return hb_bytes_t ();
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const GlyphHeader &glyph_header = *glyph_bytes.as<GlyphHeader> ();
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return glyph_bytes;
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/* Empty glyph or its size is smaller than minimum header */
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if (!glyph_header.has_data ()) return hb_bytes_t ();
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if (!needs_padding_removal) return glyph_bytes;
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return glyph_header.bytes_without_padding (glyph_bytes);
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}
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private:
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