SingleSubstFormat1.hh (6996B)
1 #ifndef OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH 2 #define OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH 3 4 #include "Common.hh" 5 6 namespace OT { 7 namespace Layout { 8 namespace GSUB_impl { 9 10 template <typename Types> 11 struct SingleSubstFormat1_3 12 { 13 protected: 14 HBUINT16 format; /* Format identifier--format = 1 */ 15 typename Types::template OffsetTo<Coverage> 16 coverage; /* Offset to Coverage table--from 17 * beginning of Substitution table */ 18 typename Types::HBUINT 19 deltaGlyphID; /* Add to original GlyphID to get 20 * substitute GlyphID, modulo 0x10000 */ 21 22 public: 23 DEFINE_SIZE_STATIC (2 + 2 * Types::size); 24 25 bool sanitize (hb_sanitize_context_t *c) const 26 { 27 TRACE_SANITIZE (this); 28 return_trace (c->check_struct (this) && 29 coverage.sanitize (c, this) && 30 /* The coverage table may use a range to represent a set 31 * of glyphs, which means a small number of bytes can 32 * generate a large glyph set. Manually modify the 33 * sanitizer max ops to take this into account. 34 * 35 * Note: This check *must* be right after coverage sanitize. */ 36 c->check_ops ((this + coverage).get_population () >> 1)); 37 } 38 39 hb_codepoint_t get_mask () const 40 { return (1 << (8 * Types::size)) - 1; } 41 42 bool intersects (const hb_set_t *glyphs) const 43 { return (this+coverage).intersects (glyphs); } 44 45 bool may_have_non_1to1 () const 46 { return false; } 47 48 void closure (hb_closure_context_t *c) const 49 { 50 hb_codepoint_t d = deltaGlyphID; 51 hb_codepoint_t mask = get_mask (); 52 53 /* Help fuzzer avoid this function as much. */ 54 unsigned pop = (this+coverage).get_population (); 55 if (pop >= mask) 56 return; 57 58 hb_set_t intersection; 59 (this+coverage).intersect_set (c->parent_active_glyphs (), intersection); 60 61 /* In degenerate fuzzer-found fonts, but not real fonts, 62 * this table can keep adding new glyphs in each round of closure. 63 * Refuse to close-over, if it maps glyph range to overlapping range. */ 64 hb_codepoint_t min_before = intersection.get_min (); 65 hb_codepoint_t max_before = intersection.get_max (); 66 hb_codepoint_t min_after = (min_before + d) & mask; 67 hb_codepoint_t max_after = (max_before + d) & mask; 68 if (intersection.get_population () == max_before - min_before + 1 && 69 ((min_before <= min_after && min_after <= max_before) || 70 (min_before <= max_after && max_after <= max_before))) 71 return; 72 73 + hb_iter (intersection) 74 | hb_map ([d, mask] (hb_codepoint_t g) { return (g + d) & mask; }) 75 | hb_sink (c->output) 76 ; 77 } 78 79 void closure_lookups (hb_closure_lookups_context_t *c) const {} 80 81 void collect_glyphs (hb_collect_glyphs_context_t *c) const 82 { 83 if (unlikely (!(this+coverage).collect_coverage (c->input))) return; 84 hb_codepoint_t d = deltaGlyphID; 85 hb_codepoint_t mask = get_mask (); 86 87 + hb_iter (this+coverage) 88 | hb_map ([d, mask] (hb_codepoint_t g) { return (g + d) & mask; }) 89 | hb_sink (c->output) 90 ; 91 } 92 93 const Coverage &get_coverage () const { return this+coverage; } 94 95 bool would_apply (hb_would_apply_context_t *c) const 96 { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; } 97 98 unsigned 99 get_glyph_alternates (hb_codepoint_t glyph_id, 100 unsigned start_offset, 101 unsigned *alternate_count /* IN/OUT. May be NULL. */, 102 hb_codepoint_t *alternate_glyphs /* OUT. May be NULL. */) const 103 { 104 unsigned int index = (this+coverage).get_coverage (glyph_id); 105 if (likely (index == NOT_COVERED)) 106 { 107 if (alternate_count) 108 *alternate_count = 0; 109 return 0; 110 } 111 112 if (alternate_count && *alternate_count) 113 { 114 hb_codepoint_t d = deltaGlyphID; 115 hb_codepoint_t mask = get_mask (); 116 117 glyph_id = (glyph_id + d) & mask; 118 119 *alternate_glyphs = glyph_id; 120 *alternate_count = 1; 121 } 122 123 return 1; 124 } 125 126 void 127 collect_glyph_alternates (hb_map_t *alternate_count /* IN/OUT */, 128 hb_map_t *alternate_glyphs /* IN/OUT */) const 129 { 130 hb_codepoint_t d = deltaGlyphID; 131 hb_codepoint_t mask = get_mask (); 132 133 + hb_iter (this+coverage) 134 | hb_map ([d, mask] (hb_codepoint_t g) { return hb_pair (g, (g + d) & mask); }) 135 | hb_apply ([&] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t> &p) -> void 136 { _hb_collect_glyph_alternates_add (p.first, p.second, 137 alternate_count, alternate_glyphs); }) 138 ; 139 } 140 141 bool apply (hb_ot_apply_context_t *c) const 142 { 143 TRACE_APPLY (this); 144 hb_codepoint_t glyph_id = c->buffer->cur().codepoint; 145 unsigned int index = (this+coverage).get_coverage (glyph_id); 146 if (index == NOT_COVERED) return_trace (false); 147 148 hb_codepoint_t d = deltaGlyphID; 149 hb_codepoint_t mask = get_mask (); 150 151 glyph_id = (glyph_id + d) & mask; 152 153 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ()) 154 { 155 c->buffer->sync_so_far (); 156 c->buffer->message (c->font, 157 "replacing glyph at %u (single substitution)", 158 c->buffer->idx); 159 } 160 161 c->replace_glyph (glyph_id); 162 163 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ()) 164 { 165 c->buffer->message (c->font, 166 "replaced glyph at %u (single substitution)", 167 c->buffer->idx - 1u); 168 } 169 170 return_trace (true); 171 } 172 173 template<typename Iterator, 174 hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))> 175 bool serialize (hb_serialize_context_t *c, 176 Iterator glyphs, 177 unsigned delta) 178 { 179 TRACE_SERIALIZE (this); 180 if (unlikely (!c->extend_min (this))) return_trace (false); 181 if (unlikely (!coverage.serialize_serialize (c, glyphs))) return_trace (false); 182 c->check_assign (deltaGlyphID, delta, HB_SERIALIZE_ERROR_INT_OVERFLOW); 183 return_trace (true); 184 } 185 186 bool subset (hb_subset_context_t *c) const 187 { 188 TRACE_SUBSET (this); 189 const hb_set_t &glyphset = *c->plan->glyphset_gsub (); 190 const hb_map_t &glyph_map = *c->plan->glyph_map; 191 192 hb_codepoint_t d = deltaGlyphID; 193 hb_codepoint_t mask = get_mask (); 194 195 hb_set_t intersection; 196 (this+coverage).intersect_set (glyphset, intersection); 197 198 auto it = 199 + hb_iter (intersection) 200 | hb_map_retains_sorting ([d, mask] (hb_codepoint_t g) { 201 return hb_codepoint_pair_t (g, 202 (g + d) & mask); }) 203 | hb_filter (glyphset, hb_second) 204 | hb_map_retains_sorting ([&] (hb_codepoint_pair_t p) -> hb_codepoint_pair_t 205 { return hb_pair (glyph_map[p.first], glyph_map[p.second]); }) 206 ; 207 208 bool ret = bool (it); 209 SingleSubst_serialize (c->serializer, it); 210 return_trace (ret); 211 } 212 }; 213 214 } 215 } 216 } 217 218 219 #endif /* OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH */