/* * 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. * * Google Author(s): Behdad Esfahbod */ #ifndef HB_OT_GLYF_TABLE_HH #define HB_OT_GLYF_TABLE_HH #include "hb-open-type-private.hh" #include "hb-ot-head-table.hh" #include "hb-subset-glyf.hh" #include "hb-subset-plan.hh" #include "hb-subset-private.hh" namespace OT { /* * loca -- Index to Location * https://docs.microsoft.com/en-us/typography/opentype/spec/loca */ #define HB_OT_TAG_loca HB_TAG('l','o','c','a') struct loca { friend struct glyf; static const hb_tag_t tableTag = HB_OT_TAG_loca; inline bool sanitize (hb_sanitize_context_t *c) const { TRACE_SANITIZE (this); return_trace (true); } protected: HBUINT8 dataZ[VAR]; /* Location data. */ DEFINE_SIZE_ARRAY (0, dataZ); }; /* * glyf -- TrueType Glyph Data * https://docs.microsoft.com/en-us/typography/opentype/spec/glyf */ #define HB_OT_TAG_glyf HB_TAG('g','l','y','f') struct glyf { static const hb_tag_t tableTag = HB_OT_TAG_glyf; inline bool sanitize (hb_sanitize_context_t *c) const { TRACE_SANITIZE (this); /* We don't check for anything specific here. The users of the * struct do all the hard work... */ return_trace (true); } inline bool subset (hb_subset_plan_t *plan) const { hb_blob_t *glyf_prime = nullptr; hb_blob_t *loca_prime = nullptr; bool success = true; bool use_short_loca = false; if (hb_subset_glyf_and_loca (plan, &use_short_loca, &glyf_prime, &loca_prime)) { success = success && plan->add_table (HB_OT_TAG_glyf, glyf_prime); success = success && plan->add_table (HB_OT_TAG_loca, loca_prime); success = success && _add_head_and_set_loca_version (plan, use_short_loca); } else { success = false; } hb_blob_destroy (loca_prime); hb_blob_destroy (glyf_prime); return success; } static bool _add_head_and_set_loca_version (hb_subset_plan_t *plan, bool use_short_loca) { hb_blob_t *head_blob = hb_sanitize_context_t().reference_table (plan->source); hb_blob_t *head_prime_blob = hb_blob_copy_writable_or_fail (head_blob); hb_blob_destroy (head_blob); if (unlikely (!head_prime_blob)) return false; head *head_prime = (head *) hb_blob_get_data_writable (head_prime_blob, nullptr); head_prime->indexToLocFormat.set (use_short_loca ? 0 : 1); bool success = plan->add_table (HB_OT_TAG_head, head_prime_blob); hb_blob_destroy (head_prime_blob); return success; } struct GlyphHeader { HBINT16 numberOfContours; /* If the number of contours is * greater than or equal to zero, * this is a simple glyph; if negative, * this is a composite glyph. */ FWORD xMin; /* Minimum x for coordinate data. */ FWORD yMin; /* Minimum y for coordinate data. */ FWORD xMax; /* Maximum x for coordinate data. */ FWORD yMax; /* Maximum y for coordinate data. */ DEFINE_SIZE_STATIC (10); }; struct CompositeGlyphHeader { enum composite_glyph_flag_t { ARG_1_AND_2_ARE_WORDS = 0x0001, ARGS_ARE_XY_VALUES = 0x0002, ROUND_XY_TO_GRID = 0x0004, WE_HAVE_A_SCALE = 0x0008, MORE_COMPONENTS = 0x0020, WE_HAVE_AN_X_AND_Y_SCALE = 0x0040, WE_HAVE_A_TWO_BY_TWO = 0x0080, WE_HAVE_INSTRUCTIONS = 0x0100, USE_MY_METRICS = 0x0200, OVERLAP_COMPOUND = 0x0400, SCALED_COMPONENT_OFFSET = 0x0800, UNSCALED_COMPONENT_OFFSET = 0x1000 }; HBUINT16 flags; HBUINT16 glyphIndex; inline unsigned int get_size (void) const { unsigned int size = min_size; if (flags & ARG_1_AND_2_ARE_WORDS) { // arg1 and 2 are int16 size += 4; } else { // arg1 and 2 are int8 size += 2; } if (flags & WE_HAVE_A_SCALE) { // One x 16 bit (scale) size += 2; } else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) { // Two x 16 bit (xscale, yscale) size += 4; } else if (flags & WE_HAVE_A_TWO_BY_TWO) { // Four x 16 bit (xscale, scale01, scale10, yscale) size += 8; } return size; } struct Iterator { const char *glyph_start; const char *glyph_end; const CompositeGlyphHeader *current; inline bool move_to_next () { if (current->flags & CompositeGlyphHeader::MORE_COMPONENTS) { const CompositeGlyphHeader *possible = &StructAfter (*current); if (!in_range (possible)) return false; current = possible; return true; } return false; } inline bool in_range (const CompositeGlyphHeader *composite) const { return (const char *) composite >= glyph_start && ((const char *) composite + CompositeGlyphHeader::min_size) <= glyph_end && ((const char *) composite + composite->get_size()) <= glyph_end; } }; static inline bool get_iterator (const char * glyph_data, unsigned int length, CompositeGlyphHeader::Iterator *iterator /* OUT */) { if (length < GlyphHeader::static_size) return false; /* Empty glyph; zero extents. */ const GlyphHeader &glyph_header = StructAtOffset (glyph_data, 0); if (glyph_header.numberOfContours < 0) { const CompositeGlyphHeader *possible = &StructAfter (glyph_header); iterator->glyph_start = glyph_data; iterator->glyph_end = (const char *) glyph_data + length; if (!iterator->in_range (possible)) return false; iterator->current = possible; return true; } return false; } DEFINE_SIZE_MIN (4); }; struct accelerator_t { inline void init (hb_face_t *face) { memset (this, 0, sizeof (accelerator_t)); hb_blob_t *head_blob = hb_sanitize_context_t().reference_table (face); const head *head_table = head_blob->as (); if (head_table == &Null(head) || (unsigned int) head_table->indexToLocFormat > 1 || head_table->glyphDataFormat != 0) { /* head table is not present, or in an unknown format. Leave num_glyphs=0, that takes care of disabling us. */ hb_blob_destroy (head_blob); return; } short_offset = 0 == head_table->indexToLocFormat; hb_blob_destroy (head_blob); loca_blob = hb_sanitize_context_t().reference_table (face); loca_table = loca_blob->as (); glyf_blob = hb_sanitize_context_t().reference_table (face); glyf_table = glyf_blob->as (); num_glyphs = MAX (1u, hb_blob_get_length (loca_blob) / (short_offset ? 2 : 4)) - 1; glyf_len = hb_blob_get_length (glyf_blob); } inline void fini (void) { hb_blob_destroy (loca_blob); hb_blob_destroy (glyf_blob); } /* * Returns true if the referenced glyph is a valid glyph and a composite glyph. * If true is returned a pointer to the composite glyph will be written into * composite. */ inline bool get_composite (hb_codepoint_t glyph, CompositeGlyphHeader::Iterator *composite /* OUT */) const { if (this->glyf_table == &Null(glyf) || !num_glyphs) return false; unsigned int start_offset, end_offset; if (!get_offsets (glyph, &start_offset, &end_offset)) return false; /* glyph not found */ return CompositeGlyphHeader::get_iterator ((const char*) this->glyf_table + start_offset, end_offset - start_offset, composite); } enum simple_glyph_flag_t { FLAG_X_SHORT = 0x02, FLAG_Y_SHORT = 0x04, FLAG_REPEAT = 0x08, FLAG_X_SAME = 0x10, FLAG_Y_SAME = 0x20 }; /* based on FontTools _g_l_y_f.py::trim */ inline bool remove_padding(unsigned int start_offset, unsigned int *end_offset) const { if (*end_offset - start_offset < GlyphHeader::static_size) return true; const char *glyph = ((const char *) glyf_table) + start_offset; const char * const glyph_end = glyph + (*end_offset - start_offset); const GlyphHeader &glyph_header = StructAtOffset (glyph, 0); int16_t num_contours = (int16_t) glyph_header.numberOfContours; if (num_contours < 0) /* Trimming for composites not implemented. * If removing hints it falls out of that. */ return true; else if (num_contours > 0) { /* simple glyph w/contours, possibly trimmable */ glyph += GlyphHeader::static_size + 2 * num_contours; if (unlikely (glyph + 2 >= glyph_end)) return false; uint16_t nCoordinates = (uint16_t) StructAtOffset(glyph - 2, 0) + 1; uint16_t nInstructions = (uint16_t) StructAtOffset(glyph, 0); glyph += 2 + nInstructions; if (unlikely (glyph + 2 >= glyph_end)) return false; unsigned int coordBytes = 0; unsigned int coordsWithFlags = 0; while (glyph < glyph_end) { uint8_t flag = (uint8_t) *glyph; glyph++; unsigned int repeat = 1; if (flag & FLAG_REPEAT) { if (glyph >= glyph_end) { DEBUG_MSG(SUBSET, nullptr, "Bad flag"); return false; } repeat = ((uint8_t) *glyph) + 1; glyph++; } unsigned int xBytes, yBytes; xBytes = yBytes = 0; if (flag & FLAG_X_SHORT) xBytes = 1; else if ((flag & FLAG_X_SAME) == 0) xBytes = 2; if (flag & FLAG_Y_SHORT) yBytes = 1; else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2; coordBytes += (xBytes + yBytes) * repeat; coordsWithFlags += repeat; if (coordsWithFlags >= nCoordinates) break; } if (coordsWithFlags != nCoordinates) { DEBUG_MSG(SUBSET, nullptr, "Expect %d coords to have flags, got flags for %d", nCoordinates, coordsWithFlags); return false; } glyph += coordBytes; if (glyph < glyph_end) *end_offset -= glyph_end - glyph; } return true; } inline bool get_offsets (hb_codepoint_t glyph, unsigned int *start_offset /* OUT */, unsigned int *end_offset /* OUT */) const { if (unlikely (glyph >= num_glyphs)) return false; if (short_offset) { const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ; *start_offset = 2 * offsets[glyph]; *end_offset = 2 * offsets[glyph + 1]; } else { const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ; *start_offset = offsets[glyph]; *end_offset = offsets[glyph + 1]; } if (*start_offset > *end_offset || *end_offset > glyf_len) return false; return true; } inline bool get_instruction_offsets(unsigned int start_offset, unsigned int end_offset, unsigned int *instruction_start /* OUT */, unsigned int *instruction_end /* OUT */) const { if (end_offset - start_offset < GlyphHeader::static_size) { *instruction_start = 0; *instruction_end = 0; return true; /* Empty glyph; no instructions. */ } const GlyphHeader &glyph_header = StructAtOffset (glyf_table, start_offset); int16_t num_contours = (int16_t) glyph_header.numberOfContours; if (num_contours < 0) { CompositeGlyphHeader::Iterator composite_it; if (unlikely (!CompositeGlyphHeader::get_iterator ( (const char*) this->glyf_table + start_offset, end_offset - start_offset, &composite_it))) return false; const CompositeGlyphHeader *last; do { last = composite_it.current; } while (composite_it.move_to_next()); if ( (uint16_t) last->flags & CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS) *instruction_start = ((char *) last - (char *) glyf_table->dataZ) + last->get_size(); else *instruction_start = end_offset; *instruction_end = end_offset; if (unlikely (*instruction_start > *instruction_end)) { DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside [%d, %d]", *instruction_start, start_offset, end_offset); return false; } } else { unsigned int instruction_length_offset = start_offset + GlyphHeader::static_size + 2 * num_contours; if (unlikely (instruction_length_offset + 2 > end_offset)) { DEBUG_MSG(SUBSET, nullptr, "Glyph size is too short, missing field instructionLength."); return false; } const HBUINT16 &instruction_length = StructAtOffset (glyf_table, instruction_length_offset); unsigned int start = instruction_length_offset + 2; unsigned int end = start + (uint16_t) instruction_length; if (unlikely (end > end_offset)) // Out of bounds of the current glyph { DEBUG_MSG(SUBSET, nullptr, "The instructions array overruns the glyph's boundaries."); return false; } *instruction_start = start; *instruction_end = end; } return true; } inline bool get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const { unsigned int start_offset, end_offset; if (!get_offsets (glyph, &start_offset, &end_offset)) return false; if (end_offset - start_offset < GlyphHeader::static_size) return true; /* Empty glyph; zero extents. */ const GlyphHeader &glyph_header = StructAtOffset (glyf_table, start_offset); extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax); extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax); extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing; extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing; return true; } private: bool short_offset; unsigned int num_glyphs; const loca *loca_table; const glyf *glyf_table; hb_blob_t *loca_blob; hb_blob_t *glyf_blob; unsigned int glyf_len; }; protected: HBUINT8 dataZ[VAR]; /* Glyphs data. */ DEFINE_SIZE_ARRAY (0, dataZ); }; } /* namespace OT */ #endif /* HB_OT_GLYF_TABLE_HH */