| // Copyright (c) 2011-2017 The OTS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "gpos.h" |
| |
| #include <limits> |
| #include <vector> |
| |
| #include "layout.h" |
| #include "maxp.h" |
| |
| // GPOS - The Glyph Positioning Table |
| // http://www.microsoft.com/typography/otspec/gpos.htm |
| |
| #define TABLE_NAME "GPOS" |
| |
| namespace { |
| |
| enum GPOS_TYPE { |
| GPOS_TYPE_SINGLE_ADJUSTMENT = 1, |
| GPOS_TYPE_PAIR_ADJUSTMENT = 2, |
| GPOS_TYPE_CURSIVE_ATTACHMENT = 3, |
| GPOS_TYPE_MARK_TO_BASE_ATTACHMENT = 4, |
| GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT = 5, |
| GPOS_TYPE_MARK_TO_MARK_ATTACHMENT = 6, |
| GPOS_TYPE_CONTEXT_POSITIONING = 7, |
| GPOS_TYPE_CHAINED_CONTEXT_POSITIONING = 8, |
| GPOS_TYPE_EXTENSION_POSITIONING = 9, |
| GPOS_TYPE_RESERVED = 10 |
| }; |
| |
| // The size of gpos header. |
| const unsigned kGposHeaderSize = 10; |
| // The maximum format number for anchor tables. |
| const uint16_t kMaxAnchorFormat = 3; |
| // The maximum number of class value. |
| const uint16_t kMaxClassDefValue = 0xFFFF; |
| |
| // Lookup type parsers. |
| bool ParseSingleAdjustment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParsePairAdjustment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseCursiveAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToBaseAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToLigatureAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseMarkToMarkAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseContextPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseChainedContextPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| bool ParseExtensionPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length); |
| |
| const ots::LookupSubtableParser::TypeParser kGposTypeParsers[] = { |
| {GPOS_TYPE_SINGLE_ADJUSTMENT, ParseSingleAdjustment}, |
| {GPOS_TYPE_PAIR_ADJUSTMENT, ParsePairAdjustment}, |
| {GPOS_TYPE_CURSIVE_ATTACHMENT, ParseCursiveAttachment}, |
| {GPOS_TYPE_MARK_TO_BASE_ATTACHMENT, ParseMarkToBaseAttachment}, |
| {GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT, ParseMarkToLigatureAttachment}, |
| {GPOS_TYPE_MARK_TO_MARK_ATTACHMENT, ParseMarkToMarkAttachment}, |
| {GPOS_TYPE_CONTEXT_POSITIONING, ParseContextPositioning}, |
| {GPOS_TYPE_CHAINED_CONTEXT_POSITIONING, ParseChainedContextPositioning}, |
| {GPOS_TYPE_EXTENSION_POSITIONING, ParseExtensionPositioning} |
| }; |
| |
| const ots::LookupSubtableParser kGposLookupSubtableParser = { |
| arraysize(kGposTypeParsers), |
| GPOS_TYPE_EXTENSION_POSITIONING, kGposTypeParsers |
| }; |
| |
| // Shared Tables: ValueRecord, Anchor Table, and MarkArray |
| |
| size_t CalcValueRecordSize(const uint16_t value_format) { |
| size_t size = 0; |
| for (unsigned i = 0; i < 8; ++i) { |
| if ((value_format >> i) & 0x1) { |
| size += 2; |
| } |
| } |
| |
| return size; |
| } |
| |
| bool ParseValueRecord(const ots::Font *font, |
| ots::Buffer* subtable, |
| const uint16_t value_format) { |
| const uint8_t *data = subtable->buffer(); |
| const size_t length = subtable->length(); |
| |
| // Check existence of adjustment fields. |
| for (unsigned i = 0; i < 4; ++i) { |
| if ((value_format >> i) & 0x1) { |
| // Just read the field since these fileds could take an arbitrary values. |
| if (!subtable->Skip(2)) { |
| return OTS_FAILURE_MSG("Failed to read value reacord component"); |
| } |
| } |
| } |
| |
| // Check existence of offsets to device table. |
| for (unsigned i = 0; i < 4; ++i) { |
| if ((value_format >> (i + 4)) & 0x1) { |
| uint16_t offset = 0; |
| if (!subtable->ReadU16(&offset)) { |
| return OTS_FAILURE_MSG("Failed to read value record offset"); |
| } |
| if (offset) { |
| // TODO(bashi): Is it possible that device tables locate before |
| // this record? No fonts contain such offset AKAIF. |
| if (offset >= length) { |
| return OTS_FAILURE_MSG("Value record offset too high %d >= %ld", offset, length); |
| } |
| if (!ots::ParseDeviceTable(font, data + offset, length - offset)) { |
| return OTS_FAILURE_MSG("Failed to parse device table in value record"); |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseAnchorTable(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t format = 0; |
| // Read format and skip 2 2-byte fields that could be arbitrary values. |
| if (!subtable.ReadU16(&format) || |
| !subtable.Skip(4)) { |
| return OTS_FAILURE_MSG("Faled to read anchor table"); |
| } |
| |
| if (format == 0 || format > kMaxAnchorFormat) { |
| return OTS_FAILURE_MSG("Bad Anchor table format %d", format); |
| } |
| |
| // Format 2 and 3 has additional fields. |
| if (format == 2) { |
| // Format 2 provides an index to a glyph contour point, which will take |
| // arbitrary value. |
| uint16_t anchor_point = 0; |
| if (!subtable.ReadU16(&anchor_point)) { |
| return OTS_FAILURE_MSG("Failed to read anchor point in format 2 Anchor Table"); |
| } |
| } else if (format == 3) { |
| uint16_t offset_x_device = 0; |
| uint16_t offset_y_device = 0; |
| if (!subtable.ReadU16(&offset_x_device) || |
| !subtable.ReadU16(&offset_y_device)) { |
| return OTS_FAILURE_MSG("Failed to read device table offsets in format 3 anchor table"); |
| } |
| const unsigned format_end = static_cast<unsigned>(10); |
| if (offset_x_device) { |
| if (offset_x_device < format_end || offset_x_device >= length) { |
| return OTS_FAILURE_MSG("Bad x device table offset %d", offset_x_device); |
| } |
| if (!ots::ParseDeviceTable(font, data + offset_x_device, |
| length - offset_x_device)) { |
| return OTS_FAILURE_MSG("Failed to parse device table in anchor table"); |
| } |
| } |
| if (offset_y_device) { |
| if (offset_y_device < format_end || offset_y_device >= length) { |
| return OTS_FAILURE_MSG("Bad y device table offset %d", offset_y_device); |
| } |
| if (!ots::ParseDeviceTable(font, data + offset_y_device, |
| length - offset_y_device)) { |
| return OTS_FAILURE_MSG("Failed to parse device table in anchor table"); |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseMarkArrayTable(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t mark_count = 0; |
| if (!subtable.ReadU16(&mark_count)) { |
| return OTS_FAILURE_MSG("Can't read mark table length"); |
| } |
| |
| // MarkRecord consists of 4-bytes. |
| const unsigned mark_records_end = 4 * static_cast<unsigned>(mark_count) + 2; |
| if (mark_records_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE_MSG("Bad mark table length"); |
| } |
| for (unsigned i = 0; i < mark_count; ++i) { |
| uint16_t class_value = 0; |
| uint16_t offset_mark_anchor = 0; |
| if (!subtable.ReadU16(&class_value) || |
| !subtable.ReadU16(&offset_mark_anchor)) { |
| return OTS_FAILURE_MSG("Can't read mark table %d", i); |
| } |
| // |class_value| may take arbitrary values including 0 here so we don't |
| // check the value. |
| if (offset_mark_anchor < mark_records_end || |
| offset_mark_anchor >= length) { |
| return OTS_FAILURE_MSG("Bad mark anchor offset %d for mark table %d", offset_mark_anchor, i); |
| } |
| if (!ParseAnchorTable(font, data + offset_mark_anchor, |
| length - offset_mark_anchor)) { |
| return OTS_FAILURE_MSG("Faled to parse anchor table for mark table %d", i); |
| } |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 1: |
| // Single Adjustment Positioning Subtable |
| bool ParseSingleAdjustment(const ots::Font *font, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t value_format = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&value_format)) { |
| return OTS_FAILURE_MSG("Can't read single adjustment information"); |
| } |
| |
| if (format == 1) { |
| // Format 1 exactly one value record. |
| if (!ParseValueRecord(font, &subtable, value_format)) { |
| return OTS_FAILURE_MSG("Failed to parse format 1 single adjustment table"); |
| } |
| } else if (format == 2) { |
| uint16_t value_count = 0; |
| if (!subtable.ReadU16(&value_count)) { |
| return OTS_FAILURE_MSG("Failed to parse format 2 single adjustment table"); |
| } |
| for (unsigned i = 0; i < value_count; ++i) { |
| if (!ParseValueRecord(font, &subtable, value_format)) { |
| return OTS_FAILURE_MSG("Failed to parse value record %d in format 2 single adjustment table", i); |
| } |
| } |
| } else { |
| return OTS_FAILURE_MSG("Bad format %d in single adjustment table", format); |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE_MSG("Bad coverage offset %d in single adjustment table", offset_coverage); |
| } |
| |
| if (!ots::ParseCoverageTable(font, data + offset_coverage, |
| length - offset_coverage, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse coverage table in single adjustment table"); |
| } |
| |
| return true; |
| } |
| |
| bool ParsePairSetTable(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t value_count = 0; |
| if (!subtable.ReadU16(&value_count)) { |
| return OTS_FAILURE_MSG("Failed to read pair set table structure"); |
| } |
| for (unsigned i = 0; i < value_count; ++i) { |
| // Check pair value record. |
| uint16_t glyph_id = 0; |
| if (!subtable.ReadU16(&glyph_id)) { |
| return OTS_FAILURE_MSG("Failed to read glyph in pair value record %d", i); |
| } |
| if (glyph_id >= num_glyphs) { |
| return OTS_FAILURE_MSG("glyph id %d too high >= %d", glyph_id, num_glyphs); |
| } |
| if (!ParseValueRecord(font, &subtable, value_format1)) { |
| return OTS_FAILURE_MSG("Failed to parse value record in format 1 pair set table"); |
| } |
| if (!ParseValueRecord(font, &subtable, value_format2)) { |
| return OTS_FAILURE_MSG("Failed to parse value record in format 2 pair set table"); |
| } |
| } |
| return true; |
| } |
| |
| bool ParsePairPosFormat1(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| // Skip 8 bytes that are already read before. |
| if (!subtable.Skip(8)) { |
| return OTS_FAILURE_MSG("Failed to read pair pos table structure"); |
| } |
| |
| uint16_t pair_set_count = 0; |
| if (!subtable.ReadU16(&pair_set_count)) { |
| return OTS_FAILURE_MSG("Failed to read pair pos set count"); |
| } |
| |
| const unsigned pair_pos_end = 2 * static_cast<unsigned>(pair_set_count) + 10; |
| if (pair_pos_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE_MSG("Bad pair set length %d", pair_pos_end); |
| } |
| for (unsigned i = 0; i < pair_set_count; ++i) { |
| uint16_t pair_set_offset = 0; |
| if (!subtable.ReadU16(&pair_set_offset)) { |
| return OTS_FAILURE_MSG("Failed to read pair set offset for pair set %d", i); |
| } |
| if (pair_set_offset < pair_pos_end || pair_set_offset >= length) { |
| return OTS_FAILURE_MSG("Bad pair set offset %d for pair set %d", pair_set_offset, i); |
| } |
| // Check pair set tables |
| if (!ParsePairSetTable(font, data + pair_set_offset, length - pair_set_offset, |
| value_format1, value_format2, |
| num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse pair set table %d", i); |
| } |
| } |
| |
| return true; |
| } |
| |
| bool ParsePairPosFormat2(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t value_format1, |
| const uint16_t value_format2, |
| const uint16_t num_glyphs) { |
| ots::Buffer subtable(data, length); |
| |
| // Skip 8 bytes that are already read before. |
| if (!subtable.Skip(8)) { |
| return OTS_FAILURE_MSG("Failed to read pair pos format 2 structure"); |
| } |
| |
| uint16_t offset_class_def1 = 0; |
| uint16_t offset_class_def2 = 0; |
| uint16_t class1_count = 0; |
| uint16_t class2_count = 0; |
| if (!subtable.ReadU16(&offset_class_def1) || |
| !subtable.ReadU16(&offset_class_def2) || |
| !subtable.ReadU16(&class1_count) || |
| !subtable.ReadU16(&class2_count)) { |
| return OTS_FAILURE_MSG("Failed to read pair pos format 2 data"); |
| } |
| |
| size_t value_record1_size = CalcValueRecordSize(value_format1); |
| size_t value_record2_size = CalcValueRecordSize(value_format2); |
| size_t value_records_size = size_t(class1_count) * size_t(class2_count) * |
| (value_record1_size + value_record2_size); |
| |
| // Check the validity of class definition offsets. |
| if (offset_class_def1 < subtable.offset() + value_records_size || |
| offset_class_def2 < subtable.offset() + value_records_size || |
| offset_class_def1 >= length || offset_class_def2 >= length) { |
| return OTS_FAILURE_MSG("Bad ParsePairPosFormat2 class definition offsets %d or %d", offset_class_def1, offset_class_def2); |
| } |
| |
| // Check class 1 records. |
| if (value_record1_size || value_record2_size) { |
| for (unsigned i = 0; i < class1_count; ++i) { |
| // Check class 2 records. |
| for (unsigned j = 0; j < class2_count; ++j) { |
| if (value_format1 && value_record2_size && |
| !ParseValueRecord(font, &subtable, value_format1)) { |
| return OTS_FAILURE_MSG("Failed to parse value record 1 %d and %d", j, i); |
| } |
| if (value_format2 && value_record2_size && |
| !ParseValueRecord(font, &subtable, value_format2)) { |
| return OTS_FAILURE_MSG("Falied to parse value record 2 %d and %d", j, i); |
| } |
| } |
| } |
| } |
| |
| // Check class definition tables. |
| if (!ots::ParseClassDefTable(font, data + offset_class_def1, |
| length - offset_class_def1, |
| num_glyphs, kMaxClassDefValue)) { |
| return OTS_FAILURE_MSG("Failed to parse class definition table 1"); |
| } |
| if (!ots::ParseClassDefTable(font, data + offset_class_def2, |
| length - offset_class_def2, |
| num_glyphs, kMaxClassDefValue)) { |
| return OTS_FAILURE_MSG("Failed to parse class definition table 2"); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 2: |
| // Pair Adjustment Positioning Subtable |
| bool ParsePairAdjustment(const ots::Font *font, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t value_format1 = 0; |
| uint16_t value_format2 = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&value_format1) || |
| !subtable.ReadU16(&value_format2)) { |
| return OTS_FAILURE_MSG("Failed to read pair adjustment structure"); |
| } |
| |
| if (format == 1) { |
| if (!ParsePairPosFormat1(font, data, length, value_format1, value_format2, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse pair pos format 1"); |
| } |
| } else if (format == 2) { |
| if (!ParsePairPosFormat2(font, data, length, value_format1, value_format2, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse pair format 2"); |
| } |
| } else { |
| return OTS_FAILURE_MSG("Bad pos pair format %d", format); |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE_MSG("Bad pair pos offset coverage %d", offset_coverage); |
| } |
| if (!ots::ParseCoverageTable(font, data + offset_coverage, |
| length - offset_coverage, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse coverage table"); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 3 |
| // Cursive Attachment Positioning Subtable |
| bool ParseCursiveAttachment(const ots::Font *font, const uint8_t *data, |
| const size_t length) { |
| ots::Buffer subtable(data, length); |
| |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage = 0; |
| uint16_t entry_exit_count = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage) || |
| !subtable.ReadU16(&entry_exit_count)) { |
| return OTS_FAILURE_MSG("Failed to read cursive attachment structure"); |
| } |
| |
| if (format != 1) { |
| return OTS_FAILURE_MSG("Bad cursive attachment format %d", format); |
| } |
| |
| // Check entry exit records. |
| const unsigned entry_exit_records_end = |
| 2 * static_cast<unsigned>(entry_exit_count) + 6; |
| if (entry_exit_records_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE_MSG("Bad entry exit record end %d", entry_exit_records_end); |
| } |
| for (unsigned i = 0; i < entry_exit_count; ++i) { |
| uint16_t offset_entry_anchor = 0; |
| uint16_t offset_exit_anchor = 0; |
| if (!subtable.ReadU16(&offset_entry_anchor) || |
| !subtable.ReadU16(&offset_exit_anchor)) { |
| return OTS_FAILURE_MSG("Can't read entry exit record %d", i); |
| } |
| // These offsets could be NULL. |
| if (offset_entry_anchor) { |
| if (offset_entry_anchor < entry_exit_records_end || |
| offset_entry_anchor >= length) { |
| return OTS_FAILURE_MSG("Bad entry anchor offset %d in entry exit record %d", offset_entry_anchor, i); |
| } |
| if (!ParseAnchorTable(font, data + offset_entry_anchor, |
| length - offset_entry_anchor)) { |
| return OTS_FAILURE_MSG("Failed to parse entry anchor table in entry exit record %d", i); |
| } |
| } |
| if (offset_exit_anchor) { |
| if (offset_exit_anchor < entry_exit_records_end || |
| offset_exit_anchor >= length) { |
| return OTS_FAILURE_MSG("Bad exit anchor offset %d in entry exit record %d", offset_exit_anchor, i); |
| } |
| if (!ParseAnchorTable(font, data + offset_exit_anchor, |
| length - offset_exit_anchor)) { |
| return OTS_FAILURE_MSG("Failed to parse exit anchor table in entry exit record %d", i); |
| } |
| } |
| } |
| |
| if (offset_coverage < subtable.offset() || offset_coverage >= length) { |
| return OTS_FAILURE_MSG("Bad coverage offset in cursive attachment %d", offset_coverage); |
| } |
| if (!ots::ParseCoverageTable(font, data + offset_coverage, |
| length - offset_coverage, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse coverage table in cursive attachment"); |
| } |
| |
| return true; |
| } |
| |
| bool ParseAnchorArrayTable(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t record_count = 0; |
| if (!subtable.ReadU16(&record_count)) { |
| return OTS_FAILURE_MSG("Can't read anchor array length"); |
| } |
| |
| const unsigned anchor_array_end = 2 * static_cast<unsigned>(record_count) * |
| static_cast<unsigned>(class_count) + 2; |
| if (anchor_array_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE_MSG("Bad end of anchor array %d", anchor_array_end); |
| } |
| for (unsigned i = 0; i < record_count; ++i) { |
| for (unsigned j = 0; j < class_count; ++j) { |
| uint16_t offset_record = 0; |
| if (!subtable.ReadU16(&offset_record)) { |
| return OTS_FAILURE_MSG("Can't read anchor array record offset for class %d and record %d", j, i); |
| } |
| // |offset_record| could be NULL. |
| if (offset_record) { |
| if (offset_record < anchor_array_end || offset_record >= length) { |
| return OTS_FAILURE_MSG("Bad record offset %d in class %d, record %d", offset_record, j, i); |
| } |
| if (!ParseAnchorTable(font, data + offset_record, |
| length - offset_record)) { |
| return OTS_FAILURE_MSG("Failed to parse anchor table for class %d, record %d", j, i); |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool ParseLigatureArrayTable(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const uint16_t class_count) { |
| ots::Buffer subtable(data, length); |
| |
| uint16_t ligature_count = 0; |
| if (!subtable.ReadU16(&ligature_count)) { |
| return OTS_FAILURE_MSG("Failed to read ligature count"); |
| } |
| for (unsigned i = 0; i < ligature_count; ++i) { |
| uint16_t offset_ligature_attach = 0; |
| if (!subtable.ReadU16(&offset_ligature_attach)) { |
| return OTS_FAILURE_MSG("Can't read ligature offset %d", i); |
| } |
| if (offset_ligature_attach < 2 || offset_ligature_attach >= length) { |
| return OTS_FAILURE_MSG("Bad ligature attachment offset %d in ligature %d", offset_ligature_attach, i); |
| } |
| if (!ParseAnchorArrayTable(font, data + offset_ligature_attach, |
| length - offset_ligature_attach, class_count)) { |
| return OTS_FAILURE_MSG("Failed to parse anchor table for ligature %d", i); |
| } |
| } |
| return true; |
| } |
| |
| // Common parser for Lookup Type 4, 5 and 6. |
| bool ParseMarkToAttachmentSubtables(const ots::Font *font, |
| const uint8_t *data, const size_t length, |
| const GPOS_TYPE type) { |
| ots::Buffer subtable(data, length); |
| |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| |
| uint16_t format = 0; |
| uint16_t offset_coverage1 = 0; |
| uint16_t offset_coverage2 = 0; |
| uint16_t class_count = 0; |
| uint16_t offset_mark_array = 0; |
| uint16_t offset_type_specific_array = 0; |
| if (!subtable.ReadU16(&format) || |
| !subtable.ReadU16(&offset_coverage1) || |
| !subtable.ReadU16(&offset_coverage2) || |
| !subtable.ReadU16(&class_count) || |
| !subtable.ReadU16(&offset_mark_array) || |
| !subtable.ReadU16(&offset_type_specific_array)) { |
| return OTS_FAILURE_MSG("Failed to read mark attachment subtable header"); |
| } |
| |
| if (format != 1) { |
| return OTS_FAILURE_MSG("bad mark attachment subtable format %d", format); |
| } |
| |
| const unsigned header_end = static_cast<unsigned>(subtable.offset()); |
| if (header_end > std::numeric_limits<uint16_t>::max()) { |
| return OTS_FAILURE_MSG("Bad mark attachment subtable size ending at %d", header_end); |
| } |
| if (offset_coverage1 < header_end || offset_coverage1 >= length) { |
| return OTS_FAILURE_MSG("Bad coverage 1 offset %d", offset_coverage1); |
| } |
| if (!ots::ParseCoverageTable(font, data + offset_coverage1, |
| length - offset_coverage1, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse converge 1 table"); |
| } |
| if (offset_coverage2 < header_end || offset_coverage2 >= length) { |
| return OTS_FAILURE_MSG("Bad coverage 2 offset %d", offset_coverage2); |
| } |
| if (!ots::ParseCoverageTable(font, data + offset_coverage2, |
| length - offset_coverage2, |
| maxp->num_glyphs)) { |
| return OTS_FAILURE_MSG("Failed to parse coverage table 2"); |
| } |
| |
| if (offset_mark_array < header_end || offset_mark_array >= length) { |
| return OTS_FAILURE_MSG("Bad mark array offset %d", offset_mark_array); |
| } |
| if (!ParseMarkArrayTable(font, data + offset_mark_array, |
| length - offset_mark_array, class_count)) { |
| return OTS_FAILURE_MSG("Failed to parse mark array"); |
| } |
| |
| if (offset_type_specific_array < header_end || |
| offset_type_specific_array >= length) { |
| return OTS_FAILURE_MSG("Bad type specific array offset %d", offset_type_specific_array); |
| } |
| if (type == GPOS_TYPE_MARK_TO_BASE_ATTACHMENT || |
| type == GPOS_TYPE_MARK_TO_MARK_ATTACHMENT) { |
| if (!ParseAnchorArrayTable(font, data + offset_type_specific_array, |
| length - offset_type_specific_array, |
| class_count)) { |
| return OTS_FAILURE_MSG("Failed to parse anchor array"); |
| } |
| } else if (type == GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT) { |
| if (!ParseLigatureArrayTable(font, data + offset_type_specific_array, |
| length - offset_type_specific_array, |
| class_count)) { |
| return OTS_FAILURE_MSG("Failed to parse ligature array"); |
| } |
| } else { |
| return OTS_FAILURE_MSG("Bad attachment type %d", type); |
| } |
| |
| return true; |
| } |
| |
| // Lookup Type 4: |
| // MarkToBase Attachment Positioning Subtable |
| bool ParseMarkToBaseAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(font, data, length, |
| GPOS_TYPE_MARK_TO_BASE_ATTACHMENT); |
| } |
| |
| // Lookup Type 5: |
| // MarkToLigature Attachment Positioning Subtable |
| bool ParseMarkToLigatureAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(font, data, length, |
| GPOS_TYPE_MARK_TO_LIGATURE_ATTACHMENT); |
| } |
| |
| // Lookup Type 6: |
| // MarkToMark Attachment Positioning Subtable |
| bool ParseMarkToMarkAttachment(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| return ParseMarkToAttachmentSubtables(font, data, length, |
| GPOS_TYPE_MARK_TO_MARK_ATTACHMENT); |
| } |
| |
| // Lookup Type 7: |
| // Contextual Positioning Subtables |
| bool ParseContextPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| ots::OpenTypeGPOS *gpos = static_cast<ots::OpenTypeGPOS*>( |
| font->GetTypedTable(OTS_TAG_GPOS)); |
| if (!gpos) { |
| return OTS_FAILURE_MSG("Internal error!"); |
| } |
| return ots::ParseContextSubtable(font, data, length, maxp->num_glyphs, |
| gpos->num_lookups); |
| } |
| |
| // Lookup Type 8: |
| // Chaining Contexual Positioning Subtable |
| bool ParseChainedContextPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>( |
| font->GetTypedTable(OTS_TAG_MAXP)); |
| if (!maxp) { |
| return OTS_FAILURE_MSG("Required maxp table missing"); |
| } |
| ots::OpenTypeGPOS *gpos = static_cast<ots::OpenTypeGPOS*>( |
| font->GetTypedTable(OTS_TAG_GPOS)); |
| if (!gpos) { |
| return OTS_FAILURE_MSG("Internal error!"); |
| } |
| return ots::ParseChainingContextSubtable(font, data, length, |
| maxp->num_glyphs, |
| gpos->num_lookups); |
| } |
| |
| // Lookup Type 9: |
| // Extension Positioning |
| bool ParseExtensionPositioning(const ots::Font *font, |
| const uint8_t *data, const size_t length) { |
| return ots::ParseExtensionSubtable(font, data, length, |
| &kGposLookupSubtableParser); |
| } |
| |
| } // namespace |
| |
| namespace ots { |
| |
| bool OpenTypeGPOS::Parse(const uint8_t *data, size_t length) { |
| Font *font = GetFont(); |
| Buffer table(data, length); |
| |
| uint32_t version = 0; |
| uint16_t offset_script_list = 0; |
| uint16_t offset_feature_list = 0; |
| uint16_t offset_lookup_list = 0; |
| if (!table.ReadU32(&version) || |
| !table.ReadU16(&offset_script_list) || |
| !table.ReadU16(&offset_feature_list) || |
| !table.ReadU16(&offset_lookup_list)) { |
| return Error("Incomplete table"); |
| } |
| |
| if (version != 0x00010000) { |
| return Error("Bad version"); |
| } |
| |
| if (offset_lookup_list) { |
| if (offset_lookup_list < kGposHeaderSize || offset_lookup_list >= length) { |
| return Error("Bad lookup list offset in table header"); |
| } |
| |
| if (!ParseLookupListTable(font, data + offset_lookup_list, |
| length - offset_lookup_list, |
| &kGposLookupSubtableParser, |
| &this->num_lookups)) { |
| return Error("Failed to parse lookup list table"); |
| } |
| } |
| |
| uint16_t num_features = 0; |
| if (offset_feature_list) { |
| if (offset_feature_list < kGposHeaderSize || offset_feature_list >= length) { |
| return Error("Bad feature list offset in table header"); |
| } |
| |
| if (!ParseFeatureListTable(font, data + offset_feature_list, |
| length - offset_feature_list, this->num_lookups, |
| &num_features)) { |
| return Error("Failed to parse feature list table"); |
| } |
| } |
| |
| if (offset_script_list) { |
| if (offset_script_list < kGposHeaderSize || offset_script_list >= length) { |
| return Error("Bad script list offset in table header"); |
| } |
| |
| if (!ParseScriptListTable(font, data + offset_script_list, |
| length - offset_script_list, num_features)) { |
| return Error("Failed to parse script list table"); |
| } |
| } |
| |
| this->m_data = data; |
| this->m_length = length; |
| return true; |
| } |
| |
| bool OpenTypeGPOS::Serialize(OTSStream *out) { |
| if (!out->Write(this->m_data, this->m_length)) { |
| return Error("Failed to write GPOS table"); |
| } |
| |
| return true; |
| } |
| |
| } // namespace ots |
| |
| #undef TABLE_NAME |
