1 /*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include <array>
9
10 #include "src/sfnt/SkOTUtils.h"
11
12 #include "include/core/SkData.h"
13 #include "include/core/SkStream.h"
14 #include "include/private/base/SkTo.h"
15 #include "src/base/SkEndian.h"
16 #include "src/core/SkAdvancedTypefaceMetrics.h"
17 #include "src/sfnt/SkOTTableTypes.h"
18 #include "src/sfnt/SkOTTable_head.h"
19 #include "src/sfnt/SkOTTable_name.h"
20 #include "src/sfnt/SkSFNTHeader.h"
21
CalcTableChecksum(SK_OT_ULONG * data,size_t length)22 uint32_t SkOTUtils::CalcTableChecksum(SK_OT_ULONG *data, size_t length) {
23 uint32_t sum = 0;
24 SK_OT_ULONG *dataEnd = data + ((length + 3) & ~3) / sizeof(SK_OT_ULONG);
25 for (; data < dataEnd; ++data) {
26 sum += SkEndian_SwapBE32(*data);
27 }
28 return sum;
29 }
30
RenameFont(SkStreamAsset * fontData,const char * fontName,int fontNameLen)31 SkData* SkOTUtils::RenameFont(SkStreamAsset* fontData, const char* fontName, int fontNameLen) {
32
33 // Get the sfnt header.
34 SkSFNTHeader sfntHeader;
35 if (fontData->read(&sfntHeader, sizeof(sfntHeader)) < sizeof(sfntHeader)) {
36 return nullptr;
37 }
38
39 // Find the existing 'name' table.
40 int tableIndex;
41 SkSFNTHeader::TableDirectoryEntry tableEntry;
42 int numTables = SkEndian_SwapBE16(sfntHeader.numTables);
43 for (tableIndex = 0; tableIndex < numTables; ++tableIndex) {
44 if (fontData->read(&tableEntry, sizeof(tableEntry)) < sizeof(tableEntry)) {
45 return nullptr;
46 }
47 if (SkOTTableName::TAG == tableEntry.tag) {
48 break;
49 }
50 }
51 if (tableIndex == numTables) {
52 return nullptr;
53 }
54
55 if (!fontData->rewind()) {
56 return nullptr;
57 }
58
59 // The required 'name' record types: Family, Style, Unique, Full and PostScript.
60 static constexpr std::array<SkOTTableName::Record::NameID::Predefined::Value, 5> names{{
61 SkOTTableName::Record::NameID::Predefined::FontFamilyName,
62 SkOTTableName::Record::NameID::Predefined::FontSubfamilyName,
63 SkOTTableName::Record::NameID::Predefined::UniqueFontIdentifier,
64 SkOTTableName::Record::NameID::Predefined::FullFontName,
65 SkOTTableName::Record::NameID::Predefined::PostscriptName,
66 }};
67
68 // GDI will not use a Symbol cmap table if there is no Symbol encoded name.
69 static constexpr std::array<SkOTTableName::Record::EncodingID::Windows::Value, 2> encodings{{
70 SkOTTableName::Record::EncodingID::Windows::Symbol,
71 SkOTTableName::Record::EncodingID::Windows::UnicodeBMPUCS2,
72 }};
73
74 // Copy the data, leaving out the old name table.
75 // In theory, we could also remove the DSIG table if it exists.
76 size_t nameTableLogicalSize = sizeof(SkOTTableName)
77 + (encodings.size() * names.size() * sizeof(SkOTTableName::Record))
78 + (fontNameLen * sizeof(SK_OT_USHORT));
79 size_t nameTablePhysicalSize = (nameTableLogicalSize + 3) & ~3; // Rounded up to a multiple of 4.
80
81 size_t oldNameTablePhysicalSize = (SkEndian_SwapBE32(tableEntry.logicalLength) + 3) & ~3; // Rounded up to a multiple of 4.
82 size_t oldNameTableOffset = SkEndian_SwapBE32(tableEntry.offset);
83
84 //originalDataSize is the size of the original data without the name table.
85 size_t originalDataSize = fontData->getLength() - oldNameTablePhysicalSize;
86 size_t newDataSize = originalDataSize + nameTablePhysicalSize;
87
88 auto rewrittenFontData = SkData::MakeUninitialized(newDataSize);
89 SK_OT_BYTE* data = static_cast<SK_OT_BYTE*>(rewrittenFontData->writable_data());
90
91 if (fontData->read(data, oldNameTableOffset) < oldNameTableOffset) {
92 return nullptr;
93 }
94 if (fontData->skip(oldNameTablePhysicalSize) < oldNameTablePhysicalSize) {
95 return nullptr;
96 }
97 if (fontData->read(data + oldNameTableOffset, originalDataSize - oldNameTableOffset) < originalDataSize - oldNameTableOffset) {
98 return nullptr;
99 }
100
101 //Fix up the offsets of the directory entries after the old 'name' table entry.
102 SkSFNTHeader::TableDirectoryEntry* currentEntry = reinterpret_cast<SkSFNTHeader::TableDirectoryEntry*>(data + sizeof(SkSFNTHeader));
103 SkSFNTHeader::TableDirectoryEntry* endEntry = currentEntry + numTables;
104 SkSFNTHeader::TableDirectoryEntry* headTableEntry = nullptr;
105 for (; currentEntry < endEntry; ++currentEntry) {
106 uint32_t oldOffset = SkEndian_SwapBE32(currentEntry->offset);
107 if (oldOffset > oldNameTableOffset) {
108 currentEntry->offset = SkEndian_SwapBE32(SkToU32(oldOffset - oldNameTablePhysicalSize));
109 }
110
111 if (SkOTTableHead::TAG == currentEntry->tag) {
112 headTableEntry = currentEntry;
113 }
114 }
115
116 // Make the table directory entry point to the new 'name' table.
117 SkSFNTHeader::TableDirectoryEntry* nameTableEntry = reinterpret_cast<SkSFNTHeader::TableDirectoryEntry*>(data + sizeof(SkSFNTHeader)) + tableIndex;
118 nameTableEntry->logicalLength = SkEndian_SwapBE32(SkToU32(nameTableLogicalSize));
119 nameTableEntry->offset = SkEndian_SwapBE32(SkToU32(originalDataSize));
120
121 // Write the new 'name' table after the original font data.
122 SkOTTableName* nameTable = reinterpret_cast<SkOTTableName*>(data + originalDataSize);
123 unsigned short stringOffset = sizeof(SkOTTableName) + (encodings.size() * names.size() * sizeof(SkOTTableName::Record));
124 nameTable->format = SkOTTableName::format_0;
125 nameTable->count = SkEndian_SwapBE16(encodings.size() * names.size());
126 nameTable->stringOffset = SkEndian_SwapBE16(stringOffset);
127
128 SkOTTableName::Record* nameRecord = reinterpret_cast<SkOTTableName::Record*>(data + originalDataSize + sizeof(SkOTTableName));
129 for (const auto& encoding : encodings) {
130 for (const auto& name : names) {
131 nameRecord->platformID.value = SkOTTableName::Record::PlatformID::Windows;
132 nameRecord->encodingID.windows.value = encoding;
133 nameRecord->languageID.windows.value = SkOTTableName::Record::LanguageID::Windows::English_UnitedStates;
134 nameRecord->nameID.predefined.value = name;
135 nameRecord->offset = SkEndian_SwapBE16(0);
136 nameRecord->length = SkEndian_SwapBE16(SkToU16(fontNameLen * sizeof(SK_OT_USHORT)));
137 ++nameRecord;
138 }
139 }
140
141 SK_OT_USHORT* nameString = reinterpret_cast<SK_OT_USHORT*>(data + originalDataSize + stringOffset);
142 for (int i = 0; i < fontNameLen; ++i) {
143 nameString[i] = SkEndian_SwapBE16(fontName[i]);
144 }
145
146 unsigned char* logical = data + originalDataSize + nameTableLogicalSize;
147 unsigned char* physical = data + originalDataSize + nameTablePhysicalSize;
148 for (; logical < physical; ++logical) {
149 *logical = 0;
150 }
151
152 // Update the table checksum in the directory entry.
153 nameTableEntry->checksum = SkEndian_SwapBE32(SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(nameTable), nameTableLogicalSize));
154
155 // Update the checksum adjustment in the head table.
156 if (headTableEntry) {
157 size_t headTableOffset = SkEndian_SwapBE32(headTableEntry->offset);
158 if (headTableOffset + sizeof(SkOTTableHead) < originalDataSize) {
159 SkOTTableHead* headTable = reinterpret_cast<SkOTTableHead*>(data + headTableOffset);
160 headTable->checksumAdjustment = SkEndian_SwapBE32(0);
161 uint32_t unadjustedFontChecksum = SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(data), originalDataSize + nameTablePhysicalSize);
162 headTable->checksumAdjustment = SkEndian_SwapBE32(SkOTTableHead::fontChecksum - unadjustedFontChecksum);
163 }
164 }
165
166 return rewrittenFontData.release();
167 }
168
169 sk_sp<SkOTUtils::LocalizedStrings_NameTable>
Make(const SkTypeface & typeface,SK_OT_USHORT types[],int typesCount)170 SkOTUtils::LocalizedStrings_NameTable::Make(const SkTypeface& typeface,
171 SK_OT_USHORT types[],
172 int typesCount)
173 {
174 static const SkFontTableTag nameTag = SkSetFourByteTag('n','a','m','e');
175 size_t nameTableSize = typeface.getTableSize(nameTag);
176 if (0 == nameTableSize) {
177 return nullptr;
178 }
179 std::unique_ptr<uint8_t[]> nameTableData(new uint8_t[nameTableSize]);
180 size_t copied = typeface.getTableData(nameTag, 0, nameTableSize, nameTableData.get());
181 if (copied != nameTableSize) {
182 return nullptr;
183 }
184
185 return sk_sp<SkOTUtils::LocalizedStrings_NameTable>(
186 new SkOTUtils::LocalizedStrings_NameTable(std::move(nameTableData), nameTableSize,
187 types, typesCount));
188 }
189
190 sk_sp<SkOTUtils::LocalizedStrings_NameTable>
MakeForFamilyNames(const SkTypeface & typeface)191 SkOTUtils::LocalizedStrings_NameTable::MakeForFamilyNames(const SkTypeface& typeface) {
192 return Make(typeface,
193 SkOTUtils::LocalizedStrings_NameTable::familyNameTypes,
194 std::size(SkOTUtils::LocalizedStrings_NameTable::familyNameTypes));
195 }
196
next(SkTypeface::LocalizedString * localizedString)197 bool SkOTUtils::LocalizedStrings_NameTable::next(SkTypeface::LocalizedString* localizedString) {
198 do {
199 SkOTTableName::Iterator::Record record;
200 if (fFamilyNameIter.next(record)) {
201 localizedString->fString = record.name;
202 localizedString->fLanguage = record.language;
203 return true;
204 }
205 if (fTypesCount == fTypesIndex + 1) {
206 return false;
207 }
208 ++fTypesIndex;
209 fFamilyNameIter.reset(fTypes[fTypesIndex]);
210 } while (true);
211 }
212
213 SK_OT_USHORT SkOTUtils::LocalizedStrings_NameTable::familyNameTypes[3] = {
214 SkOTTableName::Record::NameID::Predefined::FontFamilyName,
215 SkOTTableName::Record::NameID::Predefined::PreferredFamily,
216 SkOTTableName::Record::NameID::Predefined::WWSFamilyName,
217 };
218
SetAdvancedTypefaceFlags(SkOTTableOS2_V4::Type fsType,SkAdvancedTypefaceMetrics * info)219 void SkOTUtils::SetAdvancedTypefaceFlags(SkOTTableOS2_V4::Type fsType,
220 SkAdvancedTypefaceMetrics* info) {
221 SkASSERT(info);
222 // The logic should be identical to SkTypeface_FreeType::onGetAdvancedMetrics().
223 if (fsType.raw.value != 0) {
224 if (SkToBool(fsType.field.Restricted) || SkToBool(fsType.field.Bitmap)) {
225 info->fFlags |= SkAdvancedTypefaceMetrics::kNotEmbeddable_FontFlag;
226 }
227 if (SkToBool(fsType.field.NoSubsetting)) {
228 info->fFlags |= SkAdvancedTypefaceMetrics::kNotSubsettable_FontFlag;
229 }
230 }
231 }
232