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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkData.h"
#include "SkEndian.h"
#include "SkSFNTHeader.h"
#include "SkStream.h"
#include "SkOTTable_head.h"
#include "SkOTTable_name.h"
#include "SkOTTableTypes.h"
#include "SkOTUtils.h"
uint32_t SkOTUtils::CalcTableChecksum(SK_OT_ULONG *data, size_t length) {
uint32_t sum = 0;
SK_OT_ULONG *dataEnd = data + ((length + 3) & ~3) / sizeof(SK_OT_ULONG);
for (; data < dataEnd; ++data) {
sum += SkEndian_SwapBE32(*data);
}
return sum;
}
SkData* SkOTUtils::RenameFont(SkStream* fontData,
const char* fontName, int fontNameLen) {
// Get the sfnt header.
SkSFNTHeader sfntHeader;
if (fontData->read(&sfntHeader, sizeof(sfntHeader)) < sizeof(sfntHeader)) {
return NULL;
}
// Find the existing 'name' table.
int tableIndex;
SkSFNTTableDirectoryEntry tableEntry;
int numTables = SkEndian_SwapBE16(sfntHeader.numTables);
for (tableIndex = 0; tableIndex < numTables; ++tableIndex) {
if (fontData->read(&tableEntry, sizeof(tableEntry)) < sizeof(tableEntry)) {
return NULL;
}
if (SkOTTableName::TAG == tableEntry.tag) {
break;
}
}
if (tableIndex == numTables) {
return NULL;
}
if (!fontData->rewind()) {
return NULL;
}
// The required 'name' record types: Family, Style, Unique, Full and PostScript.
const SkOTTableNameRecord::NameID::Predefined::Value namesToCreate[] = {
SkOTTableNameRecord::NameID::Predefined::FontFamilyName,
SkOTTableNameRecord::NameID::Predefined::FontSubfamilyName,
SkOTTableNameRecord::NameID::Predefined::UniqueFontIdentifier,
SkOTTableNameRecord::NameID::Predefined::FullFontName,
SkOTTableNameRecord::NameID::Predefined::PostscriptName,
};
const int namesCount = SK_ARRAY_COUNT(namesToCreate);
// Copy the data, leaving out the old name table.
// In theory, we could also remove the DSIG table if it exists.
size_t nameTableLogicalSize = sizeof(SkOTTableName) + (namesCount * sizeof(SkOTTableNameRecord)) + (fontNameLen * sizeof(wchar_t));
size_t nameTablePhysicalSize = (nameTableLogicalSize + 3) & ~3; // Rounded up to a multiple of 4.
size_t oldNameTablePhysicalSize = (SkEndian_SwapBE32(tableEntry.logicalLength) + 3) & ~3; // Rounded up to a multiple of 4.
size_t oldNameTableOffset = SkEndian_SwapBE32(tableEntry.offset);
//originalDataSize is the size of the original data without the name table.
size_t originalDataSize = fontData->getLength() - oldNameTablePhysicalSize;
size_t newDataSize = originalDataSize + nameTablePhysicalSize;
SK_OT_BYTE* data = static_cast<SK_OT_BYTE*>(sk_malloc_throw(newDataSize));
SkAutoTUnref<SkData> rewrittenFontData(SkData::NewFromMalloc(data, newDataSize));
if (fontData->read(data, oldNameTableOffset) < oldNameTableOffset) {
return NULL;
}
if (fontData->skip(oldNameTablePhysicalSize) < oldNameTablePhysicalSize) {
return NULL;
}
if (fontData->read(data + oldNameTableOffset, originalDataSize - oldNameTableOffset) < originalDataSize - oldNameTableOffset) {
return NULL;
}
//Fix up the offsets of the directory entries after the old 'name' table entry.
SkSFNTTableDirectoryEntry* currentEntry = reinterpret_cast<SkSFNTTableDirectoryEntry*>(data + sizeof(SkSFNTHeader));
SkSFNTTableDirectoryEntry* endEntry = currentEntry + numTables;
SkSFNTTableDirectoryEntry* headTableEntry = NULL;
for (; currentEntry < endEntry; ++currentEntry) {
uint32_t oldOffset = SkEndian_SwapBE32(currentEntry->offset);
if (oldOffset > oldNameTableOffset) {
currentEntry->offset = SkEndian_SwapBE32(oldOffset - oldNameTablePhysicalSize);
}
if (SkOTTableHead::TAG == tableEntry.tag) {
headTableEntry = currentEntry;
}
}
// Make the table directory entry point to the new 'name' table.
SkSFNTTableDirectoryEntry* nameTableEntry = reinterpret_cast<SkSFNTTableDirectoryEntry*>(data + sizeof(SkSFNTHeader)) + tableIndex;
nameTableEntry->logicalLength = SkEndian_SwapBE32(nameTableLogicalSize);
nameTableEntry->offset = SkEndian_SwapBE32(originalDataSize);
// Write the new 'name' table after the original font data.
SkOTTableName* nameTable = reinterpret_cast<SkOTTableName*>(data + originalDataSize);
unsigned short stringOffset = sizeof(SkOTTableName) + (namesCount * sizeof(SkOTTableNameRecord));
nameTable->format = SkOTTableName::format_0;
nameTable->count = SkEndian_SwapBE16(namesCount);
nameTable->stringOffset = SkEndian_SwapBE16(stringOffset);
SkOTTableNameRecord* nameRecords = reinterpret_cast<SkOTTableNameRecord*>(data + originalDataSize + sizeof(SkOTTableName));
for (int i = 0; i < namesCount; ++i) {
nameRecords[i].platformID.value = SkOTTableNameRecord::PlatformID::Windows;
nameRecords[i].encodingID.windows.value = SkOTTableNameRecord::EncodingID::Windows::UnicodeBMPUCS2;
nameRecords[i].languageID.windows.value = SkOTTableNameRecord::LanguageID::Windows::English_UnitedStates;
nameRecords[i].nameID.predefined.value = namesToCreate[i];
nameRecords[i].offset = SkEndian_SwapBE16(0);
nameRecords[i].length = SkEndian_SwapBE16(fontNameLen * sizeof(wchar_t));
}
SK_OT_USHORT* nameString = reinterpret_cast<SK_OT_USHORT*>(data + originalDataSize + stringOffset);
for (int i = 0; i < fontNameLen; ++i) {
nameString[i] = SkEndian_SwapBE16(fontName[i]);
}
unsigned char* logical = data + originalDataSize + nameTableLogicalSize;
unsigned char* physical = data + originalDataSize + nameTablePhysicalSize;
for (; logical < physical; ++logical) {
*logical = 0;
}
// Update the table checksum in the directory entry.
nameTableEntry->checksum = SkEndian_SwapBE32(SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(nameTable), nameTableLogicalSize));
// Update the checksum adjustment in the head table.
if (headTableEntry) {
size_t headTableOffset = SkEndian_SwapBE32(headTableEntry->offset);
if (headTableOffset + sizeof(SkOTTableHead) < originalDataSize) {
SkOTTableHead* headTable = reinterpret_cast<SkOTTableHead*>(data + headTableOffset);
headTable->checksumAdjustment = SkEndian_SwapBE32(0);
uint32_t unadjustedFontChecksum = SkOTUtils::CalcTableChecksum(reinterpret_cast<SK_OT_ULONG*>(data), originalDataSize + nameTablePhysicalSize);
headTable->checksumAdjustment = SkEndian_SwapBE32(SkOTTableHead::fontChecksum - unadjustedFontChecksum);
}
}
return rewrittenFontData.detach();
}
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