gecko-dev/gfx/2d/SFNTData.cpp

257 lines
6.6 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "SFNTData.h"
#include <algorithm>
#include "BigEndianInts.h"
#include "Logging.h"
#include "mozilla/HashFunctions.h"
#include "SFNTNameTable.h"
namespace mozilla {
namespace gfx {
#define TRUETYPE_TAG(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d))
#pragma pack(push, 1)
struct TTCHeader
{
BigEndianUint32 ttcTag; // Always 'ttcf'
BigEndianUint32 version; // Fixed, 0x00010000
BigEndianUint32 numFonts;
};
struct OffsetTable
{
BigEndianUint32 sfntVersion; // Fixed, 0x00010000 for version 1.0.
BigEndianUint16 numTables;
BigEndianUint16 searchRange; // (Maximum power of 2 <= numTables) x 16.
BigEndianUint16 entrySelector; // Log2(maximum power of 2 <= numTables).
BigEndianUint16 rangeShift; // NumTables x 16-searchRange.
};
struct TableDirEntry
{
BigEndianUint32 tag; // 4 -byte identifier.
BigEndianUint32 checkSum; // CheckSum for this table.
BigEndianUint32 offset; // Offset from beginning of TrueType font file.
BigEndianUint32 length; // Length of this table.
friend bool operator<(const TableDirEntry& lhs, const uint32_t aTag)
{
return lhs.tag < aTag;
}
};
#pragma pack(pop)
class SFNTData::Font
{
public:
Font(const OffsetTable *aOffsetTable, const uint8_t *aFontData,
uint32_t aDataLength)
: mFontData(aFontData)
, mFirstDirEntry(reinterpret_cast<const TableDirEntry*>(aOffsetTable + 1))
, mEndOfDirEntries(mFirstDirEntry + aOffsetTable->numTables)
, mDataLength(aDataLength)
{
}
bool GetU16FullName(mozilla::u16string& aU16FullName)
{
const TableDirEntry* dirEntry =
GetDirEntry(TRUETYPE_TAG('n', 'a', 'm', 'e'));
if (!dirEntry) {
gfxWarning() << "Name table entry not found.";
return false;
}
UniquePtr<SFNTNameTable> nameTable =
SFNTNameTable::Create((mFontData + dirEntry->offset), dirEntry->length);
if (!nameTable) {
return false;
}
return nameTable->GetU16FullName(aU16FullName);
}
private:
const TableDirEntry*
GetDirEntry(const uint32_t aTag)
{
const TableDirEntry* foundDirEntry =
std::lower_bound(mFirstDirEntry, mEndOfDirEntries, aTag);
if (foundDirEntry == mEndOfDirEntries || foundDirEntry->tag != aTag) {
gfxWarning() << "Font data does not contain tag.";
return nullptr;
}
if (mDataLength < (foundDirEntry->offset + foundDirEntry->length)) {
gfxWarning() << "Font data too short to contain table.";
return nullptr;
}
return foundDirEntry;
}
const uint8_t *mFontData;
const TableDirEntry *mFirstDirEntry;
const TableDirEntry *mEndOfDirEntries;
uint32_t mDataLength;
};
/* static */
UniquePtr<SFNTData>
SFNTData::Create(const uint8_t *aFontData, uint32_t aDataLength)
{
MOZ_ASSERT(aFontData);
// Check to see if this is a font collection.
if (aDataLength < sizeof(TTCHeader)) {
gfxWarning() << "Font data too short.";
return nullptr;
}
const TTCHeader *ttcHeader = reinterpret_cast<const TTCHeader*>(aFontData);
if (ttcHeader->ttcTag == TRUETYPE_TAG('t', 't', 'c', 'f')) {
uint32_t numFonts = ttcHeader->numFonts;
if (aDataLength < sizeof(TTCHeader) + (numFonts * sizeof(BigEndianUint32))) {
gfxWarning() << "Font data too short to contain full TTC Header.";
return nullptr;
}
UniquePtr<SFNTData> sfntData(new SFNTData);
const BigEndianUint32* offset =
reinterpret_cast<const BigEndianUint32*>(aFontData + sizeof(TTCHeader));
const BigEndianUint32* endOfOffsets = offset + numFonts;
while (offset != endOfOffsets) {
if (!sfntData->AddFont(aFontData, aDataLength, *offset)) {
return nullptr;
}
++offset;
}
return Move(sfntData);
}
UniquePtr<SFNTData> sfntData(new SFNTData);
if (!sfntData->AddFont(aFontData, aDataLength, 0)) {
return nullptr;
}
return Move(sfntData);
}
/* static */
uint64_t
SFNTData::GetUniqueKey(const uint8_t *aFontData, uint32_t aDataLength,
uint32_t aVarDataSize, const void* aVarData)
{
uint64_t hash;
UniquePtr<SFNTData> sfntData = SFNTData::Create(aFontData, aDataLength);
mozilla::u16string firstName;
if (sfntData && sfntData->GetU16FullName(0, firstName)) {
hash = HashString(firstName.c_str(), firstName.length());
} else {
gfxWarning() << "Failed to get name from font data hashing whole font.";
hash = HashString(aFontData, aDataLength);
}
if (aVarDataSize) {
hash = AddToHash(hash, HashBytes(aVarData, aVarDataSize));
}
return hash << 32 | aDataLength;;
}
SFNTData::~SFNTData()
{
for (size_t i = 0; i < mFonts.length(); ++i) {
delete mFonts[i];
}
}
bool
SFNTData::GetU16FullName(uint32_t aIndex, mozilla::u16string& aU16FullName)
{
if (aIndex >= mFonts.length()) {
gfxWarning() << "aIndex to font data too high.";
return false;
}
return mFonts[aIndex]->GetU16FullName(aU16FullName);
}
bool
SFNTData::GetU16FullNames(Vector<mozilla::u16string>& aU16FullNames)
{
bool fontFound = false;
for (size_t i = 0; i < mFonts.length(); ++i) {
mozilla::u16string name;
if (mFonts[i]->GetU16FullName(name)) {
fontFound = true;
}
if (!aU16FullNames.append(Move(name))) {
return false;
}
}
return fontFound;
}
bool
SFNTData::GetIndexForU16Name(const mozilla::u16string& aU16FullName,
uint32_t* aIndex, size_t aTruncatedLen)
{
for (size_t i = 0; i < mFonts.length(); ++i) {
mozilla::u16string name;
if (!mFonts[i]->GetU16FullName(name)) {
continue;
}
if (aTruncatedLen) {
MOZ_ASSERT(aU16FullName.length() <= aTruncatedLen);
name = name.substr(0, aTruncatedLen);
}
if (name == aU16FullName) {
*aIndex = i;
return true;
}
}
return false;
}
bool
SFNTData::AddFont(const uint8_t *aFontData, uint32_t aDataLength,
uint32_t aOffset)
{
uint32_t remainingLength = aDataLength - aOffset;
if (remainingLength < sizeof(OffsetTable)) {
gfxWarning() << "Font data too short to contain OffsetTable " << aOffset;
return false;
}
const OffsetTable *offsetTable =
reinterpret_cast<const OffsetTable*>(aFontData + aOffset);
if (remainingLength <
sizeof(OffsetTable) + (offsetTable->numTables * sizeof(TableDirEntry))) {
gfxWarning() << "Font data too short to contain tables.";
return false;
}
return mFonts.append(new Font(offsetTable, aFontData, aDataLength));
}
} // gfx
} // mozilla