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/*
* Copyright (C) 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "minikin/FontFileParser.h"
#define LOG_TAG "Minikin"
#include <hb-ot.h>
#include <hb.h>
#include <cstdint>
#include <optional>
#include <string>
#include <vector>
#include "MinikinInternal.h"
#include "minikin/Constants.h"
namespace minikin {
namespace {
class SafeFontBufferReader {
public:
SafeFontBufferReader(const void* buffer, size_t size)
: mBuffer(reinterpret_cast<const uint8_t*>(buffer)),
mSize(size),
mPos(0),
mError(false) {}
template <typename T>
T readBE() {
if (mError) return T();
if ((mSize - mPos) < sizeof(T)) {
mError = true;
return T();
}
const T* data = reinterpret_cast<const T*>(mBuffer + mPos);
mPos += sizeof(T);
return *data;
}
uint16_t readU16() {
if (mError) return 0;
if ((mSize - mPos) < 2) {
mError = true;
return 0;
}
uint16_t out = ((uint32_t)mBuffer[mPos]) << 8 | ((uint32_t)mBuffer[mPos + 1]);
mPos += 2;
return out;
};
uint32_t readU32() {
if (mError) return 0;
if ((mSize - mPos) < 4) {
mError = true;
return 0;
}
uint32_t out = ((uint32_t)mBuffer[mPos]) << 24 | ((uint32_t)mBuffer[mPos + 1]) << 16 |
((uint32_t)mBuffer[mPos + 2]) << 8 | ((uint32_t)mBuffer[mPos + 3]);
mPos += 4;
return out;
};
void seek(size_t pos) {
if (mError) return;
if (pos > mSize) {
mError = true;
} else {
mPos = pos;
}
}
size_t remaining() const {
if (mError) return 0;
return mSize - mPos;
}
bool error() const { return mError; }
private:
const uint8_t* mBuffer;
size_t mSize;
size_t mPos;
bool mError;
};
bool isPostScriptNameAllowedChar(char c) {
// OpenType spec says only ASCII codes 33 to 126, ecept for the '[', ']', '(', ')', '{', '}',
// '<', '>', '/', '%'.
if (!(33 <= c && c <= 126)) {
return false;
}
if (c == '[' || c == ']' || c == '(' || c == ')' || c == '{' || c == '}' || c == '<' ||
c == '>' || c == '/' || c == '%') {
return false;
}
return true;
}
} // namespace
// static
bool FontFileParser::analyzeFontRevision(const uint8_t* head_data, size_t head_size,
uint32_t* out) {
SafeFontBufferReader reader(head_data, head_size);
if (reader.remaining() < 8) {
return false; // At least head table has 8 bytes, for version and fontRevision
}
uint32_t majorVersion = reader.readU16();
if (reader.error()) return false;
uint32_t minorVersion = reader.readU16();
if (reader.error()) return false;
// Invalid head table header.
if (majorVersion != 1 && minorVersion != 0) return false;
*out = reader.readU32();
if (reader.error()) return false;
return true;
}
// static
bool FontFileParser::checkPSName(const std::string& psName) {
if (psName.size() > 63) return false;
for (auto c : psName) {
if (!isPostScriptNameAllowedChar(c)) {
return false;
}
}
return true;
}
FontFileParser::FontFileParser(const void* buffer, size_t size, uint32_t index)
: mFace(makeHbFace(buffer, size, index)) {}
FontFileParser::FontFileParser(const HbFaceUniquePtr& face)
: mFace(hb_face_reference(face.get())) {}
FontFileParser::FontFileParser(const HbFontUniquePtr& font)
: mFace(hb_face_reference(hb_font_get_face(font.get()))) {}
FontFileParser::~FontFileParser() {}
// static
HbFaceUniquePtr FontFileParser::makeHbFace(const void* buffer, size_t size, uint32_t index) {
HbBlobUniquePtr blob(hb_blob_create(reinterpret_cast<const char*>(buffer), size,
HB_MEMORY_MODE_READONLY, nullptr, nullptr));
return HbFaceUniquePtr(hb_face_create(blob.get(), index));
}
std::optional<uint32_t> FontFileParser::getFontRevision() const {
if (!mFace) return std::optional<uint32_t>();
HbBlob headTable(mFace, MakeTag('h', 'e', 'a', 'd'));
if (!headTable) return std::optional<uint32_t>();
uint32_t out = 0;
if (!analyzeFontRevision(headTable.get(), headTable.size(), &out)) {
return std::optional<uint32_t>();
}
return out;
}
std::optional<std::string> FontFileParser::getPostScriptName() const {
if (!mFace) return std::optional<std::string>();
unsigned int size = 64; // PostScript name is up to 63 characters.
char buf[64] = {};
uint32_t result = hb_ot_name_get_utf8(mFace.get(), HB_OT_NAME_ID_POSTSCRIPT_NAME,
HB_LANGUAGE_INVALID, &size, buf);
if (result == 0) { // not found.
return std::optional<std::string>();
}
std::string out(buf, size);
if (!checkPSName(out)) { // Contains invalid characters.
return std::optional<std::string>();
}
return out;
}
std::optional<bool> FontFileParser::isPostScriptType1Font() const {
if (!mFace) return std::optional<bool>();
HbBlob cffTable(mFace, MakeTag('C', 'F', 'F', ' '));
HbBlob cff2Table(mFace, MakeTag('C', 'F', 'F', '2'));
return cffTable || cff2Table;
}
} // namespace minikin
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