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/*
* Copyright (C) 2015 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.
*/
#ifndef AAPT_RES_CHUNK_PULL_PARSER_H
#define AAPT_RES_CHUNK_PULL_PARSER_H
#include "util/Util.h"
#include <androidfw/ResourceTypes.h>
#include <string>
namespace aapt {
/**
* A pull parser, modeled after XmlPullParser, that reads
* android::ResChunk_header structs from a block of data.
*
* An android::ResChunk_header specifies a type, headerSize,
* and size. The pull parser will verify that the chunk's size
* doesn't extend beyond the available data, and will iterate
* over each chunk in the given block of data.
*
* Processing nested chunks is done by creating a new ResChunkPullParser
* pointing to the data portion of a chunk.
*/
class ResChunkPullParser {
public:
enum class Event {
StartDocument,
EndDocument,
BadDocument,
Chunk,
};
/**
* Returns false if the event is EndDocument or BadDocument.
*/
static bool isGoodEvent(Event event);
/**
* Create a ResChunkPullParser to read android::ResChunk_headers
* from the memory pointed to by data, of len bytes.
*/
ResChunkPullParser(const void* data, size_t len);
ResChunkPullParser(const ResChunkPullParser&) = delete;
Event getEvent() const;
const std::string& getLastError() const;
const android::ResChunk_header* getChunk() const;
/**
* Move to the next android::ResChunk_header.
*/
Event next();
private:
Event mEvent;
const android::ResChunk_header* mData;
size_t mLen;
const android::ResChunk_header* mCurrentChunk;
std::string mLastError;
};
template <typename T>
inline static const T* convertTo(const android::ResChunk_header* chunk) {
if (util::deviceToHost16(chunk->headerSize) < sizeof(T)) {
return nullptr;
}
return reinterpret_cast<const T*>(chunk);
}
inline static const uint8_t* getChunkData(const android::ResChunk_header* chunk) {
return reinterpret_cast<const uint8_t*>(chunk) + util::deviceToHost16(chunk->headerSize);
}
inline static uint32_t getChunkDataLen(const android::ResChunk_header* chunk) {
return util::deviceToHost32(chunk->size) - util::deviceToHost16(chunk->headerSize);
}
//
// Implementation
//
inline bool ResChunkPullParser::isGoodEvent(ResChunkPullParser::Event event) {
return event != Event::EndDocument && event != Event::BadDocument;
}
inline ResChunkPullParser::ResChunkPullParser(const void* data, size_t len) :
mEvent(Event::StartDocument),
mData(reinterpret_cast<const android::ResChunk_header*>(data)),
mLen(len),
mCurrentChunk(nullptr) {
}
inline ResChunkPullParser::Event ResChunkPullParser::getEvent() const {
return mEvent;
}
inline const std::string& ResChunkPullParser::getLastError() const {
return mLastError;
}
inline const android::ResChunk_header* ResChunkPullParser::getChunk() const {
return mCurrentChunk;
}
} // namespace aapt
#endif // AAPT_RES_CHUNK_PULL_PARSER_H