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/*
* Copyright (C) 2016 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 CHUNK_H_
#define CHUNK_H_
#include "android-base/logging.h"
#include "android-base/macros.h"
#include "utils/ByteOrder.h"
#ifdef _WIN32
#ifdef ERROR
#undef ERROR
#endif
#endif
#include "androidfw/ResourceTypes.h"
namespace android {
// Helpful wrapper around a ResChunk_header that provides getter methods
// that handle endianness conversions and provide access to the data portion
// of the chunk.
class Chunk {
public:
explicit Chunk(const ResChunk_header* chunk) : device_chunk_(chunk) {}
// Returns the type of the chunk. Caller need not worry about endianness.
inline int type() const { return dtohs(device_chunk_->type); }
// Returns the size of the entire chunk. This can be useful for skipping
// over the entire chunk. Caller need not worry about endianness.
inline size_t size() const { return dtohl(device_chunk_->size); }
// Returns the size of the header. Caller need not worry about endianness.
inline size_t header_size() const { return dtohs(device_chunk_->headerSize); }
template <typename T>
inline const T* header() const {
if (header_size() >= sizeof(T)) {
return reinterpret_cast<const T*>(device_chunk_);
}
return nullptr;
}
inline const void* data_ptr() const {
return reinterpret_cast<const uint8_t*>(device_chunk_) + header_size();
}
inline size_t data_size() const { return size() - header_size(); }
private:
const ResChunk_header* device_chunk_;
};
// Provides a Java style iterator over an array of ResChunk_header's.
// Validation is performed while iterating.
// The caller should check if there was an error during chunk validation
// by calling HadError() and GetLastError() to get the reason for failure.
// Example:
//
// ChunkIterator iter(data_ptr, data_len);
// while (iter.HasNext()) {
// const Chunk chunk = iter.Next();
// ...
// }
//
// if (iter.HadError()) {
// LOG(ERROR) << iter.GetLastError();
// }
//
class ChunkIterator {
public:
ChunkIterator(const void* data, size_t len)
: next_chunk_(reinterpret_cast<const ResChunk_header*>(data)),
len_(len),
last_error_(nullptr) {
CHECK(next_chunk_ != nullptr) << "data can't be nullptr";
VerifyNextChunk();
}
Chunk Next();
inline bool HasNext() const { return !HadError() && len_ != 0; };
inline bool HadError() const { return last_error_ != nullptr; }
inline std::string GetLastError() const { return last_error_; }
private:
DISALLOW_COPY_AND_ASSIGN(ChunkIterator);
// Returns false if there was an error.
bool VerifyNextChunk();
const ResChunk_header* next_chunk_;
size_t len_;
const char* last_error_;
};
} // namespace android
#endif /* CHUNK_H_ */
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