1/* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef AAPT_RES_CHUNK_PULL_PARSER_H 18#define AAPT_RES_CHUNK_PULL_PARSER_H 19 20#include "util/Util.h" 21 22#include <androidfw/ResourceTypes.h> 23#include <string> 24 25namespace aapt { 26 27/** 28 * A pull parser, modeled after XmlPullParser, that reads 29 * android::ResChunk_header structs from a block of data. 30 * 31 * An android::ResChunk_header specifies a type, headerSize, 32 * and size. The pull parser will verify that the chunk's size 33 * doesn't extend beyond the available data, and will iterate 34 * over each chunk in the given block of data. 35 * 36 * Processing nested chunks is done by creating a new ResChunkPullParser 37 * pointing to the data portion of a chunk. 38 */ 39class ResChunkPullParser { 40public: 41 enum class Event { 42 StartDocument, 43 EndDocument, 44 BadDocument, 45 46 Chunk, 47 }; 48 49 /** 50 * Returns false if the event is EndDocument or BadDocument. 51 */ 52 static bool isGoodEvent(Event event); 53 54 /** 55 * Create a ResChunkPullParser to read android::ResChunk_headers 56 * from the memory pointed to by data, of len bytes. 57 */ 58 ResChunkPullParser(const void* data, size_t len); 59 60 ResChunkPullParser(const ResChunkPullParser&) = delete; 61 62 Event getEvent() const; 63 const std::string& getLastError() const; 64 const android::ResChunk_header* getChunk() const; 65 66 /** 67 * Move to the next android::ResChunk_header. 68 */ 69 Event next(); 70 71private: 72 Event mEvent; 73 const android::ResChunk_header* mData; 74 size_t mLen; 75 const android::ResChunk_header* mCurrentChunk; 76 std::string mLastError; 77}; 78 79template <typename T> 80inline static const T* convertTo(const android::ResChunk_header* chunk) { 81 if (util::deviceToHost16(chunk->headerSize) < sizeof(T)) { 82 return nullptr; 83 } 84 return reinterpret_cast<const T*>(chunk); 85} 86 87inline static const uint8_t* getChunkData(const android::ResChunk_header* chunk) { 88 return reinterpret_cast<const uint8_t*>(chunk) + util::deviceToHost16(chunk->headerSize); 89} 90 91inline static uint32_t getChunkDataLen(const android::ResChunk_header* chunk) { 92 return util::deviceToHost32(chunk->size) - util::deviceToHost16(chunk->headerSize); 93} 94 95// 96// Implementation 97// 98 99inline bool ResChunkPullParser::isGoodEvent(ResChunkPullParser::Event event) { 100 return event != Event::EndDocument && event != Event::BadDocument; 101} 102 103inline ResChunkPullParser::ResChunkPullParser(const void* data, size_t len) : 104 mEvent(Event::StartDocument), 105 mData(reinterpret_cast<const android::ResChunk_header*>(data)), 106 mLen(len), 107 mCurrentChunk(nullptr) { 108} 109 110inline ResChunkPullParser::Event ResChunkPullParser::getEvent() const { 111 return mEvent; 112} 113 114inline const std::string& ResChunkPullParser::getLastError() const { 115 return mLastError; 116} 117 118inline const android::ResChunk_header* ResChunkPullParser::getChunk() const { 119 return mCurrentChunk; 120} 121 122} // namespace aapt 123 124#endif // AAPT_RES_CHUNK_PULL_PARSER_H 125