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_FORMAT_BINARY_RESCHUNKPULLPARSER_H 18 #define AAPT_FORMAT_BINARY_RESCHUNKPULLPARSER_H 19 20 #include <string> 21 22 #include "android-base/macros.h" 23 #include "androidfw/ResourceTypes.h" 24 25 #include "util/Util.h" 26 27 namespace aapt { 28 29 // A pull parser, modeled after XmlPullParser, that reads android::ResChunk_header structs from a 30 // block of data. 31 // An android::ResChunk_header specifies a type, headerSize, and size. The pull parser will verify 32 // that the chunk's size doesn't extend beyond the available data, and will iterate over each chunk 33 // in the given block of data. 34 // Processing nested chunks is done by creating a new ResChunkPullParser pointing to the data 35 // portion of a chunk. 36 class ResChunkPullParser { 37 public: 38 enum class Event { 39 kStartDocument, 40 kEndDocument, 41 kBadDocument, 42 43 kChunk, 44 }; 45 46 // Returns false if the event is EndDocument or BadDocument. 47 static bool IsGoodEvent(Event event); 48 49 // Create a ResChunkPullParser to read android::ResChunk_headers from the memory pointed to by 50 // data, of len bytes. 51 ResChunkPullParser(const void* data, size_t len); 52 53 Event event() const; 54 const std::string& error() const; 55 const android::ResChunk_header* chunk() const; 56 57 // Move to the next android::ResChunk_header. 58 Event Next(); 59 60 private: 61 DISALLOW_COPY_AND_ASSIGN(ResChunkPullParser); 62 63 Event event_; 64 const android::ResChunk_header* data_; 65 size_t len_; 66 const android::ResChunk_header* current_chunk_; 67 std::string error_; 68 }; 69 70 template <typename T, size_t MinSize = sizeof(T)> 71 inline static const T* ConvertTo(const android::ResChunk_header* chunk) { 72 if (util::DeviceToHost16(chunk->headerSize) < MinSize) { 73 return nullptr; 74 } 75 return reinterpret_cast<const T*>(chunk); 76 } 77 78 inline static const uint8_t* GetChunkData(const android::ResChunk_header* chunk) { 79 return reinterpret_cast<const uint8_t*>(chunk) + util::DeviceToHost16(chunk->headerSize); 80 } 81 82 inline static uint32_t GetChunkDataLen(const android::ResChunk_header* chunk) { 83 return util::DeviceToHost32(chunk->size) - util::DeviceToHost16(chunk->headerSize); 84 } 85 86 // 87 // Implementation 88 // 89 90 inline bool ResChunkPullParser::IsGoodEvent(ResChunkPullParser::Event event) { 91 return event != Event::kEndDocument && event != Event::kBadDocument; 92 } 93 94 inline ResChunkPullParser::ResChunkPullParser(const void* data, size_t len) 95 : event_(Event::kStartDocument), 96 data_(reinterpret_cast<const android::ResChunk_header*>(data)), 97 len_(len), 98 current_chunk_(nullptr) { 99 } 100 101 inline ResChunkPullParser::Event ResChunkPullParser::event() const { 102 return event_; 103 } 104 105 inline const std::string& ResChunkPullParser::error() const { 106 return error_; 107 } 108 109 inline const android::ResChunk_header* ResChunkPullParser::chunk() const { 110 return current_chunk_; 111 } 112 113 } // namespace aapt 114 115 #endif // AAPT_FORMAT_BINARY_RESCHUNKPULLPARSER_H 116
