1 /* 2 * Copyright (C) 2009 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 DATA_SOURCE_BASE_H_ 18 19 #define DATA_SOURCE_BASE_H_ 20 21 #include <sys/types.h> 22 #include <utils/Errors.h> 23 24 namespace android { 25 26 class String8; 27 28 class DataSourceBase { 29 public: 30 enum Flags { 31 kWantsPrefetching = 1, 32 kStreamedFromLocalHost = 2, 33 kIsCachingDataSource = 4, 34 kIsHTTPBasedSource = 8, 35 kIsLocalFileSource = 16, 36 }; 37 DataSourceBase()38 DataSourceBase() {} 39 40 virtual status_t initCheck() const = 0; 41 42 // Returns the number of bytes read, or -1 on failure. It's not an error if 43 // this returns zero; it just means the given offset is equal to, or 44 // beyond, the end of the source. 45 virtual ssize_t readAt(off64_t offset, void *data, size_t size) = 0; 46 47 // Convenience methods: 48 bool getUInt16(off64_t offset, uint16_t *x); 49 bool getUInt24(off64_t offset, uint32_t *x); // 3 byte int, returned as a 32-bit int 50 bool getUInt32(off64_t offset, uint32_t *x); 51 bool getUInt64(off64_t offset, uint64_t *x); 52 53 // read either int<N> or int<2N> into a uint<2N>_t, size is the int size in bytes. 54 bool getUInt16Var(off64_t offset, uint16_t *x, size_t size); 55 bool getUInt32Var(off64_t offset, uint32_t *x, size_t size); 56 bool getUInt64Var(off64_t offset, uint64_t *x, size_t size); 57 58 // May return ERROR_UNSUPPORTED. 59 virtual status_t getSize(off64_t *size); 60 61 virtual bool getUri(char *uriString, size_t bufferSize); 62 flags()63 virtual uint32_t flags() { 64 return 0; 65 } 66 close()67 virtual void close() {}; 68 getAvailableSize(off64_t,off64_t *)69 virtual status_t getAvailableSize(off64_t /*offset*/, off64_t * /*size*/) { 70 return -1; 71 } 72 73 protected: ~DataSourceBase()74 virtual ~DataSourceBase() {} 75 76 private: 77 DataSourceBase(const DataSourceBase &); 78 DataSourceBase &operator=(const DataSourceBase &); 79 }; 80 81 } // namespace android 82 83 #endif // DATA_SOURCE_BASE_H_ 84