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
24namespace android {
25
26class String8;
27
28class DataSourceBase {
29public:
30    enum Flags {
31        kWantsPrefetching      = 1,
32        kStreamedFromLocalHost = 2,
33        kIsCachingDataSource   = 4,
34        kIsHTTPBasedSource     = 8,
35        kIsLocalFileSource     = 16,
36    };
37
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
63    virtual uint32_t flags() {
64        return 0;
65    }
66
67    virtual void close() {};
68
69protected:
70    virtual ~DataSourceBase() {}
71
72private:
73    DataSourceBase(const DataSourceBase &);
74    DataSourceBase &operator=(const DataSourceBase &);
75};
76
77}  // namespace android
78
79#endif  // DATA_SOURCE_BASE_H_
80