1 /*
2  * Copyright 2014 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 IMG_UTILS_INPUT_H
18 #define IMG_UTILS_INPUT_H
19 
20 #include <cutils/compiler.h>
21 #include <utils/Errors.h>
22 #include <stdint.h>
23 
24 namespace android {
25 namespace img_utils {
26 
27 /**
28  * Utility class used as a source of bytes.
29  */
30 class ANDROID_API Input {
31     public:
32         virtual ~Input();
33 
34         /**
35          * Open this Input.
36          *
37          * Returns OK on success, or a negative error code.
38          */
39         virtual status_t open();
40 
41         /**
42          * Read bytes into the given buffer.  At most, the number of bytes given in the
43          * count argument will be read.  Bytes will be written into the given buffer starting
44          * at the index given in the offset argument.
45          *
46          * Returns the number of bytes read, or NOT_ENOUGH_DATA if at the end of the file.  If an
47          * error has occurred, this will return a negative error code other than NOT_ENOUGH_DATA.
48          */
49         virtual ssize_t read(uint8_t* buf, size_t offset, size_t count) = 0;
50 
51         /**
52          * Skips bytes in the input.
53          *
54          * Returns the number of bytes skipped, or NOT_ENOUGH_DATA if at the end of the file.  If an
55          * error has occurred, this will return a negative error code other than NOT_ENOUGH_DATA.
56          */
57         virtual ssize_t skip(size_t count);
58 
59         /**
60          * Close the Input.  It is not valid to call open on a previously closed Input.
61          *
62          * Returns OK on success, or a negative error code.
63          */
64         virtual status_t close();
65 };
66 
67 } /*namespace img_utils*/
68 } /*namespace android*/
69 
70 
71 #endif /*IMG_UTILS_INPUT_H*/
72