1/*
2 * Copyright (C) 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 EBMLUTIL_H_
18#define EBMLUTIL_H_
19
20#include <stdint.h>
21
22namespace webm {
23
24// Encode the id and/or size of an EBML element bytes by setting a leading length descriptor bit:
25//
26//   1xxxxxxx                                                                - 1-byte values
27//   01xxxxxx xxxxxxxx                                                       -
28//   001xxxxx xxxxxxxx xxxxxxxx                                              -
29//   0001xxxx xxxxxxxx xxxxxxxx xxxxxxxx                                     - ...
30//   00001xxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx                            -
31//   000001xx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx                   -
32//   0000001x xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx          -
33//   00000001 xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx - 8-byte values
34//
35// This function uses the least the number of bytes possible.
36uint64_t encodeUnsigned(uint64_t u);
37
38// Like above but pads the input value with leading zeros up to the specified width. The length
39// descriptor is calculated based on width.
40uint64_t encodeUnsigned(uint64_t u, int width);
41
42// Serialize an EBML coded id or size in big-endian order.
43int serializeCodedUnsigned(uint64_t u, uint8_t* bary);
44
45// Calculate the length of an EBML coded id or size from its length descriptor.
46int sizeOf(uint64_t u);
47
48}
49
50#endif /* EBMLUTIL_H_ */
51