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1 | /***************************************************************************** |
2 | * Copyright (C) 2013 x265 project | |
3 | * | |
4 | * Author: Steve Borho <steve@borho.org> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA. | |
19 | * | |
20 | * This program is also available under a commercial proprietary license. | |
21 | * For more information, contact us at license @ x265.com. | |
22 | *****************************************************************************/ | |
23 | ||
24 | #ifndef X265_BITSTREAM_H | |
25 | #define X265_BITSTREAM_H 1 | |
26 | ||
27 | namespace x265 { | |
28 | // private namespace | |
29 | ||
30 | class BitInterface | |
31 | { | |
32 | public: | |
33 | ||
34 | virtual void write(uint32_t val, uint32_t numBits) = 0; | |
35 | virtual void writeByte(uint32_t val) = 0; | |
36 | virtual void resetBits() = 0; | |
37 | virtual uint32_t getNumberOfWrittenBits() const = 0; | |
38 | virtual void writeAlignOne() = 0; | |
39 | virtual void writeAlignZero() = 0; | |
40 | virtual ~BitInterface() {} | |
41 | }; | |
42 | ||
43 | class BitCounter : public BitInterface | |
44 | { | |
45 | protected: | |
46 | ||
47 | uint32_t m_bitCounter; | |
48 | ||
49 | public: | |
50 | ||
51 | BitCounter() : m_bitCounter(0) {} | |
52 | ||
53 | void write(uint32_t, uint32_t num) { m_bitCounter += num; } | |
54 | void writeByte(uint32_t) { m_bitCounter += 8; } | |
55 | void resetBits() { m_bitCounter = 0; } | |
56 | uint32_t getNumberOfWrittenBits() const { return m_bitCounter; } | |
57 | void writeAlignOne() { } | |
58 | void writeAlignZero() { } | |
59 | }; | |
60 | ||
61 | ||
62 | class Bitstream : public BitInterface | |
63 | { | |
64 | public: | |
65 | ||
66 | Bitstream(); | |
67 | ~Bitstream() { X265_FREE(m_fifo); } | |
68 | ||
69 | void resetBits() { m_partialByteBits = m_byteOccupancy = 0; m_partialByte = 0; } | |
70 | uint32_t getNumberOfWrittenBytes() const { return m_byteOccupancy; } | |
71 | uint32_t getNumberOfWrittenBits() const { return m_byteOccupancy * 8 + m_partialByteBits; } | |
72 | const uint8_t* getFIFO() const { return m_fifo; } | |
73 | ||
74 | void write(uint32_t val, uint32_t numBits); | |
75 | void writeByte(uint32_t val); | |
76 | ||
77 | void writeAlignOne(); // insert one bits until the bitstream is byte-aligned | |
78 | void writeAlignZero(); // insert zero bits until the bitstream is byte-aligned | |
79 | void writeByteAlignment(); // insert 1 bit, then pad to byte-align with zero | |
80 | ||
81 | private: | |
82 | ||
83 | uint8_t *m_fifo; | |
84 | uint32_t m_byteAlloc; | |
85 | uint32_t m_byteOccupancy; | |
86 | uint32_t m_partialByteBits; | |
87 | uint8_t m_partialByte; | |
88 | ||
89 | void push_back(uint8_t val); | |
90 | }; | |
91 | ||
92 | static const uint8_t bitSize[256] = | |
93 | { | |
94 | 1, 1, 3, 3, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, | |
95 | 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, | |
96 | 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, | |
97 | 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, | |
98 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, | |
99 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, | |
100 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, | |
101 | 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, | |
102 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
103 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
104 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
105 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
106 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
107 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
108 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
109 | 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, | |
110 | }; | |
111 | ||
112 | static inline int bs_size_ue(unsigned int val) | |
113 | { | |
114 | return bitSize[val + 1]; | |
115 | } | |
116 | ||
117 | static inline int bs_size_ue_big(unsigned int val) | |
118 | { | |
119 | if (val < 255) | |
120 | return bitSize[val + 1]; | |
121 | else | |
122 | return bitSize[(val + 1) >> 8] + 16; | |
123 | } | |
124 | ||
125 | static inline int bs_size_se(int val) | |
126 | { | |
127 | int tmp = 1 - val * 2; | |
128 | ||
129 | if (tmp < 0) tmp = val * 2; | |
130 | if (tmp < 256) | |
131 | return bitSize[tmp]; | |
132 | else | |
133 | return bitSize[tmp >> 8] + 16; | |
134 | } | |
135 | ||
136 | class SyntaxElementWriter | |
137 | { | |
138 | public: | |
139 | ||
140 | BitInterface* m_bitIf; | |
141 | ||
142 | SyntaxElementWriter() : m_bitIf(NULL) {} | |
143 | ||
144 | /* silently discard the name of the syntax element */ | |
145 | inline void WRITE_CODE(uint32_t code, uint32_t length, const char *) { writeCode(code, length); } | |
146 | inline void WRITE_UVLC(uint32_t code, const char *) { writeUvlc(code); } | |
147 | inline void WRITE_SVLC(int32_t code, const char *) { writeSvlc(code); } | |
148 | inline void WRITE_FLAG(bool flag, const char *) { writeFlag(flag); } | |
149 | ||
150 | void writeCode(uint32_t code, uint32_t length) { m_bitIf->write(code, length); } | |
151 | void writeUvlc(uint32_t code); | |
152 | void writeSvlc(int32_t code) { uint32_t ucode = (code <= 0) ? -code << 1 : (code << 1) - 1; writeUvlc(ucode); } | |
153 | void writeFlag(bool code) { m_bitIf->write(code, 1); } | |
154 | }; | |
155 | ||
156 | } | |
157 | ||
158 | #endif // ifndef X265_BITSTREAM_H |