source: 3DVCSoftware/tags/HTM-DEV-0.1/source/Lib/TLibCommon/TComBitStream.cpp @ 324

Last change on this file since 324 was 324, checked in by tech, 11 years ago

Initial development version for update to latest HM version.
Includes MV-HEVC and basic extensions for 3D-HEVC.

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1/* The copyright in this software is being made available under the BSD
2 * License, included below. This software may be subject to other third party
3 * and contributor rights, including patent rights, and no such rights are
4 * granted under this license. 
5 *
6 * Copyright (c) 2010-2013, ITU/ISO/IEC
7 * All rights reserved.
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10 * modification, are permitted provided that the following conditions are met:
11 *
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13 *    this list of conditions and the following disclaimer.
14 *  * Redistributions in binary form must reproduce the above copyright notice,
15 *    this list of conditions and the following disclaimer in the documentation
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18 *    be used to endorse or promote products derived from this software without
19 *    specific prior written permission.
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23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
31 * THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34/** \file     TComBitStream.cpp
35    \brief    class for handling bitstream
36*/
37
38#include <stdint.h>
39#include <vector>
40#include "TComBitStream.h"
41#include <string.h>
42#include <memory.h>
43
44using namespace std;
45
46//! \ingroup TLibCommon
47//! \{
48
49// ====================================================================================================================
50// Constructor / destructor / create / destroy
51// ====================================================================================================================
52
53TComOutputBitstream::TComOutputBitstream()
54{
55  m_fifo = new vector<uint8_t>;
56  clear();
57}
58
59TComOutputBitstream::~TComOutputBitstream()
60{
61  delete m_fifo;
62}
63
64TComInputBitstream::TComInputBitstream(std::vector<uint8_t>* buf)
65{
66  m_fifo = buf;
67  m_fifo_idx = 0;
68  m_held_bits = 0;
69  m_num_held_bits = 0;
70  m_numBitsRead = 0;
71}
72
73TComInputBitstream::~TComInputBitstream()
74{
75}
76
77// ====================================================================================================================
78// Public member functions
79// ====================================================================================================================
80
81Char* TComOutputBitstream::getByteStream() const
82{
83  return (Char*) &m_fifo->front();
84}
85
86UInt TComOutputBitstream::getByteStreamLength()
87{
88  return UInt(m_fifo->size());
89}
90
91void TComOutputBitstream::clear()
92{
93  m_fifo->clear();
94  m_held_bits = 0;
95  m_num_held_bits = 0;
96}
97
98Void TComOutputBitstream::write   ( UInt uiBits, UInt uiNumberOfBits )
99{
100  assert( uiNumberOfBits <= 32 );
101  assert( uiNumberOfBits == 32 || (uiBits & (~0 << uiNumberOfBits)) == 0 );
102
103  /* any modulo 8 remainder of num_total_bits cannot be written this time,
104   * and will be held until next time. */
105  UInt num_total_bits = uiNumberOfBits + m_num_held_bits;
106  UInt next_num_held_bits = num_total_bits % 8;
107
108  /* form a byte aligned word (write_bits), by concatenating any held bits
109   * with the new bits, discarding the bits that will form the next_held_bits.
110   * eg: H = held bits, V = n new bits        /---- next_held_bits
111   * len(H)=7, len(V)=1: ... ---- HHHH HHHV . 0000 0000, next_num_held_bits=0
112   * len(H)=7, len(V)=2: ... ---- HHHH HHHV . V000 0000, next_num_held_bits=1
113   * if total_bits < 8, the value of v_ is not used */
114  UChar next_held_bits = uiBits << (8 - next_num_held_bits);
115
116  if (!(num_total_bits >> 3))
117  {
118    /* insufficient bits accumulated to write out, append new_held_bits to
119     * current held_bits */
120    /* NB, this requires that v only contains 0 in bit positions {31..n} */
121    m_held_bits |= next_held_bits;
122    m_num_held_bits = next_num_held_bits;
123    return;
124  }
125
126  /* topword serves to justify held_bits to align with the msb of uiBits */
127  UInt topword = (uiNumberOfBits - next_num_held_bits) & ~((1 << 3) -1);
128  UInt write_bits = (m_held_bits << topword) | (uiBits >> next_num_held_bits);
129
130  switch (num_total_bits >> 3)
131  {
132  case 4: m_fifo->push_back(write_bits >> 24);
133  case 3: m_fifo->push_back(write_bits >> 16);
134  case 2: m_fifo->push_back(write_bits >> 8);
135  case 1: m_fifo->push_back(write_bits);
136  }
137
138  m_held_bits = next_held_bits;
139  m_num_held_bits = next_num_held_bits;
140}
141
142Void TComOutputBitstream::writeAlignOne()
143{
144  UInt num_bits = getNumBitsUntilByteAligned();
145  write((1 << num_bits) - 1, num_bits);
146  return;
147}
148
149Void TComOutputBitstream::writeAlignZero()
150{
151  if (0 == m_num_held_bits)
152  {
153    return;
154  }
155  m_fifo->push_back(m_held_bits);
156  m_held_bits = 0;
157  m_num_held_bits = 0;
158}
159
160/**
161 - add substream to the end of the current bitstream
162 .
163 \param  pcSubstream  substream to be added
164 */
165Void   TComOutputBitstream::addSubstream( TComOutputBitstream* pcSubstream )
166{
167  UInt uiNumBits = pcSubstream->getNumberOfWrittenBits();
168
169  const vector<uint8_t>& rbsp = pcSubstream->getFIFO();
170  for (vector<uint8_t>::const_iterator it = rbsp.begin(); it != rbsp.end();)
171  {
172    write(*it++, 8);
173  }
174  if (uiNumBits&0x7)
175  {
176    write(pcSubstream->getHeldBits()>>(8-(uiNumBits&0x7)), uiNumBits&0x7);
177  }
178}
179Void TComOutputBitstream::writeByteAlignment()
180{
181  write( 1, 1);
182  writeAlignZero();
183}
184/**
185 * read #uiNumberOfBits# from bitstream without updating the bitstream
186 * state, storing the result in #ruiBits#.
187 *
188 * If reading #uiNumberOfBits# would overrun the bitstream buffer,
189 * the bitsream is effectively padded with sufficient zero-bits to
190 * avoid the overrun.
191 */
192Void TComInputBitstream::pseudoRead ( UInt uiNumberOfBits, UInt& ruiBits )
193{
194  UInt saved_num_held_bits = m_num_held_bits;
195  UChar saved_held_bits = m_held_bits;
196  UInt saved_fifo_idx = m_fifo_idx;
197
198  UInt num_bits_to_read = min(uiNumberOfBits, getNumBitsLeft());
199  read(num_bits_to_read, ruiBits);
200  ruiBits <<= (uiNumberOfBits - num_bits_to_read);
201
202  m_fifo_idx = saved_fifo_idx;
203  m_held_bits = saved_held_bits;
204  m_num_held_bits = saved_num_held_bits;
205}
206
207
208Void TComInputBitstream::read (UInt uiNumberOfBits, UInt& ruiBits)
209{
210  assert( uiNumberOfBits <= 32 );
211 
212  m_numBitsRead += uiNumberOfBits;
213
214  /* NB, bits are extracted from the MSB of each byte. */
215  UInt retval = 0;
216  if (uiNumberOfBits <= m_num_held_bits)
217  {
218    /* n=1, len(H)=7:   -VHH HHHH, shift_down=6, mask=0xfe
219     * n=3, len(H)=7:   -VVV HHHH, shift_down=4, mask=0xf8
220     */
221    retval = m_held_bits >> (m_num_held_bits - uiNumberOfBits);
222    retval &= ~(0xff << uiNumberOfBits);
223    m_num_held_bits -= uiNumberOfBits;
224    ruiBits = retval;
225    return;
226  }
227
228  /* all num_held_bits will go into retval
229   *   => need to mask leftover bits from previous extractions
230   *   => align retval with top of extracted word */
231  /* n=5, len(H)=3: ---- -VVV, mask=0x07, shift_up=5-3=2,
232   * n=9, len(H)=3: ---- -VVV, mask=0x07, shift_up=9-3=6 */
233  uiNumberOfBits -= m_num_held_bits;
234  retval = m_held_bits & ~(0xff << m_num_held_bits);
235  retval <<= uiNumberOfBits;
236
237  /* number of whole bytes that need to be loaded to form retval */
238  /* n=32, len(H)=0, load 4bytes, shift_down=0
239   * n=32, len(H)=1, load 4bytes, shift_down=1
240   * n=31, len(H)=1, load 4bytes, shift_down=1+1
241   * n=8,  len(H)=0, load 1byte,  shift_down=0
242   * n=8,  len(H)=3, load 1byte,  shift_down=3
243   * n=5,  len(H)=1, load 1byte,  shift_down=1+3
244   */
245  UInt aligned_word = 0;
246  UInt num_bytes_to_load = (uiNumberOfBits - 1) >> 3;
247  assert(m_fifo_idx + num_bytes_to_load < m_fifo->size());
248
249  switch (num_bytes_to_load)
250  {
251  case 3: aligned_word  = (*m_fifo)[m_fifo_idx++] << 24;
252  case 2: aligned_word |= (*m_fifo)[m_fifo_idx++] << 16;
253  case 1: aligned_word |= (*m_fifo)[m_fifo_idx++] <<  8;
254  case 0: aligned_word |= (*m_fifo)[m_fifo_idx++];
255  }
256
257  /* resolve remainder bits */
258  UInt next_num_held_bits = (32 - uiNumberOfBits) % 8;
259
260  /* copy required part of aligned_word into retval */
261  retval |= aligned_word >> next_num_held_bits;
262
263  /* store held bits */
264  m_num_held_bits = next_num_held_bits;
265  m_held_bits = aligned_word;
266
267  ruiBits = retval;
268}
269
270/**
271 * insert the contents of the bytealigned (and flushed) bitstream src
272 * into this at byte position pos.
273 */
274void TComOutputBitstream::insertAt(const TComOutputBitstream& src, UInt pos)
275{
276  UInt src_bits = src.getNumberOfWrittenBits();
277  assert(0 == src_bits % 8);
278
279  vector<uint8_t>::iterator at = this->m_fifo->begin() + pos;
280  this->m_fifo->insert(at, src.m_fifo->begin(), src.m_fifo->end());
281}
282
283Void TComInputBitstream::readOutTrailingBits ()
284{
285  UInt uiBits = 0;
286
287  while ( ( getNumBitsLeft() > 0 ) && (getNumBitsUntilByteAligned()!=0) )
288  {
289    read ( 1, uiBits );
290  }
291}
292
293TComOutputBitstream& TComOutputBitstream::operator= (const TComOutputBitstream& src)
294{
295  vector<uint8_t>::iterator at = this->m_fifo->begin();
296  this->m_fifo->insert(at, src.m_fifo->begin(), src.m_fifo->end());
297
298  this->m_num_held_bits             = src.m_num_held_bits;
299  this->m_held_bits                 = src.m_held_bits;
300
301  return *this;
302}
303
304/**
305 - extract substream from the current bitstream
306 .
307 \param  pcBitstream  bitstream which contains substreams
308 \param  uiNumBits    number of bits to transfer
309 */
310TComInputBitstream *TComInputBitstream::extractSubstream( UInt uiNumBits )
311{
312  UInt uiNumBytes = uiNumBits/8;
313  std::vector<uint8_t>* buf = new std::vector<uint8_t>;
314  UInt uiByte;
315  for (UInt ui = 0; ui < uiNumBytes; ui++)
316  {
317    read(8, uiByte);
318    buf->push_back(uiByte);
319  }
320  if (uiNumBits&0x7)
321  {
322    uiByte = 0;
323    read(uiNumBits&0x7, uiByte);
324    uiByte <<= 8-(uiNumBits&0x7);
325    buf->push_back(uiByte);
326  }
327  return new TComInputBitstream(buf);
328}
329
330/**
331 - delete internal fifo
332 */
333Void TComInputBitstream::deleteFifo()
334{
335  delete m_fifo;
336  m_fifo = NULL;
337}
338
339Void TComInputBitstream::readByteAlignment()
340{
341  UInt code = 0;
342  read( 1, code );
343  assert(code == 1);
344
345  UInt numBits = getNumBitsUntilByteAligned();
346  if(numBits)
347  {
348    assert(numBits <= getNumBitsLeft());
349    read( numBits, code );
350    assert(code == 0);
351  }
352}
353
354//! \}
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