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Macros | Functions | Variables
BitStream.h File Reference
#include "PGFtypes.h"

Go to the source code of this file.

Macros

#define MAKEU64(a, b)   ((UINT64) (((UINT32) (a)) | ((UINT64) ((UINT32) (b))) << 32))
 Make 64 bit unsigned integer from two 32 bit unsigned integers. More...
 

Functions

void SetBit (UINT32 *stream, UINT32 pos)
 
void ClearBit (UINT32 *stream, UINT32 pos)
 
bool GetBit (UINT32 *stream, UINT32 pos)
 
bool CompareBitBlock (UINT32 *stream, UINT32 pos, UINT32 k, UINT32 val)
 
void SetValueBlock (UINT32 *stream, UINT32 pos, UINT32 val, UINT32 k)
 
UINT32 GetValueBlock (UINT32 *stream, UINT32 pos, UINT32 k)
 
void ClearBitBlock (UINT32 *stream, UINT32 pos, UINT32 len)
 
void SetBitBlock (UINT32 *stream, UINT32 pos, UINT32 len)
 
UINT32 SeekBitRange (UINT32 *stream, UINT32 pos, UINT32 len)
 
UINT32 SeekBit1Range (UINT32 *stream, UINT32 pos, UINT32 len)
 
UINT32 AlignWordPos (UINT32 pos)
 
UINT32 NumberOfWords (UINT32 pos)
 

Variables

static const UINT32 Filled = 0xFFFFFFFF
 

Macro Definition Documentation

#define MAKEU64 (   a,
  b 
)    ((UINT64) (((UINT32) (a)) | ((UINT64) ((UINT32) (b))) << 32))

Make 64 bit unsigned integer from two 32 bit unsigned integers.

Definition at line 40 of file BitStream.h.

Function Documentation

UINT32 AlignWordPos ( UINT32  pos)
inline

Compute bit position of the next 32-bit word

Parameters
poscurrent bit stream position
Returns
bit position of next 32-bit word

Definition at line 260 of file BitStream.h.

260  {
261 // return ((pos + WordWidth - 1) >> WordWidthLog) << WordWidthLog;
262  return DWWIDTHBITS(pos);
263 }
void ClearBit ( UINT32 *  stream,
UINT32  pos 
)
inline

Set one bit of a bit stream to 0

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream

Definition at line 56 of file BitStream.h.

56  {
57  stream[pos >> WordWidthLog] &= ~(1 << (pos%WordWidth));
58 }
void ClearBitBlock ( UINT32 *  stream,
UINT32  pos,
UINT32  len 
)
inline

Clear block of size at least len at position pos in stream

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
lenNumber of bits set to 0

Definition at line 155 of file BitStream.h.

155  {
156  ASSERT(len > 0);
157  const UINT32 iFirstInt = pos >> WordWidthLog;
158  const UINT32 iLastInt = (pos + len - 1) >> WordWidthLog;
159 
160  const UINT32 startMask = Filled << (pos%WordWidth);
161 // const UINT32 endMask=Filled>>(WordWidth-1-((pos+len-1)%WordWidth));
162 
163  if (iFirstInt == iLastInt) {
164  stream[iFirstInt] &= ~(startMask /*& endMask*/);
165  } else {
166  stream[iFirstInt] &= ~startMask;
167  for (UINT32 i = iFirstInt + 1; i <= iLastInt; i++) { // changed <=
168  stream[i] = 0;
169  }
170  //stream[iLastInt] &= ~endMask;
171  }
172 }
bool CompareBitBlock ( UINT32 *  stream,
UINT32  pos,
UINT32  k,
UINT32  val 
)
inline

Compare k-bit binary representation of stream at position pos with val

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
kNumber of bits to compare
valValue to compare with
Returns
true if equal

Definition at line 77 of file BitStream.h.

77  {
78  const UINT32 iLoInt = pos >> WordWidthLog;
79  const UINT32 iHiInt = (pos + k - 1) >> WordWidthLog;
80  ASSERT(iLoInt <= iHiInt);
81  const UINT32 mask = (Filled >> (WordWidth - k));
82 
83  if (iLoInt == iHiInt) {
84  // fits into one integer
85  val &= mask;
86  val <<= (pos%WordWidth);
87  return (stream[iLoInt] & val) == val;
88  } else {
89  // must be splitted over integer boundary
90  UINT64 v1 = MAKEU64(stream[iLoInt], stream[iHiInt]);
91  UINT64 v2 = UINT64(val & mask) << (pos%WordWidth);
92  return (v1 & v2) == v2;
93  }
94 }
bool GetBit ( UINT32 *  stream,
UINT32  pos 
)
inline

Return one bit of a bit stream

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
Returns
bit at position pos of bit stream stream

Definition at line 65 of file BitStream.h.

65  {
66  return (stream[pos >> WordWidthLog] & (1 << (pos%WordWidth))) > 0;
67 
68 }
UINT32 GetValueBlock ( UINT32 *  stream,
UINT32  pos,
UINT32  k 
)
inline

Read k-bit number from stream at position pos

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
kNumber of bits to read: 1 <= k <= 32

Definition at line 128 of file BitStream.h.

128  {
129  UINT32 count, hiCount;
130  const UINT32 iLoInt = pos >> WordWidthLog; // integer of first bit
131  const UINT32 iHiInt = (pos + k - 1) >> WordWidthLog; // integer of last bit
132  const UINT32 loMask = Filled << (pos%WordWidth);
133  const UINT32 hiMask = Filled >> (WordWidth - 1 - ((pos + k - 1)%WordWidth));
134 
135  if (iLoInt == iHiInt) {
136  // inside integer boundary
137  count = stream[iLoInt] & (loMask & hiMask);
138  count >>= pos%WordWidth;
139  } else {
140  // overlapping integer boundary
141  count = stream[iLoInt] & loMask;
142  count >>= pos%WordWidth;
143  hiCount = stream[iHiInt] & hiMask;
144  hiCount <<= WordWidth - (pos%WordWidth);
145  count |= hiCount;
146  }
147  return count;
148 }
UINT32 NumberOfWords ( UINT32  pos)
inline

Compute number of the 32-bit words

Parameters
posCurrent bit stream position
Returns
Number of 32-bit words

Definition at line 269 of file BitStream.h.

269  {
270  return (pos + WordWidth - 1) >> WordWidthLog;
271 }
UINT32 SeekBit1Range ( UINT32 *  stream,
UINT32  pos,
UINT32  len 
)
inline

Returns the distance to the next 0 in stream at position pos. If no 0 is found within len bits, then len is returned.

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
lensize of search area (in bits) return The distance to the next 0 in stream at position pos

Definition at line 235 of file BitStream.h.

235  {
236  UINT32 count = 0;
237  UINT32 testMask = 1 << (pos%WordWidth);
238  UINT32* word = stream + (pos >> WordWidthLog);
239 
240  while (((*word & testMask) != 0) && (count < len)) {
241  count++;
242  testMask <<= 1;
243  if (!testMask) {
244  word++; testMask = 1;
245 
246  // fast steps if all bits in a word are one
247  while ((count + WordWidth <= len) && (*word == Filled)) {
248  word++;
249  count += WordWidth;
250  }
251  }
252  }
253  return count;
254 }
UINT32 SeekBitRange ( UINT32 *  stream,
UINT32  pos,
UINT32  len 
)
inline

Returns the distance to the next 1 in stream at position pos. If no 1 is found within len bits, then len is returned.

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
lensize of search area (in bits) return The distance to the next 1 in stream at position pos

Definition at line 206 of file BitStream.h.

206  {
207  UINT32 count = 0;
208  UINT32 testMask = 1 << (pos%WordWidth);
209  UINT32* word = stream + (pos >> WordWidthLog);
210 
211  while (((*word & testMask) == 0) && (count < len)) {
212  count++;
213  testMask <<= 1;
214  if (!testMask) {
215  word++; testMask = 1;
216 
217  // fast steps if all bits in a word are zero
218  while ((count + WordWidth <= len) && (*word == 0)) {
219  word++;
220  count += WordWidth;
221  }
222  }
223  }
224 
225  return count;
226 }
void SetBit ( UINT32 *  stream,
UINT32  pos 
)
inline

Set one bit of a bit stream to 1

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream

Definition at line 48 of file BitStream.h.

48  {
49  stream[pos >> WordWidthLog] |= (1 << (pos%WordWidth));
50 }
void SetBitBlock ( UINT32 *  stream,
UINT32  pos,
UINT32  len 
)
inline

Set block of size at least len at position pos in stream

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
lenNumber of bits set to 1

Definition at line 179 of file BitStream.h.

179  {
180  ASSERT(len > 0);
181 
182  const UINT32 iFirstInt = pos >> WordWidthLog;
183  const UINT32 iLastInt = (pos + len - 1) >> WordWidthLog;
184 
185  const UINT32 startMask = Filled << (pos%WordWidth);
186 // const UINT32 endMask=Filled>>(WordWidth-1-((pos+len-1)%WordWidth));
187 
188  if (iFirstInt == iLastInt) {
189  stream[iFirstInt] |= (startMask /*& endMask*/);
190  } else {
191  stream[iFirstInt] |= startMask;
192  for (UINT32 i = iFirstInt + 1; i <= iLastInt; i++) { // changed <=
193  stream[i] = Filled;
194  }
195  //stream[iLastInt] &= ~endMask;
196  }
197 }
void SetValueBlock ( UINT32 *  stream,
UINT32  pos,
UINT32  val,
UINT32  k 
)
inline

Store k-bit binary representation of val in stream at position pos

Parameters
streamA bit stream stored in array of unsigned integers
posA valid zero-based position in the bit stream
valValue to store in stream at position pos
kNumber of bits of integer representation of val

Definition at line 102 of file BitStream.h.

102  {
103  const UINT32 offset = pos%WordWidth;
104  const UINT32 iLoInt = pos >> WordWidthLog;
105  const UINT32 iHiInt = (pos + k - 1) >> WordWidthLog;
106  ASSERT(iLoInt <= iHiInt);
107  const UINT32 loMask = Filled << offset;
108  const UINT32 hiMask = Filled >> (WordWidth - 1 - ((pos + k - 1)%WordWidth));
109 
110  if (iLoInt == iHiInt) {
111  // fits into one integer
112  stream[iLoInt] &= ~(loMask & hiMask); // clear bits
113  stream[iLoInt] |= val << offset; // write value
114  } else {
115  // must be splitted over integer boundary
116  stream[iLoInt] &= ~loMask; // clear bits
117  stream[iLoInt] |= val << offset; // write lower part of value
118  stream[iHiInt] &= ~hiMask; // clear bits
119  stream[iHiInt] |= val >> (WordWidth - offset); // write higher part of value
120  }
121 }

Variable Documentation

const UINT32 Filled = 0xFFFFFFFF
static

Definition at line 37 of file BitStream.h.