BitStream.h(3)
| BitStream.h(3) | libpgf | BitStream.h(3) |
NAME
BitStream.h
SYNOPSIS
#include 'PGFtypes.h'
Macros
#define MAKEU64(a, b) ((UINT64) (((UINT32) (a)) | ((UINT64)
((UINT32) (b))) << 32))
Make 64 bit unsigned integer from two 32 bit unsigned integers.
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
Returns
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
pos A 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
pos A valid zero-based position in the bit stream
len Number 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
pos A valid zero-based position in the bit stream
k Number of bits to compare
val Value to compare with
Returns
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
pos A valid zero-based position in the bit stream
Returns
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
pos A valid zero-based position in the bit stream
k Number 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
Returns
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
pos A valid zero-based position in the bit stream
len size 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
pos A valid zero-based position in the bit stream
len size 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
pos A 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
pos A valid zero-based position in the bit stream
len Number 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
pos A valid zero-based position in the bit stream
val Value to store in stream at position pos
k Number 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.
Author
Generated automatically by Doxygen for libpgf from the source code.
| Sat Feb 27 2021 | Version 6.14.12 |