libpgf 6.14.12
PGF - Progressive Graphics File
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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.
 

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

◆ MAKEU64

#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

◆ AlignWordPos()

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}
#define DWWIDTHBITS(bits)
aligns scanline width in bits to DWORD value
Definition PGFplatform.h:83

◆ ClearBit()

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}
#define WordWidthLog
ld of WordWidth
Definition PGFplatform.h:74
#define WordWidth
WordBytes*8.
Definition PGFplatform.h:73

◆ ClearBitBlock()

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}
static const UINT32 Filled
Definition BitStream.h:37

◆ CompareBitBlock()

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}
#define MAKEU64(a, b)
Make 64 bit unsigned integer from two 32 bit unsigned integers.
Definition BitStream.h:40

◆ GetBit()

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}

◆ GetValueBlock()

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}

◆ NumberOfWords()

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}

◆ SeekBit1Range()

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}

◆ SeekBitRange()

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}

◆ SetBit()

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}

◆ SetBitBlock()

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}

◆ SetValueBlock()

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

◆ Filled

const UINT32 Filled = 0xFFFFFFFF
static

Definition at line 37 of file BitStream.h.