1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 20 Pathname: getbits.h 21 22 ------------------------------------------------------------------------------ 23 REVISION HISTORY 24 25 Description: Update comments for the structure 26 27 Description: Move structur to another file 28 29 Who: Date: MM/DD/YYYY 30 Description: 31 32 33 ------------------------------------------------------------------------------ 34 INCLUDE DESCRIPTION 35 36 Header file for the function getbits(). 37 38 ------------------------------------------------------------------------------ 39 */ 40 41 /*---------------------------------------------------------------------------- 42 ; CONTINUE ONLY IF NOT ALREADY DEFINED 43 ----------------------------------------------------------------------------*/ 44 #ifndef GETBITS_H 45 #define GETBITS_H 46 47 #ifdef __cplusplus 48 extern "C" 49 { 50 #endif 51 52 /*---------------------------------------------------------------------------- 53 ; INCLUDES 54 ----------------------------------------------------------------------------*/ 55 #include "pv_audio_type_defs.h" 56 #include "ibstream.h" 57 58 /*---------------------------------------------------------------------------- 59 ; MACROS 60 ; Define module specific macros here 61 ----------------------------------------------------------------------------*/ 62 63 /*---------------------------------------------------------------------------- 64 ; DEFINES 65 ; Include all pre-processor statements here. 66 ----------------------------------------------------------------------------*/ 67 68 /*---------------------------------------------------------------------------- 69 ; EXTERNAL VARIABLES REFERENCES 70 ; Declare variables used in this module but defined elsewhere 71 ----------------------------------------------------------------------------*/ 72 73 /*---------------------------------------------------------------------------- 74 ; SIMPLE TYPEDEF'S 75 ----------------------------------------------------------------------------*/ 76 77 /*---------------------------------------------------------------------------- 78 ; ENUMERATED TYPEDEF'S 79 ----------------------------------------------------------------------------*/ 80 81 /*---------------------------------------------------------------------------- 82 ; STRUCTURES TYPEDEF'S 83 ----------------------------------------------------------------------------*/ 84 85 /*---------------------------------------------------------------------------- 86 ; GLOBAL FUNCTION DEFINITIONS 87 ; Function Prototype declaration 88 ----------------------------------------------------------------------------*/ 89 90 #define INBUF_ARRAY_INDEX_SHIFT (3) 91 #define INBUF_BIT_WIDTH (1<<(INBUF_ARRAY_INDEX_SHIFT)) 92 #define INBUF_BIT_MODULO_MASK ((INBUF_BIT_WIDTH)-1) 93 94 #define MAX_GETBITS (25) 95 96 #define CHECK_INPUT_BUFFER_LIMITS 1 97 98 __inline UInt32 getbits( 99 const UInt neededBits, 100 BITS *pInputStream) 101 { 102 UInt32 returnValue = 0; 103 UInt offset; 104 UInt bitIndex; 105 UChar *pElem; /* Needs to be same type as pInput->pBuffer */ 106 107 offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; 108 109 pElem = pInputStream->pBuffer + offset; 110 111 #if CHECK_INPUT_BUFFER_LIMITS 112 113 offset = pInputStream->inputBufferCurrentLength - offset; 114 /* check if access to input buffer does not go beyond boundaries */ 115 if (offset > 3) 116 { 117 returnValue = (((UInt32) * (pElem)) << 24) | 118 (((UInt32) * (pElem + 1)) << 16) | 119 (((UInt32) * (pElem + 2)) << 8) | 120 ((UInt32) * (pElem + 3)); 121 } 122 else /* then access only available bytes */ 123 { 124 /* Access to the bitstream beyond frame boundaries are not allowed, 125 * Here, only what was available before the end of the frame will 126 * be processed. Non-accessible bytes will be filled in with zeros. 127 * Zero values guarantees that the data structures are filled in with values 128 * that eventually will signal an error (like invalid parameters) or that allow 129 * completion of the parsing routine. 130 * Overrun is detected on file pvmp4audiodecodeframe.cpp. 131 */ 132 switch (offset) 133 { 134 case 3: 135 returnValue = (((UInt32) * (pElem + 2)) << 8); 136 case 2: 137 returnValue |= (((UInt32) * (pElem + 1)) << 16); 138 case 1: 139 returnValue |= (((UInt32) * (pElem)) << 24); 140 default: 141 break; 142 } 143 } 144 145 146 #else 147 148 returnValue = (((UInt32) * (pElem)) << 24) | 149 (((UInt32) * (pElem + 1)) << 16) | 150 (((UInt32) * (pElem + 2)) << 8) | 151 ((UInt32) * (pElem + 3)); 152 #endif 153 154 /* Remove extra high bits by shifting up */ 155 bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); 156 157 /* This line is faster way to mask off the high bits. */ 158 returnValue = returnValue << (bitIndex); 159 160 /* Move the field down. */ 161 returnValue = returnValue >> (32 - neededBits); 162 163 pInputStream->usedBits += neededBits; 164 165 return (returnValue); 166 167 } 168 169 170 171 __inline UInt get1bits( 172 BITS *pInputStream) 173 { 174 UInt returnValue; 175 UInt offset; 176 UInt bitIndex; 177 UChar *pElem; /* Needs to be same type as pInput->pBuffer */ 178 179 offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; 180 181 pElem = pInputStream->pBuffer + offset; 182 183 #if CHECK_INPUT_BUFFER_LIMITS 184 returnValue = (offset < pInputStream->inputBufferCurrentLength) ? ((UInt) * (pElem)) : 0; 185 #else 186 returnValue = ((UInt32) * (pElem)); 187 #endif 188 189 190 /* Remove extra high bits by shifting up */ 191 bitIndex = (UInt)((pInputStream->usedBits++) & INBUF_BIT_MODULO_MASK); 192 193 /* This line is faster way to mask off the high bits. */ 194 returnValue = 0xFF & (returnValue << (bitIndex)); 195 196 /* Move the field down. */ 197 198 return ((UInt)(returnValue >> 7)); 199 200 } 201 202 203 204 __inline UInt get9_n_lessbits( 205 const UInt neededBits, 206 BITS *pInputStream) 207 208 { 209 UInt returnValue; 210 UInt offset; 211 UInt bitIndex; 212 UChar *pElem; /* Needs to be same type as pInput->pBuffer */ 213 214 offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; 215 216 pElem = pInputStream->pBuffer + offset; 217 218 #if CHECK_INPUT_BUFFER_LIMITS 219 220 221 offset = pInputStream->inputBufferCurrentLength - offset; 222 /* check if access to input buffer does not go beyond boundaries */ 223 if (offset > 1) 224 { 225 returnValue = (((UInt32) * (pElem)) << 8) | 226 ((UInt32) * (pElem + 1)); 227 } 228 else /* then access only available bytes */ 229 { 230 /* Access to the bitstream beyond frame boundaries are not allowed, 231 * Here, only what was available before the end of the frame will 232 * be processed. Non-accessible bytes will be filled in with zeros. 233 * Zero values guarantees that the data structures are filled in with values 234 * that eventually will signal an error (like invalid parameters) or that allow 235 * completion of the parsing routine. 236 * Overrun is detected on file pvmp4audiodecodeframe.cpp 237 */ 238 switch (offset) 239 { 240 case 1: 241 returnValue = (((UInt32) * (pElem)) << 8); 242 break; 243 default: 244 returnValue = 0; 245 break; 246 } 247 } 248 249 250 #else 251 returnValue = (((UInt32) * (pElem)) << 8) | 252 ((UInt32) * (pElem + 1)) ; 253 #endif 254 255 /* Remove extra high bits by shifting up */ 256 bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); 257 258 pInputStream->usedBits += neededBits; 259 260 /* This line is faster way to mask off the high bits. */ 261 returnValue = 0xFFFF & (returnValue << (bitIndex)); 262 263 /* Move the field down. */ 264 265 return (UInt)(returnValue >> (16 - neededBits)); 266 267 } 268 269 __inline UInt32 get17_n_lessbits( 270 const UInt neededBits, 271 BITS *pInputStream) 272 { 273 UInt32 returnValue; 274 UInt offset; 275 UInt bitIndex; 276 UChar *pElem; /* Needs to be same type as pInput->pBuffer */ 277 278 offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; 279 280 pElem = pInputStream->pBuffer + offset; 281 282 #if CHECK_INPUT_BUFFER_LIMITS 283 284 offset = pInputStream->inputBufferCurrentLength - offset; 285 /* check if access to input buffer does not go beyond boundaries */ 286 287 if (offset > 2) 288 { 289 returnValue = (((UInt32) * (pElem)) << 16) | 290 (((UInt32) * (pElem + 1)) << 8) | 291 ((UInt32) * (pElem + 2)); 292 } 293 else /* then access only available bytes */ 294 { 295 /* Access to the bitstream beyond frame boundaries are not allowed, 296 * Here, only what was available before the end of the frame will 297 * be processed. Non-accessible bytes will be filled in with zeros. 298 * Zero values guarantees that the data structures are filled in with values 299 * that eventually will signal an error (like invalid parameters) or that allow 300 * completion of the parsing routine. 301 * Overrun is detected on file pvmp4audiodecodeframe.cpp 302 */ 303 returnValue = 0; 304 switch (offset) 305 { 306 case 2: 307 returnValue = (((UInt32) * (pElem + 1)) << 8); 308 case 1: 309 returnValue |= (((UInt32) * (pElem)) << 16); 310 default: 311 break; 312 } 313 } 314 315 #else 316 317 returnValue = (((UInt32) * (pElem)) << 16) | 318 (((UInt32) * (pElem + 1)) << 8) | 319 ((UInt32) * (pElem + 2)); 320 #endif 321 322 /* Remove extra high bits by shifting up */ 323 bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); 324 325 /* This line is faster way to mask off the high bits. */ 326 returnValue = 0xFFFFFF & (returnValue << (bitIndex)); 327 328 /* Move the field down. */ 329 returnValue = returnValue >> (24 - neededBits); 330 331 pInputStream->usedBits += neededBits; 332 333 return (returnValue); 334 335 } 336 337 #ifdef __cplusplus 338 } 339 #endif 340 341 /*---------------------------------------------------------------------------- 342 ; END 343 ----------------------------------------------------------------------------*/ 344 #endif /* GETBITS_H*/ 345 346 347
