jas_fix.h (13317B)
1 /* 2 * Copyright (c) 1999-2000 Image Power, Inc. and the University of 3 * British Columbia. 4 * Copyright (c) 2001-2002 Michael David Adams. 5 * All rights reserved. 6 */ 7 8 /* __START_OF_JASPER_LICENSE__ 9 * 10 * JasPer License Version 2.0 11 * 12 * Copyright (c) 1999-2000 Image Power, Inc. 13 * Copyright (c) 1999-2000 The University of British Columbia 14 * Copyright (c) 2001-2003 Michael David Adams 15 * 16 * All rights reserved. 17 * 18 * Permission is hereby granted, free of charge, to any person (the 19 * "User") obtaining a copy of this software and associated documentation 20 * files (the "Software"), to deal in the Software without restriction, 21 * including without limitation the rights to use, copy, modify, merge, 22 * publish, distribute, and/or sell copies of the Software, and to permit 23 * persons to whom the Software is furnished to do so, subject to the 24 * following conditions: 25 * 26 * 1. The above copyright notices and this permission notice (which 27 * includes the disclaimer below) shall be included in all copies or 28 * substantial portions of the Software. 29 * 30 * 2. The name of a copyright holder shall not be used to endorse or 31 * promote products derived from the Software without specific prior 32 * written permission. 33 * 34 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS 35 * LICENSE. NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER 36 * THIS DISCLAIMER. THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 37 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 38 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 39 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO 40 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL 41 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING 42 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 43 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 44 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. NO ASSURANCES ARE 45 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE 46 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY. 47 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS 48 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL 49 * PROPERTY RIGHTS OR OTHERWISE. AS A CONDITION TO EXERCISING THE RIGHTS 50 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE 51 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY. THE SOFTWARE 52 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL 53 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES, 54 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL 55 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH 56 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH, 57 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH 58 * RISK ACTIVITIES"). THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY 59 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES. 60 * 61 * __END_OF_JASPER_LICENSE__ 62 */ 63 64 /* 65 * Fixed-Point Number Class 66 * 67 * $Id: jas_fix.h 1918 2005-07-24 14:12:08Z baford $ 68 */ 69 70 #ifndef JAS_FIX_H 71 #define JAS_FIX_H 72 73 /******************************************************************************\ 74 * Includes. 75 \******************************************************************************/ 76 77 #include <stdio.h> 78 #include <stdlib.h> 79 #include <math.h> 80 81 #include <jasper/jas_config.h> 82 #include <jasper/jas_types.h> 83 84 #ifdef __cplusplus 85 extern "C" { 86 #endif 87 88 /******************************************************************************\ 89 * Constants. 90 \******************************************************************************/ 91 92 /* The representation of the value zero. */ 93 #define JAS_FIX_ZERO(fix_t, fracbits) \ 94 JAS_CAST(fix_t, 0) 95 96 /* The representation of the value one. */ 97 #define JAS_FIX_ONE(fix_t, fracbits) \ 98 (JAS_CAST(fix_t, 1) << (fracbits)) 99 100 /* The representation of the value one half. */ 101 #define JAS_FIX_HALF(fix_t, fracbits) \ 102 (JAS_CAST(fix_t, 1) << ((fracbits) - 1)) 103 104 /******************************************************************************\ 105 * Conversion operations. 106 \******************************************************************************/ 107 108 /* Convert an int to a fixed-point number. */ 109 #define JAS_INTTOFIX(fix_t, fracbits, x) \ 110 JAS_CAST(fix_t, (x) << (fracbits)) 111 112 /* Convert a fixed-point number to an int. */ 113 #define JAS_FIXTOINT(fix_t, fracbits, x) \ 114 JAS_CAST(int, (x) >> (fracbits)) 115 116 /* Convert a fixed-point number to a double. */ 117 #define JAS_FIXTODBL(fix_t, fracbits, x) \ 118 (JAS_CAST(double, x) / (JAS_CAST(fix_t, 1) << (fracbits))) 119 120 /* Convert a double to a fixed-point number. */ 121 #define JAS_DBLTOFIX(fix_t, fracbits, x) \ 122 JAS_CAST(fix_t, ((x) * JAS_CAST(double, JAS_CAST(fix_t, 1) << (fracbits)))) 123 124 /******************************************************************************\ 125 * Basic arithmetic operations. 126 * All other arithmetic operations are synthesized from these basic operations. 127 * There are three macros for each type of arithmetic operation. 128 * One macro always performs overflow/underflow checking, one never performs 129 * overflow/underflow checking, and one is generic with its behavior 130 * depending on compile-time flags. 131 * Only the generic macros should be invoked directly by application code. 132 \******************************************************************************/ 133 134 /* Calculate the sum of two fixed-point numbers. */ 135 #if !defined(DEBUG_OVERFLOW) 136 #define JAS_FIX_ADD JAS_FIX_ADD_FAST 137 #else 138 #define JAS_FIX_ADD JAS_FIX_ADD_OFLOW 139 #endif 140 141 /* Calculate the sum of two fixed-point numbers without overflow checking. */ 142 #define JAS_FIX_ADD_FAST(fix_t, fracbits, x, y) ((x) + (y)) 143 144 /* Calculate the sum of two fixed-point numbers with overflow checking. */ 145 #define JAS_FIX_ADD_OFLOW(fix_t, fracbits, x, y) \ 146 ((x) >= 0) ? \ 147 (((y) >= 0) ? ((x) + (y) >= 0 || JAS_FIX_OFLOW(), (x) + (y)) : \ 148 ((x) + (y))) : \ 149 (((y) >= 0) ? ((x) + (y)) : ((x) + (y) < 0 || JAS_FIX_OFLOW(), \ 150 (x) + (y))) 151 152 /* Calculate the product of two fixed-point numbers. */ 153 #if !defined(DEBUG_OVERFLOW) 154 #define JAS_FIX_MUL JAS_FIX_MUL_FAST 155 #else 156 #define JAS_FIX_MUL JAS_FIX_MUL_OFLOW 157 #endif 158 159 /* Calculate the product of two fixed-point numbers without overflow 160 checking. */ 161 #define JAS_FIX_MUL_FAST(fix_t, fracbits, bigfix_t, x, y) \ 162 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y)) >> \ 163 (fracbits)) 164 165 /* Calculate the product of two fixed-point numbers with overflow 166 checking. */ 167 #define JAS_FIX_MUL_OFLOW(fix_t, fracbits, bigfix_t, x, y) \ 168 ((JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> (fracbits)) == \ 169 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \ 170 (fracbits))) ? \ 171 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \ 172 (fracbits))) : JAS_FIX_OFLOW()) 173 174 /* Calculate the product of a fixed-point number and an int. */ 175 #if !defined(DEBUG_OVERFLOW) 176 #define JAS_FIX_MULBYINT JAS_FIX_MULBYINT_FAST 177 #else 178 #define JAS_FIX_MULBYINT JAS_FIX_MULBYINT_OFLOW 179 #endif 180 181 /* Calculate the product of a fixed-point number and an int without overflow 182 checking. */ 183 #define JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y) \ 184 JAS_CAST(fix_t, ((x) * (y))) 185 186 /* Calculate the product of a fixed-point number and an int with overflow 187 checking. */ 188 #define JAS_FIX_MULBYINT_OFLOW(fix_t, fracbits, x, y) \ 189 JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y) 190 191 /* Calculate the quotient of two fixed-point numbers. */ 192 #if !defined(DEBUG_OVERFLOW) 193 #define JAS_FIX_DIV JAS_FIX_DIV_FAST 194 #else 195 #define JAS_FIX_DIV JAS_FIX_DIV_UFLOW 196 #endif 197 198 /* Calculate the quotient of two fixed-point numbers without underflow 199 checking. */ 200 #define JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y) \ 201 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) << (fracbits)) / (y)) 202 203 /* Calculate the quotient of two fixed-point numbers with underflow 204 checking. */ 205 #define JAS_FIX_DIV_UFLOW(fix_t, fracbits, bigfix_t, x, y) \ 206 JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y) 207 208 /* Negate a fixed-point number. */ 209 #if !defined(DEBUG_OVERFLOW) 210 #define JAS_FIX_NEG JAS_FIX_NEG_FAST 211 #else 212 #define JAS_FIX_NEG JAS_FIX_NEG_OFLOW 213 #endif 214 215 /* Negate a fixed-point number without overflow checking. */ 216 #define JAS_FIX_NEG_FAST(fix_t, fracbits, x) \ 217 (-(x)) 218 219 /* Negate a fixed-point number with overflow checking. */ 220 /* Yes, overflow is actually possible for two's complement representations, 221 although highly unlikely to occur. */ 222 #define JAS_FIX_NEG_OFLOW(fix_t, fracbits, x) \ 223 (((x) < 0) ? (-(x) > 0 || JAS_FIX_OFLOW(), -(x)) : (-(x))) 224 225 /* Perform an arithmetic shift left of a fixed-point number. */ 226 #if !defined(DEBUG_OVERFLOW) 227 #define JAS_FIX_ASL JAS_FIX_ASL_FAST 228 #else 229 #define JAS_FIX_ASL JAS_FIX_ASL_OFLOW 230 #endif 231 232 /* Perform an arithmetic shift left of a fixed-point number without overflow 233 checking. */ 234 #define JAS_FIX_ASL_FAST(fix_t, fracbits, x, n) \ 235 ((x) << (n)) 236 237 /* Perform an arithmetic shift left of a fixed-point number with overflow 238 checking. */ 239 #define JAS_FIX_ASL_OFLOW(fix_t, fracbits, x, n) \ 240 ((((x) << (n)) >> (n)) == (x) || JAS_FIX_OFLOW(), (x) << (n)) 241 242 /* Perform an arithmetic shift right of a fixed-point number. */ 243 #if !defined(DEBUG_OVERFLOW) 244 #define JAS_FIX_ASR JAS_FIX_ASR_FAST 245 #else 246 #define JAS_FIX_ASR JAS_FIX_ASR_UFLOW 247 #endif 248 249 /* Perform an arithmetic shift right of a fixed-point number without underflow 250 checking. */ 251 #define JAS_FIX_ASR_FAST(fix_t, fracbits, x, n) \ 252 ((x) >> (n)) 253 254 /* Perform an arithmetic shift right of a fixed-point number with underflow 255 checking. */ 256 #define JAS_FIX_ASR_UFLOW(fix_t, fracbits, x, n) \ 257 JAS_FIX_ASR_FAST(fix_t, fracbits, x, n) 258 259 /******************************************************************************\ 260 * Other basic arithmetic operations. 261 \******************************************************************************/ 262 263 /* Calculate the difference between two fixed-point numbers. */ 264 #define JAS_FIX_SUB(fix_t, fracbits, x, y) \ 265 JAS_FIX_ADD(fix_t, fracbits, x, JAS_FIX_NEG(fix_t, fracbits, y)) 266 267 /* Add one fixed-point number to another. */ 268 #define JAS_FIX_PLUSEQ(fix_t, fracbits, x, y) \ 269 ((x) = JAS_FIX_ADD(fix_t, fracbits, x, y)) 270 271 /* Subtract one fixed-point number from another. */ 272 #define JAS_FIX_MINUSEQ(fix_t, fracbits, x, y) \ 273 ((x) = JAS_FIX_SUB(fix_t, fracbits, x, y)) 274 275 /* Multiply one fixed-point number by another. */ 276 #define JAS_FIX_MULEQ(fix_t, fracbits, bigfix_t, x, y) \ 277 ((x) = JAS_FIX_MUL(fix_t, fracbits, bigfix_t, x, y)) 278 279 /******************************************************************************\ 280 * Miscellaneous operations. 281 \******************************************************************************/ 282 283 /* Calculate the absolute value of a fixed-point number. */ 284 #define JAS_FIX_ABS(fix_t, fracbits, x) \ 285 (((x) >= 0) ? (x) : (JAS_FIX_NEG(fix_t, fracbits, x))) 286 287 /* Is a fixed-point number an integer? */ 288 #define JAS_FIX_ISINT(fix_t, fracbits, x) \ 289 (JAS_FIX_FLOOR(fix_t, fracbits, x) == (x)) 290 291 /* Get the sign of a fixed-point number. */ 292 #define JAS_FIX_SGN(fix_t, fracbits, x) \ 293 ((x) >= 0 ? 1 : (-1)) 294 295 /******************************************************************************\ 296 * Relational operations. 297 \******************************************************************************/ 298 299 /* Compare two fixed-point numbers. */ 300 #define JAS_FIX_CMP(fix_t, fracbits, x, y) \ 301 ((x) > (y) ? 1 : (((x) == (y)) ? 0 : (-1))) 302 303 /* Less than. */ 304 #define JAS_FIX_LT(fix_t, fracbits, x, y) \ 305 ((x) < (y)) 306 307 /* Less than or equal. */ 308 #define JAS_FIX_LTE(fix_t, fracbits, x, y) \ 309 ((x) <= (y)) 310 311 /* Greater than. */ 312 #define JAS_FIX_GT(fix_t, fracbits, x, y) \ 313 ((x) > (y)) 314 315 /* Greater than or equal. */ 316 #define JAS_FIX_GTE(fix_t, fracbits, x, y) \ 317 ((x) >= (y)) 318 319 /******************************************************************************\ 320 * Rounding functions. 321 \******************************************************************************/ 322 323 /* Round a fixed-point number to the nearest integer. */ 324 #define JAS_FIX_ROUND(fix_t, fracbits, x) \ 325 (((x) < 0) ? JAS_FIX_FLOOR(fix_t, fracbits, JAS_FIX_ADD(fix_t, fracbits, \ 326 (x), JAS_FIX_HALF(fix_t, fracbits))) : \ 327 JAS_FIX_NEG(fix_t, fracbits, JAS_FIX_FLOOR(fix_t, fracbits, \ 328 JAS_FIX_ADD(fix_t, fracbits, (-(x)), JAS_FIX_HALF(fix_t, fracbits))))) 329 330 /* Round a fixed-point number to the nearest integer in the direction of 331 negative infinity (i.e., the floor function). */ 332 #define JAS_FIX_FLOOR(fix_t, fracbits, x) \ 333 ((x) & (~((JAS_CAST(fix_t, 1) << (fracbits)) - 1))) 334 335 /* Round a fixed-point number to the nearest integer in the direction 336 of zero. */ 337 #define JAS_FIX_TRUNC(fix_t, fracbits, x) \ 338 (((x) >= 0) ? JAS_FIX_FLOOR(fix_t, fracbits, x) : \ 339 JAS_FIX_CEIL(fix_t, fracbits, x)) 340 341 /******************************************************************************\ 342 * The below macros are for internal library use only. Do not invoke them 343 * directly in application code. 344 \******************************************************************************/ 345 346 /* Handle overflow. */ 347 #define JAS_FIX_OFLOW() \ 348 fprintf(stderr, "overflow error: file %s, line %d\n", __FILE__, __LINE__) 349 350 /* Handle underflow. */ 351 #define JAS_FIX_UFLOW() \ 352 fprintf(stderr, "underflow error: file %s, line %d\n", __FILE__, __LINE__) 353 354 #ifdef __cplusplus 355 } 356 #endif 357 358 #endif