JasPer 2.0.33
jas_fix.h
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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) 2001-2006 Michael David Adams
13 * Copyright (c) 1999-2000 Image Power, Inc.
14 * Copyright (c) 1999-2000 The University of British Columbia
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62 */
63
69#ifndef JAS_FIX_H
70#define JAS_FIX_H
71
72/******************************************************************************\
73* Includes.
74\******************************************************************************/
75
76/* The configuration header file should be included first. */
77#include <jasper/jas_config.h> /* IWYU pragma: keep */
78
79#include <jasper/jas_types.h>
80
81#ifdef __cplusplus
82extern "C" {
83#endif
84
85/******************************************************************************\
86* Constants.
87\******************************************************************************/
88
89/* The representation of the value zero. */
90#define JAS_FIX_ZERO(fix_t, fracbits) \
91 JAS_INTTOFIX(fix_t, fracbits, 0)
92
93/* The representation of the value one. */
94#define JAS_FIX_ONE(fix_t, fracbits) \
95 JAS_INTTOFIX(fix_t, fracbits, 1)
96
97/* The representation of the value one half. */
98#define JAS_FIX_HALF(fix_t, fracbits) \
99 (JAS_CAST(fix_t, 1) << ((fracbits) - 1))
100
101/******************************************************************************\
102* Conversion operations.
103\******************************************************************************/
104
105/* Convert an int to a fixed-point number. */
106#define JAS_INTTOFIX(fix_t, fracbits, x) \
107 (JAS_CAST(fix_t, x) << (fracbits))
108
109/* Convert a fixed-point number to an int. */
110#define JAS_FIXTOINT(fix_t, fracbits, x) \
111 JAS_CAST(int, (x) >> (fracbits))
112
113/* Convert a fixed-point number to a double. */
114#define JAS_FIXTODBL(fix_t, fracbits, x) \
115 (JAS_CAST(double, x) / JAS_FIX_ONE(fix_t, fracbits))
116
117/* Convert a double to a fixed-point number. */
118#define JAS_DBLTOFIX(fix_t, fracbits, x) \
119 JAS_CAST(fix_t, ((x) * JAS_CAST(double, JAS_FIX_ONE(fix_t, fracbits))))
120
121/******************************************************************************\
122* Basic arithmetic operations.
123* All other arithmetic operations are synthesized from these basic operations.
124* There are three macros for each type of arithmetic operation.
125* One macro always performs overflow/underflow checking, one never performs
126* overflow/underflow checking, and one is generic with its behavior
127* depending on compile-time flags.
128* Only the generic macros should be invoked directly by application code.
129\******************************************************************************/
130
131/* Calculate the sum of two fixed-point numbers. */
132#if !defined(DEBUG_OVERFLOW)
133#define JAS_FIX_ADD JAS_FIX_ADD_FAST
134#else
135#define JAS_FIX_ADD JAS_FIX_ADD_OFLOW
136#endif
137
138/* Calculate the sum of two fixed-point numbers without overflow checking. */
139#define JAS_FIX_ADD_FAST(fix_t, fracbits, x, y) ((x) + (y))
140
141/* Calculate the sum of two fixed-point numbers with overflow checking. */
142#define JAS_FIX_ADD_OFLOW(fix_t, fracbits, x, y) \
143 ((x) >= 0) ? \
144 (((y) >= 0) ? ((x) + (y) >= 0 || JAS_FIX_OFLOW(), (x) + (y)) : \
145 ((x) + (y))) : \
146 (((y) >= 0) ? ((x) + (y)) : ((x) + (y) < 0 || JAS_FIX_OFLOW(), \
147 (x) + (y)))
148
149/* Calculate the product of two fixed-point numbers. */
150#if !defined(DEBUG_OVERFLOW)
151#define JAS_FIX_MUL JAS_FIX_MUL_FAST
152#else
153#define JAS_FIX_MUL JAS_FIX_MUL_OFLOW
154#endif
155
156/* Calculate the product of two fixed-point numbers without overflow
157 checking. */
158#define JAS_FIX_MUL_FAST(fix_t, fracbits, bigfix_t, x, y) \
159 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y)) >> \
160 (fracbits))
161
162/* Calculate the product of two fixed-point numbers with overflow
163 checking. */
164#define JAS_FIX_MUL_OFLOW(fix_t, fracbits, bigfix_t, x, y) \
165 ((JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> (fracbits)) == \
166 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \
167 (fracbits))) ? \
168 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) * JAS_CAST(bigfix_t, y) >> \
169 (fracbits))) : JAS_FIX_OFLOW())
170
171/* Calculate the product of a fixed-point number and an int. */
172#if !defined(DEBUG_OVERFLOW)
173#define JAS_FIX_MULBYINT JAS_FIX_MULBYINT_FAST
174#else
175#define JAS_FIX_MULBYINT JAS_FIX_MULBYINT_OFLOW
176#endif
177
178/* Calculate the product of a fixed-point number and an int without overflow
179 checking. */
180#define JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y) \
181 JAS_CAST(fix_t, ((x) * (y)))
182
183/* Calculate the product of a fixed-point number and an int with overflow
184 checking. */
185#define JAS_FIX_MULBYINT_OFLOW(fix_t, fracbits, x, y) \
186 JAS_FIX_MULBYINT_FAST(fix_t, fracbits, x, y)
187
188/* Calculate the quotient of two fixed-point numbers. */
189#if !defined(DEBUG_OVERFLOW)
190#define JAS_FIX_DIV JAS_FIX_DIV_FAST
191#else
192#define JAS_FIX_DIV JAS_FIX_DIV_UFLOW
193#endif
194
195/* Calculate the quotient of two fixed-point numbers without underflow
196 checking. */
197#define JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y) \
198 JAS_CAST(fix_t, (JAS_CAST(bigfix_t, x) << (fracbits)) / (y))
199
200/* Calculate the quotient of two fixed-point numbers with underflow
201 checking. */
202#define JAS_FIX_DIV_UFLOW(fix_t, fracbits, bigfix_t, x, y) \
203 JAS_FIX_DIV_FAST(fix_t, fracbits, bigfix_t, x, y)
204
205/* Negate a fixed-point number. */
206#if !defined(DEBUG_OVERFLOW)
207#define JAS_FIX_NEG JAS_FIX_NEG_FAST
208#else
209#define JAS_FIX_NEG JAS_FIX_NEG_OFLOW
210#endif
211
212/* Negate a fixed-point number without overflow checking. */
213#define JAS_FIX_NEG_FAST(fix_t, fracbits, x) \
214 (-(x))
215
216/* Negate a fixed-point number with overflow checking. */
217/* Yes, overflow is actually possible for two's complement representations,
218 although highly unlikely to occur. */
219#define JAS_FIX_NEG_OFLOW(fix_t, fracbits, x) \
220 (((x) < 0) ? (-(x) > 0 || JAS_FIX_OFLOW(), -(x)) : (-(x)))
221
222/* Perform an arithmetic shift left of a fixed-point number. */
223#if !defined(DEBUG_OVERFLOW)
224#define JAS_FIX_ASL JAS_FIX_ASL_FAST
225#else
226#define JAS_FIX_ASL JAS_FIX_ASL_OFLOW
227#endif
228
229/* Perform an arithmetic shift left of a fixed-point number without overflow
230 checking. */
231#define JAS_FIX_ASL_FAST(fix_t, fracbits, x, n) \
232 ((x) << (n))
233
234/* Perform an arithmetic shift left of a fixed-point number with overflow
235 checking. */
236#define JAS_FIX_ASL_OFLOW(fix_t, fracbits, x, n) \
237 ((((x) << (n)) >> (n)) == (x) || JAS_FIX_OFLOW(), (x) << (n))
238
239/* Perform an arithmetic shift right of a fixed-point number. */
240#if !defined(DEBUG_OVERFLOW)
241#define JAS_FIX_ASR JAS_FIX_ASR_FAST
242#else
243#define JAS_FIX_ASR JAS_FIX_ASR_UFLOW
244#endif
245
246/* Perform an arithmetic shift right of a fixed-point number without underflow
247 checking. */
248#define JAS_FIX_ASR_FAST(fix_t, fracbits, x, n) \
249 ((x) >> (n))
250
251/* Perform an arithmetic shift right of a fixed-point number with underflow
252 checking. */
253#define JAS_FIX_ASR_UFLOW(fix_t, fracbits, x, n) \
254 JAS_FIX_ASR_FAST(fix_t, fracbits, x, n)
255
256/******************************************************************************\
257* Other basic arithmetic operations.
258\******************************************************************************/
259
260/* Calculate the difference between two fixed-point numbers. */
261#define JAS_FIX_SUB(fix_t, fracbits, x, y) \
262 JAS_FIX_ADD(fix_t, fracbits, x, JAS_FIX_NEG(fix_t, fracbits, y))
263
264/* Add one fixed-point number to another. */
265#define JAS_FIX_PLUSEQ(fix_t, fracbits, x, y) \
266 ((x) = JAS_FIX_ADD(fix_t, fracbits, x, y))
267
268/* Subtract one fixed-point number from another. */
269#define JAS_FIX_MINUSEQ(fix_t, fracbits, x, y) \
270 ((x) = JAS_FIX_SUB(fix_t, fracbits, x, y))
271
272/* Multiply one fixed-point number by another. */
273#define JAS_FIX_MULEQ(fix_t, fracbits, bigfix_t, x, y) \
274 ((x) = JAS_FIX_MUL(fix_t, fracbits, bigfix_t, x, y))
275
276/******************************************************************************\
277* Miscellaneous operations.
278\******************************************************************************/
279
280/* Calculate the absolute value of a fixed-point number. */
281#define JAS_FIX_ABS(fix_t, fracbits, x) \
282 (((x) >= 0) ? (x) : (JAS_FIX_NEG(fix_t, fracbits, x)))
283
284/* Is a fixed-point number an integer? */
285#define JAS_FIX_ISINT(fix_t, fracbits, x) \
286 (JAS_FIX_FLOOR(fix_t, fracbits, x) == (x))
287
288/* Get the sign of a fixed-point number. */
289#define JAS_FIX_SGN(fix_t, fracbits, x) \
290 ((x) >= 0 ? 1 : (-1))
291
292/******************************************************************************\
293* Relational operations.
294\******************************************************************************/
295
296/* Compare two fixed-point numbers. */
297#define JAS_FIX_CMP(fix_t, fracbits, x, y) \
298 ((x) > (y) ? 1 : (((x) == (y)) ? 0 : (-1)))
299
300/* Less than. */
301#define JAS_FIX_LT(fix_t, fracbits, x, y) \
302 ((x) < (y))
303
304/* Less than or equal. */
305#define JAS_FIX_LTE(fix_t, fracbits, x, y) \
306 ((x) <= (y))
307
308/* Greater than. */
309#define JAS_FIX_GT(fix_t, fracbits, x, y) \
310 ((x) > (y))
311
312/* Greater than or equal. */
313#define JAS_FIX_GTE(fix_t, fracbits, x, y) \
314 ((x) >= (y))
315
316/******************************************************************************\
317* Rounding functions.
318\******************************************************************************/
319
320/* Round a fixed-point number to the nearest integer. */
321#define JAS_FIX_ROUND(fix_t, fracbits, x) \
322 (((x) < 0) ? JAS_FIX_FLOOR(fix_t, fracbits, JAS_FIX_ADD(fix_t, fracbits, \
323 (x), JAS_FIX_HALF(fix_t, fracbits))) : \
324 JAS_FIX_NEG(fix_t, fracbits, JAS_FIX_FLOOR(fix_t, fracbits, \
325 JAS_FIX_ADD(fix_t, fracbits, (-(x)), JAS_FIX_HALF(fix_t, fracbits)))))
326
327/* Round a fixed-point number to the nearest integer in the direction of
328 negative infinity (i.e., the floor function). */
329#define JAS_FIX_FLOOR(fix_t, fracbits, x) \
330 ((x) & (~(JAS_FIX_ONE(fix_t, fracbits) - 1)))
331
332/******************************************************************************\
333* The below macros are for internal library use only. Do not invoke them
334* directly in application code.
335\******************************************************************************/
336
337/* Handle overflow. */
338#define JAS_FIX_OFLOW() \
339 jas_eprintf("overflow error: file %s, line %d\n", __FILE__, __LINE__)
340
341/* Handle underflow. */
342#define JAS_FIX_UFLOW() \
343 jas_eprintf("underflow error: file %s, line %d\n", __FILE__, __LINE__)
344
345#ifdef __cplusplus
346}
347#endif
348
349#endif
Primitive Types.