src/util/imports.h

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file imports.h
  28  * Standard C library function wrappers.
  29  *
  30  * This file provides wrappers for all the standard C library functions
  31  * like malloc(), free(), printf(), getenv(), etc.
  32  */
  33
  34
  35 #ifndef IMPORTS_H
  36 #define IMPORTS_H
  37
  38
  39 #include <stdlib.h>
  40 #include <stdarg.h>
  41 #include <string.h>
  42 #include "util/compiler.h"
  43 #include "util/bitscan.h"
  44 #include "util/u_memory.h"
  45
  46 #ifdef __cplusplus
  47 extern "C" {
  48 #endif
  49
  50
  51 /*
  52  * For GL_ARB_vertex_buffer_object we need to treat vertex array pointers
  53  * as offsets into buffer stores.  Since the vertex array pointer and
  54  * buffer store pointer are both pointers and we need to add them, we use
  55  * this macro.
  56  * Both pointers/offsets are expressed in bytes.
  57  */
  58 #define ADD_POINTERS(A, B)  ( (uint8_t *) (A) + (uintptr_t) (B) )
  59
  60
  61 /**
  62  * Sometimes we treat floats as ints.  On x86 systems, moving a float
  63  * as an int (thereby using integer registers instead of FP registers) is
  64  * a performance win.  Typically, this can be done with ordinary casts.
  65  * But with gcc's -fstrict-aliasing flag (which defaults to on in gcc 3.0)
  66  * these casts generate warnings.
  67  * The following union typedef is used to solve that.
  68  */
  69 typedef union { float f; int i; unsigned u; } fi_type;
  70
  71
  72
  73 /*@}*/
  74
  75
  76 /***
  77  *** LOG2: Log base 2 of float
  78  ***/
  79 static inline float LOG2(float x)
  80 {
  81 #if 0
  82    /* This is pretty fast, but not accurate enough (only 2 fractional bits).
  83     * Based on code from http://www.stereopsis.com/log2.html
  84     */
  85    const float y = x * x * x * x;
  86    const unsigned ix = *((unsigned *) &y);
  87    const unsigned exp = (ix >> 23) & 0xFF;
  88    const int log2 = ((int) exp) - 127;
  89    return (float) log2 * (1.0 / 4.0);  /* 4, because of x^4 above */
  90 #endif
  91    /* Pretty fast, and accurate.
  92     * Based on code from http://www.flipcode.com/totd/
  93     */
  94    fi_type num;
  95    int log_2;
  96    num.f = x;
  97    log_2 = ((num.i >> 23) & 255) - 128;
  98    num.i &= ~(255 << 23);
  99    num.i += 127 << 23;
 100    num.f = ((-1.0f/3) * num.f + 2) * num.f - 2.0f/3;
 101    return num.f + log_2;
 102 }
 103
 104
 105
 106 /**
 107  * finite macro.
 108  */
 109 #if defined(_MSC_VER)
 110 #  define finite _finite
 111 #endif
 112
 113
 114 /***
 115  *** IS_INF_OR_NAN: test if float is infinite or NaN
 116  ***/
 117 #if defined(isfinite)
 118 #define IS_INF_OR_NAN(x)        (!isfinite(x))
 119 #elif defined(finite)
 120 #define IS_INF_OR_NAN(x)        (!finite(x))
 121 #elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
 122 #define IS_INF_OR_NAN(x)        (!isfinite(x))
 123 #else
 124 #define IS_INF_OR_NAN(x)        (!finite(x))
 125 #endif
 126
 127
 128 /**
 129  * Convert float to int by rounding to nearest integer, away from zero.
 130  */
 131 static inline int IROUND(float f)
 132 {
 133    return (int) ((f >= 0.0F) ? (f + 0.5F) : (f - 0.5F));
 134 }
 135
 136 /**
 137  * Convert double to int by rounding to nearest integer, away from zero.
 138  */
 139 static inline int IROUNDD(double d)
 140 {
 141    return (int) ((d >= 0.0) ? (d + 0.5) : (d - 0.5));
 142 }
 143
 144 /**
 145  * Convert float to int64 by rounding to nearest integer.
 146  */
 147 static inline int64_t IROUND64(float f)
 148 {
 149    return (int64_t) ((f >= 0.0F) ? (f + 0.5F) : (f - 0.5F));
 150 }
 151
 152
 153 /**
 154  * Convert positive float to int by rounding to nearest integer.
 155  */
 156 static inline int IROUND_POS(float f)
 157 {
 158    assert(f >= 0.0F);
 159    return (int) (f + 0.5F);
 160 }
 161
 162 /** Return (as an integer) floor of float */
 163 static inline int IFLOOR(float f)
 164 {
 165 #if defined(USE_X86_ASM) && defined(__GNUC__) && defined(__i386__)
 166    /*
 167     * IEEE floor for computers that round to nearest or even.
 168     * 'f' must be between -4194304 and 4194303.
 169     * This floor operation is done by "(iround(f + .5) + iround(f - .5)) >> 1",
 170     * but uses some IEEE specific tricks for better speed.
 171     * Contributed by Josh Vanderhoof
 172     */
 173    int ai, bi;
 174    double af, bf;
 175    af = (3 << 22) + 0.5 + (double)f;
 176    bf = (3 << 22) + 0.5 - (double)f;
 177    /* GCC generates an extra fstp/fld without this. */
 178    __asm__ ("fstps %0" : "=m" (ai) : "t" (af) : "st");
 179    __asm__ ("fstps %0" : "=m" (bi) : "t" (bf) : "st");
 180    return (ai - bi) >> 1;
 181 #else
 182    int ai, bi;
 183    double af, bf;
 184    fi_type u;
 185    af = (3 << 22) + 0.5 + (double)f;
 186    bf = (3 << 22) + 0.5 - (double)f;
 187    u.f = (float) af;  ai = u.i;
 188    u.f = (float) bf;  bi = u.i;
 189    return (ai - bi) >> 1;
 190 #endif
 191 }
 192
 193
 194 /**
 195  * Is x a power of two?
 196  */
 197 static inline int
 198 _mesa_is_pow_two(int x)
 199 {
 200    return !(x & (x - 1));
 201 }
 202
 203 /**
 204  * Round given integer to next higer power of two
 205  * If X is zero result is undefined.
 206  *
 207  * Source for the fallback implementation is
 208  * Sean Eron Anderson's webpage "Bit Twiddling Hacks"
 209  * http://graphics.stanford.edu/~seander/bithacks.html
 210  *
 211  * When using builtin function have to do some work
 212  * for case when passed values 1 to prevent hiting
 213  * undefined result from __builtin_clz. Undefined
 214  * results would be different depending on optimization
 215  * level used for build.
 216  */
 217 static inline int32_t
 218 _mesa_next_pow_two_32(uint32_t x)
 219 {
 220 #ifdef HAVE___BUILTIN_CLZ
 221         uint32_t y = (x != 1);
 222         return (1 + y) << ((__builtin_clz(x - y) ^ 31) );
 223 #else
 224         x--;
 225         x |= x >> 1;
 226         x |= x >> 2;
 227         x |= x >> 4;
 228         x |= x >> 8;
 229         x |= x >> 16;
 230         x++;
 231         return x;
 232 #endif
 233 }
 234
 235 static inline int64_t
 236 _mesa_next_pow_two_64(uint64_t x)
 237 {
 238 #ifdef HAVE___BUILTIN_CLZLL
 239         uint64_t y = (x != 1);
 240         STATIC_ASSERT(sizeof(x) == sizeof(long long));
 241         return (1 + y) << ((__builtin_clzll(x - y) ^ 63));
 242 #else
 243         x--;
 244         x |= x >> 1;
 245         x |= x >> 2;
 246         x |= x >> 4;
 247         x |= x >> 8;
 248         x |= x >> 16;
 249         x |= x >> 32;
 250         x++;
 251         return x;
 252 #endif
 253 }
 254
 255
 256 /*
 257  * Returns the floor form of binary logarithm for a 32-bit integer.
 258  */
 259 static inline unsigned
 260 _mesa_logbase2(unsigned n)
 261 {
 262 #ifdef HAVE___BUILTIN_CLZ
 263    return (31 - __builtin_clz(n | 1));
 264 #else
 265    unsigned pos = 0;
 266    if (n >= 1<<16) { n >>= 16; pos += 16; }
 267    if (n >= 1<< 8) { n >>=  8; pos +=  8; }
 268    if (n >= 1<< 4) { n >>=  4; pos +=  4; }
 269    if (n >= 1<< 2) { n >>=  2; pos +=  2; }
 270    if (n >= 1<< 1) {           pos +=  1; }
 271    return pos;
 272 #endif
 273 }
 274
 275
 276 /**********************************************************************
 277  * Functions
 278  */
 279
 280 extern void *
 281 _mesa_align_malloc( size_t bytes, unsigned long alignment );
 282
 283 extern void *
 284 _mesa_align_calloc( size_t bytes, unsigned long alignment );
 285
 286 extern void
 287 _mesa_align_free( void *ptr );
 288
 289 extern void *
 290 _mesa_align_realloc(void *oldBuffer, size_t oldSize, size_t newSize,
 291                     unsigned long alignment);
 292
 293 extern int
 294 _mesa_snprintf( char *str, size_t size, const char *fmt, ... ) PRINTFLIKE(3, 4);
 295
 296 extern int
 297 _mesa_vsnprintf(char *str, size_t size, const char *fmt, va_list arg);
 298
 299
 300 #if defined(_WIN32) && !defined(HAVE_STRTOK_R)
 301 #define strtok_r strtok_s
 302 #endif
 303
 304 #ifdef __cplusplus
 305 }
 306 #endif
 307
 308
 309 #endif /* IMPORTS_H */