/* * Cogl * * An object oriented GL/GLES Abstraction/Utility Layer * * Copyright (C) 2007,2008,2009,2010 Intel Corporation. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library. If not, see . * * */ #ifndef __COGL_UTIL_H #define __COGL_UTIL_H #include #include #include "cogl-defines.h" #ifndef COGL_HAS_GLIB_SUPPORT #include #endif int _cogl_util_next_p2 (int a); /* The signbit macro is defined by ISO C99 so it should be available, however if it's not we can fallback to an evil hack */ #ifdef signbit #define cogl_util_float_signbit(x) signbit(x) #else /* This trick was stolen from here: http://lists.boost.org/Archives/boost/2006/08/108731.php It xors the integer reinterpretations of -1.0f and 1.0f. In theory they should only differ by the signbit so that gives a mask for the sign which we can just test against the value */ static inline gboolean cogl_util_float_signbit (float x) { static const union { float f; guint32 i; } negative_one = { -1.0f }; static const union { float f; guint32 i; } positive_one = { +1.0f }; union { float f; guint32 i; } value = { x }; return !!((negative_one.i ^ positive_one.i) & value.i); } #endif /* This is a replacement for the nearbyint function which always rounds to the nearest integer. nearbyint is apparently a C99 function so it might not always be available but also it seems in glibc it is defined as a function call so this macro could end up faster anyway. We can't just add 0.5f because it will break for negative numbers. */ #define COGL_UTIL_NEARBYINT(x) ((int) ((x) < 0.0f ? (x) - 0.5f : (x) + 0.5f)) /* Returns whether the given integer is a power of two */ static inline gboolean _cogl_util_is_pot (unsigned int num) { /* Make sure there is only one bit set */ return (num & (num - 1)) == 0; } /* Split Bob Jenkins' One-at-a-Time hash * * This uses the One-at-a-Time hash algorithm designed by Bob Jenkins * but the mixing step is split out so the function can be used in a * more incremental fashion. */ static inline unsigned int _cogl_util_one_at_a_time_hash (unsigned int hash, void *key, size_t bytes) { unsigned char *p = key; int i; for (i = 0; i < bytes; i++) { hash += p[i]; hash += (hash << 10); hash ^= (hash >> 6); } return hash; } unsigned int _cogl_util_one_at_a_time_mix (unsigned int hash); /* The 'ffs' function is part of C99 so it isn't always available */ #ifdef HAVE_FFS #define _cogl_util_ffs ffs #else int _cogl_util_ffs (int num); #endif /* The 'ffsl' function is non-standard but GCC has a builtin for it since 3.4 which we can use */ #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) #define _cogl_util_ffsl __builtin_ffsl #define COGL_UTIL_HAVE_BUILTIN_FFSL #else /* If ints and longs are the same size we can just use ffs. Hopefully the compiler will optimise away this conditional */ #define _cogl_util_ffsl(x) \ (sizeof (long int) == sizeof (int) ? _cogl_util_ffs ((int) x) : \ _cogl_util_ffsl_wrapper (x)) int _cogl_util_ffsl_wrapper (long int num); #endif #ifdef COGL_HAS_GLIB_SUPPORT #define _COGL_RETURN_IF_FAIL(EXPR) g_return_if_fail(EXPR) #define _COGL_RETURN_VAL_IF_FAIL(EXPR, VAL) g_return_val_if_fail(EXPR, VAL) #else #define _COGL_RETURN_IF_FAIL(EXPR) do { \ if (!(EXPR)) \ { \ fprintf (stderr, "file %s: line %d: assertion `%s' failed", \ __FILE__, \ __LINE__, \ #EXPR); \ return; \ }; \ } while(0) #define _COGL_RETURN_VAL_IF_FAIL(EXPR, VAL) do { \ if (!(EXPR)) \ { \ fprintf (stderr, "file %s: line %d: assertion `%s' failed", \ __FILE__, \ __LINE__, \ #EXPR); \ return (VAL); \ }; \ } while(0) #endif /* COGL_HAS_GLIB_SUPPORT */ #endif /* __COGL_UTIL_H */