/*
* 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 <http://www.gnu.org/licenses/>.
*
*
*/
#ifndef __COGL_UTIL_H
#define __COGL_UTIL_H
#include <glib.h>
#include <math.h>
#include <cogl/cogl-defines.h>
#include "cogl-types.h"
#ifndef COGL_HAS_GLIB_SUPPORT
#include <stdio.h>
#endif
/* Double check that config.h has been included */
#if !defined (GETTEXT_PACKAGE) && !defined (_COGL_IN_TEST_BITMASK)
#error "config.h must be included before including cogl-util.h"
#endif
/* When compiling with Visual Studio, symbols that represent data that
are exported out of the DLL need to be marked with the dllexport
attribute. */
#ifdef _MSC_VER
#ifdef COGL_BUILD_EXP
#define COGL_EXPORT __declspec(dllexport)
#else
#define COGL_EXPORT __declspec(dllimport)
#endif
#else
#define COGL_EXPORT
#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 CoglBool
cogl_util_float_signbit (float x)
{
static const union { float f; uint32_t i; } negative_one = { -1.0f };
static const union { float f; uint32_t i; } positive_one = { +1.0f };
union { float f; uint32_t 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 CoglBool
_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,
const void *key,
size_t bytes)
{
const 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);
/* These two builtins are available since GCC 3.4 */
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
#define COGL_UTIL_HAVE_BUILTIN_FFSL
#define COGL_UTIL_HAVE_BUILTIN_POPCOUNTL
#define COGL_UTIL_HAVE_BUILTIN_CLZ
#endif
/* 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 */
#ifdef COGL_UTIL_HAVE_BUILTIN_FFSL
#define _cogl_util_ffsl __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 /* COGL_UTIL_HAVE_BUILTIN_FFSL */
static inline unsigned int
_cogl_util_fls (unsigned int n)
{
#ifdef COGL_UTIL_HAVE_BUILTIN_CLZ
return n == 0 ? 0 : sizeof (unsigned int) * 8 - __builtin_clz (n);
#else
unsigned int v = 1;
if (n == 0)
return 0;
while (n >>= 1)
v++;
return v;
#endif
}
#ifdef COGL_UTIL_HAVE_BUILTIN_POPCOUNTL
#define _cogl_util_popcountl __builtin_popcountl
#else
extern const unsigned char _cogl_util_popcount_table[256];
/* There are many ways of doing popcount but doing a table lookup
seems to be the most robust against different sizes for long. Some
pages seem to claim it's the fastest method anyway. */
static inline int
_cogl_util_popcountl (unsigned long num)
{
int i;
int sum = 0;
/* Let's hope GCC will unroll this loop.. */
for (i = 0; i < sizeof (num); i++)
sum += _cogl_util_popcount_table[(num >> (i * 8)) & 0xff];
return sum;
}
#endif /* COGL_UTIL_HAVE_BUILTIN_POPCOUNTL */
#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
#ifdef COGL_ENABLE_DEBUG
#define _COGL_RETURN_START do {
#define _COGL_RETURN_END } while (0)
#else /* COGL_ENABLE_DEBUG */
/* If debugging is disabled then we don't actually want to do the
* check but we still want the code for the expression to be generated
* so that it won't give loads of warnings about unused variables.
* Therefore we just surround the block with if(0) */
#define _COGL_RETURN_START do { if (0) {
#define _COGL_RETURN_END } } while (0)
#endif /* COGL_ENABLE_DEBUG */
#define _COGL_RETURN_IF_FAIL(EXPR) _COGL_RETURN_START { \
if (!(EXPR)) \
{ \
fprintf (stderr, "file %s: line %d: assertion `%s' failed", \
__FILE__, \
__LINE__, \
#EXPR); \
return; \
}; \
} _COGL_RETURN_END
#define _COGL_RETURN_VAL_IF_FAIL(EXPR, VAL) _COGL_RETURN_START { \
if (!(EXPR)) \
{ \
fprintf (stderr, "file %s: line %d: assertion `%s' failed", \
__FILE__, \
__LINE__, \
#EXPR); \
return (VAL); \
}; \
} _COGL_RETURN_END
#endif /* COGL_HAS_GLIB_SUPPORT */
/* Match a CoglPixelFormat according to channel masks, color depth,
* bits per pixel and byte order. These information are provided by
* the Visual and XImage structures.
*
* If no specific pixel format could be found, COGL_PIXEL_FORMAT_ANY
* is returned.
*/
CoglPixelFormat
_cogl_util_pixel_format_from_masks (unsigned long r_mask,
unsigned long g_mask,
unsigned long b_mask,
int depth, int bpp,
int byte_order);
/* Since we can't rely on _Static_assert always being available for
* all compilers we have limited static assert that can be used in
* C code but not in headers.
*/
#define _COGL_TYPEDEF_ASSERT(EXPRESSION) \
typedef struct { char Compile_Time_Assertion[(EXPRESSION) ? 1 : -1]; } \
G_PASTE (_GStaticAssert_, __LINE__)
/* _COGL_STATIC_ASSERT:
* @expression: An expression to assert evaluates to true at compile
* time.
* @message: A message to print to the console if the assertion fails
* at compile time.
*
* Allows you to assert that an expression evaluates to true at
* compile time and aborts compilation if not. If possible message
* will also be printed if the assertion fails.
*
* Note: Only Gcc >= 4.6 supports the c11 _Static_assert which lets us
* print a nice message if the compile time assertion fails.
*
* Note: this assertion macro can only be used in C code where it is
* valid to use a typedef. This macro should not be used in headers
* because we can't guarantee a unique name for the typedef due to
* the name being based on the line number of the file it's used in.
*
* Although we can remove this limitation if the compiler supports
* _Static_assert we currently choose to maintain the limitation in
* any case to help ensure we don't accidentally create code that
* doesn't compile on some toolchains because we forgot about this
* limitation.
*/
#ifdef HAVE_STATIC_ASSERT
#define _COGL_STATIC_ASSERT(EXPRESSION, MESSAGE) \
_Static_assert (EXPRESSION, MESSAGE); \
_COGL_TYPEDEF_ASSERT(EXPRESSION)
#else
#define _COGL_STATIC_ASSERT(EXPRESSION, MESSAGE) \
_COGL_TYPEDEF_ASSERT(EXPRESSION)
/* So that we can safely use _Static_assert() if we want to add
* assertions to internal headers we define it to a NOP here
* if it's not supported by the compiler. */
#define _Static_assert(EXPRESSION, MESSAGE)
#endif
#ifdef HAVE_MEMMEM
#define _cogl_util_memmem memmem
#else
char *
_cogl_util_memmem (const void *haystack,
size_t haystack_len,
const void *needle,
size_t needle_len);
#endif
static inline void
_cogl_util_scissor_intersect (int rect_x0,
int rect_y0,
int rect_x1,
int rect_y1,
int *scissor_x0,
int *scissor_y0,
int *scissor_x1,
int *scissor_y1)
{
*scissor_x0 = MAX (*scissor_x0, rect_x0);
*scissor_y0 = MAX (*scissor_y0, rect_y0);
*scissor_x1 = MIN (*scissor_x1, rect_x1);
*scissor_y1 = MIN (*scissor_y1, rect_y1);
}
#endif /* __COGL_UTIL_H */