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b72f255c0a
Since we've had several developers from admirable projects say they would like to use Cogl but would really prefer not to pull in gobject,gmodule and glib as extra dependencies we are investigating if we can get to the point where glib is only an optional dependency. Actually we feel like we only make minimal use of glib anyway, so it may well be quite straightforward to achieve this. This adds a --disable-glib configure option that can be used to disable features that depend on glib. Actually --disable-glib doesn't strictly disable glib at this point because it's more helpful if cogl continues to build as we make incremental progress towards this. The first use of glib that this patch tackles is the use of g_return_val_if_fail and g_return_if_fail which have been replaced with equivalent _COGL_RETURN_VAL_IF_FAIL and _COGL_RETURN_IF_FAIL macros. Reviewed-by: Neil Roberts <neil@linux.intel.com>
137 lines
4.2 KiB
C
137 lines
4.2 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*/
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#ifndef __COGL_UTIL_H
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#define __COGL_UTIL_H
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#include <glib.h>
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#include <math.h>
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#ifndef COGL_HAS_GLIB_SUPPORT
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#include <stdio.h>
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#endif
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int
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_cogl_util_next_p2 (int a);
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/* The signbit macro is defined by ISO C99 so it should be available,
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however if it's not we can fallback to an evil hack */
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#ifdef signbit
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#define cogl_util_float_signbit(x) signbit(x)
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#else
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/* This trick was stolen from here:
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http://lists.boost.org/Archives/boost/2006/08/108731.php
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It xors the integer reinterpretations of -1.0f and 1.0f. In theory
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they should only differ by the signbit so that gives a mask for the
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sign which we can just test against the value */
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static inline gboolean
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cogl_util_float_signbit (float x)
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{
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static const union { float f; guint32 i; } negative_one = { -1.0f };
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static const union { float f; guint32 i; } positive_one = { +1.0f };
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union { float f; guint32 i; } value = { x };
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return !!((negative_one.i ^ positive_one.i) & value.i);
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}
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#endif
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/* This is a replacement for the nearbyint function which always
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rounds to the nearest integer. nearbyint is apparently a C99
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function so it might not always be available but also it seems in
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glibc it is defined as a function call so this macro could end up
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faster anyway. We can't just add 0.5f because it will break for
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negative numbers. */
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#define COGL_UTIL_NEARBYINT(x) ((int) ((x) < 0.0f ? (x) - 0.5f : (x) + 0.5f))
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/* Returns whether the given integer is a power of two */
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static inline gboolean
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_cogl_util_is_pot (unsigned int num)
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{
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/* Make sure there is only one bit set */
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return (num & (num - 1)) == 0;
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}
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/* Split Bob Jenkins' One-at-a-Time hash
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*
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* This uses the One-at-a-Time hash algorithm designed by Bob Jenkins
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* but the mixing step is split out so the function can be used in a
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* more incremental fashion.
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*/
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static inline unsigned int
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_cogl_util_one_at_a_time_hash (unsigned int hash,
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void *key,
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size_t bytes)
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{
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unsigned char *p = key;
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int i;
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for (i = 0; i < bytes; i++)
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{
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hash += p[i];
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hash += (hash << 10);
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hash ^= (hash >> 6);
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}
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return hash;
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}
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unsigned int
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_cogl_util_one_at_a_time_mix (unsigned int hash);
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/* The 'ffs' function is part of C99 so it isn't always available */
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#ifdef HAVE_FFS
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#define _cogl_util_ffs ffs
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#else
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int
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_cogl_util_ffs (int num);
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#endif
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#ifdef COGL_HAS_GLIB_SUPPORT
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#define _COGL_RETURN_IF_FAIL(EXPR) g_return_if_fail(EXPR)
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#define _COGL_RETURN_VAL_IF_FAIL(EXPR, VAL) g_return_val_if_fail(EXPR, VAL)
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#else
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#define _COGL_RETURN_IF_FAIL(EXPR) do { \
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if (!(EXPR)) \
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{ \
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fprintf (stderr, "file %s: line %d: assertion `%s' failed", \
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__FILE__, \
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__LINE__, \
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#EXPR); \
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return; \
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}; \
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} while(0)
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#define _COGL_RETURN_VAL_IF_FAIL(EXPR, VAL) do { \
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if (!(EXPR)) \
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{ \
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fprintf (stderr, "file %s: line %d: assertion `%s' failed", \
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__FILE__, \
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__LINE__, \
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#EXPR); \
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return (VAL); \
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}; \
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} while(0)
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#endif /* COGL_HAS_GLIB_SUPPORT */
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#endif /* __COGL_UTIL_H */
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