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Don't clobber refcounting in SDL_Init.

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- Fixes bug 1712 by not overwriting SDL_SubsystemRefCount in SDL_Init.
       - Removes the SDL_initialized variable, and makes SDL_SubsystemRefCount
         the canonical source of truth for whether or not a subsystem has been
         initialized.
       - Refactors SDL_InitSubSystem and SDL_QuitSubSystem to use helper
         functions to manage refcount.
       - Adds automated tests for SDL_Init/Quit*.
       - Adds SDL_bits.h which contains SDL_MostSignificantBitIndex.
This commit is contained in:
Jørgen P. Tjernø 2013-02-12 11:47:31 -08:00
parent 781ab3764f
commit f85aeb98c7
9 changed files with 411 additions and 140 deletions
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102
include/SDL_bits.h Normal file
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
/**
* \file SDL_bits.h
*
* Functions for fiddling with bits and bitmasks.
*/
#ifndef _SDL_bits_h
#define _SDL_bits_h
#include "SDL_stdinc.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif
/**
* \file SDL_bits.h
*
* Uses inline functions for compilers that support them, and static
* functions for those that do not. Because these functions become
* static for compilers that do not support inline functions, this
* header should only be included in files that actually use them.
*/
/**
* Get the index of the most significant bit. Result is undefined when called
* with 0. This operation can also be stated as "count leading zeroes" and
* "log base 2".
*
* \return Index of the most significant bit.
*/
static __inline__ Sint8
SDL_MostSignificantBitIndex32(Uint32 x)
{
#if defined(__GNUC__)
/* Count Leading Zeroes builtin in GCC.
* http://gcc.gnu.org/onlinedocs/gcc-4.3.4/gcc/Other-Builtins.html
*/
return 31 - __builtin_clz(x);
#else
/* Based off of Bit Twiddling Hacks by Sean Eron Anderson
* <seander@cs.stanford.edu>, released in the public domain.
* http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
*/
static const Sint8 LogTable256[256] =
{
#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
-1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
#undef LT
};
register unsigned int t, tt;
if (tt = x >> 16)
{
return ((t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt]);
}
else
{
return ((t = x >> 8) ? 8 + LogTable256[t] : LogTable256[x]);
}
#endif
}
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"
#endif /* _SDL_bits_h */
/* vi: set ts=4 sw=4 expandtab: */