mirror of https://github.com/encounter/SDL.git
53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "SDL_internal.h"
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#include "SDL_utils_c.h"
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/* Common utility functions that aren't in the public API */
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int SDL_powerof2(int x)
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{
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int value;
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if (x <= 0) {
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/* Return some sane value - we shouldn't hit this in our use cases */
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return 1;
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}
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/* This trick works for 32-bit values */
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{
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SDL_COMPILE_TIME_ASSERT(SDL_powerof2, sizeof(x) == sizeof(Uint32));
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}
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value = x;
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value -= 1;
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value |= value >> 1;
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value |= value >> 2;
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value |= value >> 4;
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value |= value >> 8;
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value |= value >> 16;
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value += 1;
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return value;
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}
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/* vi: set ts=4 sw=4 expandtab: */
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