mirror of https://github.com/encounter/SDL.git
53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
/*
|
|
Simple DirectMedia Layer
|
|
Copyright (C) 1997-2022 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.
|
|
*/
|
|
#include "SDL_internal.h"
|
|
|
|
#include "SDL_utils_c.h"
|
|
|
|
/* Common utility functions that aren't in the public API */
|
|
|
|
int SDL_powerof2(int x)
|
|
{
|
|
int value;
|
|
|
|
if (x <= 0) {
|
|
/* Return some sane value - we shouldn't hit this in our use cases */
|
|
return 1;
|
|
}
|
|
|
|
/* This trick works for 32-bit values */
|
|
{
|
|
SDL_COMPILE_TIME_ASSERT(SDL_powerof2, sizeof(x) == sizeof(Uint32));
|
|
}
|
|
value = x;
|
|
value -= 1;
|
|
value |= value >> 1;
|
|
value |= value >> 2;
|
|
value |= value >> 4;
|
|
value |= value >> 8;
|
|
value |= value >> 16;
|
|
value += 1;
|
|
|
|
return value;
|
|
}
|
|
|
|
/* vi: set ts=4 sw=4 expandtab: */
|