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116 lines
3.1 KiB
116 lines
3.1 KiB
4 years ago
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/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2020 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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/**
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* \file SDL_test_random.h
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*
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* Include file for SDL test framework.
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*
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* This code is a part of the SDL2_test library, not the main SDL library.
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*/
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/*
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A "32-bit Multiply with carry random number generator. Very fast.
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Includes a list of recommended multipliers.
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multiply-with-carry generator: x(n) = a*x(n-1) + carry mod 2^32.
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period: (a*2^31)-1
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*/
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#ifndef SDL_test_random_h_
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#define SDL_test_random_h_
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#include "begin_code.h"
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* --- Definitions */
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/*
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* Macros that return a random number in a specific format.
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*/
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#define SDLTest_RandomInt(c) ((int)SDLTest_Random(c))
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/*
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* Context structure for the random number generator state.
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*/
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typedef struct {
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unsigned int a;
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unsigned int x;
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unsigned int c;
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unsigned int ah;
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unsigned int al;
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} SDLTest_RandomContext;
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/* --- Function prototypes */
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/**
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* \brief Initialize random number generator with two integers.
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*
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* Note: The random sequence of numbers returned by ...Random() is the
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* same for the same two integers and has a period of 2^31.
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*
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* \param rndContext pointer to context structure
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* \param xi integer that defines the random sequence
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* \param ci integer that defines the random sequence
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*
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*/
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void SDLTest_RandomInit(SDLTest_RandomContext * rndContext, unsigned int xi,
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unsigned int ci);
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/**
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* \brief Initialize random number generator based on current system time.
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*
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* \param rndContext pointer to context structure
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*
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*/
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void SDLTest_RandomInitTime(SDLTest_RandomContext *rndContext);
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/**
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* \brief Initialize random number generator based on current system time.
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*
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* Note: ...RandomInit() or ...RandomInitTime() must have been called
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* before using this function.
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*
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* \param rndContext pointer to context structure
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*
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* \returns A random number (32bit unsigned integer)
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*
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*/
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unsigned int SDLTest_Random(SDLTest_RandomContext *rndContext);
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include "close_code.h"
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#endif /* SDL_test_random_h_ */
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/* vi: set ts=4 sw=4 expandtab: */
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