1 /* 2 Simple DirectMedia Layer 3 Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org> 4 5 This software is provided 'as-is', without any express or implied 6 warranty. In no event will the authors be held liable for any damages 7 arising from the use of this software. 8 9 Permission is granted to anyone to use this software for any purpose, 10 including commercial applications, and to alter it and redistribute it 11 freely, subject to the following restrictions: 12 13 1. The origin of this software must not be misrepresented; you must not 14 claim that you wrote the original software. If you use this software 15 in a product, an acknowledgment in the product documentation would be 16 appreciated but is not required. 17 2. Altered source versions must be plainly marked as such, and must not be 18 misrepresented as being the original software. 19 3. This notice may not be removed or altered from any source distribution. 20 */ 21 22 /** 23 * \file SDL_test_random.h 24 * 25 * Include file for SDL test framework. 26 * 27 * This code is a part of the SDL2_test library, not the main SDL library. 28 */ 29 30 /* 31 32 A "32-bit Multiply with carry random number generator. Very fast. 33 Includes a list of recommended multipliers. 34 35 multiply-with-carry generator: x(n) = a*x(n-1) + carry mod 2^32. 36 period: (a*2^31)-1 37 38 */ 39 40 #ifndef _SDL_test_random_h 41 #define _SDL_test_random_h 42 43 #include "begin_code.h" 44 /* Set up for C function definitions, even when using C++ */ 45 #ifdef __cplusplus 46 extern "C" { 47 #endif 48 49 /* --- Definitions */ 50 51 /* 52 * Macros that return a random number in a specific format. 53 */ 54 #define SDLTest_RandomInt(c) ((int)SDLTest_Random(c)) 55 56 /* 57 * Context structure for the random number generator state. 58 */ 59 typedef struct { 60 unsigned int a; 61 unsigned int x; 62 unsigned int c; 63 unsigned int ah; 64 unsigned int al; 65 } SDLTest_RandomContext; 66 67 68 /* --- Function prototypes */ 69 70 /** 71 * \brief Initialize random number generator with two integers. 72 * 73 * Note: The random sequence of numbers returned by ...Random() is the 74 * same for the same two integers and has a period of 2^31. 75 * 76 * \param rndContext pointer to context structure 77 * \param xi integer that defines the random sequence 78 * \param ci integer that defines the random sequence 79 * 80 */ 81 void SDLTest_RandomInit(SDLTest_RandomContext * rndContext, unsigned int xi, 82 unsigned int ci); 83 84 /** 85 * \brief Initialize random number generator based on current system time. 86 * 87 * \param rndContext pointer to context structure 88 * 89 */ 90 void SDLTest_RandomInitTime(SDLTest_RandomContext *rndContext); 91 92 93 /** 94 * \brief Initialize random number generator based on current system time. 95 * 96 * Note: ...RandomInit() or ...RandomInitTime() must have been called 97 * before using this function. 98 * 99 * \param rndContext pointer to context structure 100 * 101 * \returns A random number (32bit unsigned integer) 102 * 103 */ 104 unsigned int SDLTest_Random(SDLTest_RandomContext *rndContext); 105 106 107 /* Ends C function definitions when using C++ */ 108 #ifdef __cplusplus 109 } 110 #endif 111 #include "close_code.h" 112 113 #endif /* _SDL_test_random_h */ 114 115 /* vi: set ts=4 sw=4 expandtab: */ 116