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| 1 | pmbaty | 1 | /* |
| 2 | Simple DirectMedia Layer |
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| 3 | Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org> |
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| 4 | |||
| 5 | This software is provided 'as-is', without any express or implied |
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| 6 | warranty. In no event will the authors be held liable for any damages |
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| 7 | arising from the use of this software. |
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| 8 | |||
| 9 | Permission is granted to anyone to use this software for any purpose, |
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| 10 | including commercial applications, and to alter it and redistribute it |
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| 11 | freely, subject to the following restrictions: |
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| 12 | |||
| 13 | 1. The origin of this software must not be misrepresented; you must not |
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| 14 | claim that you wrote the original software. If you use this software |
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| 15 | in a product, an acknowledgment in the product documentation would be |
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| 16 | appreciated but is not required. |
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| 17 | 2. Altered source versions must be plainly marked as such, and must not be |
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| 18 | misrepresented as being the original software. |
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| 19 | 3. This notice may not be removed or altered from any source distribution. |
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| 20 | */ |
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| 21 | |||
| 22 | /** |
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| 23 | * \file SDL_test_random.h |
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| 24 | * |
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| 25 | * Include file for SDL test framework. |
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| 26 | * |
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| 27 | * This code is a part of the SDL2_test library, not the main SDL library. |
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| 28 | */ |
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| 29 | |||
| 30 | /* |
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| 31 | |||
| 32 | A "32-bit Multiply with carry random number generator. Very fast. |
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| 33 | Includes a list of recommended multipliers. |
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| 34 | |||
| 35 | multiply-with-carry generator: x(n) = a*x(n-1) + carry mod 2^32. |
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| 36 | period: (a*2^31)-1 |
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| 37 | |||
| 38 | */ |
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| 39 | |||
| 40 | #ifndef SDL_test_random_h_ |
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| 41 | #define SDL_test_random_h_ |
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| 42 | |||
| 43 | #include "begin_code.h" |
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| 44 | /* Set up for C function definitions, even when using C++ */ |
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| 45 | #ifdef __cplusplus |
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| 46 | extern "C" { |
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| 47 | #endif |
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| 48 | |||
| 49 | /* --- Definitions */ |
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| 50 | |||
| 51 | /* |
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| 52 | * Macros that return a random number in a specific format. |
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| 53 | */ |
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| 54 | #define SDLTest_RandomInt(c) ((int)SDLTest_Random(c)) |
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| 55 | |||
| 56 | /* |
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| 57 | * Context structure for the random number generator state. |
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| 58 | */ |
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| 59 | typedef struct { |
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| 60 | unsigned int a; |
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| 61 | unsigned int x; |
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| 62 | unsigned int c; |
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| 63 | unsigned int ah; |
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| 64 | unsigned int al; |
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| 65 | } SDLTest_RandomContext; |
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| 66 | |||
| 67 | |||
| 68 | /* --- Function prototypes */ |
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| 69 | |||
| 70 | /** |
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| 71 | * \brief Initialize random number generator with two integers. |
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| 72 | * |
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| 73 | * Note: The random sequence of numbers returned by ...Random() is the |
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| 74 | * same for the same two integers and has a period of 2^31. |
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| 75 | * |
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| 76 | * \param rndContext pointer to context structure |
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| 77 | * \param xi integer that defines the random sequence |
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| 78 | * \param ci integer that defines the random sequence |
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| 79 | * |
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| 80 | */ |
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| 81 | void SDLTest_RandomInit(SDLTest_RandomContext * rndContext, unsigned int xi, |
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| 82 | unsigned int ci); |
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| 83 | |||
| 84 | /** |
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| 85 | * \brief Initialize random number generator based on current system time. |
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| 86 | * |
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| 87 | * \param rndContext pointer to context structure |
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| 88 | * |
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| 89 | */ |
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| 90 | void SDLTest_RandomInitTime(SDLTest_RandomContext *rndContext); |
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| 91 | |||
| 92 | |||
| 93 | /** |
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| 94 | * \brief Initialize random number generator based on current system time. |
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| 95 | * |
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| 96 | * Note: ...RandomInit() or ...RandomInitTime() must have been called |
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| 97 | * before using this function. |
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| 98 | * |
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| 99 | * \param rndContext pointer to context structure |
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| 100 | * |
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| 101 | * \returns a random number (32bit unsigned integer) |
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| 102 | * |
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| 103 | */ |
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| 104 | unsigned int SDLTest_Random(SDLTest_RandomContext *rndContext); |
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| 105 | |||
| 106 | |||
| 107 | /* Ends C function definitions when using C++ */ |
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| 108 | #ifdef __cplusplus |
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| 109 | } |
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| 110 | #endif |
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| 111 | #include "close_code.h" |
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| 112 | |||
| 113 | #endif /* SDL_test_random_h_ */ |
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| 114 | |||
| 115 | /* vi: set ts=4 sw=4 expandtab: */ |