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include/SDL_test_random.h

author | Ryan C. Gordon |

Wed, 27 May 2015 19:00:56 -0400 | |

changeset 9656 | 8a4bcbdeba1c |

parent 9619 | b94b6d0bff0f |

child 9998 | f67cf37e9cd4 |

permissions | -rw-r--r-- |

Patched to compile on C89 compilers.

1 /*

2 Simple DirectMedia Layer

3 Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>

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.

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:

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 */

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 */

30 /*

32 A "32-bit Multiply with carry random number generator. Very fast.

33 Includes a list of recommended multipliers.

35 multiply-with-carry generator: x(n) = a*x(n-1) + carry mod 2^32.

36 period: (a*2^31)-1

38 */

40 #ifndef _SDL_test_random_h

41 #define _SDL_test_random_h

43 #include "begin_code.h"

44 /* Set up for C function definitions, even when using C++ */

45 #ifdef __cplusplus

46 extern "C" {

47 #endif

49 /* --- Definitions */

51 /*

52 * Macros that return a random number in a specific format.

53 */

54 #define SDLTest_RandomInt(c) ((int)SDLTest_Random(c))

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;

68 /* --- Function prototypes */

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);

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);

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);

107 /* Ends C function definitions when using C++ */

108 #ifdef __cplusplus

109 }

110 #endif

111 #include "close_code.h"

113 #endif /* _SDL_test_random_h */

115 /* vi: set ts=4 sw=4 expandtab: */