Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libsum/sum-prng.c
1808 views
1
/***********************************************************************

2
*                                                                      *

3
*               This software is part of the ast package               *

4
*          Copyright (c) 1996-2011 AT&T Intellectual Property          *

5
*                      and is licensed under the                       *

6
*                 Eclipse Public License, Version 1.0                  *

7
*                    by AT&T Intellectual Property                     *

8
*                                                                      *

9
*                A copy of the License is available at                 *

10
*          http://www.eclipse.org/org/documents/epl-v10.html           *

11
*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

12
*                                                                      *

13
*              Information and Software Systems Research               *

14
*                            AT&T Research                             *

15
*                           Florham Park NJ                            *

16
*                                                                      *

17
*                 Glenn Fowler <[email protected]>                  *

18
*                                                                      *

19
***********************************************************************/

20
#pragma prototyped

21


22
/*

23
 * prng

24
 */

25


26
#include <fnv.h>

27


28
#define prng_description \

29
	"32 bit PRNG (pseudo random number generator) hash."

30
#define prng_options	"\

31
[+mpy?The 32 bit PRNG multiplier.]:[number:=0x01000193]\

32
[+add?The 32 bit PRNG addend.]:[number:=0]\

33
[+init?The PRNG initial value. 0xffffffff is used if \anumber\a is omitted.]:?[number:=0x811c9dc5]\

34
"

35
#define prng_match	"prng"

36
#define prng_done	long_done

37
#define prng_print	long_print

38
#define prng_data	long_data

39
#define prng_scale	0

40


41
typedef uint32_t Prngnum_t;

42


43
typedef struct Prng_s

44
{

45
	_SUM_PUBLIC_

46
	_SUM_PRIVATE_

47
	_INTEGRAL_PRIVATE_

48
	Prngnum_t		init;

49
	Prngnum_t		mpy;

50
	Prngnum_t		add;

51
} Prng_t;

52


53
static Sum_t*

54
prng_open(const Method_t* method, const char* name)

55
{

56
	register Prng_t*	sum;

57
	register const char*	s;

58
	register const char*	t;

59
	register const char*	v;

60
	register int		i;

61


62
	if (sum = newof(0, Prng_t, 1, 0))

63
	{

64
		sum->method = (Method_t*)method;

65
		sum->name = name;

66
	}

67
	s = name;

68
	while (*(t = s))

69
	{

70
		for (t = s, v = 0; *s && *s != '-'; s++)

71
			if (*s == '=' && !v)

72
				v = s;

73
		i = (v ? v : s) - t;

74
		if (isdigit(*t) || v && strneq(t, "mpy", i) && (t = v + 1))

75
			sum->mpy = strtoul(t, NiL, 0);

76
		else if (strneq(t, "add", i))

77
			sum->add = v ? strtoul(v + 1, NiL, 0) : ~sum->add;

78
		else if (strneq(t, "init", i))

79
			sum->init = v ? strtoul(v + 1, NiL, 0) : ~sum->init;

80
		if (*s == '-')

81
			s++;

82
	}

83
	if (!sum->mpy)

84
	{

85
		sum->mpy = FNV_MULT;

86
		if (!sum->init)

87
			sum->init = FNV_INIT;

88
	}

89
	return (Sum_t*)sum;

90
}

91


92
static int

93
prng_init(Sum_t* p)

94
{

95
	Prng_t*		sum = (Prng_t*)p;

96


97
	sum->sum = sum->init;

98
	return 0;

99
}

100


101
static int

102
prng_block(Sum_t* p, const void* s, size_t n)

103
{

104
	Prng_t*			sum = (Prng_t*)p;

105
	register Prngnum_t	c = sum->sum;

106
	register unsigned char*	b = (unsigned char*)s;

107
	register unsigned char*	e = b + n;

108


109
	while (b < e)

110
		c = c * sum->mpy + sum->add + *b++;

111
	sum->sum = c;

112
	return 0;

113
}

114


115