aboutsummaryrefslogtreecommitdiff
path: root/src/z_random.c
blob: 9a4bb9eff46c78864dead4965c0482c72f03dc43 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143

/* 1008:forum::für::umläute:2001 */

/*
  urn :  "generate random numbers without duplicates"
  very max-like
*/

#include "zexy.h"

/* ------------------------- urn ------------------------------- */

static t_class *urn_class;

typedef struct _urn
{
  t_object x_obj;
  unsigned int x_seed;       /* the seed of the generator */

  unsigned int x_range;      /* max. random-number + 1 */
  unsigned int x_count;      /* how many random numbers have we generated ? */
  char  *x_state;            /* has this number been generated already ? */

  t_outlet *x_floatout, *x_bangout;
  char x_noauto;
} t_urn;

static int makeseed(void)
{
  static unsigned int random_nextseed = 1489853723;
  random_nextseed = random_nextseed * 435898247 + 938284287;
  return (random_nextseed & 0x7fffffff);
}

static void makestate(t_urn *x, unsigned int newrange)
{
  if (x->x_range == newrange)return;

  if (x->x_range && x->x_state) {
    freebytes(x->x_state, sizeof(char)*x->x_range);
    x->x_state=0;
  }

  x->x_range=newrange;
  x->x_state=getbytes(sizeof(char)*x->x_range);
}

static void urn_clear(t_urn *x)
{
  unsigned int i=x->x_range;
  char *dummy=x->x_state;
  if (!dummy || !i)return;
  while(i--)*dummy++=0;
  x->x_count=0;
}
static void urn_bang(t_urn *x)
{
  int range = (x->x_range<1?1:x->x_range);
  unsigned int randval = x->x_seed;

  int nval, used=1;

  if (x->x_count>=range){
    outlet_bang(x->x_bangout);
    if (x->x_noauto)return;
    urn_clear(x);
  }

  while (used) {
    randval = randval * 472940017 + 832416023;
    nval = ((double)range) * ((double)randval)
    	* (1./4294967296.);
    if (nval >= range) nval = range-1;
    used=x->x_state[nval];
  }

  x->x_count++;
  x->x_state[nval]=1;
  x->x_seed = randval;
  outlet_float(x->x_floatout, nval);
}

static void urn_flt2(t_urn *x, t_float f)
{
  unsigned int range = (f<1)?1:f;
  makestate(x, range);
  urn_clear(x);
}


static void urn_seed(t_urn *x, t_float f)
{
  x->x_seed = f;
}

static void *urn_new(t_symbol *s, int argc, t_atom *argv)
{
  t_urn *x = (t_urn *)pd_new(urn_class);

  t_float f=0.;

  inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("float"), gensym(""));
  x->x_floatout=outlet_new(&x->x_obj, &s_float);
  x->x_bangout =outlet_new(&x->x_obj, &s_bang);

  x->x_seed = makeseed();
  x->x_noauto = 0;

  while(argc--){
    if (argv->a_type==A_SYMBOL) {
      if (atom_getsymbol(argv)==gensym("no_auto")) {
	x->x_noauto=1;
      }
    } else f = atom_getfloat(argv);
    argv++;
  }

  if (f<1.0)f=1.0;
  makestate(x, f);
  x->x_range = f;
  urn_clear(x);

  return (x);
}

static void urn_setup(void)
{
  urn_class = class_new(gensym("urn"), (t_newmethod)urn_new, 
			      0, sizeof(t_urn), 0, A_GIMME,  0);
  
  class_addbang (urn_class, urn_bang);
  class_addmethod(urn_class, (t_method)urn_clear, gensym("clear"), 0);
  class_addmethod(urn_class, (t_method)urn_flt2, gensym(""), A_DEFFLOAT, 0);
  class_addmethod(urn_class, (t_method)urn_seed, gensym("seed"), A_DEFFLOAT, 0);
  

  class_sethelpsymbol(urn_class, gensym("zexy/urn"));
}

void z_random_setup(void)
{
  urn_setup();
}