git.distorted.org.uk Git - u/mdw/catacomb/blob - rand/grand.h

   1 /* -*-c-*-
   2  *
   3  * Generic interface to random number generators
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef CATACOMB_GRAND_H
  29 #define CATACOMB_GRAND_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <assert.h>
  38 #include <stddef.h>
  39
  40 #include <mLib/bits.h>
  41
  42 /*----- Generic random number generator interface -------------------------*/
  43
  44 typedef struct grand {
  45   const struct grand_ops *ops;
  46 } grand;
  47
  48 typedef struct grand_ops {
  49
  50   /* --- Various important properties --- */
  51
  52   const char *name;                     /* Generator's name */
  53   unsigned f;                           /* Various flags */
  54   uint32 max;                           /* Maximum raw output */
  55
  56   /* --- Maintenance methods --- */
  57
  58   int (*misc)(grand */*r*/, unsigned /*op*/, ...); /* Miscellaneous ops */
  59   void (*destroy)(grand */*r*/);        /* Destroy generator context */
  60
  61   /* --- Output methods --- *
  62    *
  63    * Only one of these operations need actually be implemented.  All the
  64    * other operations may be synthesized.  Of course, performance is improved
  65    * if more are provided.
  66    */
  67
  68   uint32 (*raw)(grand */*r*/);          /* Uniform over %$[0, max)$% */
  69   octet (*byte)(grand */*r*/);          /* Uniform over %$[0, 256)$% */
  70   uint32 (*word)(grand */*r*/);         /* Uniform over %$[0, 2^{32})$% */
  71   uint32 (*range)(grand */*r*/, uint32 /*l*/); /* Uniform over %$[0, l)$% */
  72   void (*fill)(grand */*r*/, void */*p*/, size_t /*sz*/); /* Fill buffer */
  73 } grand_ops;
  74
  75 #define GR_DESTROY(r)           (r)->ops->destroy((r))
  76 #define GR_RAW(r)               (r)->ops->raw((r))
  77 #define GR_WORD(r)              (r)->ops->word((r))
  78 #define GR_RANGE(r, l)          (r)->ops->range((r), (l))
  79 #define GR_FILL(r, p, sz)       (r)->ops->fill((r), (p), (sz))
  80
  81 /* --- Flag types --- */
  82
  83 #define GRAND_CRYPTO 1u                 /* Cryptographically strong */
  84
  85 /* --- Operation types --- */
  86
  87 enum {
  88
  89   /* --- Required operations --- */
  90
  91   GRAND_CHECK,                          /* @unsigned op2@ */
  92
  93   /* --- Standard seeding operations --- */
  94
  95   GRAND_SEEDINT,                        /* @int i@ */
  96   GRAND_SEEDUINT32,                     /* @uint32 i@ */
  97   GRAND_SEEDBLOCK,                      /* @const void *p, size_t sz@ */
  98   GRAND_SEEDMP,                         /* @mp *m@ */
  99   GRAND_SEEDRAND                        /* @grand *g@ */
 100
 101   /* --- Generator-specific operations --- */
 102
 103 #define GRAND_SPECIFIC(ch) ((unsigned)(ch) << 8)
 104 };
 105
 106 #define GRAND_BADOP assert(((void)"bad grand_misc op", 0))
 107
 108 /*----- Functions provided ------------------------------------------------*/
 109
 110 /* --- @grand_byte@ --- *
 111  *
 112  * Arguments:   @grand *r@ = pointet to generic generator
 113  *
 114  * Returns:     A uniformly-distributed pseudorandom integer in the interval
 115  *              %$[0, 256)$%.
 116  */
 117
 118 extern octet grand_byte(grand */*r*/);
 119
 120 /* --- @grand_word@ --- *
 121  *
 122  * Arguments:   @grand *r@ = pointet to generic generator
 123  *
 124  * Returns:     A uniformly-distributed pseudorandom integer in the interval
 125  *              %$[0, 2^{32})$%.
 126  */
 127
 128 extern uint32 grand_word(grand */*r*/);
 129
 130 /* --- @grand_range@ --- *
 131  *
 132  * Arguments:   @grand *r@ = pointet to generic generator
 133  *              @uint32 l@ = limit for acceptable results
 134  *
 135  * Returns:     A uniformly-distributed pseudorandom integer in the interval
 136  *              %$[0, l)$%.
 137  */
 138
 139 extern uint32 grand_range(grand */*r*/, uint32 /*l*/);
 140
 141 /* --- @grand_fill@ --- *
 142  *
 143  * Arguments:   @grand *r@ = pointet to generic generator
 144  *              @void *p@ = pointer to a buffer
 145  *              @size_t sz@ = size of the buffer
 146  *
 147  * Returns:     ---
 148  *
 149  * Use:         Fills a buffer with uniformly distributed pseudorandom bytes
 150  *              (see @grand_byte@).
 151  */
 152
 153 extern void grand_fill(grand */*r*/, void */*p*/, size_t /*sz*/);
 154
 155 /*----- That's all, folks -------------------------------------------------*/
 156
 157 #ifdef __cplusplus
 158   }
 159 #endif
 160
 161 #endif