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[u/mdw/catacomb] / math / limlee.h

diff --git a/math/limlee.h b/math/limlee.h
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+/* -*-c-*-
+ *
+ * Generate Lim-Lee primes
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#ifndef CATACOMB_LIMLEE_H
+#define CATACOMB_LIMLEE_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#ifndef CATACOMB_GRAND_H
+#  include "grand.h"
+#endif
+
+#ifndef CATACOMB_MP_H
+#  include "mp.h"
+#endif
+
+#ifndef CATACOMB_PGEN_H
+#  include "pgen.h"
+#endif
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct limlee_factor {
+  mp *p;                               /* The actual prime */
+  unsigned tag;                                /* A tag, usable by the generator */
+  void *more;                          /* Pointer to more data */
+} limlee_factor;
+
+typedef struct limlee_stepctx {
+
+  /* --- To be initialized by the caller --- */
+
+  unsigned f;                          /* Various useful flags */
+  mp *newp;                            /* Initial valid for new primes */
+  unsigned ql, pl;                     /* Size of factors and result */
+  const struct limlee_primeops *pops;  /* Pointer to generator ops */
+  void *pc;                            /* Context ptr for generator ops */
+  pgen_proc *iev;                      /* Event handler for inner @pgen@ */
+  void *iec;                           /* Context for inner @pgen@ */
+  grand *r;                            /* Random number generator */
+
+  /* --- Output values --- */
+
+  size_t nf;                           /* Number of factors wanted */
+  limlee_factor *v;                    /* Vector of factors */
+
+  /* --- Maintained internally --- */
+
+  octet *c;                            /* Combination byte-flag vector */
+  unsigned long seq;                   /* Sequence number for primes */
+  size_t poolsz;                       /* Size of the small-prime pool */
+  dstr d;                              /* String for subprime name */
+  limlee_factor qq;                    /* Big prime to pick up slack */
+
+} limlee_stepctx;
+
+typedef struct limlee_primeops {
+  void (*pgen)(limlee_factor */*f*/, unsigned /*pl*/, limlee_stepctx */*l*/);
+  void (*pfree)(limlee_factor */*f*/, limlee_stepctx */*l*/);
+} limlee_primeops;
+
+/* --- Flags --- */
+
+#define LIMLEE_KEEPFACTORS 1u
+
+/*----- The Lim-Lee stepper function --------------------------------------*/
+
+extern pgen_proc limlee_step;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @limlee@ --- *
+ *
+ * Arguments:  @const char *name@ = pointer to name root
+ *             @mp *d@ = pointer to destination integer
+ *             @mp *newp@ = how to generate factor primes
+ *             @unsigned ql@ = size of individual factors
+ *             @unsigned pl@ = size of large prime
+ *             @grand *r@ = a random number source
+ *             @unsigned on@ = number of outer attempts to make
+ *             @pgen_proc *oev@ = outer event handler function
+ *             @void *oec@ = argument for the outer event handler
+ *             @pgen_proc *iev@ = inner event handler function
+ *             @void *iec@ = argument for the inner event handler
+ *             @size_t *nf@, @mp ***f@ = output array for factors
+ *
+ * Returns:    A Lim-Lee prime, or null if generation failed.
+ *
+ * Use:                Generates Lim-Lee primes.  A Lim-Lee prime %$p$% is one which
+ *             satisfies %$p = 2 \prod_i q_i + 1$%, where all of the %$q_i$%
+ *             are large enough to resist square-root discrete log
+ *             algorithms.
+ *
+ *             If we succeed, and @f@ is non-null, we write the array of
+ *             factors chosen to @f@ for the benefit of the caller.
+ */
+
+extern mp *limlee(const char */*name*/, mp */*d*/, mp */*newp*/,
+                 unsigned /*ql*/, unsigned /*pl*/, grand */*r*/,
+                 unsigned /*on*/, pgen_proc */*oev*/, void */*oec*/,
+                 pgen_proc */*iev*/, void */*iec*/,
+                 size_t */*nf*/, mp ***/*f*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif