Prime number generator and tester.

[u/mdw/catacomb] / pgen.h

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+/* -*-c-*-
+ *
+ * $Id: pgen.h,v 1.1 1999/11/19 13:17:57 mdw Exp $
+ *
+ * Finding and testing prime numbers
+ *
+ * (c) 1999 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.
+ */
+
+/*----- Revision history --------------------------------------------------* 
+ *
+ * $Log: pgen.h,v $
+ * Revision 1.1  1999/11/19 13:17:57  mdw
+ * Prime number generator and tester.
+ *
+ */
+
+#ifndef PGEN_H
+#define PGEN_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#ifndef MP_H
+#  include "mp.h"
+#endif
+
+#ifndef PTAB_H
+#  include "ptab.h"
+#endif
+
+/*----- Constants ---------------------------------------------------------*/
+
+#define PGEN_COMPOSITE (-1)            /* Number is definitely composite */
+#define PGEN_MAYBE (0)                 /* Number may be prime */
+#define PGEN_PRIME (1)                 /* Number is definitely prime */
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct pgen {
+  mp *m;
+  unsigned char r[NPRIME];
+} pgen;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @pgen_create@ --- *
+ *
+ * Arguments:  @pgen *p@ = pointer to prime generation context
+ *             @mp *m@ = pointer to initial number to test
+ *
+ * Returns:    One of the @PGEN@ constants above.
+ *
+ * Use:                Tests an initial number for primality by computing its
+ *             residue modulo various small prime numbers.  This is fairly
+ *             quick, but not particularly certain.  If a @PGEN_MAYBE@
+ *             result is returned, perform Rabin-Miller tests to confirm.
+ */
+
+extern int pgen_create(pgen */*p*/, mp */*m*/);
+
+/* --- @pgen_destroy@ --- *
+ *
+ * Arguments:  @pgen *p@ = pointer to prime generation context
+ *
+ * Returns:    ---
+ *
+ * Use:                Discards a context and all the resources it holds.
+ */
+
+extern void pgen_destroy(pgen */*p*/);
+
+/* --- @pgen_step@ --- *
+ *
+ * Arguments:  @pgen *p@ = pointer to prime generation context
+ *             @mpw step@ = how much to step the number
+ *
+ * Returns:    One of the @PGEN@ constants above.
+ *
+ * Use:                Steps a number by a small amount.  Stepping is much faster
+ *             than initializing with a new number.  The test performed is
+ *             the same simple one used by @ptab_create@, so @PGEN_MAYBE@
+ *             results should be followed up by a Rabin-Miller test.
+ */
+
+extern int pgen_step(pgen */*p*/, mpw /*step*/);
+
+/* --- @pgen_jump@ --- *
+ *
+ * Arguments:  @pgen *p@ = pointer to prime generation context
+ *             @pgen *j@ = pointer to another generation context
+ *
+ * Returns:    One of the @PGEN@ constants above.
+ *
+ * Use:                Steps a number by a large amount.  Even so, jumping is much
+ *             faster than initializing a new number.  The test peformed is
+ *             the same simple one used by @ptab_create@, so @PGEN_MAYBE@
+ *             results should be followed up by a Rabin-Miller test.
+ *
+ *             Note that the number stored in the @j@ context is probably
+ *             better off being even than prime.  The important thing is
+ *             that all of the residues for the number have already been
+ *             computed.
+ */
+
+extern int pgen_jump(pgen */*p*/, pgen */*j*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif