X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/5233862aa438102e71474baa9eec7f6e3d6a2c36..b0ab12e6a6cb035df2b6312df7ad1736af0a6128:/field.h

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+/* -*-c-*-
+ *
+ * $Id: field.h,v 1.1 2001/04/29 18:12:33 mdw Exp $
+ *
+ * Definitions for field arithmetic
+ *
+ * (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.
+ */
+
+/*----- Revision history --------------------------------------------------* 
+ *
+ * $Log: field.h,v $
+ * Revision 1.1  2001/04/29 18:12:33  mdw
+ * Prototype version.
+ *
+ */
+
+#ifndef CATACOMB_FIELD_H
+#define CATACOMB_FIELD_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#ifndef CATACOMB_MP_H
+#  include "mp.h"
+#endif
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct field {
+  const struct field_ops *ops;		/* Field operations */
+  mp *zero, *one;			/* Identities in the field */
+} field;
+
+typedef struct field_ops {
+
+  /* --- Universal operations --- */
+
+  void (*destroy)(field */*f*/);
+
+  mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
+  mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
+
+  mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+  mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+  mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+  mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
+  mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
+  mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
+
+  /* --- Operations for prime fields only --- */
+
+  mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
+  mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
+  mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
+
+} field_ops;
+
+#define F_DESTROY(f)		(f)->ops->destroy((f))
+
+#define F_IN(f, d, x)		(f)->ops->in((f), (d), (x))
+#define F_OUT(f, d, x)		(f)->ops->out((f), (d), (x))
+#define F_ADD(f, d, x, y)	(f)->ops->add((f), (d), (x), (y))
+#define F_SUB(f, d, x, y)	(f)->ops->sub((f), (d), (x), (y))
+#define F_MUL(f, d, x, y)	(f)->ops->mul((f), (d), (x), (y))
+#define F_SQR(f, d, x)		(f)->ops->sqr((f), (d), (x))
+#define F_INV(f, d, x)		(f)->ops->inv((f), (d), (x))
+#define F_REDUCE(f, d, x)	(f)->ops->reduce((f), (d), (x))
+
+#define F_DBL(f, d, x)		(f)->ops->dbl((f), (d), (x))
+#define F_TPL(f, d, x)		(f)->ops->tpl((f), (d), (x))
+#define F_SQRT(f, d, x)		(f)->ops->sqrt((f), (d), (x))
+
+/*----- Creating fields ---------------------------------------------------*/
+
+/* --- @field_prime@ --- *
+ *
+ * Arguments:	@mp *p@ = the characteristic of the field
+ *
+ * Returns:	A pointer to the field.
+ *
+ * Use:		Creates a field structure for a prime field of size %$p$%,
+ *		using Montgomery reduction for arithmetic.
+ */
+
+extern field *field_prime(mp */*p*/);
+
+/* --- @field_binpoly@ --- *
+ *
+ * Arguments:	@mp *p@ = an irreducible polynomial over %$\gf{2}$%
+ *
+ * Returns:	A pointer to the field.
+ *
+ * Use:		Creates a field structure for a binary field using naive
+ *		arithmetic.
+ */
+
+extern field *field_binpoly(mp */*p*/);
+
+/* --- @field_binsparsepoly@ --- *
+ *
+ * Arguments:	@unsigned deg@ = the degree of the field polynomial
+ *		@const unsigned *c@ = degrees of nonzero coefficients
+ *
+ * Returns:	A pointer to the field.
+ *
+ * Use:		Creates a field structure for a binary field taking advantage
+ *		of the sparseness of the given polynomial to improve
+ *		reduction performance.
+ */
+
+extern field *field_binsparsepoly(unsigned /*deg*/, const unsigned */*c*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif