X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/math/gfn.h

diff --git a/math/gfn.h b/math/gfn.h
new file mode 100644
index 0000000..11ecb44
--- /dev/null
+++ b/math/gfn.h
@@ -0,0 +1,130 @@
+/* -*-c-*-
+ *
+ * Normal-basis translation for binary fields
+ *
+ * (c) 2004 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_GFN_H
+#define CATACOMB_GFN_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "gf.h"
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct gfn {
+  size_t n;				/* Number of rows */
+  mp **r;				/* Array of the rows */
+} gfn;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @gfn_copy@ --- *
+ *
+ * Arguments:	@gfn *d@ = where to put the copy
+ *		@const gfn *s@ = where the source is
+ *
+ * Returns:	---
+ *
+ * Use:		Makes a copy of a translation matrix.
+ */
+
+extern void gfn_copy(gfn */*d*/, const gfn */*s*/);
+
+/* --- @gfn_destroy@ --- *
+ *
+ * Arguments:	@gfn *m@ = a transformation matrix to free
+ *
+ * Returns:	---
+ *
+ * Use:		Frees up a transformation matrix when it's no longer wanted.
+ */
+
+extern void gfn_destroy(gfn */*m*/);
+
+/* --- @gfn_identity@ --- *
+ *
+ * Arguments:	@gfn *m@ = where to put the matrix
+ *		@size_t n@ = size of the matrix
+ *
+ * Returns:	---
+ *
+ * Use:		Fills @m@ with an identity matrix.
+ */
+
+extern void gfn_identity(gfn */*m*/, size_t /*n*/);
+
+/* --- @gfn_invert@ --- *
+ *
+ * Arguments:	@gfn *m@ = a transformation matrix
+ *
+ * Returns:	Zero if successful, nonzero if the matrix was singular.
+ *
+ * Use:		Inverts a transformation matrix.
+ */
+
+extern int gfn_invert(gfn */*m*/);
+
+/* --- @gfn_transform@ --- *
+ *
+ * Arguments:	@gfn *m@ = conversion matrix to apply
+ *		@mp *d@ = destination pointer
+ *		@mp *x@ = input value
+ *
+ * Returns:	The transformed element.
+ *
+ * Use:		Transforms a field element according to the given matrix.
+ */
+
+extern mp *gfn_transform(gfn */*m*/, mp */*d*/, mp */*x*/);
+
+/* --- @gfn_create@ --- *
+ *
+ * Arguments:	@mp *p@ = modulus for polynomial basis
+ *		@mp *beta@ = the generator of the normal basis, expressed
+ *			relative to the polynomial basis
+ *		@gfn *ntop@ = output normal-to-polynomail conversion matrix
+ *		@gfn *pton@ = output polynomial-to-normal conversion matrix
+ *
+ * Returns:	Zero if it worked, nonzero otherwise (e.g., if %$\beta$%
+ *		doesn't generate a proper basis).
+ *
+ * Use:		Constructs conversion matrices between polynomial and normal
+ *		basis representations of binary field elements.
+ */
+
+extern int gfn_create(mp */*p*/, mp */*beta*/, gfn */*ntop*/, gfn */*pton*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif