git.distorted.org.uk Git - u/mdw/catacomb/blob - math/gfn.h

   1 /* -*-c-*-
   2  *
   3  * Normal-basis translation for binary fields
   4  *
   5  * (c) 2004 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_GFN_H
  29 #define CATACOMB_GFN_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include "gf.h"
  38
  39 /*----- Data structures ---------------------------------------------------*/
  40
  41 typedef struct gfn {
  42   size_t n;                             /* Number of rows */
  43   mp **r;                               /* Array of the rows */
  44 } gfn;
  45
  46 /*----- Functions provided ------------------------------------------------*/
  47
  48 /* --- @gfn_copy@ --- *
  49  *
  50  * Arguments:   @gfn *d@ = where to put the copy
  51  *              @const gfn *s@ = where the source is
  52  *
  53  * Returns:     ---
  54  *
  55  * Use:         Makes a copy of a translation matrix.
  56  */
  57
  58 extern void gfn_copy(gfn */*d*/, const gfn */*s*/);
  59
  60 /* --- @gfn_destroy@ --- *
  61  *
  62  * Arguments:   @gfn *m@ = a transformation matrix to free
  63  *
  64  * Returns:     ---
  65  *
  66  * Use:         Frees up a transformation matrix when it's no longer wanted.
  67  */
  68
  69 extern void gfn_destroy(gfn */*m*/);
  70
  71 /* --- @gfn_identity@ --- *
  72  *
  73  * Arguments:   @gfn *m@ = where to put the matrix
  74  *              @size_t n@ = size of the matrix
  75  *
  76  * Returns:     ---
  77  *
  78  * Use:         Fills @m@ with an identity matrix.
  79  */
  80
  81 extern void gfn_identity(gfn */*m*/, size_t /*n*/);
  82
  83 /* --- @gfn_invert@ --- *
  84  *
  85  * Arguments:   @gfn *m@ = a transformation matrix
  86  *
  87  * Returns:     Zero if successful, nonzero if the matrix was singular.
  88  *
  89  * Use:         Inverts a transformation matrix.
  90  */
  91
  92 extern int gfn_invert(gfn */*m*/);
  93
  94 /* --- @gfn_transform@ --- *
  95  *
  96  * Arguments:   @gfn *m@ = conversion matrix to apply
  97  *              @mp *d@ = destination pointer
  98  *              @mp *x@ = input value
  99  *
 100  * Returns:     The transformed element.
 101  *
 102  * Use:         Transforms a field element according to the given matrix.
 103  */
 104
 105 extern mp *gfn_transform(gfn */*m*/, mp */*d*/, mp */*x*/);
 106
 107 /* --- @gfn_create@ --- *
 108  *
 109  * Arguments:   @mp *p@ = modulus for polynomial basis
 110  *              @mp *beta@ = the generator of the normal basis, expressed
 111  *                      relative to the polynomial basis
 112  *              @gfn *ntop@ = output normal-to-polynomail conversion matrix
 113  *              @gfn *pton@ = output polynomial-to-normal conversion matrix
 114  *
 115  * Returns:     Zero if it worked, nonzero otherwise (e.g., if %$\beta$%
 116  *              doesn't generate a proper basis).
 117  *
 118  * Use:         Constructs conversion matrices between polynomial and normal
 119  *              basis representations of binary field elements.
 120  */
 121
 122 extern int gfn_create(mp */*p*/, mp */*beta*/, gfn */*ntop*/, gfn */*pton*/);
 123
 124 /*----- That's all, folks -------------------------------------------------*/
 125
 126 #ifdef __cplusplus
 127   }
 128 #endif
 129
 130 #endif