Add cyclic group abstraction, with test code. Separate off exponentation

[u/mdw/catacomb] / field.c

diff --git a/field.c b/field.c
index c7e7559..f0968dd 100644 (file)
--- a/field.c
+++ b/field.c
@@ -1,8 +1,9 @@
 /* -*-c-*-
  *
- * $Id: field.c,v 1.1 2001/05/07 17:30:13 mdw Exp $
+ * $Id: field.c,v 1.3 2004/04/01 12:50:09 mdw Exp $
+ *
+ * Abstract field operations
  *
- * [Abstract field operations *
  * (c) 2001 Straylight/Edgeware
  */
 
@@ -29,6 +30,19 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: field.c,v $
+ * Revision 1.3  2004/04/01 12:50:09  mdw
+ * Add cyclic group abstraction, with test code.  Separate off exponentation
+ * functions for better static linking.  Fix a buttload of bugs on the way.
+ * Generally ensure that negative exponents do inversion correctly.  Add
+ * table of standard prime-field subgroups.  (Binary field subgroups are
+ * currently unimplemented but easy to add if anyone ever finds a good one.)
+ *
+ * Revision 1.2  2004/03/21 22:52:06  mdw
+ * Merge and close elliptic curve branch.
+ *
+ * Revision 1.1.4.1  2003/06/10 13:43:53  mdw
+ * Simple (non-projective) curves over prime fields now seem to work.
+ *
  * Revision 1.1  2001/05/07 17:30:13  mdw
  * Add an internal-representation no-op function.
  *
@@ -60,4 +74,35 @@ mp *field_id(field *f, mp *d, mp *x)
   return (x);
 }
 
+/* --- @field_samep@ --- *
+ *
+ * Arguments:  @field *f, *g@ = two fields
+ *
+ * Returns:    Nonzero if the fields are identical (not just isomorphic).
+ *
+ * Use:                Checks for sameness of fields.  This function does the full
+ *             check, not just the field-type-specific check done by the
+ *             @sampep@ field operation.
+ */
+
+int field_samep(field *f, field *g)
+{
+  return (f->ops == g->ops && F_SAMEP(f, g));
+}
+
+/* --- @field_stdsamep@ --- *
+ *
+ * Arguments:  @field *f, *g@ = two fields
+ *
+ * Returns:    Nonzero if the fields are identical (not just isomorphic).
+ *
+ * Use:                Standard sameness check, based on equality of the @m@
+ *             member.
+ */
+
+int field_stdsamep(field *f, field *g)
+{
+  return (MP_EQ(f->m, g->m));
+}
+
 /*----- That's all, folks -------------------------------------------------*/