X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/5ff5e6589e2b702516cb11c37e91ed69ad4eae8a..578a86d91941a0f722b87973d88e84ec2cf9a608:/buf.c

diff --git a/buf.c b/buf.c
index 5e0a069..3a09365 100644
--- a/buf.c
+++ b/buf.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: buf.c,v 1.2 2003/11/10 22:18:30 mdw Exp $
+ * $Id: buf.c,v 1.4 2004/04/08 01:36:15 mdw Exp $
  *
  * Buffer handling
  *
@@ -27,35 +27,12 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: buf.c,v $
- * Revision 1.2  2003/11/10 22:18:30  mdw
- * Build fixes.
- *
- * Revision 1.1  2003/10/11 21:02:33  mdw
- * Import buf stuff from tripe.
- *
- * Revision 1.4  2001/06/19 22:09:54  mdw
- * Expose interface, for use in the proxy.
- *
- * Revision 1.3  2001/03/03 12:06:48  mdw
- * Use 16-bit lengths on MPs, since there's a packet limit of 64K anyway.
- *
- * Revision 1.2  2001/02/16 21:23:20  mdw
- * Various minor changes.  Check that MPs are in canonical form when
- * loading.
- *
- * Revision 1.1  2001/02/03 20:26:37  mdw
- * Initial checkin.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <string.h>
 
 #include "mp.h"
+#include "ec.h"
 #include "buf.h"
 
 /*----- Main code ---------------------------------------------------------*/
@@ -280,11 +257,13 @@ int buf_putu32(buf *b, uint32 w)
 mp *buf_getmp(buf *b)
 {
   uint16 sz;
+  size_t n;
   mp *m;
   if (buf_getu16(b, &sz) || buf_ensure(b, sz))
     return (0);
   m = mp_loadb(MP_NEW, BCUR(b), sz);
-  if (mp_octets(m) != sz) {
+  n = mp_octets(m);
+  if (n != sz && n != 0 && sz != 1) {
     mp_drop(m);
     return (0);
   }
@@ -306,6 +285,7 @@ int buf_putmp(buf *b, mp *m)
 {
   size_t sz = mp_octets(m);
   assert(sz < MASK16);
+  if (!sz) sz = 1;
   if (buf_putu16(b, sz) || buf_ensure(b, sz))
     return (-1);
   mp_storeb(m, BCUR(b), sz);
@@ -313,4 +293,45 @@ int buf_putmp(buf *b, mp *m)
   return (0);
 }
 
+/* --- @buf_getec@ --- *
+ *
+ * Arguments:	@buf *b@ = pointer to a buffer block
+ *		@ec *p@ = where to put the point
+ *
+ * Returns:	Zero if it worked, nonzero if it failed.
+ *
+ * Use:		Gets a multiprecision integer from a buffer.  The point must
+ *		be initialized.
+ */
+
+int buf_getec(buf *b, ec *p)
+{
+  mp *x = 0, *y = 0;
+  uint16 n;
+  if (buf_ensure(b, 2)) return (-1);
+  n = LOAD16(BCUR(b)); if (!n) { BSTEP(b, 2); EC_SETINF(p); return (0); }
+  if ((x = buf_getmp(b)) == 0 || (y = buf_getmp(b)) == 0) {
+    mp_drop(x); mp_drop(y); return (-1);
+  }
+  EC_DESTROY(p); p->x = x; p->y = y; p->z = 0;
+  return (0);
+}
+
+/* --- @buf_putec@ --- *
+ *
+ * Arguments:	@buf *b@ = pointer to a buffer block
+ *		@ec *p@ = an elliptic curve point
+ *
+ * Returns:	Zero if it worked, nonzero if there wasn't enough space.
+ *
+ * Use:		Puts an elliptic curve point to a buffer.
+ */
+
+int buf_putec(buf *b, ec *p)
+{
+  if (EC_ATINF(p)) return (buf_putu16(b, 0));
+  if (buf_putmp(b, p->x) || buf_putmp(b, p->y)) return (-1);
+  return (0);
+}
+
 /*----- That's all, folks -------------------------------------------------*/