diff bn_mp_read_signed_bin.c @ 1:22d5cf7d4b1a libtommath

Renaming branch
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:23:46 +0000
parents
children d29b64170cf0
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/bn_mp_read_signed_bin.c	Mon May 31 18:23:46 2004 +0000
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+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://math.libtomcrypt.org
+ */
+#include <tommath.h>
+
+/* read signed bin, big endian, first byte is 0==positive or 1==negative */
+int
+mp_read_signed_bin (mp_int * a, unsigned char *b, int c)
+{
+  int     res;
+
+  /* read magnitude */
+  if ((res = mp_read_unsigned_bin (a, b + 1, c - 1)) != MP_OKAY) {
+    return res;
+  }
+
+  /* first byte is 0 for positive, non-zero for negative */
+  if (b[0] == 0) {
+     a->sign = MP_ZPOS;
+  } else {
+     a->sign = MP_NEG;
+  }
+
+  return MP_OKAY;
+}