propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)

to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)

--HG--
extra : convert_revision : fdf4a7a3b97ae5046139915de7e40399cceb2c01

libtommath/bn_mp_read_signed_bin.c

@@ -0,0 +1,38 @@
+#include <tommath.h>
+#ifdef BN_MP_READ_SIGNED_BIN_C
+/* 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, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+
+/* 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;
+}
+#endif