1 files changed, 51 insertions, 0 deletions
diff --git a/libtommath/bn_mp_read_unsigned_bin.c b/libtommath/bn_mp_read_unsigned_bin.c
new file mode 100644
index 0000000..caf5be0
--- /dev/null
+++ b/libtommath/bn_mp_read_unsigned_bin.c
@@ -0,0 +1,51 @@
+#include <tommath.h>
+#ifdef BN_MP_READ_UNSIGNED_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@gmail.com, http://math.libtomcrypt.com
+ */
+
+/* reads a unsigned char array, assumes the msb is stored first [big endian] */
+int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c)
+{
+  int     res;
+
+  /* make sure there are at least two digits */
+  if (a->alloc < 2) {
+     if ((res = mp_grow(a, 2)) != MP_OKAY) {
+        return res;
+     }
+  }
+
+  /* zero the int */
+  mp_zero (a);
+
+  /* read the bytes in */
+  while (c-- > 0) {
+    if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
+      return res;
+    }
+
+#ifndef MP_8BIT
+      a->dp[0] |= *b++;
+      a->used += 1;
+#else
+      a->dp[0] = (*b & MP_MASK);
+      a->dp[1] |= ((*b++ >> 7U) & 1);
+      a->used += 2;
+#endif
+  }
+  mp_clamp (a);
+  return MP_OKAY;
+}
+#endif