1 files changed, 73 insertions, 0 deletions
diff --git a/libtommath/bn_mp_import.c b/libtommath/bn_mp_import.c
new file mode 100644
index 0000000..ca2a5e9
--- /dev/null
+++ b/libtommath/bn_mp_import.c
@@ -0,0 +1,73 @@
+#include <tommath_private.h>
+#ifdef BN_MP_IMPORT_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, tstdenis82@gmail.com, http://libtom.org
+ */
+
+/* based on gmp's mpz_import.
+ * see http://gmplib.org/manual/Integer-Import-and-Export.html
+ */
+int mp_import(mp_int* rop, size_t count, int order, size_t size, 
+                            int endian, size_t nails, const void* op) {
+	int result;
+	size_t odd_nails, nail_bytes, i, j;
+	unsigned char odd_nail_mask;
+
+	mp_zero(rop);
+
+	if (endian == 0) {
+		union {
+			unsigned int i;
+			char c[4];
+		} lint;
+		lint.i = 0x01020304;
+
+		endian = (lint.c[0] == 4) ? -1 : 1;
+	}
+
+	odd_nails = (nails % 8);
+	odd_nail_mask = 0xff;
+	for (i = 0; i < odd_nails; ++i) {
+		odd_nail_mask ^= (1 << (7 - i));
+	}
+	nail_bytes = nails / 8;
+
+	for (i = 0; i < count; ++i) {
+		for (j = 0; j < (size - nail_bytes); ++j) {
+			unsigned char byte = *(
+					(unsigned char*)op + 
+					(((order == 1) ? i : ((count - 1) - i)) * size) +
+					((endian == 1) ? (j + nail_bytes) : (((size - 1) - j) - nail_bytes))
+				);
+
+			if (
+				(result = mp_mul_2d(rop, ((j == 0) ? (8 - odd_nails) : 8), rop)) != MP_OKAY) {
+				return result;
+			}
+
+			rop->dp[0] |= (j == 0) ? (byte & odd_nail_mask) : byte;
+			rop->used  += 1;
+		}
+	}
+
+	mp_clamp(rop);
+
+	return MP_OKAY;
+}
+
+#endif
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */