summaryrefslogtreecommitdiffstats
path: root/libtommath/bn_mp_fread.c
diff options
context:
space:
mode:
authorKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
committerKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
commitb9cf65a08e6a59e434685e894e3189c201ac6791 (patch)
tree1f0868ef44c9f17d83d10dc94343df7b8cfe1842 /libtommath/bn_mp_fread.c
parentc6a259aeeca4814a97cf6694814c63e74e4e18fa (diff)
downloadtcl-b9cf65a08e6a59e434685e894e3189c201ac6791.zip
tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.gz
tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.bz2
Import of libtommath 0.33
Diffstat (limited to 'libtommath/bn_mp_fread.c')
-rw-r--r--libtommath/bn_mp_fread.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/libtommath/bn_mp_fread.c b/libtommath/bn_mp_fread.c
new file mode 100644
index 0000000..293df3f
--- /dev/null
+++ b/libtommath/bn_mp_fread.c
@@ -0,0 +1,63 @@
+#include <tommath.h>
+#ifdef BN_MP_FREAD_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 a bigint from a file stream in ASCII */
+int mp_fread(mp_int *a, int radix, FILE *stream)
+{
+ int err, ch, neg, y;
+
+ /* clear a */
+ mp_zero(a);
+
+ /* if first digit is - then set negative */
+ ch = fgetc(stream);
+ if (ch == '-') {
+ neg = MP_NEG;
+ ch = fgetc(stream);
+ } else {
+ neg = MP_ZPOS;
+ }
+
+ for (;;) {
+ /* find y in the radix map */
+ for (y = 0; y < radix; y++) {
+ if (mp_s_rmap[y] == ch) {
+ break;
+ }
+ }
+ if (y == radix) {
+ break;
+ }
+
+ /* shift up and add */
+ if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
+ return err;
+ }
+ if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
+ return err;
+ }
+
+ ch = fgetc(stream);
+ }
+ if (mp_cmp_d(a, 0) != MP_EQ) {
+ a->sign = neg;
+ }
+
+ return MP_OKAY;
+}
+
+#endif