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authorMatt Johnston <matt@ucc.asn.au>2006-06-10 16:39:40 +0000
committerMatt Johnston <matt@ucc.asn.au>2006-06-10 16:39:40 +0000
commitc9d3c0bc90f21886e0b78595c53e748256e299bf (patch)
tree0bb2d3bf2f98dae918f07727f55a36d0a637b9f5 /libtommath/bn_mp_fread.c
parent94d86427ff20ed544e299d3a2de5ecc2cc04c191 (diff)
parent3b0e6a29698c8580b9556332e678e5301e697959 (diff)
merge of 332f709a4cb39cde4cedab7c3be89e05f3023067
and ca4ca78b82c5d430c69ce01bf794e8886ce81431 --HG-- extra : convert_revision : 74020525425a1de06739c6c3bed9ef35e4ad867e
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
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+++ b/libtommath/bn_mp_fread.c
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+#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