From 496df00f3bb616fdae35ed08cea0b5cd20bc77ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Tue, 18 Oct 2005 20:58:26 +0200
Subject: [PATCH] (nettle_mpz_from_octets): Removed sign argument. If
mpz_import is available, define nettle_mpz_from_octets as a macro calling
mpz_import. (nettle_mpz_from_octets): Start by setting x to zero; callers no
longer need to do that. (nettle_mpz_set_str_256_s): New logic for the
handling of negative numbers. Convert in the same way as for positive
numbers, and then subtract the appropriate power of two.
Rev: src/nettle/bignum.c:1.9
---
bignum.c | 42 ++++++++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 16 deletions(-)
diff --git a/bignum.c b/bignum.c
index a4cb99a3..04a7920d 100644
--- a/bignum.c
+++ b/bignum.c
@@ -131,54 +131,64 @@ nettle_mpz_get_str_256(unsigned length, uint8_t *s, const mpz_t x)
}
/* Converting from strings */
+
+#ifdef mpz_import
+/* Was introduced in GMP-4.1 */
+# define nettle_mpz_from_octets(x, length, s) \
+ mpz_import((x), (length), 1, 1, 0, 0, (s))
+#else
static void
nettle_mpz_from_octets(mpz_t x,
- unsigned length, const uint8_t *s,
- uint8_t sign)
+ unsigned length, const uint8_t *s)
{
unsigned i;
- /* FIXME: See if we can use something like
- mpz_import(x, length, 1, 1, 0, 0, s). */
+ mpz_set_ui(x, 0);
+
for (i = 0; i < length; i++)
{
mpz_mul_2exp(x, x, 8);
- mpz_add_ui(x, x, sign ^ s[i]);
+ mpz_add_ui(x, x, s[i]);
}
}
+#endif
void
nettle_mpz_set_str_256_u(mpz_t x,
unsigned length, const uint8_t *s)
{
- mpz_set_ui(x, 0);
- nettle_mpz_from_octets(x, length, s, 0);
+ nettle_mpz_from_octets(x, length, s);
}
void
nettle_mpz_init_set_str_256_u(mpz_t x,
unsigned length, const uint8_t *s)
{
- mpz_init_set_ui(x, 0);
- nettle_mpz_from_octets(x, length, s, 0);
+ mpz_init(x);
+ nettle_mpz_from_octets(x, length, s);
}
void
nettle_mpz_set_str_256_s(mpz_t x,
unsigned length, const uint8_t *s)
{
- mpz_set_ui(x, 0);
-
if (!length)
- return;
+ {
+ mpz_set_ui(x, 0);
+ return;
+ }
+ nettle_mpz_from_octets(x, length, s);
+
if (s[0] & 0x80)
{
- nettle_mpz_from_octets(x, length, s, 0xff);
- mpz_com(x, x);
+ mpz_t t;
+
+ mpz_init_set_ui(t, 1);
+ mpz_mul_2exp(t, t, length*8);
+ mpz_sub(x, x, t);
+ mpz_clear(t);
}
- else
- nettle_mpz_from_octets(x, length, s, 0);
}
void
--
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