X-Git-Url: http://de.git.xonotic.org/?p=xonotic%2Fd0_blind_id.git;a=blobdiff_plain;f=d0_bignum-gmp.c;h=6a2f703e2d69796903fd198d95e2de6f25bfd05e;hp=a66096dff4b910835e52ae3b9ac1131030a7653f;hb=587bbd752e2037d8c1488a51d99c99f29a660f0d;hpb=698fe0ac106c840671df6668946135e7c8ef4963

diff --git a/d0_bignum-gmp.c b/d0_bignum-gmp.c
index a66096d..6a2f703 100644
--- a/d0_bignum-gmp.c
+++ b/d0_bignum-gmp.c
@@ -20,6 +20,8 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include "d0_bignum.h"
 
 #include <gmp.h>
+#include <string.h>
+#include <stdlib.h>
 
 struct d0_bignum_s
 {
@@ -31,13 +33,15 @@ static d0_bignum_t temp;
 
 #include <time.h>
 #include <stdio.h>
-void d0_bignum_INITIALIZE()
+void d0_bignum_INITIALIZE(void)
 {
 	FILE *f;
 	d0_bignum_init(&temp);
 	gmp_randinit_mt(RANDSTATE);
 	gmp_randseed_ui(RANDSTATE, time(NULL));
-	f = fopen("/dev/random", "rb");
+	f = fopen("/dev/urandom", "rb");
+	if(!f)
+		f = fopen("/dev/random", "rb");
 	if(f)
 	{
 		unsigned char buf[256];
@@ -51,7 +55,7 @@ void d0_bignum_INITIALIZE()
 	}
 }
 
-void d0_bignum_SHUTDOWN()
+void d0_bignum_SHUTDOWN(void)
 {
 	d0_bignum_clear(&temp);
 	gmp_randclear(RANDSTATE);
@@ -94,7 +98,55 @@ d0_bignum_t *d0_iobuf_read_bignum(d0_iobuf_t *buf, d0_bignum_t *bignum)
 	return bignum;
 }
 
-d0_bignum_t *d0_bignum_new()
+ssize_t d0_bignum_export_unsigned(const d0_bignum_t *bignum, void *buf, size_t bufsize)
+{
+	size_t count;
+	count = (mpz_sizeinbase(bignum->z, 2) + 7) / 8;
+	if(count > bufsize)
+		return -1;
+	if(bufsize > count)
+	{
+		// pad from left (big endian numbers!)
+		memset(buf, 0, bufsize - count);
+		buf += bufsize - count;
+	}
+	bufsize = count;
+	mpz_export(buf, &bufsize, 1, 1, 0, 0, bignum->z);
+	if(bufsize > count)
+	{
+		// REALLY BAD
+		// mpz_sizeinbase lied to us
+		// buffer overflow
+		// there is no sane way whatsoever to handle this
+		abort();
+	}
+	if(bufsize < count)
+	{
+		// BAD
+		// mpz_sizeinbase lied to us
+		// move the number
+		if(bufsize == 0)
+		{
+			memset(buf, 0, count);
+		}
+		else
+		{
+			memmove(buf + count - bufsize, buf, bufsize);
+			memset(buf, 0, count - bufsize);
+		}
+	}
+	return bufsize;
+}
+
+d0_bignum_t *d0_bignum_import_unsigned(d0_bignum_t *bignum, const void *buf, size_t bufsize)
+{
+	size_t count;
+	if(!bignum) bignum = d0_bignum_new(); if(!bignum) return NULL;
+	mpz_import(bignum->z, bufsize, 1, 1, 0, 0, buf);
+	return bignum;
+}
+
+d0_bignum_t *d0_bignum_new(void)
 {
 	d0_bignum_t *b = d0_malloc(sizeof(d0_bignum_t));
 	mpz_init(b->z);