fix build of rijndael lib

[xonotic/d0_blind_id.git] / d0_bignum-gmp.c

diff --git a/d0_bignum-gmp.c b/d0_bignum-gmp.c
index 26414498c6342d6abe68211d9808f82006e0de0c..6a2f703e2d69796903fd198d95e2de6f25bfd05e 100644 (file)
--- 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
 {
@@ -96,6 +98,54 @@ d0_bignum_t *d0_iobuf_read_bignum(d0_iobuf_t *buf, d0_bignum_t *bignum)
        return bignum;
 }
 
+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));