diff options
Diffstat (limited to 'src/libmp/port/mprand.c')
-rw-r--r-- | src/libmp/port/mprand.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/libmp/port/mprand.c b/src/libmp/port/mprand.c new file mode 100644 index 00000000..fd288f24 --- /dev/null +++ b/src/libmp/port/mprand.c @@ -0,0 +1,42 @@ +#include "os.h" +#include <mp.h> +#include <libsec.h> +#include "dat.h" + +mpint* +mprand(int bits, void (*gen)(uchar*, int), mpint *b) +{ + int n, m; + mpdigit mask; + uchar *p; + + n = DIGITS(bits); + if(b == nil) + b = mpnew(bits); + else + mpbits(b, bits); + + p = malloc(n*Dbytes); + if(p == nil) + return nil; + (*gen)(p, n*Dbytes); + betomp(p, n*Dbytes, b); + free(p); + + // make sure we don't give too many bits + m = bits%Dbits; + n--; + if(m > 0){ + mask = 1; + mask <<= m; + mask--; + b->p[n] &= mask; + } + + for(; n >= 0; n--) + if(b->p[n] != 0) + break; + b->top = n+1; + b->sign = 1; + return b; +} |