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#include <stdlib.h>
static randbuf rand48buf;
#define A_0 0xE66D
#define A_1 0xDEEC
#define A_2 0x5
#define C 0xB
static randbuf a = { A_0, A_1, A_2 };
static unsigned short c = C;
static void calc_next(randbuf buf) {
randbuf tmp;
long t;
t = buf[0] * a[0] + c;
tmp[0] = t & 0xffff;
tmp[1] = (t >> 16) & 0xffff;
t = buf[1] * a[0] + buf[0] * a[1] + tmp[1];
tmp[1] = t & 0xffff;
tmp[2] = (t >> 16) & 0xffff;
t = buf[2] * a[0] + buf[1] * a[1] + buf[0] * a[2] + tmp[2];
tmp[2] = t & 0xffff;
buf[0] = tmp[0];
buf[1] = tmp[1];
buf[2] = tmp[2];
}
double drand48(void) {
return erand48(rand48buf);
}
long lrand48(void) {
return nrand48(rand48buf);
}
long mrand48(void) {
return jrand48(rand48buf);
}
void srand48(long seed) {
rand48buf[1] = (seed >> 16) & 0xffff;
rand48buf[2] = seed & 0xffff;
rand48buf[0] = 0x330e;
a[0] = A_0;
a[1] = A_1;
a[2] = A_2;
c = C;
}
unsigned short *seed48(randbuf buf) {
static randbuf oldx;
int i;
for (i = 0; i < 3; i++) {
oldx[i] = rand48buf[i];
rand48buf[i] = buf[i];
}
a[0] = A_0;
a[1] = A_1;
a[2] = A_2;
c = C;
return (unsigned short *)&oldx;
}
void lcong48(unsigned short param[7]) {
int i;
for (i = 0; i < 3; i++) {
rand48buf[i] = param[i];
a[i] = param[i + 3];
}
c = param[6];
}
long jrand48(randbuf buf) {
long ret;
ret = buf[2] << 16 | buf[1];
calc_next(buf);
return ret;
}
long nrand48(randbuf buf) {
return jrand48(buf) & 0x7FFFFFFFL;
}
double erand48(randbuf buf) {
double ret;
ret = ((buf[0] / 65536.0 + buf[1]) / 65536.0 + buf[2]) / 65536.0;
calc_next(buf);
return ret;
}
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