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#include <stdio.h>
#include <stdint.h> // for intptr_t
#include <stdlib.h>
#include <gmp.h>
#include "pbc_random.h"
#include "pbc_utils.h"
#include "pbc_memory.h"
void pbc_init_random(void);
// Must use pointer due to lack of gmp_randstate_ptr.
static gmp_randstate_t *get_rs(void) {
static int rs_is_ready;
static gmp_randstate_t rs;
if (!rs_is_ready) {
gmp_randinit_default(rs);
rs_is_ready = 1;
}
return &rs;
}
static void deterministic_mpz_random(mpz_t z, mpz_t limit, void *data) {
UNUSED_VAR (data);
mpz_urandomm(z, *get_rs(), limit);
}
static void file_mpz_random(mpz_t r, mpz_t limit, void *data) {
char *filename = (char *) data;
FILE *fp;
int n, bytecount, leftover;
unsigned char *bytes;
mpz_t z;
mpz_init(z);
fp = fopen(filename, "rb");
if (!fp) return;
n = mpz_sizeinbase(limit, 2);
bytecount = (n + 7) / 8;
leftover = n % 8;
bytes = (unsigned char *) pbc_malloc(bytecount);
for (;;) {
if (!fread(bytes, 1, bytecount, fp)) {
pbc_warn("error reading source of random bits");
return;
}
if (leftover) {
*bytes = *bytes % (1 << leftover);
}
mpz_import(z, bytecount, 1, 1, 0, 0, bytes);
if (mpz_cmp(z, limit) < 0) break;
}
fclose(fp);
mpz_set(r, z);
mpz_clear(z);
pbc_free(bytes);
}
static void (*current_mpz_random)(mpz_t, mpz_t, void *);
static void *current_random_data;
static int random_function_ready = 0;
void pbc_random_set_function(void (*fun)(mpz_t, mpz_t, void *), void *data) {
current_mpz_random = fun;
current_random_data = data;
random_function_ready = 1;
}
void pbc_mpz_random(mpz_t z, mpz_t limit) {
if (!random_function_ready) pbc_init_random();
current_mpz_random(z, limit, current_random_data);
}
void pbc_mpz_randomb(mpz_t z, unsigned int bits) {
mpz_t limit;
mpz_init(limit);
mpz_setbit(limit, bits);
pbc_mpz_random(z, limit);
mpz_clear(limit);
}
void pbc_random_set_deterministic(unsigned int seed) {
gmp_randseed_ui(*get_rs(), seed);
pbc_random_set_function(deterministic_mpz_random, NULL);
}
void pbc_random_set_file(char *filename) {
pbc_random_set_function(file_mpz_random, filename);
}
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