diff options
Diffstat (limited to 'src/zrand.c')
| -rw-r--r-- | src/zrand.c | 161 |
1 files changed, 133 insertions, 28 deletions
diff --git a/src/zrand.c b/src/zrand.c index 5945ad8..3d70452 100644 --- a/src/zrand.c +++ b/src/zrand.c @@ -2,6 +2,8 @@ #include "internals.h" #include <fcntl.h> +#include <stdlib.h> +#include <time.h> #include <unistd.h> #ifndef FAST_RANDOM_PATHNAME @@ -14,23 +16,110 @@ static void -zrand_get_random_bits(z_t r, size_t bits, int fd) +zrand_libc_rand(void *out, size_t n, void *statep) { - size_t read_total = 0, n, chars = CEILING_BITS_TO_CHARS(bits); - ssize_t read_just; - zahl_char_t mask = 1; - char *buf; + static char inited = 0; - ENSURE_SIZE(r, chars); - buf = (char *)(r->chars); + unsigned int ri; + double rd; + unsigned char *buf = out; + + if (!inited) { + inited = 1; + srand((intptr_t)out | time(NULL)); + } + + while (n--) { + ri = rand(); + rd = (double)ri / ((double)RAND_MAX + 1); +#ifdef GOOD_RAND + rd *= 256 * 256; + ri = (unsigned int)rd; + buf[n] = (unsigned char)((ri >> 0) & 255); + if (!n--) break; + buf[n] = (unsigned char)((ri >> 8) & 255); +#else + rd *= 256; + buf[n] = (unsigned char)rd; +#endif + } + + (void) statep; +} + +static void +zrand_libc_rand48(void *out, size_t n, void *statep) +{ + static char inited = 0; + + long int r0, r1; + unsigned char *buf = out; - for (n = chars * sizeof(zahl_char_t); n;) { + if (!inited) { + inited = 1; + srand48((intptr_t)out | time(NULL)); + } + + while (n--) { + r0 = lrand48() & 15; + r1 = lrand48() & 15; + buf[n] = (r0 << 4) | r1; + } + + (void) statep; +} + +static void +zrand_libc_random(void *out, size_t n, void *statep) +{ + static char inited = 0; + + long int ri; + unsigned char *buf = out; + + if (!inited) { + inited = 1; + srandom((intptr_t)out | time(NULL)); + } + + while (n--) { + ri = random(); + buf[n] = (unsigned char)((ri >> 0) & 255); + if (!n--) break; + buf[n] = (unsigned char)((ri >> 8) & 255); + if (!n--) break; + buf[n] = (unsigned char)((ri >> 16) & 255); + } + + (void) statep; +} + +static void +zrand_fd(void *out, size_t n, void *statep) +{ + int fd = *(int *)statep; + ssize_t read_just; + size_t read_total = 0; + char *buf = out; + + while (n) { read_just = read(fd, buf + read_total, n); if (unlikely(read_just < 0)) libzahl_failure(errno); read_total += (size_t)read_just; n -= (size_t)read_just; } +} + +static void +zrand_get_random_bits(z_t r, size_t bits, void (*fun)(void *, size_t, void *), void *statep) +{ + size_t n, chars = CEILING_BITS_TO_CHARS(bits); + zahl_char_t mask = 1; + + ENSURE_SIZE(r, chars); + + fun(r->chars, chars * sizeof(zahl_char_t), statep); bits = BITS_IN_LAST_CHAR(bits); mask <<= bits; @@ -50,19 +139,41 @@ zrand_get_random_bits(z_t r, size_t bits, int fd) void zrand(z_t r, enum zranddev dev, enum zranddist dist, z_t n) { +#define RANDOM_UNIFORM(RETRY)\ + do {\ + if (unlikely(znegative(n)))\ + libzahl_failure(-ZERROR_NEGATIVE);\ + bits = zbits(n);\ + do\ + zrand_get_random_bits(r, bits, random_fun, statep);\ + while (RETRY && unlikely(zcmpmag(r, n) > 0));\ + } while (0) + + const char *pathname = 0; size_t bits; - int fd; + int fd = -1; + void *statep = 0; + void (*random_fun)(void *, size_t, void *) = &zrand_fd; switch (dev) { - case DEFAULT_RANDOM: - case FASTEST_RANDOM: case FAST_RANDOM: pathname = FAST_RANDOM_PATHNAME; break; case SECURE_RANDOM: pathname = SECURE_RANDOM_PATHNAME; break; + case LIBC_RAND_RANDOM: + random_fun = &zrand_libc_rand; + break; + case DEFAULT_RANDOM: + case FASTEST_RANDOM: + case LIBC_RANDOM_RANDOM: + random_fun = &zrand_libc_random; + break; + case LIBC_RAND48_RANDOM: + random_fun = &zrand_libc_rand48; + break; default: libzahl_failure(EINVAL); } @@ -72,34 +183,27 @@ zrand(z_t r, enum zranddev dev, enum zranddist dist, z_t n) return; } - fd = open(pathname, O_RDONLY); - if (unlikely(fd < 0)) - libzahl_failure(errno); + if (pathname) { + fd = open(pathname, O_RDONLY); + if (unlikely(fd < 0)) + libzahl_failure(errno); + statep = &fd; + } switch (dist) { case QUASIUNIFORM: - if (unlikely(znegative(n))) - libzahl_failure(-ZERROR_NEGATIVE); - bits = zbits(n); - zrand_get_random_bits(r, bits, fd); + RANDOM_UNIFORM(0); zadd(r, r, libzahl_const_1); zmul(r, r, n); zrsh(r, r, bits); break; case UNIFORM: - if (unlikely(znegative(n))) - libzahl_failure(-ZERROR_NEGATIVE); - bits = zbits(n); - do - zrand_get_random_bits(r, bits, fd); - while (unlikely(zcmpmag(r, n) > 0)); + RANDOM_UNIFORM(1); break; case MODUNIFORM: - if (unlikely(znegative(n))) - libzahl_failure(-ZERROR_NEGATIVE); - zrand_get_random_bits(r, zbits(n), fd); + RANDOM_UNIFORM(0); if (unlikely(zcmpmag(r, n) > 0)) zsub(r, r, n); break; @@ -108,5 +212,6 @@ zrand(z_t r, enum zranddev dev, enum zranddist dist, z_t n) libzahl_failure(EINVAL); } - close(fd); + if (fd >= 0) + close(fd); } |