chibi-scheme/lib/srfi/27/rand.c

243 lines
8.6 KiB
C

/* rand.c -- rand_r/random_r interface */
/* Copyright (c) 2009-2014 Alex Shinn. All rights reserved. */
/* BSD-style license: http://synthcode.com/license.txt */
#include <time.h>
#include <chibi/eval.h>
#define SEXP_RANDOM_STATE_SIZE 128
#define ZERO sexp_make_fixnum(0)
#define ONE sexp_make_fixnum(1)
#define STATE_SIZE sexp_make_fixnum(SEXP_RANDOM_STATE_SIZE)
#define sexp_random_source_p(x) sexp_check_tag(x, rs_type_id)
#define sexp_random_state(x) (sexp_slot_ref((x), 0))
#define sexp_random_data(x) ((sexp_random_t*)(&sexp_slot_ref((x), 1)))
#define sexp_sizeof_random (sexp_sizeof_header + sizeof(sexp_random_t) + sizeof(sexp))
static sexp_uint_t rs_type_id = 0;
static sexp default_random_source;
#ifdef __GNU_LIBRARY__
typedef struct random_data sexp_random_t;
#define sexp_random_init(rs, seed) \
initstate_r(seed, \
sexp_bytes_data(sexp_random_state(rs)), \
SEXP_RANDOM_STATE_SIZE, \
sexp_random_data(rs))
#define sexp_call_random(rs, dst) random_r(sexp_random_data(rs), &dst)
#define sexp_seed_random(n, rs) srandom_r(n, sexp_random_data(rs))
#else
typedef unsigned int sexp_random_t;
#define sexp_random_init(rs, seed) *sexp_random_data(rs) = (seed)
#define sexp_call_random(rs, dst) ((dst) = rand_r(sexp_random_data(rs)))
#define sexp_seed_random(n, rs) *sexp_random_data(rs) = (n)
#endif
static sexp sexp_rs_random_integer (sexp ctx, sexp self, sexp_sint_t n, sexp rs, sexp bound) {
sexp res;
sexp_int32_t m;
#if SEXP_USE_BIGNUMS
sexp_uint_t mod;
sexp_uint32_t *data;
sexp_int32_t hi, len, i;
#endif
if (! sexp_random_source_p(rs))
res = sexp_type_exception(ctx, self, rs_type_id, rs);
if (sexp_fixnump(bound)) {
sexp_call_random(rs, m);
res = sexp_make_fixnum(m % sexp_unbox_fixnum(bound));
#if SEXP_USE_BIGNUMS
} else if (sexp_bignump(bound)) {
hi = sexp_bignum_hi(bound);
len = hi * (sizeof(sexp_uint_t) / sizeof(sexp_int32_t));
res = sexp_make_bignum(ctx, hi + 1);
data = (sexp_uint32_t*) sexp_bignum_data(res);
for (i=0; i<len; i++) {
sexp_call_random(rs, m);
data[i] = m;
}
/* Scan down, modding bigits > bound to < bound, and stop as */
/* soon as we are sure the result is within bound. */
for (i = hi-1; i >= 0; --i) {
mod = sexp_bignum_data(bound)[i];
if (mod) {
if (i > 0 && mod < SEXP_UINT_T_MAX) {
/* allow non-final bigits to be == */
++mod;
}
if (sexp_bignum_data(res)[i] >= mod)
sexp_bignum_data(res)[i] %= mod;
} else {
sexp_bignum_data(res)[i] = 0;
}
if (sexp_bignum_data(res)[i] < sexp_bignum_data(bound)[i]) {
break;
}
if (i == 0) {
/* handle the case where all bigits are == */
if (sexp_bignum_data(res)[i] > 0)
--sexp_bignum_data(res)[i];
else
res = sexp_sub(ctx, res, SEXP_ONE);
}
}
#endif
} else {
res = sexp_type_exception(ctx, self, SEXP_FIXNUM, bound);
}
return res;
}
static sexp sexp_random_integer (sexp ctx, sexp self, sexp_sint_t n, sexp bound) {
return sexp_rs_random_integer(ctx, self, n, default_random_source, bound);
}
static sexp sexp_rs_random_real (sexp ctx, sexp self, sexp_sint_t n, sexp rs) {
sexp_int32_t res;
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
sexp_call_random(rs, res);
return sexp_make_flonum(ctx, (double)res / (double)RAND_MAX);
}
static sexp sexp_random_real (sexp ctx, sexp self, sexp_sint_t n) {
return sexp_rs_random_real(ctx, self, n, default_random_source);
}
#if SEXP_BSD || defined(__CYGWIN__)
static sexp sexp_make_random_source (sexp ctx, sexp self, sexp_sint_t n) {
sexp res;
res = sexp_alloc_tagged(ctx, sexp_sizeof_random, rs_type_id);
*sexp_random_data(res) = 1;
return res;
}
static sexp sexp_random_source_state_ref (sexp ctx, sexp self, sexp_sint_t n, sexp rs) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
else
return sexp_make_integer(ctx, *sexp_random_data(rs));
}
static sexp sexp_random_source_state_set (sexp ctx, sexp self, sexp_sint_t n, sexp rs, sexp state) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
else if (sexp_fixnump(state))
*sexp_random_data(rs) = sexp_unbox_fixnum(state);
#if SEXP_USE_BIGNUMS
else if (sexp_bignump(state))
*sexp_random_data(rs)
= sexp_bignum_data(state)[0]*sexp_bignum_sign(state);
#endif
else
return sexp_type_exception(ctx, self, SEXP_FIXNUM, state);
return SEXP_VOID;
}
#else
static sexp sexp_make_random_source (sexp ctx, sexp self, sexp_sint_t n) {
sexp res;
sexp_gc_var1(state);
sexp_gc_preserve1(ctx, state);
state = sexp_make_bytes(ctx, STATE_SIZE, SEXP_UNDEF);
res = sexp_alloc_tagged(ctx, sexp_sizeof_random, rs_type_id);
if (sexp_exceptionp(res)) return res;
sexp_random_state(res) = state;
sexp_random_init(res, 1);
sexp_gc_release1(ctx);
return res;
}
static sexp sexp_random_source_state_ref (sexp ctx, sexp self, sexp_sint_t n, sexp rs) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
else
return sexp_subbytes(ctx, sexp_random_state(rs), ZERO, STATE_SIZE);
}
static sexp sexp_random_source_state_set (sexp ctx, sexp self, sexp_sint_t n, sexp rs, sexp state) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
else if (! (sexp_bytesp(state)
&& (sexp_bytes_length(state) == SEXP_RANDOM_STATE_SIZE)))
return sexp_type_exception(ctx, self, SEXP_BYTES, state);
sexp_random_state(rs) = sexp_subbytes(ctx, state, ZERO, STATE_SIZE);
sexp_random_init(rs, 1);
return SEXP_VOID;
}
#endif
static sexp sexp_random_source_randomize (sexp ctx, sexp self, sexp_sint_t n, sexp rs) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
sexp_seed_random(time(NULL), rs);
return SEXP_VOID;
}
static sexp sexp_random_source_pseudo_randomize (sexp ctx, sexp self, sexp_sint_t n, sexp rs, sexp seed1, sexp seed2) {
if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs);
if (! sexp_fixnump(seed1))
return sexp_type_exception(ctx, self, rs_type_id, seed1);
if (! sexp_fixnump(seed2))
return sexp_type_exception(ctx, self, rs_type_id, seed2);
sexp_seed_random(sexp_unbox_fixnum(seed1) ^ sexp_unbox_fixnum(seed2), rs);
return SEXP_VOID;
}
sexp sexp_init_library (sexp ctx, sexp self, sexp_sint_t n, sexp env, const char* version, const sexp_abi_identifier_t abi) {
sexp_gc_var2(name, op);
if (!(sexp_version_compatible(ctx, version, sexp_version)
&& sexp_abi_compatible(ctx, abi, SEXP_ABI_IDENTIFIER)))
return SEXP_ABI_ERROR;
sexp_gc_preserve2(ctx, name, op);
name = sexp_c_string(ctx, "random-source", -1);
op = sexp_register_type(ctx, name, SEXP_FALSE, SEXP_FALSE,
sexp_make_fixnum(sexp_offsetof_slot0),
ONE, ONE, ZERO, ZERO,
sexp_make_fixnum(sexp_sizeof_random), ZERO,
ZERO, ZERO, ZERO, ZERO, ZERO, ZERO, NULL, NULL, NULL);
if (sexp_exceptionp(op))
return op;
rs_type_id = sexp_type_tag(op);
name = sexp_c_string(ctx, "random-source?", -1);
op = sexp_make_type_predicate(ctx, name, sexp_make_fixnum(rs_type_id));
name = sexp_intern(ctx, "random-source?", -1);
sexp_env_define(ctx, env, name, op);
sexp_define_foreign(ctx, env, "make-random-source", 0, sexp_make_random_source);
sexp_define_foreign(ctx, env, "%random-integer", 2, sexp_rs_random_integer);
sexp_define_foreign(ctx, env, "random-integer", 1, sexp_random_integer);
sexp_define_foreign(ctx, env, "%random-real", 1, sexp_rs_random_real);
sexp_define_foreign(ctx, env, "random-real", 0, sexp_random_real);
sexp_define_foreign(ctx, env, "random-source-state-ref", 1, sexp_random_source_state_ref);
sexp_define_foreign(ctx, env, "random-source-state-set!", 2, sexp_random_source_state_set);
sexp_define_foreign(ctx, env, "random-source-randomize!", 1, sexp_random_source_randomize);
sexp_define_foreign(ctx, env, "random-source-pseudo-randomize!", 3, sexp_random_source_pseudo_randomize);
default_random_source = op = sexp_make_random_source(ctx, NULL, 0);
name = sexp_intern(ctx, "default-random-source", -1);
sexp_env_define(ctx, env, name, default_random_source);
sexp_random_source_randomize(ctx, NULL, 0, default_random_source);
sexp_gc_release2(ctx);
return SEXP_VOID;
}