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Using bytevectors for random state.

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This commit is contained in:
Alex Shinn 2014-05-28 23:17:53 +09:00
parent 09221ec87d
commit 22246a6ac8
2 changed files with 15 additions and 8 deletions
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14
lib/srfi/27/rand.c
View file

@ -15,7 +15,7 @@
#define sexp_random_init(x, seed) \ #define sexp_random_init(x, seed) \
initstate_r(seed, \ initstate_r(seed, \
sexp_string_data(sexp_random_state(x)), \ sexp_bytes_data(sexp_random_state(x)), \
SEXP_RANDOM_STATE_SIZE, \ SEXP_RANDOM_STATE_SIZE, \
sexp_random_data(x)) sexp_random_data(x))
@ -121,7 +121,7 @@ static sexp sexp_make_random_source (sexp ctx, sexp self, sexp_sint_t n) {
sexp res; sexp res;
sexp_gc_var1(state); sexp_gc_var1(state);
sexp_gc_preserve1(ctx, state); sexp_gc_preserve1(ctx, state);
state = sexp_make_string(ctx, STATE_SIZE, SEXP_UNDEF); state = sexp_make_bytes(ctx, STATE_SIZE, SEXP_UNDEF);
res = sexp_alloc_tagged(ctx, sexp_sizeof_random, rs_type_id); res = sexp_alloc_tagged(ctx, sexp_sizeof_random, rs_type_id);
if (sexp_exceptionp(res)) return res; if (sexp_exceptionp(res)) return res;
sexp_random_state(res) = state; sexp_random_state(res) = state;
@ -134,16 +134,16 @@ static sexp sexp_random_source_state_ref (sexp ctx, sexp self, sexp_sint_t n, se
if (! sexp_random_source_p(rs)) if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs); return sexp_type_exception(ctx, self, rs_type_id, rs);
else else
return sexp_substring(ctx, sexp_random_state(rs), ZERO, STATE_SIZE); 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) { 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)) if (! sexp_random_source_p(rs))
return sexp_type_exception(ctx, self, rs_type_id, rs); return sexp_type_exception(ctx, self, rs_type_id, rs);
else if (! (sexp_stringp(state) else if (! (sexp_bytesp(state)
&& (sexp_string_size(state) == SEXP_RANDOM_STATE_SIZE))) && (sexp_bytes_length(state) == SEXP_RANDOM_STATE_SIZE)))
return sexp_type_exception(ctx, self, SEXP_STRING, state); return sexp_type_exception(ctx, self, SEXP_BYTES, state);
sexp_random_state(rs) = state; sexp_random_state(rs) = sexp_subbytes(ctx, state, ZERO, STATE_SIZE);
sexp_random_init(rs, 1); sexp_random_init(rs, 1);
return SEXP_VOID; return SEXP_VOID;
} }

9
tests/srfi-27-tests.scm
View file

@ -15,6 +15,13 @@
(do ((k 0 (+ k 5)) (do ((k 0 (+ k 5))
(n 1 (* n 2))) (n 1 (* n 2)))
((> k 1024)) ((> k 1024))
(test-random rand n)))) (test-random rand n))
(let* ((state (random-source-state-ref rs))
(x (rand 1000000)))
;; the next int won't be the same, but it will be after
;; resetting the state
(test-not (= x (rand 1000000)))
(random-source-state-set! rs state)
(test x (rand 1000000)))))
(test-end) (test-end)