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author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-11 17:24:46 +0000 |
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committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-11 17:24:46 +0000 |
commit | 17c1e454055eaa8e6884e23a195a5fc65ed4277f (patch) | |
tree | 4414b1c1988382252e40ed7a9dcdd6dc3152a5bd /random.c | |
parent | 3f405a768880bf6c042c072fd833d7be47162034 (diff) | |
download | ruby-17c1e454055eaa8e6884e23a195a5fc65ed4277f.tar.gz |
* random.c (rand_init): use fixed buffer for small numbers.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24034 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'random.c')
-rw-r--r-- | random.c | 63 |
1 files changed, 32 insertions, 31 deletions
@@ -223,6 +223,8 @@ rb_genrand_real(void) return genrand_real(&default_mt.mt); } +#define roomof(n, m) (int)(((n)+(m)-1) / (m)) +#define numberof(array) (int)(sizeof(array) / sizeof((array)[0])) #define SIZEOF_INT32 (31/CHAR_BIT + 1) static VALUE @@ -230,49 +232,48 @@ rand_init(struct MT *mt, VALUE vseed) { volatile VALUE seed; long blen = 0; - int len; - unsigned int *buf; + int i, j, len; + unsigned int buf0[SIZEOF_LONG / SIZEOF_INT32 * 4], *buf = buf0; seed = rb_to_int(vseed); switch (TYPE(seed)) { case T_FIXNUM: - len = (int)sizeof(VALUE); + len = 1; + buf[0] = (unsigned int)(FIX2ULONG(seed) & 0xffffffff); +#if SIZEOF_LONG > SIZEOF_INT32 + if ((buf[1] = (unsigned int)(FIX2ULONG(seed) >> 32)) != 0) ++len; +#endif break; case T_BIGNUM: blen = RBIGNUM_LEN(seed); - if (blen == 0) - len = 4; - else if (blen > MT_MAX_STATE * SIZEOF_INT32 / SIZEOF_BDIGITS) + if (blen == 0) { + len = 1; + } + else if (blen > MT_MAX_STATE * SIZEOF_INT32 / SIZEOF_BDIGITS) { blen = (len = MT_MAX_STATE) * SIZEOF_INT32 / SIZEOF_BDIGITS; - else - len = (int)blen * SIZEOF_BDIGITS; + len = roomof(len, SIZEOF_INT32); + } + else { + len = roomof((int)blen * SIZEOF_BDIGITS, SIZEOF_INT32); + } + /* allocate ints for init_by_array */ + if (len > numberof(buf0)) buf = ALLOC_N(unsigned int, len); + memset(buf, 0, len * sizeof(*buf)); + len = 0; + for (i = (int)(blen-1); 0 <= i; i--) { + j = i * SIZEOF_BDIGITS / SIZEOF_INT32; +#if SIZEOF_BDIGITS < SIZEOF_INT32 + buf[j] <<= SIZEOF_BDIGITS * CHAR_BIT; +#endif + buf[j] |= RBIGNUM_DIGITS(seed)[i]; + if (!len && buf[j]) len = j; + } + ++len; break; default: rb_raise(rb_eTypeError, "failed to convert %s into Integer", rb_obj_classname(vseed)); } - len = (len + 3) / 4; /* number of 32bit words */ - buf = ALLOC_N(unsigned int, len); /* allocate longs for init_by_array */ - memset(buf, 0, len * sizeof(int)); - if (FIXNUM_P(seed)) { - buf[0] = (unsigned int)(FIX2ULONG(seed) & 0xffffffff); -#if SIZEOF_LONG > 4 - buf[1] = (unsigned int)(FIX2ULONG(seed) >> 32); -#endif - } - else { - long i, j; - for (i = blen-1; 0 <= i; i--) { - j = i * SIZEOF_BDIGITS / 4; -#if SIZEOF_BDIGITS < 4 - buf[j] <<= SIZEOF_BDIGITS * 8; -#endif - buf[j] |= RBIGNUM_DIGITS(seed)[i]; - } - } - while (1 < len && buf[len-1] == 0) { - len--; - } if (len <= 1) { init_genrand(mt, buf[0]); } @@ -281,7 +282,7 @@ rand_init(struct MT *mt, VALUE vseed) len--; init_by_array(mt, buf, len); } - xfree(buf); + if (buf != buf0) xfree(buf); return seed; } |