diff options
Diffstat (limited to 'array.c')
| -rw-r--r-- | array.c | 40 |
1 files changed, 25 insertions, 15 deletions
@@ -3996,7 +3996,7 @@ rb_ary_flatten(int argc, VALUE *argv, VALUE ary) (argc > 0 && !NIL_P((opts) = rb_check_hash_type(argv[argc-1])) && (--argc, 1)) static VALUE sym_random; -#define RAND_UPTO(max) (long)(rb_random_real(randgen)*(max)) +#define RAND_UPTO(max) (long)rb_random_ulong_limited((randgen), (max)-1) /* * call-seq: @@ -4091,7 +4091,7 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary) VALUE nv, result, *ptr; VALUE opts, randgen = rb_cRandom; long n, len, i, j, k, idx[10]; - double rnds[numberof(idx)]; + long rnds[numberof(idx)]; if (OPTHASH_GIVEN_P(opts)) { randgen = rb_hash_lookup2(opts, sym_random, randgen); @@ -4104,11 +4104,11 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary) i = 0; } else { - double x = rb_random_real(randgen); - if ((len = RARRAY_LEN(ary)) == 0) return Qnil; - i = (long)(x * len); + i = RAND_UPTO(len); + if ((len = RARRAY_LEN(ary)) <= i) return Qnil; + ptr = RARRAY_PTR(ary); } - return RARRAY_PTR(ary)[i]; + return ptr[i]; } rb_scan_args(argc, argv, "1", &nv); n = NUM2LONG(nv); @@ -4116,27 +4116,37 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary) if (n > len) n = len; if (n <= numberof(idx)) { for (i = 0; i < n; ++i) { - rnds[i] = rb_random_real(randgen); + rnds[i] = RAND_UPTO(len - i); } } + k = len; len = RARRAY_LEN(ary); ptr = RARRAY_PTR(ary); + if (len < k) { + if (n <= numberof(idx)) { + for (i = 0; i < n; ++i) { + if (rnds[i] >= len) { + return rb_ary_new2(0); + } + } + } + } if (n > len) n = len; switch (n) { case 0: return rb_ary_new2(0); case 1: - i = (long)(rnds[0] * len); + i = rnds[0]; return rb_ary_new4(1, &ptr[i]); case 2: - i = (long)(rnds[0] * len); - j = (long)(rnds[1] * (len-1)); + i = rnds[0]; + j = rnds[1]; if (j >= i) j++; return rb_ary_new3(2, ptr[i], ptr[j]); case 3: - i = (long)(rnds[0] * len); - j = (long)(rnds[1] * (len-1)); - k = (long)(rnds[2] * (len-2)); + i = rnds[0]; + j = rnds[1]; + k = rnds[2]; { long l = j, g = i; if (j >= i) l = i, g = ++j; @@ -4147,9 +4157,9 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary) if (n <= numberof(idx)) { VALUE *ptr_result; long sorted[numberof(idx)]; - sorted[0] = idx[0] = (long)(rnds[0] * len); + sorted[0] = idx[0] = rnds[0]; for (i=1; i<n; i++) { - k = (long)(rnds[i] * --len); + k = rnds[i]; for (j = 0; j < i; ++j) { if (k < sorted[j]) break; ++k; |