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* array.c (RAND_UPTO): macro for random number.

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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29067 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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nobu 2010-08-21 21:46:31 +00:00
parent 6eb922763f
commit 119da02e87
2 changed files with 17 additions and 11 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
Sun Aug 22 06:46:21 2010 Nobuyoshi Nakada <nobu@ruby-lang.org>
* array.c (RAND_UPTO): macro for random number.
Sun Aug 22 05:55:01 2010 Nobuyoshi Nakada <nobu@ruby-lang.org> Sun Aug 22 05:55:01 2010 Nobuyoshi Nakada <nobu@ruby-lang.org>
* configure.in: fix typo. a patch from Eric Wong at * configure.in: fix typo. a patch from Eric Wong at

24
array.c
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@ -3730,6 +3730,8 @@ rb_ary_flatten(int argc, VALUE *argv, VALUE ary)
return result; return result;
} }
#define RAND_UPTO(max) (long)(rb_genrand_real()*(max))
/* /*
* call-seq: * call-seq:
* ary.shuffle! -> ary * ary.shuffle! -> ary
@ -3747,7 +3749,7 @@ rb_ary_shuffle_bang(VALUE ary)
rb_ary_modify(ary); rb_ary_modify(ary);
ptr = RARRAY_PTR(ary); ptr = RARRAY_PTR(ary);
while (i) { while (i) {
long j = (long)(rb_genrand_real()*i); long j = RAND_UPTO(i);
VALUE tmp = ptr[--i]; VALUE tmp = ptr[--i];
ptr[i] = ptr[j]; ptr[i] = ptr[j];
ptr[j] = tmp; ptr[j] = tmp;
@ -3798,7 +3800,7 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
len = RARRAY_LEN(ary); len = RARRAY_LEN(ary);
if (argc == 0) { if (argc == 0) {
if (len == 0) return Qnil; if (len == 0) return Qnil;
i = len == 1 ? 0 : (long)(rb_genrand_real()*len); i = len == 1 ? 0 : RAND_UPTO(len);
return RARRAY_PTR(ary)[i]; return RARRAY_PTR(ary)[i];
} }
rb_scan_args(argc, argv, "1", &nv); rb_scan_args(argc, argv, "1", &nv);
@ -3810,16 +3812,16 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
switch (n) { switch (n) {
case 0: return rb_ary_new2(0); case 0: return rb_ary_new2(0);
case 1: case 1:
return rb_ary_new4(1, &ptr[(long)(rb_genrand_real()*len)]); return rb_ary_new4(1, &ptr[RAND_UPTO(len)]);
case 2: case 2:
i = (long)(rb_genrand_real()*len); i = RAND_UPTO(len);
j = (long)(rb_genrand_real()*(len-1)); j = RAND_UPTO(len-1);
if (j >= i) j++; if (j >= i) j++;
return rb_ary_new3(2, ptr[i], ptr[j]); return rb_ary_new3(2, ptr[i], ptr[j]);
case 3: case 3:
i = (long)(rb_genrand_real()*len); i = RAND_UPTO(len);
j = (long)(rb_genrand_real()*(len-1)); j = RAND_UPTO(len-1);
k = (long)(rb_genrand_real()*(len-2)); k = RAND_UPTO(len-2);
{ {
long l = j, g = i; long l = j, g = i;
if (j >= i) l = i, g = ++j; if (j >= i) l = i, g = ++j;
@ -3830,9 +3832,9 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
if ((size_t)n < sizeof(idx)/sizeof(idx[0])) { if ((size_t)n < sizeof(idx)/sizeof(idx[0])) {
VALUE *ptr_result; VALUE *ptr_result;
long sorted[sizeof(idx)/sizeof(idx[0])]; long sorted[sizeof(idx)/sizeof(idx[0])];
sorted[0] = idx[0] = (long)(rb_genrand_real()*len); sorted[0] = idx[0] = RAND_UPTO(len);
for (i=1; i<n; i++) { for (i=1; i<n; i++) {
k = (long)(rb_genrand_real()*--len); k = RAND_UPTO(--len);
for (j = 0; j < i; ++j) { for (j = 0; j < i; ++j) {
if (k < sorted[j]) break; if (k < sorted[j]) break;
++k; ++k;
@ -3852,7 +3854,7 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
ptr_result = RARRAY_PTR(result); ptr_result = RARRAY_PTR(result);
RB_GC_GUARD(ary); RB_GC_GUARD(ary);
for (i=0; i<n; i++) { for (i=0; i<n; i++) {
j = (long)(rb_genrand_real()*(len-i)) + i; j = RAND_UPTO(len-i) + i;
nv = ptr_result[j]; nv = ptr_result[j];
ptr_result[j] = ptr_result[i]; ptr_result[j] = ptr_result[i];
ptr_result[i] = nv; ptr_result[i] = nv;