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array.c: non-recursive rcombinate0

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* array.c (rcombinate0): remove recursion, by looping with indexes
  stored in `p`.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46428 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
nobu 2014-06-14 01:55:25 +00:00
parent 4802149e44
commit b654e0719a
3 changed files with 30 additions and 14 deletions
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5
ChangeLog
View file

@ -1,4 +1,7 @@
Sat Jun 14 10:53:49 2014 Nobuyoshi Nakada <nobu@ruby-lang.org> Sat Jun 14 10:54:08 2014 Nobuyoshi Nakada <nobu@ruby-lang.org>
* array.c (rcombinate0): remove recursion, by looping with indexes
stored in `p`.
* array.c (rpermute0): remove recursion, by looping with indexes * array.c (rpermute0): remove recursion, by looping with indexes
stored in `p`. stored in `p`.

33
array.c
View file

@ -5087,18 +5087,25 @@ rb_ary_repeated_permutation(VALUE ary, VALUE num)
} }
static void static void
rcombinate0(long n, long r, long *p, long index, long rest, VALUE values) rcombinate0(const long n, const long r, long *const p, const long rest, const VALUE values)
{ {
if (rest > 0) { long i = 0, index = 0;
for (; index < n; ++index) {
p[r-rest] = index; p[index] = i;
rcombinate0(n, r, p, index, rest-1, values); for (;;) {
if (++index < r-1) {
p[index] = i;
continue;
} }
} for (; i < n; ++i) {
else { p[index] = i;
if (!yield_indexed_values(values, r, p)) { if (!yield_indexed_values(values, r, p)) {
rb_raise(rb_eRuntimeError, "repeated combination reentered"); rb_raise(rb_eRuntimeError, "repeated combination reentered");
}
} }
do {
if (index <= 0) return;
} while ((i = ++p[--index]) >= n);
} }
} }
@ -5163,13 +5170,13 @@ rb_ary_repeated_combination(VALUE ary, VALUE num)
/* yield nothing */ /* yield nothing */
} }
else { else {
volatile VALUE t0 = tmpbuf(n, sizeof(long)); volatile VALUE t0;
long *p = (long*)RSTRING_PTR(t0); long *p = ALLOCV_N(long, t0, n);
VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */ VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
RBASIC_CLEAR_CLASS(ary0); RBASIC_CLEAR_CLASS(ary0);
rcombinate0(len, n, p, 0, n, ary0); /* compute and yield repeated combinations */ rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
tmpbuf_discard(t0); ALLOCV_END(t0);
RBASIC_SET_CLASS_RAW(ary0, rb_cArray); RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
} }
return ary; return ary;

6
test/ruby/test_array.rb
View file

@ -1815,6 +1815,12 @@ class TestArray < Test::Unit::TestCase
a = @cls[0, 1, 2, 3, 4][1, 4].repeated_combination(2) a = @cls[0, 1, 2, 3, 4][1, 4].repeated_combination(2)
assert_empty(a.reject {|x| !x.include?(0)}) assert_empty(a.reject {|x| !x.include?(0)})
assert_separately([], <<-"end;") # do
assert_nothing_raised(SystemStackError) do
assert_equal(:ok, Array.new(100_000, nil).repeated_combination(500_000) {break :ok})
end
end;
end end
def test_take def test_take