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array.c: replace sort! method implementation

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- use heap sort (O(1)) instead of merge sort (O(n)) for better space
  complexity.

- method implemented in C for better performance

As a result, simple sorting now consumes far less memory and is faster.
Since it's implemented in C, fiber context switching is not allowed from
comparison, but we consider the risk is minimal (no one switches context
in the comparison, right?)
This commit is contained in:
Yukihiro "Matz" Matsumoto
2024-06-26 08:24:48 +09:00
parent b521d0816f
commit 5bd63d6232
2 changed files with 71 additions and 72 deletions
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src/array.c
+71
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@@ -1409,6 +1409,76 @@ mrb_ary_delete(mrb_state *mrb, mrb_value self)
return ret;
}
static mrb_bool
sort_cmp(mrb_state *mrb, mrb_value *p, mrb_int a, mrb_int b, mrb_value blk)
{
mrb_int cmp;
if (mrb_nil_p(blk)) {
cmp = mrb_cmp(mrb, p[a], p[b]);
}
else {
mrb_value c = mrb_funcall_id(mrb, blk, MRB_SYM(call), 2, p[a], p[b]);
if (mrb_nil_p(c) || !mrb_fixnum_p(c)) {
mrb_raisef(mrb, E_ARGUMENT_ERROR, "comparison of %!v and %!v failed", p[a], p[b]);
}
cmp = mrb_fixnum(c);
}
return cmp > 0;
}
static void
heapify(mrb_state *mrb, mrb_value *a, mrb_int index, mrb_int size, mrb_value blk)
{
mrb_int max = index;
mrb_int left_index = 2 * index + 1;
mrb_int right_index = left_index + 1;
if (left_index < size && sort_cmp(mrb, a, left_index, max, blk)) {
max = left_index;
}
if (right_index < size && sort_cmp(mrb, a, right_index, max, blk)) {
max = right_index;
}
if (max != index) {
mrb_value tmp = a[max];
a[max] = a[index];
a[index] = tmp;
heapify(mrb, a, max, size, blk);
}
}
/*
* call-seq:
* array.sort! -> self
* array.sort! {|a, b| ... } -> self
*
* Sort all elements and replace +self+ with these
* elements.
*/
static mrb_value
mrb_ary_sort_bang(mrb_state *mrb, mrb_value ary)
{
mrb_value blk;
mrb_int n = RARRAY_LEN(ary);
if (n < 2) return ary;
ary_modify(mrb, mrb_ary_ptr(ary));
mrb_get_args(mrb, "&", &blk);
mrb_value *a = RARRAY_PTR(ary);
for (mrb_int i = n / 2 - 1; i > -1; i--) {
heapify(mrb, a, i, n, blk);
}
for (mrb_int i = n - 1; i > 0; i--) {
mrb_value tmp = a[0];
a[0] = a[i];
a[i] = tmp;
heapify(mrb, a, 0, i, blk);
}
return ary;
}
void
mrb_init_array(mrb_state *mrb)
{
@@ -1446,6 +1516,7 @@ mrb_init_array(mrb_state *mrb)
mrb_define_method_id(mrb, a, MRB_SYM(unshift), mrb_ary_unshift_m, MRB_ARGS_ANY()); /* 15.2.12.5.30 */
mrb_define_method_id(mrb, a, MRB_SYM(to_s), mrb_ary_to_s, MRB_ARGS_NONE());
mrb_define_method_id(mrb, a, MRB_SYM(inspect), mrb_ary_to_s, MRB_ARGS_NONE());
mrb_define_method_id(mrb, a, MRB_SYM_B(sort), mrb_ary_sort_bang, MRB_ARGS_NONE());
mrb_define_method_id(mrb, a, MRB_SYM(__ary_eq), mrb_ary_eq, MRB_ARGS_REQ(1));
mrb_define_method_id(mrb, a, MRB_SYM(__ary_cmp), mrb_ary_cmp, MRB_ARGS_REQ(1));