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feat(util/list): avoid recursion at for_each template

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-11-18 15:52:31 -08:00
parent 87775cbc07
commit d67bf995ed
2 changed files with 23 additions and 5 deletions
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18
src/tests/util/list.cpp
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@ -8,6 +8,7 @@ Author: Leonardo de Moura
#include "util/test.h"
#include "util/list.h"
#include "util/list_fn.h"
#include "util/timeit.h"
using namespace lean;
static void tst1() {
@ -114,6 +115,22 @@ static void tst9(int sz) {
std::cout << l3 << "\n";
}
static void tst10(int sz, int num) {
list<int> l;
for (int i = 0; i < sz; i++) {
l = cons(i, l);
}
{
timeit timer(std::cout, "for_each");
unsigned sum = 0;
for (int i = 0; i < num; i++) {
sum = 0;
for_each(l, [&](int v) { sum += v; });
}
std::cout << "sum: " << sum << "\n";
}
}
int main() {
tst1();
tst2();
@ -124,5 +141,6 @@ int main() {
tst7();
tst8();
tst9(100);
tst10(1000, 5);
return has_violations() ? 1 : 0;
}

10
src/util/list_fn.h
View file

@ -160,11 +160,11 @@ template<typename T, typename F>
void for_each(list<T> const & l, F f) {
static_assert(std::is_same<typename std::result_of<F(T const &)>::type, void>::value,
"for_each: return type of f is not void");
if (is_nil(l)) {
return;
} else {
f(head(l));
return for_each(tail(l), f);
typedef typename list<T>::cell cell;
cell * it = l.raw();
while (it) {
f(it->head());
it = it->tail().raw();
}
}