yosys/kernel/toposort.h

105 lines
2.4 KiB
C++

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#ifndef TOPOSORT_H
#define TOPOSORT_H
template<typename T>
struct TopoSort
{
bool analyze_loops, found_loops;
std::map<T, std::set<T>> database;
std::set<std::set<T>> loops;
std::vector<T> sorted;
TopoSort()
{
analyze_loops = true;
found_loops = false;
}
void node(T n)
{
if (database.count(n) == 0)
database[n] = std::set<T>();
}
void edge(T left, T right)
{
node(left);
database[right].insert(left);
}
void sort_worker(const T &n, std::set<T> &marked_cells, std::set<T> &active_cells, std::vector<T> &active_stack)
{
if (active_cells.count(n)) {
found_loops = false;
if (analyze_loops) {
std::set<T> loop;
for (int i = SIZE(active_stack)-1; i >= 0; i--) {
loop.insert(active_stack[i]);
if (active_stack[i] == n)
break;
}
loops.insert(loop);
}
return;
}
if (marked_cells.count(n))
return;
if (!database.at(n).empty())
{
if (analyze_loops)
active_stack.push_back(n);
active_cells.insert(n);
for (auto &left_n : database.at(n))
sort_worker(left_n, marked_cells, active_cells, active_stack);
if (analyze_loops)
active_stack.pop_back();
active_cells.erase(n);
}
marked_cells.insert(n);
sorted.push_back(n);
}
bool sort()
{
loops.clear();
sorted.clear();
found_loops = false;
std::set<T> marked_cells;
std::set<T> active_cells;
std::vector<T> active_stack;
for (auto &it : database)
sort_worker(it.first, marked_cells, active_cells, active_stack);
log_assert(SIZE(sorted) == SIZE(database));
return !found_loops;
}
};
#endif