Adding generic Python range and iterator bindings

Signed-off-by: David Shah <davey1576@gmail.com>

common/pybindings.cc

@@ -1,15 +1,95 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2018  David Shah <dave@ds0.me>
+ *
+ *  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.
+ *
+ */
+
 #include "design.h"
 #include "chip.h"
-
+#include <utility>
+#include <stdexcept>
 #include <boost/python.hpp>
 #include <boost/python/suite/indexing/vector_indexing_suite.hpp>
 #include <boost/python/suite/indexing/map_indexing_suite.hpp>
+#include <boost/python/suite/indexing/map_indexing_suite.hpp>
+
 using namespace boost::python;
 
 #define PASTER(x, y) x ## _ ## y
 #define EVALUATOR(x, y)  PASTER(x,y)
 #define MODULE_NAME EVALUATOR(nextpnrpy, ARCHNAME)
 
+/*
+A wrapper for a Pythonised nextpnr Iterator. The actual class wrapped is a
+pair<Iterator, Iterator> containing (current, end)
+*/
+template<typename T>
+struct iterator_wrapper {
+    typedef decltype(*(std::declval<T>())) value_t;
+
+    static value_t next(std::pair<T, T> &iter) {
+        if (iter.first != iter.second) {
+            value_t val = *iter.first;
+            ++iter.first;
+            return val;
+        } else {
+            PyErr_SetString(PyExc_StopIteration, "End of range reached");
+            boost::python::throw_error_already_set();
+            // Should be unreachable, but prevent control may reach end of non-void
+            throw std::runtime_error("unreachable");
+        }
+    }
+
+    static void wrap(const char *python_name) {
+        class_<std::pair<T, T>>(python_name, no_init)
+                .def("next", next);
+    }
+};
+
+/*
+A wrapper for a nextpnr Range. Ranges should have two functions, begin()
+and end() which return iterator-like objects supporting ++, * and !=
+Full STL iterator semantics are not required, unlike the standard Boost wrappers
+*/
+inline object pass_through(object const &o) { return o; }
+
+template<typename T>
+struct range_wrapper {
+    typedef decltype(std::declval<T>().begin()) iterator_t;
+
+    static std::pair<iterator_t, iterator_t> iter(T &range) {
+        return std::make_pair(range.begin(), range.end());
+    }
+
+    static void wrap(const char *range_name, const char *iter_name) {
+        class_<T>(range_name, no_init)
+                .def("__iter__", iter);
+        iterator_wrapper<iterator_t>().wrap(iter_name);
+    }
+};
+
+#define WRAP_RANGE(t) range_wrapper<t##Range>().wrap(#t "Range", #t "Iterator")
+
 BOOST_PYTHON_MODULE (MODULE_NAME) {
+    // From Chip.h
+    class_<ChipArgs>("ChipArgs");
+    WRAP_RANGE(Bels);
+    WRAP_RANGE(AllWires);
+    WRAP_RANGE(WireDelay);
+    WRAP_RANGE(BelPin);
 
 }