Change object representation from 1 big union to individual structs.

A big change.  Micro Python objects are allocated as individual structs
with the first element being a pointer to the type information (which
is itself an object).  This scheme follows CPython.  Much more flexible,
not necessarily slower, uses same heap memory, and can allocate objects
statically.

Also change name prefix, from py_ to mp_ (mp for Micro Python).

1 files changed, 88 insertions, 0 deletions

diff --git a/py/objrange.c b/py/objrange.c
new file mode 100644
index 000000000..b7fd17fa0
--- /dev/null
+++ b/py/objrange.c
@@ -0,0 +1,88 @@
+#include <stdlib.h>
+#include <stdint.h>
+
+#include "nlr.h"
+#include "misc.h"
+#include "mpconfig.h"
+#include "obj.h"
+
+/******************************************************************************/
+/* range                                                                      */
+
+typedef struct _mp_obj_range_t {
+    mp_obj_base_t base;
+    // TODO make these values generic objects or something
+    machine_int_t start;
+    machine_int_t stop;
+    machine_int_t step;
+} mp_obj_range_t;
+
+mp_obj_t range_getiter(mp_obj_t o_in) {
+    mp_obj_range_t *o = o_in;
+    return mp_obj_new_range_iterator(o->start, o->stop, o->step);
+}
+
+static const mp_obj_type_t range_type = {
+    { &mp_const_type} ,
+    "range",
+    NULL, // print
+    NULL, // call_n
+    NULL, // unary_op
+    NULL, // binary_op
+    range_getiter,
+    NULL, // iternext
+    {{NULL, NULL},}, // method list
+};
+
+// range is a class and instances are immutable sequence objects
+mp_obj_t mp_obj_new_range(int start, int stop, int step) {
+    mp_obj_range_t *o = m_new_obj(mp_obj_range_t);
+    o->base.type = &range_type;
+    o->start = start;
+    o->stop = stop;
+    o->step = step;
+    return o;
+}
+
+/******************************************************************************/
+/* range iterator                                                             */
+
+typedef struct _mp_obj_range_it_t {
+    mp_obj_base_t base;
+    // TODO make these values generic objects or something
+    machine_int_t cur;
+    machine_int_t stop;
+    machine_int_t step;
+} mp_obj_range_it_t;
+
+mp_obj_t range_it_iternext(mp_obj_t o_in) {
+    mp_obj_range_it_t *o = o_in;
+    if ((o->step > 0 && o->cur < o->stop) || (o->step < 0 && o->cur > o->stop)) {
+        mp_obj_t o_out = MP_OBJ_NEW_SMALL_INT(o->cur);
+        o->cur += o->step;
+        return o_out;
+    } else {
+        return mp_const_stop_iteration;
+    }
+}
+
+static const mp_obj_type_t range_it_type = {
+    { &mp_const_type },
+    "range_iterator",
+    NULL, // print
+    NULL, // call_n
+    NULL, // unary_op
+    NULL, // binary_op
+    NULL, // getiter
+    range_it_iternext,
+    {{NULL, NULL},}, // method list
+};
+
+mp_obj_t mp_obj_new_range_iterator(int cur, int stop, int step) {
+    mp_obj_range_it_t *o = m_new_obj(mp_obj_range_it_t);
+    o->base.type = &range_it_type;
+    o->cur = cur;
+    o->stop = stop;
+    o->step = step;
+    return o;
+}