py/objdict.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the Micro Python project, http://micropython.org/
  *
  * The MIT License (MIT)
  *
  * Copyright (c) 2013, 2014 Damien P. George
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include <string.h>
 #include <assert.h>

 #include "py/nlr.h"
 #include "py/obj.h"
 #include "py/runtime0.h"
 #include "py/runtime.h"
 #include "py/builtin.h"
 #include "py/objtype.h"

 #define MP_OBJ_IS_DICT_TYPE(o) (MP_OBJ_IS_OBJ(o) && ((mp_obj_base_t*)MP_OBJ_TO_PTR(o))->type->make_new == dict_make_new)

 STATIC mp_obj_t dict_update(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs);

 // This is a helper function to iterate through a dictionary.  The state of
 // the iteration is held in *cur and should be initialised with zero for the
 // first call.  Will return NULL when no more elements are available.
 STATIC mp_map_elem_t *dict_iter_next(mp_obj_dict_t *dict, size_t *cur) {
     size_t max = dict->map.alloc;
     mp_map_t *map = &dict->map;

     for (size_t i = *cur; i < max; i++) {
         if (MP_MAP_SLOT_IS_FILLED(map, i)) {
             *cur = i + 1;
             return &(map->table[i]);
         }
     }

     return NULL;
 }

 STATIC void dict_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     bool first = true;
     if (!(MICROPY_PY_UJSON && kind == PRINT_JSON)) {
         kind = PRINT_REPR;
     }
     if (MICROPY_PY_COLLECTIONS_ORDEREDDICT && self->base.type != &mp_type_dict) {
         mp_printf(print, "%q(", self->base.type->name);
     }
     mp_print_str(print, "{");
     size_t cur = 0;
     mp_map_elem_t *next = NULL;
     while ((next = dict_iter_next(self, &cur)) != NULL) {
         if (!first) {
             mp_print_str(print, ", ");
         }
         first = false;
         mp_obj_print_helper(print, next->key, kind);
         mp_print_str(print, ": ");
         mp_obj_print_helper(print, next->value, kind);
     }
     mp_print_str(print, "}");
     if (MICROPY_PY_COLLECTIONS_ORDEREDDICT && self->base.type != &mp_type_dict) {
         mp_print_str(print, ")");
     }
 }

 STATIC mp_obj_t dict_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_t dict_out = mp_obj_new_dict(0);
     mp_obj_dict_t *dict = MP_OBJ_TO_PTR(dict_out);
     dict->base.type = type;
     #if MICROPY_PY_COLLECTIONS_ORDEREDDICT
     if (type == &mp_type_ordereddict) {
         dict->map.is_ordered = 1;
     }
     #endif
     if (n_args > 0 || n_kw > 0) {
         mp_obj_t args2[2] = {dict_out, args[0]}; // args[0] is always valid, even if it's not a positional arg
         mp_map_t kwargs;
         mp_map_init_fixed_table(&kwargs, n_kw, args + n_args);
         dict_update(n_args + 1, args2, &kwargs); // dict_update will check that n_args + 1 == 1 or 2
     }
     return dict_out;
 }

 STATIC mp_obj_t dict_unary_op(mp_uint_t op, mp_obj_t self_in) {
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     switch (op) {
         case MP_UNARY_OP_BOOL: return mp_obj_new_bool(self->map.used != 0);
         case MP_UNARY_OP_LEN: return MP_OBJ_NEW_SMALL_INT(self->map.used);
         default: return MP_OBJ_NULL; // op not supported
     }
 }

 STATIC mp_obj_t dict_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     mp_obj_dict_t *o = MP_OBJ_TO_PTR(lhs_in);
     switch (op) {
         case MP_BINARY_OP_IN: {
             mp_map_elem_t *elem = mp_map_lookup(&o->map, rhs_in, MP_MAP_LOOKUP);
             return mp_obj_new_bool(elem != NULL);
         }
         case MP_BINARY_OP_EQUAL: {
             #if MICROPY_PY_COLLECTIONS_ORDEREDDICT
             if (MP_UNLIKELY(MP_OBJ_IS_TYPE(lhs_in, &mp_type_ordereddict) && MP_OBJ_IS_TYPE(rhs_in, &mp_type_ordereddict))) {
                 // Iterate through both dictionaries simultaneously and compare keys and values.
                 mp_obj_dict_t *rhs = MP_OBJ_TO_PTR(rhs_in);
                 size_t c1 = 0, c2 = 0;
                 mp_map_elem_t *e1 = dict_iter_next(o, &c1), *e2 = dict_iter_next(rhs, &c2);
                 for (; e1 != NULL && e2 != NULL; e1 = dict_iter_next(o, &c1), e2 = dict_iter_next(rhs, &c2)) {
                     if (!mp_obj_equal(e1->key, e2->key) || !mp_obj_equal(e1->value, e2->value)) {
                         return mp_const_false;
                     }
                 }
                 return e1 == NULL && e2 == NULL ? mp_const_true : mp_const_false;
             } else
             #endif
             if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_dict)) {
                 mp_obj_dict_t *rhs = MP_OBJ_TO_PTR(rhs_in);
                 if (o->map.used != rhs->map.used) {
                     return mp_const_false;
                 }

                 size_t cur = 0;
                 mp_map_elem_t *next = NULL;
                 while ((next = dict_iter_next(o, &cur)) != NULL) {
                     mp_map_elem_t *elem = mp_map_lookup(&rhs->map, next->key, MP_MAP_LOOKUP);
                     if (elem == NULL || !mp_obj_equal(next->value, elem->value)) {
                         return mp_const_false;
                     }
                 }
                 return mp_const_true;
             } else {
                 // dict is not equal to instance of any other type
                 return mp_const_false;
             }
         }
         default:
             // op not supported
             return MP_OBJ_NULL;
     }
 }

 // TODO: Make sure this is inlined in dict_subscr() below.
 mp_obj_t mp_obj_dict_get(mp_obj_t self_in, mp_obj_t index) {
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     mp_map_elem_t *elem = mp_map_lookup(&self->map, index, MP_MAP_LOOKUP);
     if (elem == NULL) {
         nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, index));
     } else {
         return elem->value;
     }
 }

 STATIC mp_obj_t dict_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
     if (value == MP_OBJ_NULL) {
         // delete
         mp_obj_dict_delete(self_in, index);
         return mp_const_none;
     } else if (value == MP_OBJ_SENTINEL) {
         // load
         mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
         mp_map_elem_t *elem = mp_map_lookup(&self->map, index, MP_MAP_LOOKUP);
         if (elem == NULL) {
             nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, index));
         } else {
             return elem->value;
         }
     } else {
         // store
         mp_obj_dict_store(self_in, index, value);
         return mp_const_none;
     }
 }

 /******************************************************************************/
 /* dict iterator                                                              */

 typedef struct _mp_obj_dict_it_t {
     mp_obj_base_t base;
     mp_fun_1_t iternext;
     mp_obj_t dict;
     size_t cur;
 } mp_obj_dict_it_t;

 STATIC mp_obj_t dict_it_iternext(mp_obj_t self_in) {
     mp_obj_dict_it_t *self = MP_OBJ_TO_PTR(self_in);
     mp_map_elem_t *next = dict_iter_next(MP_OBJ_TO_PTR(self->dict), &self->cur);

     if (next == NULL) {
         return MP_OBJ_STOP_ITERATION;
     } else {
         return next->key;
     }
 }

 STATIC mp_obj_t dict_getiter(mp_obj_t self_in, mp_obj_iter_buf_t *iter_buf) {
     assert(sizeof(mp_obj_dict_it_t) <= sizeof(mp_obj_iter_buf_t));
     mp_obj_dict_it_t *o = (mp_obj_dict_it_t*)iter_buf;
     o->base.type = &mp_type_polymorph_iter;
     o->iternext = dict_it_iternext;
     o->dict = self_in;
     o->cur = 0;
     return MP_OBJ_FROM_PTR(o);
 }

 /******************************************************************************/
 /* dict methods                                                               */

 STATIC mp_obj_t dict_clear(mp_obj_t self_in) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);

     mp_map_clear(&self->map);

     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_clear_obj, dict_clear);

 STATIC mp_obj_t dict_copy(mp_obj_t self_in) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     mp_obj_t other_out = mp_obj_new_dict(self->map.alloc);
     mp_obj_dict_t *other = MP_OBJ_TO_PTR(other_out);
     other->base.type = self->base.type;
     other->map.used = self->map.used;
     other->map.all_keys_are_qstrs = self->map.all_keys_are_qstrs;
     other->map.is_fixed = 0;
     other->map.is_ordered = self->map.is_ordered;
     memcpy(other->map.table, self->map.table, self->map.alloc * sizeof(mp_map_elem_t));
     return other_out;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_copy_obj, dict_copy);

 // this is a classmethod
 STATIC mp_obj_t dict_fromkeys(size_t n_args, const mp_obj_t *args) {
     mp_obj_t iter = mp_getiter(args[1], NULL);
     mp_obj_t value = mp_const_none;
     mp_obj_t next = MP_OBJ_NULL;

     if (n_args > 2) {
         value = args[2];
     }

     // optimisation to allocate result based on len of argument
     mp_obj_t self_out;
     mp_obj_t len = mp_obj_len_maybe(args[1]);
     if (len == MP_OBJ_NULL) {
         /* object's type doesn't have a __len__ slot */
         self_out = mp_obj_new_dict(0);
     } else {
         self_out = mp_obj_new_dict(MP_OBJ_SMALL_INT_VALUE(len));
     }

     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_out);
     while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
         mp_map_lookup(&self->map, next, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
     }

     return self_out;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_fromkeys_fun_obj, 2, 3, dict_fromkeys);
 STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(dict_fromkeys_obj, MP_ROM_PTR(&dict_fromkeys_fun_obj));

 STATIC mp_obj_t dict_get_helper(mp_map_t *self, mp_obj_t key, mp_obj_t deflt, mp_map_lookup_kind_t lookup_kind) {
     mp_map_elem_t *elem = mp_map_lookup(self, key, lookup_kind);
     mp_obj_t value;
     if (elem == NULL || elem->value == MP_OBJ_NULL) {
         if (deflt == MP_OBJ_NULL) {
             if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
                 nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, key));
             } else {
                 value = mp_const_none;
             }
         } else {
             value = deflt;
         }
         if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
             elem->value = value;
         }
     } else {
         value = elem->value;
         if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
             elem->value = MP_OBJ_NULL; // so that GC can collect the deleted value
         }
     }
     return value;
 }

 STATIC mp_obj_t dict_get(size_t n_args, const mp_obj_t *args) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

     return dict_get_helper(&self->map,
                            args[1],
                            n_args == 3 ? args[2] : MP_OBJ_NULL,
                            MP_MAP_LOOKUP);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_get_obj, 2, 3, dict_get);

 STATIC mp_obj_t dict_pop(size_t n_args, const mp_obj_t *args) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

     return dict_get_helper(&self->map,
                            args[1],
                            n_args == 3 ? args[2] : MP_OBJ_NULL,
                            MP_MAP_LOOKUP_REMOVE_IF_FOUND);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_pop_obj, 2, 3, dict_pop);


 STATIC mp_obj_t dict_setdefault(size_t n_args, const mp_obj_t *args) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

     return dict_get_helper(&self->map,
                            args[1],
                            n_args == 3 ? args[2] : MP_OBJ_NULL,
                            MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_setdefault_obj, 2, 3, dict_setdefault);


 STATIC mp_obj_t dict_popitem(mp_obj_t self_in) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     size_t cur = 0;
     mp_map_elem_t *next = dict_iter_next(self, &cur);
     if (next == NULL) {
         mp_raise_msg(&mp_type_KeyError, "popitem(): dictionary is empty");
     }
     self->map.used--;
     mp_obj_t items[] = {next->key, next->value};
     next->key = MP_OBJ_SENTINEL; // must mark key as sentinel to indicate that it was deleted
     next->value = MP_OBJ_NULL;
     mp_obj_t tuple = mp_obj_new_tuple(2, items);

     return tuple;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_popitem_obj, dict_popitem);

 STATIC mp_obj_t dict_update(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

     mp_arg_check_num(n_args, kwargs->used, 1, 2, true);

     if (n_args == 2) {
         // given a positional argument

         if (MP_OBJ_IS_DICT_TYPE(args[1])) {
             // update from other dictionary (make sure other is not self)
             if (args[1] != args[0]) {
                 size_t cur = 0;
                 mp_map_elem_t *elem = NULL;
                 while ((elem = dict_iter_next((mp_obj_dict_t*)MP_OBJ_TO_PTR(args[1]), &cur)) != NULL) {
                     mp_map_lookup(&self->map, elem->key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = elem->value;
                 }
             }
         } else {
             // update from a generic iterable of pairs
             mp_obj_t iter = mp_getiter(args[1], NULL);
             mp_obj_t next = MP_OBJ_NULL;
             while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
                 mp_obj_t inneriter = mp_getiter(next, NULL);
                 mp_obj_t key = mp_iternext(inneriter);
                 mp_obj_t value = mp_iternext(inneriter);
                 mp_obj_t stop = mp_iternext(inneriter);
                 if (key == MP_OBJ_STOP_ITERATION
                     || value == MP_OBJ_STOP_ITERATION
                     || stop != MP_OBJ_STOP_ITERATION) {
                     mp_raise_ValueError("dictionary update sequence has the wrong length");
                 } else {
                     mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
                 }
             }
         }
     }

     // update the dict with any keyword args
     for (size_t i = 0; i < kwargs->alloc; i++) {
         if (MP_MAP_SLOT_IS_FILLED(kwargs, i)) {
             mp_map_lookup(&self->map, kwargs->table[i].key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = kwargs->table[i].value;
         }
     }

     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(dict_update_obj, 1, dict_update);


 /******************************************************************************/
 /* dict views                                                                 */

 STATIC const mp_obj_type_t dict_view_type;
 STATIC const mp_obj_type_t dict_view_it_type;

 typedef enum _mp_dict_view_kind_t {
     MP_DICT_VIEW_ITEMS,
     MP_DICT_VIEW_KEYS,
     MP_DICT_VIEW_VALUES,
 } mp_dict_view_kind_t;

 STATIC const char *const mp_dict_view_names[] = {"dict_items", "dict_keys", "dict_values"};

 typedef struct _mp_obj_dict_view_it_t {
     mp_obj_base_t base;
     mp_dict_view_kind_t kind;
     mp_obj_t dict;
     size_t cur;
 } mp_obj_dict_view_it_t;

 typedef struct _mp_obj_dict_view_t {
     mp_obj_base_t base;
     mp_obj_t dict;
     mp_dict_view_kind_t kind;
 } mp_obj_dict_view_t;

 STATIC mp_obj_t dict_view_it_iternext(mp_obj_t self_in) {
     mp_check_self(MP_OBJ_IS_TYPE(self_in, &dict_view_it_type));
     mp_obj_dict_view_it_t *self = MP_OBJ_TO_PTR(self_in);
     mp_map_elem_t *next = dict_iter_next(MP_OBJ_TO_PTR(self->dict), &self->cur);

     if (next == NULL) {
         return MP_OBJ_STOP_ITERATION;
     } else {
         switch (self->kind) {
             case MP_DICT_VIEW_ITEMS:
             default: {
                 mp_obj_t items[] = {next->key, next->value};
                 return mp_obj_new_tuple(2, items);
             }
             case MP_DICT_VIEW_KEYS:
                 return next->key;
             case MP_DICT_VIEW_VALUES:
                 return next->value;
         }
     }
 }

 STATIC const mp_obj_type_t dict_view_it_type = {
     { &mp_type_type },
     .name = MP_QSTR_iterator,
     .getiter = mp_identity_getiter,
     .iternext = dict_view_it_iternext,
 };

 STATIC mp_obj_t dict_view_getiter(mp_obj_t view_in, mp_obj_iter_buf_t *iter_buf) {
     assert(sizeof(mp_obj_dict_view_it_t) <= sizeof(mp_obj_iter_buf_t));
     mp_check_self(MP_OBJ_IS_TYPE(view_in, &dict_view_type));
     mp_obj_dict_view_t *view = MP_OBJ_TO_PTR(view_in);
     mp_obj_dict_view_it_t *o = (mp_obj_dict_view_it_t*)iter_buf;
     o->base.type = &dict_view_it_type;
     o->kind = view->kind;
     o->dict = view->dict;
     o->cur = 0;
     return MP_OBJ_FROM_PTR(o);
 }

 STATIC void dict_view_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_check_self(MP_OBJ_IS_TYPE(self_in, &dict_view_type));
     mp_obj_dict_view_t *self = MP_OBJ_TO_PTR(self_in);
     bool first = true;
     mp_print_str(print, mp_dict_view_names[self->kind]);
     mp_print_str(print, "([");
     mp_obj_iter_buf_t iter_buf;
     mp_obj_t self_iter = dict_view_getiter(self_in, &iter_buf);
     mp_obj_t next = MP_OBJ_NULL;
     while ((next = dict_view_it_iternext(self_iter)) != MP_OBJ_STOP_ITERATION) {
         if (!first) {
             mp_print_str(print, ", ");
         }
         first = false;
         mp_obj_print_helper(print, next, PRINT_REPR);
     }
     mp_print_str(print, "])");
 }

 STATIC mp_obj_t dict_view_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     // only supported for the 'keys' kind until sets and dicts are refactored
     mp_obj_dict_view_t *o = MP_OBJ_TO_PTR(lhs_in);
     if (o->kind != MP_DICT_VIEW_KEYS) {
         return MP_OBJ_NULL; // op not supported
     }
     if (op != MP_BINARY_OP_IN) {
         return MP_OBJ_NULL; // op not supported
     }
     return dict_binary_op(op, o->dict, rhs_in);
 }

 STATIC const mp_obj_type_t dict_view_type = {
     { &mp_type_type },
     .name = MP_QSTR_dict_view,
     .print = dict_view_print,
     .binary_op = dict_view_binary_op,
     .getiter = dict_view_getiter,
 };

 STATIC mp_obj_t mp_obj_new_dict_view(mp_obj_t dict, mp_dict_view_kind_t kind) {
     mp_obj_dict_view_t *o = m_new_obj(mp_obj_dict_view_t);
     o->base.type = &dict_view_type;
     o->dict = dict;
     o->kind = kind;
     return MP_OBJ_FROM_PTR(o);
 }

 STATIC mp_obj_t dict_view(mp_obj_t self_in, mp_dict_view_kind_t kind) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     return mp_obj_new_dict_view(self_in, kind);
 }

 STATIC mp_obj_t dict_items(mp_obj_t self_in) {
     return dict_view(self_in, MP_DICT_VIEW_ITEMS);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_items_obj, dict_items);

 STATIC mp_obj_t dict_keys(mp_obj_t self_in) {
     return dict_view(self_in, MP_DICT_VIEW_KEYS);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_keys_obj, dict_keys);

 STATIC mp_obj_t dict_values(mp_obj_t self_in) {
     return dict_view(self_in, MP_DICT_VIEW_VALUES);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_values_obj, dict_values);

 /******************************************************************************/
 /* dict constructors & public C API                                           */

 STATIC const mp_rom_map_elem_t dict_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&dict_clear_obj) },
     { MP_ROM_QSTR(MP_QSTR_copy), MP_ROM_PTR(&dict_copy_obj) },
     { MP_ROM_QSTR(MP_QSTR_fromkeys), MP_ROM_PTR(&dict_fromkeys_obj) },
     { MP_ROM_QSTR(MP_QSTR_get), MP_ROM_PTR(&dict_get_obj) },
     { MP_ROM_QSTR(MP_QSTR_items), MP_ROM_PTR(&dict_items_obj) },
     { MP_ROM_QSTR(MP_QSTR_keys), MP_ROM_PTR(&dict_keys_obj) },
     { MP_ROM_QSTR(MP_QSTR_pop), MP_ROM_PTR(&dict_pop_obj) },
     { MP_ROM_QSTR(MP_QSTR_popitem), MP_ROM_PTR(&dict_popitem_obj) },
     { MP_ROM_QSTR(MP_QSTR_setdefault), MP_ROM_PTR(&dict_setdefault_obj) },
     { MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&dict_update_obj) },
     { MP_ROM_QSTR(MP_QSTR_values), MP_ROM_PTR(&dict_values_obj) },
     { MP_ROM_QSTR(MP_QSTR___getitem__), MP_ROM_PTR(&mp_op_getitem_obj) },
     { MP_ROM_QSTR(MP_QSTR___setitem__), MP_ROM_PTR(&mp_op_setitem_obj) },
     { MP_ROM_QSTR(MP_QSTR___delitem__), MP_ROM_PTR(&mp_op_delitem_obj) },
 };

 STATIC MP_DEFINE_CONST_DICT(dict_locals_dict, dict_locals_dict_table);

 const mp_obj_type_t mp_type_dict = {
     { &mp_type_type },
     .name = MP_QSTR_dict,
     .print = dict_print,
     .make_new = dict_make_new,
     .unary_op = dict_unary_op,
     .binary_op = dict_binary_op,
     .subscr = dict_subscr,
     .getiter = dict_getiter,
     .locals_dict = (mp_obj_dict_t*)&dict_locals_dict,
 };

 #if MICROPY_PY_COLLECTIONS_ORDEREDDICT
 STATIC const mp_rom_obj_tuple_t ordereddict_base_tuple = {{&mp_type_tuple}, 1, {MP_ROM_PTR(&mp_type_dict)}};

 const mp_obj_type_t mp_type_ordereddict = {
     { &mp_type_type },
     .name = MP_QSTR_OrderedDict,
     .print = dict_print,
     .make_new = dict_make_new,
     .unary_op = dict_unary_op,
     .binary_op = dict_binary_op,
     .subscr = dict_subscr,
     .getiter = dict_getiter,
     .bases_tuple = (mp_obj_tuple_t*)(mp_rom_obj_tuple_t*)&ordereddict_base_tuple,
     .locals_dict = (mp_obj_dict_t*)&dict_locals_dict,
 };
 #endif

 void mp_obj_dict_init(mp_obj_dict_t *dict, size_t n_args) {
     dict->base.type = &mp_type_dict;
     mp_map_init(&dict->map, n_args);
 }

 mp_obj_t mp_obj_new_dict(size_t n_args) {
     mp_obj_dict_t *o = m_new_obj(mp_obj_dict_t);
     mp_obj_dict_init(o, n_args);
     return MP_OBJ_FROM_PTR(o);
 }

 size_t mp_obj_dict_len(mp_obj_t self_in) {
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     return self->map.used;
 }

 mp_obj_t mp_obj_dict_store(mp_obj_t self_in, mp_obj_t key, mp_obj_t value) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
     return self_in;
 }

 mp_obj_t mp_obj_dict_delete(mp_obj_t self_in, mp_obj_t key) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     dict_get_helper(&self->map, key, MP_OBJ_NULL, MP_MAP_LOOKUP_REMOVE_IF_FOUND);
     return self_in;
 }

 mp_map_t *mp_obj_dict_get_map(mp_obj_t self_in) {
     mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
     mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
     return &self->map;
 }
	/*
	* This file is part of the Micro Python project, http://micropython.org/
	*
	* The MIT License (MIT)
	*
	* Copyright (c) 2013, 2014 Damien P. George
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include <string.h>
	#include <assert.h>

	#include "py/nlr.h"
	#include "py/obj.h"
	#include "py/runtime0.h"
	#include "py/runtime.h"
	#include "py/builtin.h"
	#include "py/objtype.h"

	#define MP_OBJ_IS_DICT_TYPE(o) (MP_OBJ_IS_OBJ(o) && ((mp_obj_base_t*)MP_OBJ_TO_PTR(o))->type->make_new == dict_make_new)

	STATIC mp_obj_t dict_update(size_t n_args, const mp_obj_t args, mp_map_t kwargs);

	// This is a helper function to iterate through a dictionary. The state of
	// the iteration is held in *cur and should be initialised with zero for the
	// first call. Will return NULL when no more elements are available.
	STATIC mp_map_elem_t dict_iter_next(mp_obj_dict_t dict, size_t *cur) {
	size_t max = dict->map.alloc;
	mp_map_t *map = &dict->map;

	for (size_t i = *cur; i < max; i++) {
	if (MP_MAP_SLOT_IS_FILLED(map, i)) {
	*cur = i + 1;
	return &(map->table[i]);
	}
	}

	return NULL;
	}

	STATIC void dict_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	bool first = true;
	if (!(MICROPY_PY_UJSON && kind == PRINT_JSON)) {
	kind = PRINT_REPR;
	}
	if (MICROPY_PY_COLLECTIONS_ORDEREDDICT && self->base.type != &mp_type_dict) {
	mp_printf(print, "%q(", self->base.type->name);
	}
	mp_print_str(print, "{");
	size_t cur = 0;
	mp_map_elem_t *next = NULL;
	while ((next = dict_iter_next(self, &cur)) != NULL) {
	if (!first) {
	mp_print_str(print, ", ");
	}
	first = false;
	mp_obj_print_helper(print, next->key, kind);
	mp_print_str(print, ": ");
	mp_obj_print_helper(print, next->value, kind);
	}
	mp_print_str(print, "}");
	if (MICROPY_PY_COLLECTIONS_ORDEREDDICT && self->base.type != &mp_type_dict) {
	mp_print_str(print, ")");
	}
	}

	STATIC mp_obj_t dict_make_new(const mp_obj_type_t type, size_t n_args, size_t n_kw, const mp_obj_t args) {
	mp_obj_t dict_out = mp_obj_new_dict(0);
	mp_obj_dict_t *dict = MP_OBJ_TO_PTR(dict_out);
	dict->base.type = type;
	#if MICROPY_PY_COLLECTIONS_ORDEREDDICT
	if (type == &mp_type_ordereddict) {
	dict->map.is_ordered = 1;
	}
	#endif
	if (n_args > 0 \|\| n_kw > 0) {
	mp_obj_t args2[2] = {dict_out, args[0]}; // args[0] is always valid, even if it's not a positional arg
	mp_map_t kwargs;
	mp_map_init_fixed_table(&kwargs, n_kw, args + n_args);
	dict_update(n_args + 1, args2, &kwargs); // dict_update will check that n_args + 1 == 1 or 2
	}
	return dict_out;
	}

	STATIC mp_obj_t dict_unary_op(mp_uint_t op, mp_obj_t self_in) {
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	switch (op) {
	case MP_UNARY_OP_BOOL: return mp_obj_new_bool(self->map.used != 0);
	case MP_UNARY_OP_LEN: return MP_OBJ_NEW_SMALL_INT(self->map.used);
	default: return MP_OBJ_NULL; // op not supported
	}
	}

	STATIC mp_obj_t dict_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
	mp_obj_dict_t *o = MP_OBJ_TO_PTR(lhs_in);
	switch (op) {
	case MP_BINARY_OP_IN: {
	mp_map_elem_t *elem = mp_map_lookup(&o->map, rhs_in, MP_MAP_LOOKUP);
	return mp_obj_new_bool(elem != NULL);
	}
	case MP_BINARY_OP_EQUAL: {
	#if MICROPY_PY_COLLECTIONS_ORDEREDDICT
	if (MP_UNLIKELY(MP_OBJ_IS_TYPE(lhs_in, &mp_type_ordereddict) && MP_OBJ_IS_TYPE(rhs_in, &mp_type_ordereddict))) {
	// Iterate through both dictionaries simultaneously and compare keys and values.
	mp_obj_dict_t *rhs = MP_OBJ_TO_PTR(rhs_in);
	size_t c1 = 0, c2 = 0;
	mp_map_elem_t e1 = dict_iter_next(o, &c1), e2 = dict_iter_next(rhs, &c2);
	for (; e1 != NULL && e2 != NULL; e1 = dict_iter_next(o, &c1), e2 = dict_iter_next(rhs, &c2)) {
	if (!mp_obj_equal(e1->key, e2->key) \|\| !mp_obj_equal(e1->value, e2->value)) {
	return mp_const_false;
	}
	}
	return e1 == NULL && e2 == NULL ? mp_const_true : mp_const_false;
	} else
	#endif
	if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_dict)) {
	mp_obj_dict_t *rhs = MP_OBJ_TO_PTR(rhs_in);
	if (o->map.used != rhs->map.used) {
	return mp_const_false;
	}

	size_t cur = 0;
	mp_map_elem_t *next = NULL;
	while ((next = dict_iter_next(o, &cur)) != NULL) {
	mp_map_elem_t *elem = mp_map_lookup(&rhs->map, next->key, MP_MAP_LOOKUP);
	if (elem == NULL \|\| !mp_obj_equal(next->value, elem->value)) {
	return mp_const_false;
	}
	}
	return mp_const_true;
	} else {
	// dict is not equal to instance of any other type
	return mp_const_false;
	}
	}
	default:
	// op not supported
	return MP_OBJ_NULL;
	}
	}

	// TODO: Make sure this is inlined in dict_subscr() below.
	mp_obj_t mp_obj_dict_get(mp_obj_t self_in, mp_obj_t index) {
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	mp_map_elem_t *elem = mp_map_lookup(&self->map, index, MP_MAP_LOOKUP);
	if (elem == NULL) {
	nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, index));
	} else {
	return elem->value;
	}
	}

	STATIC mp_obj_t dict_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
	if (value == MP_OBJ_NULL) {
	// delete
	mp_obj_dict_delete(self_in, index);
	return mp_const_none;
	} else if (value == MP_OBJ_SENTINEL) {
	// load
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	mp_map_elem_t *elem = mp_map_lookup(&self->map, index, MP_MAP_LOOKUP);
	if (elem == NULL) {
	nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, index));
	} else {
	return elem->value;
	}
	} else {
	// store
	mp_obj_dict_store(self_in, index, value);
	return mp_const_none;
	}
	}

	/******************************************************************************/
	/* dict iterator */

	typedef struct _mp_obj_dict_it_t {
	mp_obj_base_t base;
	mp_fun_1_t iternext;
	mp_obj_t dict;
	size_t cur;
	} mp_obj_dict_it_t;

	STATIC mp_obj_t dict_it_iternext(mp_obj_t self_in) {
	mp_obj_dict_it_t *self = MP_OBJ_TO_PTR(self_in);
	mp_map_elem_t *next = dict_iter_next(MP_OBJ_TO_PTR(self->dict), &self->cur);

	if (next == NULL) {
	return MP_OBJ_STOP_ITERATION;
	} else {
	return next->key;
	}
	}

	STATIC mp_obj_t dict_getiter(mp_obj_t self_in, mp_obj_iter_buf_t *iter_buf) {
	assert(sizeof(mp_obj_dict_it_t) <= sizeof(mp_obj_iter_buf_t));
	mp_obj_dict_it_t o = (mp_obj_dict_it_t)iter_buf;
	o->base.type = &mp_type_polymorph_iter;
	o->iternext = dict_it_iternext;
	o->dict = self_in;
	o->cur = 0;
	return MP_OBJ_FROM_PTR(o);
	}

	/******************************************************************************/
	/* dict methods */

	STATIC mp_obj_t dict_clear(mp_obj_t self_in) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);

	mp_map_clear(&self->map);

	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_clear_obj, dict_clear);

	STATIC mp_obj_t dict_copy(mp_obj_t self_in) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	mp_obj_t other_out = mp_obj_new_dict(self->map.alloc);
	mp_obj_dict_t *other = MP_OBJ_TO_PTR(other_out);
	other->base.type = self->base.type;
	other->map.used = self->map.used;
	other->map.all_keys_are_qstrs = self->map.all_keys_are_qstrs;
	other->map.is_fixed = 0;
	other->map.is_ordered = self->map.is_ordered;
	memcpy(other->map.table, self->map.table, self->map.alloc * sizeof(mp_map_elem_t));
	return other_out;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_copy_obj, dict_copy);

	// this is a classmethod
	STATIC mp_obj_t dict_fromkeys(size_t n_args, const mp_obj_t *args) {
	mp_obj_t iter = mp_getiter(args[1], NULL);
	mp_obj_t value = mp_const_none;
	mp_obj_t next = MP_OBJ_NULL;

	if (n_args > 2) {
	value = args[2];
	}

	// optimisation to allocate result based on len of argument
	mp_obj_t self_out;
	mp_obj_t len = mp_obj_len_maybe(args[1]);
	if (len == MP_OBJ_NULL) {
	/* object's type doesn't have a __len__ slot */
	self_out = mp_obj_new_dict(0);
	} else {
	self_out = mp_obj_new_dict(MP_OBJ_SMALL_INT_VALUE(len));
	}

	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_out);
	while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
	mp_map_lookup(&self->map, next, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
	}

	return self_out;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_fromkeys_fun_obj, 2, 3, dict_fromkeys);
	STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(dict_fromkeys_obj, MP_ROM_PTR(&dict_fromkeys_fun_obj));

	STATIC mp_obj_t dict_get_helper(mp_map_t *self, mp_obj_t key, mp_obj_t deflt, mp_map_lookup_kind_t lookup_kind) {
	mp_map_elem_t *elem = mp_map_lookup(self, key, lookup_kind);
	mp_obj_t value;
	if (elem == NULL \|\| elem->value == MP_OBJ_NULL) {
	if (deflt == MP_OBJ_NULL) {
	if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
	nlr_raise(mp_obj_new_exception_arg1(&mp_type_KeyError, key));
	} else {
	value = mp_const_none;
	}
	} else {
	value = deflt;
	}
	if (lookup_kind == MP_MAP_LOOKUP_ADD_IF_NOT_FOUND) {
	elem->value = value;
	}
	} else {
	value = elem->value;
	if (lookup_kind == MP_MAP_LOOKUP_REMOVE_IF_FOUND) {
	elem->value = MP_OBJ_NULL; // so that GC can collect the deleted value
	}
	}
	return value;
	}

	STATIC mp_obj_t dict_get(size_t n_args, const mp_obj_t *args) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

	return dict_get_helper(&self->map,
	args[1],
	n_args == 3 ? args[2] : MP_OBJ_NULL,
	MP_MAP_LOOKUP);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_get_obj, 2, 3, dict_get);

	STATIC mp_obj_t dict_pop(size_t n_args, const mp_obj_t *args) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

	return dict_get_helper(&self->map,
	args[1],
	n_args == 3 ? args[2] : MP_OBJ_NULL,
	MP_MAP_LOOKUP_REMOVE_IF_FOUND);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_pop_obj, 2, 3, dict_pop);


	STATIC mp_obj_t dict_setdefault(size_t n_args, const mp_obj_t *args) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

	return dict_get_helper(&self->map,
	args[1],
	n_args == 3 ? args[2] : MP_OBJ_NULL,
	MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(dict_setdefault_obj, 2, 3, dict_setdefault);


	STATIC mp_obj_t dict_popitem(mp_obj_t self_in) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	size_t cur = 0;
	mp_map_elem_t *next = dict_iter_next(self, &cur);
	if (next == NULL) {
	mp_raise_msg(&mp_type_KeyError, "popitem(): dictionary is empty");
	}
	self->map.used--;
	mp_obj_t items[] = {next->key, next->value};
	next->key = MP_OBJ_SENTINEL; // must mark key as sentinel to indicate that it was deleted
	next->value = MP_OBJ_NULL;
	mp_obj_t tuple = mp_obj_new_tuple(2, items);

	return tuple;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_popitem_obj, dict_popitem);

	STATIC mp_obj_t dict_update(size_t n_args, const mp_obj_t args, mp_map_t kwargs) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(args[0]));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(args[0]);

	mp_arg_check_num(n_args, kwargs->used, 1, 2, true);

	if (n_args == 2) {
	// given a positional argument

	if (MP_OBJ_IS_DICT_TYPE(args[1])) {
	// update from other dictionary (make sure other is not self)
	if (args[1] != args[0]) {
	size_t cur = 0;
	mp_map_elem_t *elem = NULL;
	while ((elem = dict_iter_next((mp_obj_dict_t*)MP_OBJ_TO_PTR(args[1]), &cur)) != NULL) {
	mp_map_lookup(&self->map, elem->key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = elem->value;
	}
	}
	} else {
	// update from a generic iterable of pairs
	mp_obj_t iter = mp_getiter(args[1], NULL);
	mp_obj_t next = MP_OBJ_NULL;
	while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
	mp_obj_t inneriter = mp_getiter(next, NULL);
	mp_obj_t key = mp_iternext(inneriter);
	mp_obj_t value = mp_iternext(inneriter);
	mp_obj_t stop = mp_iternext(inneriter);
	if (key == MP_OBJ_STOP_ITERATION
	\|\| value == MP_OBJ_STOP_ITERATION
	\|\| stop != MP_OBJ_STOP_ITERATION) {
	mp_raise_ValueError("dictionary update sequence has the wrong length");
	} else {
	mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
	}
	}
	}
	}

	// update the dict with any keyword args
	for (size_t i = 0; i < kwargs->alloc; i++) {
	if (MP_MAP_SLOT_IS_FILLED(kwargs, i)) {
	mp_map_lookup(&self->map, kwargs->table[i].key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = kwargs->table[i].value;
	}
	}

	return mp_const_none;
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_KW(dict_update_obj, 1, dict_update);


	/******************************************************************************/
	/* dict views */

	STATIC const mp_obj_type_t dict_view_type;
	STATIC const mp_obj_type_t dict_view_it_type;

	typedef enum _mp_dict_view_kind_t {
	MP_DICT_VIEW_ITEMS,
	MP_DICT_VIEW_KEYS,
	MP_DICT_VIEW_VALUES,
	} mp_dict_view_kind_t;

	STATIC const char *const mp_dict_view_names[] = {"dict_items", "dict_keys", "dict_values"};

	typedef struct _mp_obj_dict_view_it_t {
	mp_obj_base_t base;
	mp_dict_view_kind_t kind;
	mp_obj_t dict;
	size_t cur;
	} mp_obj_dict_view_it_t;

	typedef struct _mp_obj_dict_view_t {
	mp_obj_base_t base;
	mp_obj_t dict;
	mp_dict_view_kind_t kind;
	} mp_obj_dict_view_t;

	STATIC mp_obj_t dict_view_it_iternext(mp_obj_t self_in) {
	mp_check_self(MP_OBJ_IS_TYPE(self_in, &dict_view_it_type));
	mp_obj_dict_view_it_t *self = MP_OBJ_TO_PTR(self_in);
	mp_map_elem_t *next = dict_iter_next(MP_OBJ_TO_PTR(self->dict), &self->cur);

	if (next == NULL) {
	return MP_OBJ_STOP_ITERATION;
	} else {
	switch (self->kind) {
	case MP_DICT_VIEW_ITEMS:
	default: {
	mp_obj_t items[] = {next->key, next->value};
	return mp_obj_new_tuple(2, items);
	}
	case MP_DICT_VIEW_KEYS:
	return next->key;
	case MP_DICT_VIEW_VALUES:
	return next->value;
	}
	}
	}

	STATIC const mp_obj_type_t dict_view_it_type = {
	{ &mp_type_type },
	.name = MP_QSTR_iterator,
	.getiter = mp_identity_getiter,
	.iternext = dict_view_it_iternext,
	};

	STATIC mp_obj_t dict_view_getiter(mp_obj_t view_in, mp_obj_iter_buf_t *iter_buf) {
	assert(sizeof(mp_obj_dict_view_it_t) <= sizeof(mp_obj_iter_buf_t));
	mp_check_self(MP_OBJ_IS_TYPE(view_in, &dict_view_type));
	mp_obj_dict_view_t *view = MP_OBJ_TO_PTR(view_in);
	mp_obj_dict_view_it_t o = (mp_obj_dict_view_it_t)iter_buf;
	o->base.type = &dict_view_it_type;
	o->kind = view->kind;
	o->dict = view->dict;
	o->cur = 0;
	return MP_OBJ_FROM_PTR(o);
	}

	STATIC void dict_view_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	(void)kind;
	mp_check_self(MP_OBJ_IS_TYPE(self_in, &dict_view_type));
	mp_obj_dict_view_t *self = MP_OBJ_TO_PTR(self_in);
	bool first = true;
	mp_print_str(print, mp_dict_view_names[self->kind]);
	mp_print_str(print, "([");
	mp_obj_iter_buf_t iter_buf;
	mp_obj_t self_iter = dict_view_getiter(self_in, &iter_buf);
	mp_obj_t next = MP_OBJ_NULL;
	while ((next = dict_view_it_iternext(self_iter)) != MP_OBJ_STOP_ITERATION) {
	if (!first) {
	mp_print_str(print, ", ");
	}
	first = false;
	mp_obj_print_helper(print, next, PRINT_REPR);
	}
	mp_print_str(print, "])");
	}

	STATIC mp_obj_t dict_view_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
	// only supported for the 'keys' kind until sets and dicts are refactored
	mp_obj_dict_view_t *o = MP_OBJ_TO_PTR(lhs_in);
	if (o->kind != MP_DICT_VIEW_KEYS) {
	return MP_OBJ_NULL; // op not supported
	}
	if (op != MP_BINARY_OP_IN) {
	return MP_OBJ_NULL; // op not supported
	}
	return dict_binary_op(op, o->dict, rhs_in);
	}

	STATIC const mp_obj_type_t dict_view_type = {
	{ &mp_type_type },
	.name = MP_QSTR_dict_view,
	.print = dict_view_print,
	.binary_op = dict_view_binary_op,
	.getiter = dict_view_getiter,
	};

	STATIC mp_obj_t mp_obj_new_dict_view(mp_obj_t dict, mp_dict_view_kind_t kind) {
	mp_obj_dict_view_t *o = m_new_obj(mp_obj_dict_view_t);
	o->base.type = &dict_view_type;
	o->dict = dict;
	o->kind = kind;
	return MP_OBJ_FROM_PTR(o);
	}

	STATIC mp_obj_t dict_view(mp_obj_t self_in, mp_dict_view_kind_t kind) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	return mp_obj_new_dict_view(self_in, kind);
	}

	STATIC mp_obj_t dict_items(mp_obj_t self_in) {
	return dict_view(self_in, MP_DICT_VIEW_ITEMS);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_items_obj, dict_items);

	STATIC mp_obj_t dict_keys(mp_obj_t self_in) {
	return dict_view(self_in, MP_DICT_VIEW_KEYS);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_keys_obj, dict_keys);

	STATIC mp_obj_t dict_values(mp_obj_t self_in) {
	return dict_view(self_in, MP_DICT_VIEW_VALUES);
	}
	STATIC MP_DEFINE_CONST_FUN_OBJ_1(dict_values_obj, dict_values);

	/******************************************************************************/
	/* dict constructors & public C API */

	STATIC const mp_rom_map_elem_t dict_locals_dict_table[] = {
	{ MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&dict_clear_obj) },
	{ MP_ROM_QSTR(MP_QSTR_copy), MP_ROM_PTR(&dict_copy_obj) },
	{ MP_ROM_QSTR(MP_QSTR_fromkeys), MP_ROM_PTR(&dict_fromkeys_obj) },
	{ MP_ROM_QSTR(MP_QSTR_get), MP_ROM_PTR(&dict_get_obj) },
	{ MP_ROM_QSTR(MP_QSTR_items), MP_ROM_PTR(&dict_items_obj) },
	{ MP_ROM_QSTR(MP_QSTR_keys), MP_ROM_PTR(&dict_keys_obj) },
	{ MP_ROM_QSTR(MP_QSTR_pop), MP_ROM_PTR(&dict_pop_obj) },
	{ MP_ROM_QSTR(MP_QSTR_popitem), MP_ROM_PTR(&dict_popitem_obj) },
	{ MP_ROM_QSTR(MP_QSTR_setdefault), MP_ROM_PTR(&dict_setdefault_obj) },
	{ MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&dict_update_obj) },
	{ MP_ROM_QSTR(MP_QSTR_values), MP_ROM_PTR(&dict_values_obj) },
	{ MP_ROM_QSTR(MP_QSTR___getitem__), MP_ROM_PTR(&mp_op_getitem_obj) },
	{ MP_ROM_QSTR(MP_QSTR___setitem__), MP_ROM_PTR(&mp_op_setitem_obj) },
	{ MP_ROM_QSTR(MP_QSTR___delitem__), MP_ROM_PTR(&mp_op_delitem_obj) },
	};

	STATIC MP_DEFINE_CONST_DICT(dict_locals_dict, dict_locals_dict_table);

	const mp_obj_type_t mp_type_dict = {
	{ &mp_type_type },
	.name = MP_QSTR_dict,
	.print = dict_print,
	.make_new = dict_make_new,
	.unary_op = dict_unary_op,
	.binary_op = dict_binary_op,
	.subscr = dict_subscr,
	.getiter = dict_getiter,
	.locals_dict = (mp_obj_dict_t*)&dict_locals_dict,
	};

	#if MICROPY_PY_COLLECTIONS_ORDEREDDICT
	STATIC const mp_rom_obj_tuple_t ordereddict_base_tuple = {{&mp_type_tuple}, 1, {MP_ROM_PTR(&mp_type_dict)}};

	const mp_obj_type_t mp_type_ordereddict = {
	{ &mp_type_type },
	.name = MP_QSTR_OrderedDict,
	.print = dict_print,
	.make_new = dict_make_new,
	.unary_op = dict_unary_op,
	.binary_op = dict_binary_op,
	.subscr = dict_subscr,
	.getiter = dict_getiter,
	.bases_tuple = (mp_obj_tuple_t)(mp_rom_obj_tuple_t)&ordereddict_base_tuple,
	.locals_dict = (mp_obj_dict_t*)&dict_locals_dict,
	};
	#endif

	void mp_obj_dict_init(mp_obj_dict_t *dict, size_t n_args) {
	dict->base.type = &mp_type_dict;
	mp_map_init(&dict->map, n_args);
	}

	mp_obj_t mp_obj_new_dict(size_t n_args) {
	mp_obj_dict_t *o = m_new_obj(mp_obj_dict_t);
	mp_obj_dict_init(o, n_args);
	return MP_OBJ_FROM_PTR(o);
	}

	size_t mp_obj_dict_len(mp_obj_t self_in) {
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	return self->map.used;
	}

	mp_obj_t mp_obj_dict_store(mp_obj_t self_in, mp_obj_t key, mp_obj_t value) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	mp_map_lookup(&self->map, key, MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
	return self_in;
	}

	mp_obj_t mp_obj_dict_delete(mp_obj_t self_in, mp_obj_t key) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	dict_get_helper(&self->map, key, MP_OBJ_NULL, MP_MAP_LOOKUP_REMOVE_IF_FOUND);
	return self_in;
	}

	mp_map_t *mp_obj_dict_get_map(mp_obj_t self_in) {
	mp_check_self(MP_OBJ_IS_DICT_TYPE(self_in));
	mp_obj_dict_t *self = MP_OBJ_TO_PTR(self_in);
	return &self->map;
	}