micropython/py/objreversed.c

75 lines
2.6 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 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 <stdlib.h>
#include <assert.h>
#include "mpconfig.h"
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
typedef struct _mp_obj_reversed_t {
mp_obj_base_t base;
mp_obj_t seq; // sequence object that we are reversing
mp_uint_t cur_index; // current index, plus 1; 0=no more, 1=last one (index 0)
} mp_obj_reversed_t;
STATIC mp_obj_t reversed_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 1, 1, false);
mp_obj_reversed_t *o = m_new_obj(mp_obj_reversed_t);
o->base.type = &mp_type_reversed;
o->seq = args[0];
o->cur_index = mp_obj_get_int(mp_obj_len(args[0])); // start at the end of the sequence
return o;
}
STATIC mp_obj_t reversed_iternext(mp_obj_t self_in) {
assert(MP_OBJ_IS_TYPE(self_in, &mp_type_reversed));
mp_obj_reversed_t *self = self_in;
// "raise" stop iteration if we are at the end (the start) of the sequence
if (self->cur_index == 0) {
return MP_OBJ_STOP_ITERATION;
}
// pre-decrement and index sequence
self->cur_index -= 1;
return mp_obj_subscr(self->seq, MP_OBJ_NEW_SMALL_INT(self->cur_index), MP_OBJ_SENTINEL);
}
const mp_obj_type_t mp_type_reversed = {
{ &mp_type_type },
.name = MP_QSTR_reversed,
.make_new = reversed_make_new,
.getiter = mp_identity,
.iternext = reversed_iternext,
};