80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2014 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include <assert.h>
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#include "py/runtime.h"
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#if MICROPY_PY_BUILTINS_REVERSED
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typedef struct _mp_obj_reversed_t {
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mp_obj_base_t base;
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mp_obj_t seq; // sequence object that we are reversing
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mp_uint_t cur_index; // current index, plus 1; 0=no more, 1=last one (index 0)
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} mp_obj_reversed_t;
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STATIC mp_obj_t reversed_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
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mp_arg_check_num(n_args, n_kw, 1, 1, false);
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// check if __reversed__ exists, and if so delegate to it
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mp_obj_t dest[2];
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mp_load_method_maybe(args[0], MP_QSTR___reversed__, dest);
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if (dest[0] != MP_OBJ_NULL) {
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return mp_call_method_n_kw(0, 0, dest);
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}
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mp_obj_reversed_t *o = mp_obj_malloc(mp_obj_reversed_t, type);
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o->seq = args[0];
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o->cur_index = mp_obj_get_int(mp_obj_len(args[0])); // start at the end of the sequence
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return MP_OBJ_FROM_PTR(o);
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}
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STATIC mp_obj_t reversed_iternext(mp_obj_t self_in) {
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mp_check_self(mp_obj_is_type(self_in, &mp_type_reversed));
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mp_obj_reversed_t *self = MP_OBJ_TO_PTR(self_in);
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// "raise" stop iteration if we are at the end (the start) of the sequence
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if (self->cur_index == 0) {
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return MP_OBJ_STOP_ITERATION;
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}
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// pre-decrement and index sequence
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self->cur_index -= 1;
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return mp_obj_subscr(self->seq, MP_OBJ_NEW_SMALL_INT(self->cur_index), MP_OBJ_SENTINEL);
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}
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const mp_obj_type_t mp_type_reversed = {
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{ &mp_type_type },
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.name = MP_QSTR_reversed,
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.make_new = reversed_make_new,
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.getiter = mp_identity_getiter,
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.iternext = reversed_iternext,
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};
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#endif // MICROPY_PY_BUILTINS_REVERSED
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