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circuitpython/extmod/moduheapq.c

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/*
* This file is part of the MicroPython 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 "py/objlist.h"
#include "py/runtime.h"
#include "supervisor/shared/translate.h"
#if MICROPY_PY_UHEAPQ
// the algorithm here is modelled on CPython's heapq.py
STATIC mp_obj_list_t *get_heap(mp_obj_t heap_in) {
if (!MP_OBJ_IS_TYPE(heap_in, &mp_type_list)) {
mp_raise_TypeError(translate("heap must be a list"));
}
return MP_OBJ_TO_PTR(heap_in);
}
STATIC void heap_siftdown(mp_obj_list_t *heap, mp_uint_t start_pos, mp_uint_t pos) {
mp_obj_t item = heap->items[pos];
while (pos > start_pos) {
mp_uint_t parent_pos = (pos - 1) >> 1;
mp_obj_t parent = heap->items[parent_pos];
if (mp_binary_op(MP_BINARY_OP_LESS, item, parent) == mp_const_true) {
heap->items[pos] = parent;
pos = parent_pos;
} else {
break;
}
}
heap->items[pos] = item;
}
STATIC void heap_siftup(mp_obj_list_t *heap, mp_uint_t pos) {
mp_uint_t start_pos = pos;
mp_uint_t end_pos = heap->len;
mp_obj_t item = heap->items[pos];
for (mp_uint_t child_pos = 2 * pos + 1; child_pos < end_pos; child_pos = 2 * pos + 1) {
// choose right child if it's <= left child
if (child_pos + 1 < end_pos && mp_binary_op(MP_BINARY_OP_LESS, heap->items[child_pos], heap->items[child_pos + 1]) == mp_const_false) {
child_pos += 1;
}
// bubble up the smaller child
heap->items[pos] = heap->items[child_pos];
pos = child_pos;
}
heap->items[pos] = item;
heap_siftdown(heap, start_pos, pos);
}
STATIC mp_obj_t mod_uheapq_heappush(mp_obj_t heap_in, mp_obj_t item) {
mp_obj_list_t *heap = get_heap(heap_in);
mp_obj_list_append(heap_in, item);
heap_siftdown(heap, 0, heap->len - 1);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_uheapq_heappush_obj, mod_uheapq_heappush);
STATIC mp_obj_t mod_uheapq_heappop(mp_obj_t heap_in) {
mp_obj_list_t *heap = get_heap(heap_in);
if (heap->len == 0) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_IndexError, translate("empty heap")));
}
mp_obj_t item = heap->items[0];
heap->len -= 1;
heap->items[0] = heap->items[heap->len];
heap->items[heap->len] = MP_OBJ_NULL; // so we don't retain a pointer
if (heap->len) {
heap_siftup(heap, 0);
}
return item;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_uheapq_heappop_obj, mod_uheapq_heappop);
STATIC mp_obj_t mod_uheapq_heapify(mp_obj_t heap_in) {
mp_obj_list_t *heap = get_heap(heap_in);
for (mp_uint_t i = heap->len / 2; i > 0;) {
heap_siftup(heap, --i);
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_uheapq_heapify_obj, mod_uheapq_heapify);
STATIC const mp_rom_map_elem_t mp_module_uheapq_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_uheapq) },
{ MP_ROM_QSTR(MP_QSTR_heappush), MP_ROM_PTR(&mod_uheapq_heappush_obj) },
{ MP_ROM_QSTR(MP_QSTR_heappop), MP_ROM_PTR(&mod_uheapq_heappop_obj) },
{ MP_ROM_QSTR(MP_QSTR_heapify), MP_ROM_PTR(&mod_uheapq_heapify_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_uheapq_globals, mp_module_uheapq_globals_table);
const mp_obj_module_t mp_module_uheapq = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t*)&mp_module_uheapq_globals,
};
#endif //MICROPY_PY_UHEAPQ