126 lines
4.5 KiB
C
126 lines
4.5 KiB
C
/*
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* This file is part of the Micro Python 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 <unistd.h>
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#include "py/nlr.h"
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#include "py/objlist.h"
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#include "py/runtime0.h"
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#include "py/runtime.h"
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#if MICROPY_PY_UHEAPQ
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// the algorithm here is modelled on CPython's heapq.py
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STATIC mp_obj_list_t *get_heap(mp_obj_t heap_in) {
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if (!MP_OBJ_IS_TYPE(heap_in, &mp_type_list)) {
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nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "heap must be a list"));
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}
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return heap_in;
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}
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STATIC void heap_siftdown(mp_obj_list_t *heap, mp_uint_t start_pos, mp_uint_t pos) {
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mp_obj_t item = heap->items[pos];
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while (pos > start_pos) {
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mp_uint_t parent_pos = (pos - 1) >> 1;
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mp_obj_t parent = heap->items[parent_pos];
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if (mp_binary_op(MP_BINARY_OP_LESS, item, parent) == mp_const_true) {
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heap->items[pos] = parent;
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pos = parent_pos;
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} else {
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break;
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}
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}
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heap->items[pos] = item;
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}
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STATIC void heap_siftup(mp_obj_list_t *heap, mp_uint_t pos) {
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mp_uint_t start_pos = pos;
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mp_uint_t end_pos = heap->len;
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mp_obj_t item = heap->items[pos];
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for (mp_uint_t child_pos = 2 * pos + 1; child_pos < end_pos; child_pos = 2 * pos + 1) {
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// choose right child if it's <= left child
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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) {
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child_pos += 1;
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}
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// bubble up the smaller child
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heap->items[pos] = heap->items[child_pos];
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pos = child_pos;
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}
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heap->items[pos] = item;
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heap_siftdown(heap, start_pos, pos);
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}
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STATIC mp_obj_t mod_uheapq_heappush(mp_obj_t heap_in, mp_obj_t item) {
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mp_obj_list_t *heap = get_heap(heap_in);
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mp_obj_list_append(heap, item);
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heap_siftdown(heap, 0, heap->len - 1);
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_uheapq_heappush_obj, mod_uheapq_heappush);
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STATIC mp_obj_t mod_uheapq_heappop(mp_obj_t heap_in) {
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mp_obj_list_t *heap = get_heap(heap_in);
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if (heap->len == 0) {
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nlr_raise(mp_obj_new_exception_msg(&mp_type_IndexError, "empty heap"));
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}
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mp_obj_t item = heap->items[0];
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heap->len -= 1;
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heap->items[0] = heap->items[heap->len];
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heap->items[heap->len] = MP_OBJ_NULL; // so we don't retain a pointer
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if (heap->len) {
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heap_siftup(heap, 0);
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}
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return item;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_uheapq_heappop_obj, mod_uheapq_heappop);
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STATIC mp_obj_t mod_uheapq_heapify(mp_obj_t heap_in) {
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mp_obj_list_t *heap = get_heap(heap_in);
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for (mp_uint_t i = heap->len / 2; i > 0;) {
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heap_siftup(heap, --i);
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}
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_uheapq_heapify_obj, mod_uheapq_heapify);
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STATIC const mp_map_elem_t mp_module_uheapq_globals_table[] = {
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{ MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_uheapq) },
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{ MP_OBJ_NEW_QSTR(MP_QSTR_heappush), (mp_obj_t)&mod_uheapq_heappush_obj },
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{ MP_OBJ_NEW_QSTR(MP_QSTR_heappop), (mp_obj_t)&mod_uheapq_heappop_obj },
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{ MP_OBJ_NEW_QSTR(MP_QSTR_heapify), (mp_obj_t)&mod_uheapq_heapify_obj },
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};
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STATIC MP_DEFINE_CONST_DICT(mp_module_uheapq_globals, mp_module_uheapq_globals_table);
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const mp_obj_module_t mp_module_uheapq = {
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.base = { &mp_type_module },
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.name = MP_QSTR_uheapq,
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.globals = (mp_obj_dict_t*)&mp_module_uheapq_globals,
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};
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#endif //MICROPY_PY_UHEAPQ
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