openmv/src/omv/common/array.c
2020-12-18 23:16:55 +02:00

179 lines
4.5 KiB
C

/*
* This file is part of the OpenMV project.
*
* Copyright (c) 2013-2019 Ibrahim Abdelkader <iabdalkader@openmv.io>
* Copyright (c) 2013-2019 Kwabena W. Agyeman <kwagyeman@openmv.io>
*
* This work is licensed under the MIT license, see the file LICENSE for details.
*
* Dynamic array.
*/
#include <string.h>
#include "py/runtime.h"
#include "py/stackctrl.h"
#include "xalloc.h"
#include "array.h"
#define ARRAY_INIT_SIZE (4) // Size of one GC block.
void array_alloc(array_t **a, array_dtor_t dtor)
{
array_t *array = xalloc(sizeof(array_t));
array->index = 0;
array->length = ARRAY_INIT_SIZE;
array->dtor = dtor;
array->data = xalloc(ARRAY_INIT_SIZE * sizeof(void*));
*a = array;
}
void array_alloc_init(array_t **a, array_dtor_t dtor, int size)
{
array_t *array = xalloc(sizeof(array_t));
array->index = 0;
array->length = size;
array->dtor = dtor;
array->data = xalloc(size * sizeof(void*));
*a = array;
}
void array_clear(array_t *array)
{
if (array->dtor != NULL) {
for (int i=0, j=array->index; i<j; i++) {
array->dtor(array->data[i]);
}
}
xfree(array->data);
array->index = 0;
array->length = 0;
array->data = NULL;
// Note: realloc with null pointer and (size != 0) returns valid pointer.
// Note: realloc with valid pointer and (size == 0) returns null pointer.
}
void array_free(array_t *array)
{
array_clear(array);
xfree(array);
}
int array_length(array_t *array)
{
return array->index; // index is the actual length, length is the max length
}
void *array_at(array_t *array, int idx)
{
return array->data[idx];
}
void array_push_back(array_t *array, void *element)
{
if (array->index == array->length) {
array->length += ARRAY_INIT_SIZE;
array->data = xrealloc(array->data, array->length * sizeof(void*));
}
array->data[array->index++] = element;
}
void *array_pop_back(array_t *array)
{
void *el=NULL;
if (array->index) {
el = array->data[--array->index];
}
return el;
}
void *array_take(array_t *array, int idx)
{
void *el=array->data[idx];
if ((1 < array->index) && (idx < (array->index - 1))) {
/* Since dst is always < src we can just use memcpy */
memcpy(array->data+idx, array->data+idx+1, (array->index-idx-1) * sizeof(void*));
}
array->index--;
return el;
}
void array_erase(array_t *array, int idx)
{
if (array->dtor) {
array->dtor(array->data[idx]);
}
array_take(array, idx);
}
void array_resize(array_t *array, int num)
{
if (array->index != num) {
if (!num) {
array_clear(array);
} else {
if (array->index > num) {
if (array->dtor != NULL) {
for (int i=num, j=array->index; i<j; i++) {
array->dtor(array->data[i]);
}
}
array->index = num;
}
// resize array
array->length = num;
array->data = xrealloc(array->data, array->length * sizeof(void*));
}
}
}
// see micropython quicksort (objlist.c -> mp_quicksort)
static void quicksort(void **head, void **tail, array_comp_t comp)
{
MP_STACK_CHECK();
while (head < tail) {
void **h = head - 1;
void **t = tail;
void *v = tail[0];
for (;;) {
do ++h; while(h < t && comp(h[0], v) < 0);
do --t; while(h < t && comp(v, t[0]) < 0);
if (h >= t) break;
void *x = h[0];
h[0] = t[0];
t[0] = x;
}
void *x = h[0];
h[0] = tail[0];
tail[0] = x;
// do the smaller recursive call first, to keep stack within O(log(N))
if (t - head < tail - h - 1) {
quicksort(head, t, comp);
head = h + 1;
} else {
quicksort(h + 1, tail, comp);
tail = t;
}
}
}
// TODO Python defines sort to be stable but ours is not
void array_sort(array_t *array, array_comp_t comp)
{
if (array->index > 1) {
quicksort(array->data, array->data + array->index - 1, comp);
}
}
void array_isort(array_t *array, array_comp_t comp)
{
if (array->index > 1) {
for (int i = 1; i < array->index; i++) {
int j = i-1;
void *t = array->data[i];
while (j >= 0 && comp(array->data[j], t)) {
array->data[j+1] = array->data[j];
j--;
}
array->data[j+1] = t;
}
}
}