动态数组
本文实现了可以存储固定大小数据的动态数组.
动态数组就是在内存中分配连续的区域，存储固定大小的结构数组。并能根据插入或删除的值，自动调节大小。
类似std::vector。
但本文采用C语言实现。
/**********************************************************************
* darray.h - Dynamic array for any type data *
**********************************************************************/
#ifndef DARRAY_H_INCLUDED
#define DARRAY_H_INCLUDED
#ifdef __cplusplus
extern "C" {
#endif
typedef unsigned int size_t;
#define DARRAY_BLOCK_NUMS 128
typedef struct _darray_t *darray, *DARRAY;
/* A prototype of callbacked function called by list_destroy(), NULL for no use. */
typedef void(*pfcb_darray_free_element)(void* element);
/** create a darray and initialize it
* darray arrPts;
* darray_create(&arrPts, 128, sizeof(POINT));
* ...
* darray_free(arrPts, 0, 0);
*/
void darray_create(darray *arr, size_t nums, size_t elementsize);
/* count of elements */
size_t darray_count(darray arr);
/* free a darray */
void darray_free(darray arr, pfcb_darray_free_element pfcbFreeElement, void *element);
/* erase elems */
void darray_erase(darray arr, int index, size_t num, pfcb_darray_free_element pfcbFreeElement, void *element);
/* clear all elems */
void darray_clear(darray arr, pfcb_darray_free_element pfcbFreeElement, void *element);
/* append elem to the end of array */
void darray_push_back(darray arr, void *newelement);
/* insert elem to the first of array */
void darray_push_first(darray arr, void *newelement);
/* erase last element of array and return pointer to it */
size_t darray_pop_back(darray arr, void *back);
/* erase first element of array and return pointer to it */
size_t darray_pop_first(darray arr, void *first);
/* replace elem at pos and return the one replaced */
void array_replace_at(darray arr, int index, void *replace_by, void *element);
/* get elem at index */
void darray_at(darray arr, int index, void *element);
/* */
#ifdef __cplusplus
}
#endif
#endif /* DARRAY_H_INCLUDED */
/**********************************************************************
* darray.c *
**********************************************************************/
#include "darray.h"
#include <assert.h>
#include <memory.h>
#include <malloc.h>
typedef struct _darray_t
{
unsigned char *pbytes;
size_t num_elems;
size_t maxsize; /* max capacity of bytes */
size_t elemsize; /* size of element by bytes */
}darray_t;
void darray_create(darray *arr, size_t nums, size_t elementsize)
{
darray_t *p = (darray_t*) malloc(sizeof(darray_t));
assert(p);
p->num_elems = 0;
p->elemsize = elementsize;
p->maxsize = nums * elementsize;
p->pbytes = malloc(p->maxsize);
*arr = p;
}
size_t darray_count(darray arr)
{
return arr->num_elems;
}
void darray_free(darray arr, pfcb_darray_free_element pfcbFreeElement, void *element)
{
if (pfcbFreeElement) {
size_t i;
for (i=0; i<arr->num_elems; i++) {
darray_at(arr, i, element);
(*pfcbFreeElement) (element);
}
}
free(arr->pbytes);
free(arr);
}
void darray_clear(darray arr, pfcb_darray_free_element pfcbFreeElement, void *elem)
{
size_t i, nums;
nums = arr->num_elems;
arr->num_elems = 0;
if (pfcbFreeElement) {
for (i=0; i<nums; i++) {
darray_at(arr, i, elem);
(*pfcbFreeElement) (elem);
}
}
}
void darray_erase(darray arr, int index, size_t num, pfcb_darray_free_element pfcbFreeElement, void *elem)
{
size_t i;
size_t num_elems = arr->num_elems;
for (i=index+num; i<num_elems; i++) {
if (pfcbFreeElement) {
darray_at(arr, i, elem);
(*pfcbFreeElement)(elem);
}
memcpy(arr->pbytes+(i-num)*arr->elemsize, arr->pbytes+i*arr->elemsize, arr->elemsize);
}
if (i>index+num)
arr->num_elems -= num;
if (arr->num_elems <= arr->maxsize/arr->elemsize-DARRAY_BLOCK_NUMS) {
arr->maxsize -= DARRAY_BLOCK_NUMS*arr->elemsize;
arr->pbytes = realloc(arr->pbytes, arr->maxsize);
}
}
void darray_push_back(darray arr, void *newelement)
{
if (arr->maxsize < (arr->num_elems+1)*arr->elemsize) {
arr->maxsize += (DARRAY_BLOCK_NUMS*arr->elemsize);
arr->pbytes = realloc(arr->pbytes, arr->maxsize);
assert(arr->pbytes);
}
memcpy(arr->pbytes+arr->num_elems*arr->elemsize, newelement, arr->elemsize);
arr->num_elems++;
}
void darray_push_first(darray arr, void *newelement)
{
if (arr->maxsize < (arr->num_elems+1)*arr->elemsize) {
arr->maxsize += (DARRAY_BLOCK_NUMS*arr->elemsize);
arr->pbytes = realloc(arr->pbytes, arr->maxsize);
assert(arr->pbytes);
}
memcpy(arr->pbytes+arr->elemsize, arr->pbytes, arr->elemsize*arr->num_elems);
memcpy(arr->pbytes, newelement, arr->elemsize);
arr->num_elems++;
}
size_t darray_pop_back(darray arr, void *back)
{
if (arr->num_elems > 0) {
if (back)
memcpy(back, (arr->pbytes+(arr->num_elems-1)*arr->elemsize), arr->elemsize);
arr->num_elems--;
if (arr->num_elems <= arr->maxsize/arr->elemsize-DARRAY_BLOCK_NUMS) {
arr->maxsize -= DARRAY_BLOCK_NUMS*arr->elemsize;
arr->pbytes = realloc(arr->pbytes, arr->maxsize);
}
}
return arr->num_elems;
}
size_t darray_pop_first(darray arr, void *first)
{
if (arr->num_elems > 0)
{
size_t i;
if (first)
memcpy(first, arr->pbytes, arr->elemsize);
for (i=1; i<arr->num_elems; i++)
memcpy(arr->pbytes+(i-1)*arr->elemsize, arr->pbytes+i*arr->elemsize, arr->elemsize);
arr->num_elems--;
if (arr->num_elems <= arr->maxsize/arr->elemsize-DARRAY_BLOCK_NUMS) {
arr->maxsize -= DARRAY_BLOCK_NUMS*arr->elemsize;
arr->pbytes = realloc(arr->pbytes, arr->maxsize);
}
}
return arr->num_elems;
}
void array_replace_at(darray arr, int index, void *replace_by, void *element)
{
assert(index >= 0 && index <(int)arr->num_elems);
if (element)
memcpy(element, arr->pbytes+index*arr->elemsize, arr->elemsize);
memcpy(arr->pbytes+index*arr->elemsize, replace_by, arr->elemsize);
}
void darray_at(darray arr, int index, void *element)
{
assert(index >= 0 && index <(int)arr->num_elems);
memcpy(element, arr->pbytes+index*arr->elemsize, arr->elemsize);
}
