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darray.c
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darray.c
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#include <assert.h>
#include <stdlib.h>
#include "darray.h"
/*
* for type-safe dynamic array, see
* https://github.com/nothings/stb/blob/master/stretchy_buffer.h
*/
#define DARRAY_RAW_DATA(darray) ((int*)(darray) - 2)
#define DARRAY_CAPACITY(darray) (DARRAY_RAW_DATA(darray)[0])
#define DARRAY_OCCUPIED(darray) (DARRAY_RAW_DATA(darray)[1])
int darray_size(void *darray) {
return darray != NULL ? DARRAY_OCCUPIED(darray) : 0;
}
void darray_free(void *darray) {
if (darray != NULL) {
free(DARRAY_RAW_DATA(darray));
}
}
void *darray_hold(void *darray, int count, int item_size) {
int header_size = sizeof(int) * 2;
assert(count > 0 && item_size > 0);
if (darray == NULL) {
int raw_size = header_size + item_size * count;
int *base = (int*)malloc(raw_size);
base[0] = count; /* capacity */
base[1] = count; /* occupied */
return base + 2;
} else if (DARRAY_OCCUPIED(darray) + count <= DARRAY_CAPACITY(darray)) {
DARRAY_OCCUPIED(darray) += count;
return darray;
} else {
int needed_size = DARRAY_OCCUPIED(darray) + count;
int double_curr = DARRAY_CAPACITY(darray) * 2;
int capacity = needed_size > double_curr ? needed_size : double_curr;
int occupied = needed_size;
int raw_size = header_size + item_size * capacity;
int *base = (int*)realloc(DARRAY_RAW_DATA(darray), raw_size);
base[0] = capacity;
base[1] = occupied;
return base + 2;
}
}