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/****************************************************************************
* bfs *
* Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
#include "darray.h"
#include <stdlib.h>
#include <string.h>
/**
* The darray header.
*/
struct darray {
/** The current capacity of the array, as a count of elements. */
size_t capacity;
/** The current length of the array. */
size_t length;
// The array elements are stored after this header in memory. Not using
// a flexible array member to avoid worrying about strict aliasing. We
// assume that 2*sizeof(size_t) keeps any memory allocation suitably
// aligned for the element type.
};
/** Get the header for a darray. */
static struct darray *darray_header(const void *da) {
return (struct darray *)da - 1;
}
/** Get the array from a darray header. */
static char *darray_data(struct darray *header) {
return (char *)(header + 1);
}
size_t darray_length(const void *da) {
if (da) {
return darray_header(da)->length;
} else {
return 0;
}
}
void *darray_push(void *da, const void *item, size_t size) {
struct darray *header;
if (da) {
header = darray_header(da);
} else {
header = malloc(sizeof(*header) + size);
if (!header) {
return NULL;
}
header->capacity = 1;
header->length = 0;
}
size_t capacity = header->capacity;
size_t i = header->length++;
if (i >= capacity) {
capacity *= 2;
header = realloc(header, sizeof(*header) + capacity*size);
if (!header) {
// This failure will be detected by darray_check()
return da;
}
header->capacity = capacity;
}
char *data = darray_data(header);
memcpy(data + i*size, item, size);
return data;
}
int darray_check(void *da) {
if (!da) {
return -1;
}
struct darray *header = darray_header(da);
if (header->length <= header->capacity) {
return 0;
} else {
// realloc() failed in darray_push(), so reset the length and report the failure
header->length = header->capacity;
return -1;
}
}
void darray_free(void *da) {
if (da) {
free(darray_header(da));
}
}
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