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/*********************************************************************
* bfs *
* Copyright (C) 2016 Tavian Barnes <tavianator@tavianator.com> *
* *
* This program is free software. It comes without any warranty, to *
* the extent permitted by applicable law. You can redistribute it *
* and/or modify it under the terms of the Do What The Fuck You Want *
* To Public License, Version 2, as published by Sam Hocevar. See *
* the COPYING file or http://www.wtfpl.net/ for more details. *
*********************************************************************/
#include "dstring.h"
#include <stdlib.h>
#include <string.h>
/**
* The memory representation of a dynamic string. Users get a pointer to data.
*/
struct dstring {
size_t capacity;
size_t length;
char data[];
};
static struct dstring *dstrheader(const char *dstr) {
return (struct dstring *)(dstr - offsetof(struct dstring, data));
}
static size_t dstrsize(size_t capacity) {
return sizeof(struct dstring) + capacity + 1;
}
char *dstralloc(size_t capacity) {
struct dstring *header = malloc(dstrsize(capacity));
if (!header) {
return NULL;
}
header->capacity = capacity;
header->length = 0;
return header->data;
}
size_t dstrlen(const char *dstr) {
return dstrheader(dstr)->length;
}
int dstreserve(char **dstr, size_t capacity) {
struct dstring *header = dstrheader(*dstr);
if (capacity > header->capacity) {
capacity *= 2;
header = realloc(header, dstrsize(capacity));
if (!header) {
return -1;
}
header->capacity = capacity;
*dstr = header->data;
}
return 0;
}
int dstresize(char **dstr, size_t length) {
if (dstreserve(dstr, length) != 0) {
return -1;
}
struct dstring *header = dstrheader(*dstr);
header->length = length;
header->data[length] = '\0';
return 0;
}
static int dstrcat_impl(char **dest, const char *src, size_t srclen) {
size_t oldlen = dstrlen(*dest);
size_t newlen = oldlen + srclen;
if (dstresize(dest, newlen) != 0) {
return -1;
}
memcpy(*dest + oldlen, src, srclen);
return 0;
}
int dstrcat(char **dest, const char *src) {
return dstrcat_impl(dest, src, strlen(src));
}
int dstrncat(char **dest, const char *src, size_t n) {
return dstrcat_impl(dest, src, strnlen(src, n));
}
int dstrapp(char **str, char c) {
return dstrcat_impl(str, &c, 1);
}
void dstrfree(char *dstr) {
if (dstr) {
free(dstrheader(dstr));
}
}
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