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/*
* bytearray.c
* simple byte array implementation
*
* Copyright (c) 2011 Nikias Bassen, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include <stdint.h>
#include "bytearray.h"
#define PAGE_SIZE 4096
bytearray_t *byte_array_new(size_t initial)
{
bytearray_t *a = (bytearray_t*)malloc(sizeof(bytearray_t));
if (!a) {
return NULL;
}
if (initial > PAGE_SIZE) {
if (initial > SIZE_MAX - (PAGE_SIZE-1)) {
/* rounding up to the page size would overflow */
free(a);
return NULL;
}
a->capacity = (initial+(PAGE_SIZE-1)) & (~(PAGE_SIZE-1));
} else {
a->capacity = PAGE_SIZE;
}
a->data = malloc(a->capacity);
if (!a->data) {
free(a);
return NULL;
}
a->len = 0;
a->stream = NULL;
return a;
}
bytearray_t *byte_array_new_for_stream(FILE *stream)
{
bytearray_t *a = (bytearray_t*)malloc(sizeof(bytearray_t));
if (!a) {
return NULL;
}
a->capacity = (size_t)-1;
a->data = NULL;
a->len = 0;
a->stream = stream;
return a;
}
void byte_array_free(bytearray_t *ba)
{
if (!ba) return;
if (ba->data) {
free(ba->data);
}
free(ba);
}
void byte_array_grow(bytearray_t *ba, size_t amount)
{
if (ba->stream || !ba->data) {
return;
}
size_t increase;
if (amount > PAGE_SIZE) {
/* round up to the page size, guarding against integer overflow */
increase = (amount <= SIZE_MAX - (PAGE_SIZE-1)) ? ((amount+(PAGE_SIZE-1)) & (~(PAGE_SIZE-1))) : 0;
} else {
increase = PAGE_SIZE;
}
if (increase == 0 || increase > SIZE_MAX - ba->capacity) {
/* integer overflow */
free(ba->data);
ba->data = NULL;
ba->len = 0;
ba->capacity = 0;
return;
}
/* grow geometrically (doubling) to keep repeated appends linear; if that
* fails, fall back to the minimum required size before giving up */
void *newdata = NULL;
if (ba->capacity <= ((size_t)-1) / 2 && ba->capacity > increase) {
newdata = realloc(ba->data, ba->capacity * 2);
if (newdata) {
increase = ba->capacity;
}
}
if (!newdata) {
newdata = realloc(ba->data, ba->capacity + increase);
}
if (!newdata) {
/* out of memory: put the array into a failed state (data == NULL),
* further appends are ignored and callers must check ba->data */
free(ba->data);
ba->data = NULL;
ba->len = 0;
ba->capacity = 0;
return;
}
ba->data = newdata;
ba->capacity += increase;
}
void byte_array_append(bytearray_t *ba, void *buf, size_t len)
{
if (!ba || (!ba->stream && !ba->data) || (len <= 0)) return;
if (ba->stream) {
if (fwrite(buf, 1, len, ba->stream) < len) {
#if DEBUG
fprintf(stderr, "ERROR: Failed to write to stream.\n");
#endif
}
} else {
if (len > SIZE_MAX - ba->len) {
/* integer overflow when computing the new total length */
return;
}
size_t remaining = ba->capacity-ba->len;
if (len > remaining) {
size_t needed = len - remaining;
byte_array_grow(ba, needed);
if (!ba->data) {
return;
}
}
memcpy(((char*)ba->data) + ba->len, buf, len);
}
ba->len += len;
}
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