/**
* Enlarge an autobuffer if necessary
* @param autobuf pointer to autobuf object
* @param new_size number of bytes necessary in autobuffer
* @return -1 if an out-of-memory error happened, 0 otherwise
*/
static int
_autobuf_enlarge(struct autobuf *autobuf, size_t new_size)
{
char *p;
size_t roundUpSize;
new_size++;
if (new_size > autobuf->_total) {
roundUpSize = ROUND_UP_TO_POWER_OF_2(new_size+1, getpagesize());
p = realloc(autobuf->_buf, roundUpSize);
if (p == NULL) {
#ifdef WIN32
WSASetLastError(ENOMEM);
#else
errno = ENOMEM;
#endif
autobuf->_error = true;
return -1;
}
autobuf->_buf = p;
memset(&autobuf->_buf[autobuf->_total], 0, roundUpSize - autobuf->_total);
autobuf->_total = roundUpSize;
}
return 0;
}
/**
* Remove a prefix from an autobuffer. This function can be used
* to create an autobuffer based fifo.
* @param autobuf pointer to autobuf object
* @param file code file where this function was called (supplied by macro)
* @param line line number in file where this function was called (supplied by macro)
* @param file code file where this function was called (supplied by macro)
* @param line line number in file where this function was called (supplied by macro)
* @param len number of bytes to be removed
*/
void
abuf_pull(struct autobuf * autobuf, int len) {
char *p;
int newsize;
if (autobuf == NULL) return;
if (len != autobuf->len) {
memmove(autobuf->buf, &autobuf->buf[len], autobuf->len - len);
}
autobuf->len -= len;
newsize = ROUND_UP_TO_POWER_OF_2(autobuf->len + 1, AUTOBUFCHUNK);
if (newsize + 2*AUTOBUFCHUNK >= autobuf->size) {
/* only reduce buffer size if difference is larger than two chunks */
return;
}
/* generate smaller buffer */
p = autobuf_realloc(autobuf->buf, newsize);
if (p == NULL) {
/* keep the longer buffer if we cannot get a smaller one */
return;
}
autobuf->buf = p;
autobuf->size = newsize;
return;
}
/**
* Initialize an autobuffer and allocate a chunk of memory
* @param autobuf pointer to autobuf object
* @param file code file where this function was called (supplied by macro)
* @param line line number in file where this function was called (supplied by macro)
* @param initial_size size of allocated memory, might be 0
* @return -1 if an out-of-memory error happened, 0 otherwise
*/
int
abuf_init(struct autobuf *autobuf, int initial_size)
{
autobuf->len = 0;
if (initial_size <= 0) {
autobuf->size = 0;
autobuf->buf = NULL;
return 0;
}
autobuf->size = ROUND_UP_TO_POWER_OF_2(initial_size, AUTOBUFCHUNK);
autobuf->buf = autobuf_malloc(autobuf->size);
if (autobuf->buf == NULL) {
autobuf->size = 0;
return -1;
}
*autobuf->buf = '\0';
return 0;
}
/**
* Enlarge an autobuffer if necessary
* @param autobuf pointer to autobuf object
* @param file code file where this function was called (supplied by macro)
* @param line line number in file where this function was called (supplied by macro)
* @param new_size number of bytes necessary in autobuffer
* @return -1 if an out-of-memory error happened, 0 otherwise
*/
static int
int_autobuf_enlarge(struct autobuf *autobuf, int new_size)
{
new_size++;
if (new_size > autobuf->size) {
char *p;
int roundUpSize = ROUND_UP_TO_POWER_OF_2(new_size, AUTOBUFCHUNK);
p = autobuf_realloc(autobuf->buf, roundUpSize);
if (p == NULL) {
#ifdef WIN32
WSASetLastError(ENOMEM);
#else
errno = ENOMEM;
#endif
return -1;
}
autobuf->buf = p;
memset(&autobuf->buf[autobuf->size], 0, roundUpSize - autobuf->size);
autobuf->size = roundUpSize;
}
return 0;
}
