/* Append data to the front of the buffer */
static int buffer_read_from(struct buffer *buf, int fd)
{
int bytes_read, total_bytes_read = 0;
unsigned nbytes;
/* Empty list needs initialized */
if(!buf->head) {
buf->head = buffer_node_new(buf);
buf->tail = buf->head;
}
do {
nbytes = buf->node_size - buf->tail->end;
bytes_read = read(fd, buf->tail->data + buf->tail->end, nbytes);
if(bytes_read < 1) {
if(errno != EAGAIN)
rb_sys_fail("read");
return total_bytes_read;
}
total_bytes_read += bytes_read;
buf->tail->end += nbytes;
buf->size += nbytes;
if(buf->tail->end == buf->node_size) {
buf->tail->next = buffer_node_new(buf);
buf->tail = buf->tail->next;
}
} while(bytes_read == nbytes);
return total_bytes_read;
}
/* Append data to the front of the buffer */
static void buffer_append(struct buffer *buf, char *str, unsigned len)
{
unsigned nbytes;
buf->size += len;
/* If it fits in the remaining space in the tail */
if(buf->tail && len <= buf->node_size - buf->tail->end) {
memcpy(buf->tail->data + buf->tail->end, str, len);
buf->tail->end += len;
return;
}
/* Empty list needs initialized */
if(!buf->head) {
buf->head = buffer_node_new(buf);
buf->tail = buf->head;
}
/* Build links out of the data */
while(len > 0) {
nbytes = buf->node_size - buf->tail->end;
if(len < nbytes) nbytes = len;
memcpy(buf->tail->data + buf->tail->end, str, nbytes);
str += nbytes;
len -= nbytes;
buf->tail->end += nbytes;
if(len > 0) {
buf->tail->next = buffer_node_new(buf);
buf->tail = buf->tail->next;
}
}
}
/* Prepend data to the front of the buffer */
static void buffer_prepend(struct buffer *buf, char *str, unsigned len)
{
struct buffer_node *node, *tmp;
buf->size += len;
/* If it fits in the beginning of the head */
if(buf->head && buf->head->start >= len) {
buf->head->start -= len;
memcpy(buf->head->data + buf->head->start, str, len);
} else {
node = buffer_node_new(buf);
node->next = buf->head;
buf->head = node;
if(!buf->tail) buf->tail = node;
while(len > buf->node_size) {
memcpy(node->data, str, buf->node_size);
node->end = buf->node_size;
tmp = buffer_node_new(buf);
tmp->next = node->next;
node->next = tmp;
if(buf->tail == node) buf->tail = tmp;
node = tmp;
str += buf->node_size;
len -= buf->node_size;
}
if(len > 0) {
memcpy(node->data, str, len);
node->end = len;
}
}
}
static inline void buffer_push(struct buffer *b, char *data, int size) {
if (b->offset == DATA_SIZE) {
_again:
b->cur = b->cur->next = buffer_node_new();
b->offset = 0;
}
if (b->offset <= DATA_SIZE - size) {
memcpy(b->cur->data+b->offset, data, size);
b->offset += size;
b->size += size;
} else {
int _size = DATA_SIZE-b->offset;
memcpy(b->cur->data+b->offset, data, _size);
data += _size;
b->size += _size;
size -= _size;
goto _again;
}
}
