Function vstring_extend

lib_acl/src/stdlib/acl_vstring.c:37–119

/* vstring_extend - variable-length string buffer extension policy */

static int vstring_extend(ACL_VBUF *bp, ssize_t incr)
{
	const char *myname = "vstring_extend";
	ssize_t used = (ssize_t) (bp->ptr - bp->data), new_len;
	ACL_VSTRING *vp = (ACL_VSTRING *) bp;

	if (vp->maxlen > 0 && (ssize_t) ACL_VSTRING_LEN(vp) >= vp->maxlen) {
		ACL_VSTRING_AT_OFFSET(vp, vp->maxlen - 1);
		ACL_VSTRING_TERMINATE(vp);
		acl_msg_warn("%s(%d), %s: overflow maxlen: %ld, %ld",
			__FILE__, __LINE__, myname, (long) vp->maxlen,
			(long) ACL_VSTRING_LEN(vp));
		bp->flags |= ACL_VBUF_FLAG_EOF;
		return ACL_VBUF_EOF;
	}

#ifdef ACL_WINDOWS
	if (bp->fd == ACL_FILE_INVALID && (bp->flags & ACL_VBUF_FLAG_FIXED))
#else
	if (bp->fd < 0 && (bp->flags & ACL_VBUF_FLAG_FIXED))
#endif
	{
		acl_msg_warn("%s(%d), %s: can't extend fixed buffer",
			__FILE__, __LINE__, myname);
		return ACL_VBUF_EOF;
	}

	/*
	 * Note: vp->vbuf.len is the current buffer size (both on entry and on
	 * exit of this routine). We round up the increment size to the buffer
	 * size to avoid silly little buffer increments. With really large
	 * strings we might want to abandon the length doubling strategy, and
	 * go to fixed increments.
	 */
#ifdef INCR_NO_DOUBLE
	/* below come from redis-server/sds.c/sdsMakeRoomFor, which can
	 * avoid memory double growing too large --- 2015.2.2, zsx
	 */
	new_len = bp->len + incr;
	if (new_len < MAX_PREALLOC) {
		new_len *= 2;
	} else {
		new_len += MAX_PREALLOC;
	}
#else
	new_len = bp->len + (bp->len > incr ? bp->len : incr);
#endif

	if (vp->maxlen > 0 && new_len > vp->maxlen) {
		new_len = vp->maxlen;
	}

	if (vp->vbuf.flags & ACL_VBUF_FLAG_SLICE) {
		bp->data = (unsigned char *) acl_slice_pool_realloc(__FILE__,
			__LINE__, bp->alloc.slice, bp->data, new_len);
	} else if (vp->vbuf.flags & ACL_VBUF_FLAG_DBUF) {
		const unsigned char *data = bp->data;
		bp->data = (unsigned char *)