X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=buffer_tree.c;h=28999df50a38b31277a156acfd012e2e54806535;hp=7b3355a28b98aa601431029c83063aac016d2d9d;hb=c87045a40b9462ebeb28cc169d7bb3721c9a81d3;hpb=d1e55304068a6a82553f40ae7bee746f5ca2233d

diff --git a/buffer_tree.c b/buffer_tree.c
index 7b3355a2..28999df5 100644
--- a/buffer_tree.c
+++ b/buffer_tree.c
@@ -47,7 +47,7 @@ struct btr_node {
 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
 	list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
 
-struct btr_node *btr_new_node(char *name, struct btr_node *parent,
+struct btr_node *btr_new_node(const char *name, struct btr_node *parent,
 		btr_command_handler handler, void *context)
 {
 	struct btr_node *btrn = para_malloc(sizeof(*btrn));
@@ -287,3 +287,51 @@ void *btr_context(struct btr_node *btrn)
 {
 	return btrn->context;
 }
+
+/**
+ * Merge the first two input buffers into one.
+ *
+ * This is a quite expensive operation.
+ *
+ * \return The number of buffers that have been merged (zero, one or two).
+ */
+int btr_merge(struct btr_node *btrn)
+{
+	struct btr_buffer_reference *brs[2], *br;
+	char *bufs[2], *buf;
+	size_t szs[2], sz;
+	int i;
+
+	if (list_empty(&btrn->input_queue))
+		return 0;
+	if (list_is_singular(&btrn->input_queue))
+		return 1;
+	i = 0;
+	/* get references to the first two buffers */
+	FOR_EACH_BUFFER_REF(br, btrn) {
+		brs[i] = br;
+		szs[i] = btr_get_buffer_by_reference(brs[i], bufs + i);
+		i++;
+		if (i == 2)
+			break;
+	}
+	/* make a new btrb that combines the two buffers and a br to it. */
+	sz = szs[0] + szs[1];
+	//PARA_CRIT_LOG("merging input buffers: (%zu, %zu) -> %zu\n",
+	//	szs[0], szs[1], sz);
+	buf = para_malloc(sz);
+	/* TODO: Avoid this memcopy by introducing btr buffer pool. */
+	memcpy(buf, bufs[0], szs[0]);
+	memcpy(buf + szs[0], bufs[1], szs[1]);
+
+	br = para_malloc(sizeof(*br));
+	br->btrb = new_btrb(buf, sz);
+	br->btrb->refcount = 1;
+	br->consumed = 0;
+
+	/* replace the first two refs by the new one */
+	btr_drop_buffer_reference(brs[0]);
+	btr_drop_buffer_reference(brs[1]);
+	para_list_add(&br->node, &btrn->input_queue);
+	return 2;
+}