X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=buffer_tree.c;h=9884c2e2ff1b1fc4661bab71b585bede6d2eba6a;hp=4aeb790a6e3c6e8efe9a841e4b12fbe331f360f9;hb=a4f75cecaaee538edb7aae3f0ff19168a1dab59d;hpb=a09516998f148e8892bb8665ffe3dcf58ac7e5c5

diff --git a/buffer_tree.c b/buffer_tree.c
index 4aeb790a..9884c2e2 100644
--- a/buffer_tree.c
+++ b/buffer_tree.c
@@ -1,3 +1,10 @@
+/*
+ * Copyright (C) 2009-2010 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file buffer_tree.c Buffer tree and buffer pool implementations. */
 #include <regex.h>
 #include <stdbool.h>
 
@@ -159,6 +166,35 @@ size_t btr_pool_get_buffer(struct btr_pool *btrp, char **result)
 	return btr_pool_available(btrp);
 }
 
+/**
+ * Get references to buffers pointing to free space of the buffer pool area.
+ *
+ * \param btrp The buffer pool.
+ * \param iov The scatter array.
+ *
+ * \return Zero if the buffer pool is full, one if the free space of the buffer
+ * pool area is available as a single contiguous buffer, two if the free space
+ * consists of two buffers. If this function returns the value n, then n
+ * elements of \a iov are initialized.
+ */
+int btr_pool_get_buffers(struct btr_pool *btrp, struct iovec iov[2])
+{
+	size_t sz, unused;
+	char *buf;
+
+	sz = btr_pool_get_buffer(btrp, &buf);
+	if (sz == 0)
+		return 0;
+	iov[0].iov_len = sz;
+	iov[0].iov_base = buf;
+	unused = btr_pool_unused(btrp);
+	if (sz == unused)
+		return 1;
+	iov[1].iov_len = unused - sz;
+	iov[1].iov_base = btrp->area_start;
+	return 2;
+}
+
 /**
  * Mark a part of the buffer pool area as allocated.
  *
@@ -727,12 +763,15 @@ void btr_splice_out_node(struct btr_node *btrn)
 	assert(list_empty(&btrn->children));
 }
 
-/*
- * Return the size of the largest input queue.
+/**
+ * Return number of queued output bytes of a buffer tree node.
+ *
+ * \param btrn The node whose output queue size should be computed.
  *
- * Iterates over all children of the given node.
+ * This function iterates over all children of the given node and returns the
+ * size of the largest input queue.
  */
-static size_t btr_bytes_pending(struct btr_node *btrn)
+size_t btr_get_output_queue_size(struct btr_node *btrn)
 {
 	size_t max_size = 0;
 	struct btr_node *ch;
@@ -822,7 +861,7 @@ static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
 	struct btr_buffer_reference *br, *wbr = NULL;
 	int num_refs; /* including wrap buffer */
 	char *buf, *buf1 = NULL, *buf2 = NULL;
-	size_t sz, sz1 = 0, sz2 = 0, wsz;
+	size_t sz, sz1 = 0, sz2 = 0, wb_consumed = 0;
 
 	br = get_first_input_br(btrn);
 	if (!br || br_available_bytes(br) >= dest_size)
@@ -839,6 +878,7 @@ static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
 			wbr = br;
 			if (sz >= dest_size)
 				return;
+			wb_consumed = br->consumed;
 			continue;
 		}
 		if (!buf1) {
@@ -858,7 +898,7 @@ static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
 		assert(buf2 + sz2 == buf);
 		sz2 += sz;
 next:
-		if (sz1 + sz2 >= dest_size)
+		if (sz1 + sz2 >= dest_size + wb_consumed)
 			break;
 	}
 	if (!buf2) /* nothing to do */
@@ -890,7 +930,6 @@ next:
 	 * We already have a wrap buffer, but it is too small. It might be
 	 * partially used.
 	 */
-	wsz = br_available_bytes(wbr);
 	if (wbr->wrap_count == sz1 && wbr->btrb->size >= sz1 + sz2) /* nothing we can do about it */
 		return;
 	sz = sz1 + sz2 - wbr->btrb->size; /* amount of new data */
@@ -1074,7 +1113,7 @@ int btr_node_status(struct btr_node *btrn, size_t min_iqs,
 	if (type != BTR_NT_LEAF) {
 		if (btr_no_children(btrn))
 			return -E_BTR_NO_CHILD;
-		if (btr_bytes_pending(btrn) > BTRN_MAX_PENDING)
+		if (btr_get_output_queue_size(btrn) > BTRN_MAX_PENDING)
 			return 0;
 	}
 	if (type != BTR_NT_ROOT) {