[ccan] [PATCH 7/7] aga: Add edge costs

[David Gibson]

This adds support for the edge_info function giving a cost or length for an
edge.  This can be given as a (long) integer or a (double) float.  Or both,
but that might have odd effects.

Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
---
 ccan/aga/aga.c |  4 ++++
 ccan/aga/aga.h | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/ccan/aga/aga.c b/ccan/aga/aga.c
index ee3f810..1737923 100644
--- a/ccan/aga/aga.c
+++ b/ccan/aga/aga.c
@@ -87,7 +87,11 @@ int aga_edge_info(const struct aga_graph *g, const struct aga_node *n,
 	int rc;
 
 	ei->to = NULL;
+	ei->icost = 1;
+	ei->fcost = 1.0;
 	rc = g->edge_info(g, n, e, ei);
 	assert(rc <= 0);
+	if ((ei->fcost == 1.0) && (ei->icost != 1))
+		ei->fcost = (aga_fcost_t)ei->icost;
 	return rc;
 }
diff --git a/ccan/aga/aga.h b/ccan/aga/aga.h
index 4ec6bc6..ea79b73 100644
--- a/ccan/aga/aga.h
+++ b/ccan/aga/aga.h
@@ -72,6 +72,16 @@
  *   reference to that node by the edge callback for *any* node and
  *   index MUST use the same pointer.
  *
+ * - The ei->icost field MAY be set by the edge_info callback to
+ *   indicate the edge's cost / length represented as an integer (of
+ *   type aga_icost_t),  Otherwise the cost defaults to 1.
+ *
+ * - The ei->fcost field MAY be set by the edge_info callback to
+ *   indicate the edge's cost / length represented as a floating point
+ *   number (of type aga_fcost_t).  If edge_info sets icost but not
+ *   fcost, fcost will be set to icost converted to floating point.
+ *   Otherwise, it defaults to 1.0.
+ *
  * Concurrency
  * ===========
  *
@@ -129,8 +139,13 @@ struct aga_node {
 	} u;
 };
 
+typedef long aga_icost_t;
+typedef double aga_fcost_t;
+
 struct aga_edge_info {
 	struct aga_node *to;
+	aga_icost_t icost; /* integer edge cost */
+	aga_fcost_t fcost; /* floating point edge cost */
 };
 
 typedef const void *(*aga_first_edge_fn)(const struct aga_graph *g,
-- 
2.4.3