X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fintmap%2Fintmap.h;h=834c969fa7c77e46dcc262b50b7b4c80b3c9b4d5;hp=207b7c9d2b18f993fd3a2a7692f8146391e3f864;hb=7aac849abf06ef469c2aad9a0dd6e3bb82ef1f96;hpb=f7ead5da96bfb5ce3ebffe11256bbcb5f4b4f750

diff --git a/ccan/intmap/intmap.h b/ccan/intmap/intmap.h
index 207b7c9d..834c969f 100644
--- a/ccan/intmap/intmap.h
+++ b/ccan/intmap/intmap.h
@@ -309,6 +309,32 @@ void *intmap_after_(const struct intmap *map, intmap_index_t *indexp);
 	tcon_cast((smap), sintmap_canary,				\
 		  sintmap_after_(sintmap_unwrap_(smap), (indexp)))
 
+/**
+ * uintmap_before - get the closest preceding index in an unsigned intmap
+ * @umap: the typed intmap to iterate through.
+ * @indexp: the succeeding index (may not exist)
+ *
+ * Returns NULL if the there is no entry < @indexp, otherwise
+ * populates *@indexp and returns the highest entry < @indexp.
+ */
+#define uintmap_before(umap, indexp)					\
+	tcon_cast((umap), uintmap_canary,				\
+		  intmap_before_(uintmap_unwrap_(umap), (indexp)))
+
+void *intmap_before_(const struct intmap *map, intmap_index_t *indexp);
+
+/**
+ * sintmap_before - get the closest preceding index in a signed intmap
+ * @smap: the typed intmap to iterate through.
+ * @indexp: the succeeding index (may not exist)
+ *
+ * Returns NULL if the there is no entry < @indexp, otherwise
+ * populates *@indexp and returns the highest entry < @indexp.
+ */
+#define sintmap_before(smap, indexp)					\
+	tcon_cast((smap), sintmap_canary,				\
+		  sintmap_before_(sintmap_unwrap_(smap), (indexp)))
+
 /**
  * uintmap_last - get last value in an unsigned intmap
  * @umap: the typed intmap to iterate through.
@@ -455,6 +481,15 @@ static inline void *sintmap_after_(const struct intmap *map,
 	return ret;
 }
 
+static inline void *sintmap_before_(const struct intmap *map,
+				   sintmap_index_t *indexp)
+{
+	intmap_index_t i = SINTMAP_OFF(*indexp);
+	void *ret = intmap_before_(map, &i);
+	*indexp = SINTMAP_UNOFF(i);
+	return ret;
+}
+
 static inline void *sintmap_last_(const struct intmap *map,
 				  sintmap_index_t *indexp)
 {