[PATCH 1/5] idmap: add api for finding a certain id in map

[Dragos Tatulea <dragos@endocode.com>]

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---
 src/idmap.c | 12 ++++++++++++
 src/idmap.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/src/idmap.c b/src/idmap.c
index c097eb4..da32d96 100644
--- a/src/idmap.c
+++ b/src/idmap.c
@@ -166,6 +166,18 @@ void idmap_take(struct idmap *idmap, unsigned int id)
 	idmap->bits[offset] |= 1UL << (bit % BITS_PER_LONG);
 }
 
+int idmap_find(struct idmap *idmap, unsigned int id)
+{
+	unsigned int bit = id - idmap->min;
+	unsigned int offset;
+
+	if (bit >= idmap->size)
+		return 0;
+
+	offset = bit / BITS_PER_LONG;
+	return (idmap->bits[offset] & (1UL << (bit % BITS_PER_LONG))) != 0;
+}
+
 /*
  * Allocate the next bit skipping the ids up to and including last.  If there
  * is no free ids until the max id is encountered, the counter is wrapped back
diff --git a/src/idmap.h b/src/idmap.h
index ebda177..97a6f04 100644
--- a/src/idmap.h
+++ b/src/idmap.h
@@ -25,6 +25,7 @@ struct idmap *idmap_new(unsigned int size);
 void idmap_free(struct idmap *idmap);
 void idmap_put(struct idmap *idmap, unsigned int id);
 void idmap_take(struct idmap *idmap, unsigned int id);
+int idmap_find(struct idmap *idmap, unsigned int id);
 unsigned int idmap_alloc(struct idmap *idmap);
 unsigned int idmap_alloc_next(struct idmap *idmap, unsigned int last);
 struct idmap *idmap_new_from_range(unsigned int min, unsigned int max);
-- 
2.5.0