bitmap: Add basic bitmap ops

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[stewart@linux.vnet.ibm.com: add (C) header]
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/include/bitmap.h b/include/bitmap.h
new file mode 100644
index 00000000..12913ea0
--- /dev/null
+++ b/include/bitmap.h
@@ -0,0 +1,69 @@
+/* Copyright 2016 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __BITMAP_H
+#define __BITMAP_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef unsigned long bitmap_elem_t;
+typedef bitmap_elem_t bitmap_t[];
+
+#define BITMAP_ELSZ	(sizeof(bitmap_elem_t) << 3)
+
+/* Number of elements for _n bits (rounded up) */
+#define BITMAP_ELEMS(_n)	(((_n) + (BITMAP_ELSZ - 1)) / BITMAP_ELSZ)
+/* Number of bytes for _n bits (rounded up) */
+#define BITMAP_BYTES(_n)	(BITMAP_ELEMS(_n) * sizeof(bitmap_elem_t))
+/* Bit number within an elemnt for bit _n */
+#define BITMAP_BIT(_n)		((_n) & (BITMAP_ELSZ - 1))
+/* Corresponding mask */
+#define BITMAP_MASK(_n)		(1ul << BITMAP_BIT(_n))
+/* Element number for bit _n */
+#define BITMAP_ELEM(_n)		((_n) / BITMAP_ELSZ)
+
+static inline void bitmap_set_bit(bitmap_t map, unsigned int bit)
+{
+	map[BITMAP_ELEM(bit)] |= BITMAP_MASK(bit);
+}
+
+static inline void bitmap_clr_bit(bitmap_t map, unsigned int bit)
+{
+	map[BITMAP_ELEM(bit)] &= ~BITMAP_MASK(bit);
+}
+
+static inline bool bitmap_tst_bit(bitmap_t map, unsigned int bit)
+{
+	return map[BITMAP_ELEM(bit)] & BITMAP_MASK(bit);
+}
+
+extern int bitmap_find_zero_bit(bitmap_t map, unsigned int start,
+				unsigned int count);
+extern int bitmap_find_one_bit(bitmap_t map, unsigned int start,
+				unsigned int count);
+
+#define bitmap_for_each_zero(map, size, bit)                   \
+	for (bit = bitmap_find_zero_bit(map, 0, size);         \
+	     bit >= 0;					       \
+	     bit = bitmap_find_zero_bit(map, bit + 1, size))
+
+#define bitmap_for_each_one(map, size, bit)                    \
+	for (bit = bitmap_find_one_bit(map, 0, size);          \
+	     bit >= 0;					       \
+	     bit = bitmap_find_one_bit(map, bit + 1, size))
+
+#endif /* __BITMAP_H */