1 files changed, 56 insertions, 0 deletions
diff --git a/kern/bitmap_i.h b/kern/bitmap_i.h
new file mode 100644
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--- /dev/null
+++ b/kern/bitmap_i.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2013 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _KERN_BITMAP_I_H
+#define _KERN_BITMAP_I_H
+
+#include <kern/limits.h>
+#include <kern/macros.h>
+
+#define BITMAP_LONGS(nr_bits) DIV_CEIL(nr_bits, LONG_BIT)
+
+/*
+ * Adjust the bitmap pointer and the bit index so that the latter refers
+ * to a bit inside the word pointed by the former.
+ *
+ * Implemented as a macro for const-correctness.
+ */
+#define bitmap_lookup(bm, bit)          \
+MACRO_BEGIN                             \
+    int i;                              \
+                                        \
+    i = BITMAP_LONGS((bit) + 1) - 1;    \
+    (bm) += i;                          \
+    (bit) -= i * LONG_BIT;              \
+MACRO_END
+
+static inline unsigned long
+bitmap_mask(int bit)
+{
+    return (1UL << bit);
+}
+
+/*
+ * Return the index of the next set bit in the bitmap, starting (and
+ * including) the given bit index, or -1 if the bitmap is empty. If
+ * complement is true, bits are toggled before searching so that the
+ * result is the index of the next zero bit.
+ */
+int bitmap_find_next_bit(const unsigned long *bm, int nr_bits, int bit,
+                         int complement);
+
+#endif /* _KERN_BITMAP_I_H */