Merge branch 'mainstream'

[sliver-openvswitch.git] / lib / bitmap.c

diff --git a/lib/bitmap.c b/lib/bitmap.c
index f021a7e..ac568e9 100644 (file)
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2011 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,28 @@
 #include "bitmap.h"
 #include <string.h>
 
+/* Allocates and returns a bitmap initialized to all-1-bits. */
+unsigned long *
+bitmap_allocate1(size_t n_bits)
+{
+    size_t n_bytes = bitmap_n_bytes(n_bits);
+    size_t n_longs = bitmap_n_longs(n_bits);
+    size_t r_bits = n_bits % BITMAP_ULONG_BITS;
+    unsigned long *bitmap;
+
+    /* Allocate and initialize most of the bitmap. */
+    bitmap = xmalloc(n_bytes);
+    memset(bitmap, 0xff, n_bytes);
+
+    /* Ensure that the last "unsigned long" in the bitmap only has as many
+     * 1-bits as there actually should be. */
+    if (r_bits) {
+        bitmap[n_longs - 1] = (1UL << r_bits) - 1;
+    }
+
+    return bitmap;
+}
+
 /* Sets 'count' consecutive bits in 'bitmap', starting at bit offset 'start',
  * to 'value'. */
 void
@@ -53,3 +75,20 @@ bitmap_equal(const unsigned long *a, const unsigned long *b, size_t n)
     }
     return true;
 }
+
+/* Scans 'bitmap' from bit offset 'start' to 'end', excluding 'end' itself.
+ * Returns the bit offset of the lowest-numbered bit set to 1, or 'end' if
+ * all of the bits are set to 0. */
+size_t
+bitmap_scan(const unsigned long int *bitmap, size_t start, size_t end)
+{
+    /* XXX slow */
+    size_t i;
+
+    for (i = start; i < end; i++) {
+        if (bitmap_is_set(bitmap, i)) {
+            break;
+        }
+    }
+    return i;
+}