1 files changed, 116 insertions, 0 deletions
diff --git a/bitmap.c b/bitmap.c
new file mode 100644
index 0000000..7ac1662
--- /dev/null
+++ b/bitmap.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2013-2015 Richard Braun.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <limits.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "bitmap.h"
+#include "bitmap_i.h"
+
+int
+bitmap_cmp(const unsigned long *a, const unsigned long *b, int nr_bits)
+{
+    unsigned long last_a, last_b, mask;
+    int n, rv;
+
+    n = BITMAP_LONGS(nr_bits) - 1;
+
+    if (n != 0) {
+        rv = memcmp(a, b, n * sizeof(unsigned long));
+
+        if (rv != 0)
+            return rv;
+
+        nr_bits -= n * LONG_BIT;
+    }
+
+    last_a = a[n];
+    last_b = b[n];
+
+    if (nr_bits != LONG_BIT) {
+        mask = (1UL << nr_bits) - 1;
+        last_a &= mask;
+        last_b &= mask;
+    }
+
+    if (last_a == last_b)
+        return 0;
+    else if (last_a < last_b)
+        return -1;
+    else
+        return 1;
+}
+
+static inline unsigned long
+bitmap_find_next_compute_complement(unsigned long word, int nr_bits)
+{
+    if (nr_bits < LONG_BIT)
+        word |= (((unsigned long)-1) << nr_bits);
+
+    return ~word;
+}
+
+int
+bitmap_find_next_bit(const unsigned long *bm, int nr_bits, int bit,
+                     int complement)
+{
+    const unsigned long *start, *end;
+    unsigned long word;
+
+    start = bm;
+    end = bm + BITMAP_LONGS(nr_bits);
+
+    if (bit >= LONG_BIT) {
+        bitmap_lookup(bm, bit);
+        nr_bits -= ((bm - start) * LONG_BIT);
+    }
+
+    word = *bm;
+
+    if (complement)
+        word = bitmap_find_next_compute_complement(word, nr_bits);
+
+    if (bit < LONG_BIT)
+        word &= ~(bitmap_mask(bit) - 1);
+
+    for (;;) {
+        bit = __builtin_ffsl(word);
+
+        if (bit != 0)
+            return ((bm - start) * LONG_BIT) + bit - 1;
+
+        bm++;
+
+        if (bm >= end)
+            return -1;
+
+        nr_bits -= LONG_BIT;
+        word = *bm;
+
+        if (complement)
+            word = bitmap_find_next_compute_complement(word, nr_bits);
+    }
+}