1 files changed, 124 insertions, 0 deletions
diff --git a/src/bitmap.c b/src/bitmap.c
new file mode 100644
index 0000000..d449c3d
--- /dev/null
+++ b/src/bitmap.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2013-2015 Richard Braun.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ */
+
+#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);
+        }
+    }
+}