bitmap: Add bitmap_copy_with_{src|dst}_offset()

These helpers copy the source bitmap to destination bitmap with a
shift either on the src or dst bitmap.

Meanwhile, we never have bitmap tests but we should.

This patch also introduces the initial test cases for utils/bitmap.c
but it only tests the newly introduced functions.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20190603065056.25211-5-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

---

Bitmap test used sizeof(unsigned long) instead of BITS_PER_LONG.

1 files changed, 72 insertions, 0 deletions

diff --git a/tests/test-bitmap.c b/tests/test-bitmap.c
new file mode 100644
index 0000000000..cb7c5e462d
--- /dev/null
+++ b/tests/test-bitmap.c
@@ -0,0 +1,72 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Bitmap.c unit-tests.
+ *
+ * Copyright (C) 2019, Red Hat, Inc.
+ *
+ * Author: Peter Xu <peterx@redhat.com>
+ */
+
+#include <stdlib.h>
+#include "qemu/osdep.h"
+#include "qemu/bitmap.h"
+
+#define BMAP_SIZE  1024
+
+static void check_bitmap_copy_with_offset(void)
+{
+    unsigned long *bmap1, *bmap2, *bmap3, total;
+
+    bmap1 = bitmap_new(BMAP_SIZE);
+    bmap2 = bitmap_new(BMAP_SIZE);
+    bmap3 = bitmap_new(BMAP_SIZE);
+
+    bmap1[0] = random();
+    bmap1[1] = random();
+    bmap1[2] = random();
+    bmap1[3] = random();
+    total = BITS_PER_LONG * 4;
+
+    /* Shift 115 bits into bmap2 */
+    bitmap_copy_with_dst_offset(bmap2, bmap1, 115, total);
+    /* Shift another 85 bits into bmap3 */
+    bitmap_copy_with_dst_offset(bmap3, bmap2, 85, total + 115);
+    /* Shift back 200 bits back */
+    bitmap_copy_with_src_offset(bmap2, bmap3, 200, total);
+
+    g_assert_cmpmem(bmap1, total / BITS_PER_LONG,
+                    bmap2, total / BITS_PER_LONG);
+
+    bitmap_clear(bmap1, 0, BMAP_SIZE);
+    /* Set bits in bmap1 are 100-245 */
+    bitmap_set(bmap1, 100, 145);
+
+    /* Set bits in bmap2 are 60-205 */
+    bitmap_copy_with_src_offset(bmap2, bmap1, 40, 250);
+    g_assert_cmpint(find_first_bit(bmap2, 60), ==, 60);
+    g_assert_cmpint(find_next_zero_bit(bmap2, 205, 60), ==, 205);
+    g_assert(test_bit(205, bmap2) == 0);
+
+    /* Set bits in bmap3 are 135-280 */
+    bitmap_copy_with_dst_offset(bmap3, bmap1, 35, 250);
+    g_assert_cmpint(find_first_bit(bmap3, 135), ==, 135);
+    g_assert_cmpint(find_next_zero_bit(bmap3, 280, 135), ==, 280);
+    g_assert(test_bit(280, bmap3) == 0);
+
+    g_free(bmap1);
+    g_free(bmap2);
+    g_free(bmap3);
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    g_test_add_func("/bitmap/bitmap_copy_with_offset",
+                    check_bitmap_copy_with_offset);
+
+    g_test_run();
+
+    return 0;
+}