[Xen-devel] [PATCH v6] libxl: provide libxl_bitmap_{or,and}

[Linda Jacobson <lindaj@xxxxxxxx>]

There are new functions to provide logical and and or of two bitmaps.

Signed-off-by: Linda Jacobson <lindaj@xxxxxxxx>

---

v.1 The new functions were added.
v.2 The comments and format were corrected.
v.3 The bitmap functions were rewritten to manipulate bytes not bits.
v.4 Several non-modified parameters, and local variables were changed to const
    Also the code formatting was fixed.
v.5 The commit subject line now has versions and is simpler.
v.6 All descriptions in the commit history are now complete sentences.
    Extraneous blank lines are gone.
---
 tools/libxl/libxl_utils.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_utils.h |  7 +++++
 2 files changed, 77 insertions(+)

diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c
index 9053b27..f552700 100644
--- a/tools/libxl/libxl_utils.c
+++ b/tools/libxl/libxl_utils.c
@@ -691,6 +691,76 @@ void libxl_bitmap_reset(libxl_bitmap *bitmap, int bit)
     bitmap->map[bit / 8] &= ~(1 << (bit & 7));
 }
 
+int libxl_bitmap_or(libxl_ctx *ctx, libxl_bitmap *or_map,
+                    const libxl_bitmap *map1, const libxl_bitmap *map2)
+{
+    GC_INIT(ctx);
+    int rc;
+    uint32_t i;
+    const libxl_bitmap *large_map;
+    const libxl_bitmap *small_map;
+
+    if (map1->size > map2->size) {
+        large_map = map1;
+        small_map = map2;
+    } else {
+        large_map = map2;
+        small_map = map1;
+    }
+
+    rc = libxl_bitmap_alloc(ctx, or_map, large_map->size * 8);
+    if (rc)
+        goto out;
+
+    /*
+     *  If bitmaps aren't the same size, their union (logical or) will
+     *  be size of larger bit map.  Any bit past the end of the
+     *  smaller bit map, will match the larger one.
+     */
+    for (i = 0; i < small_map->size; i++)
+        or_map->map[i] = (small_map->map[i] | large_map->map[i]);
+
+    for (i = small_map->size; i < large_map->size; i++)
+        or_map->map[i] = large_map->map[i];
+
+out:
+    GC_FREE;
+    return rc;
+}
+
+int libxl_bitmap_and(libxl_ctx *ctx, libxl_bitmap *and_map,
+                     const libxl_bitmap *map1, const libxl_bitmap *map2)
+{
+    GC_INIT(ctx);    
+    int rc;
+    uint32_t i;
+    const libxl_bitmap *large_map;
+    const libxl_bitmap *small_map;
+
+    if (map1->size > map2->size) {
+        large_map = map1;
+        small_map = map2;
+    } else {
+        large_map = map2;
+        small_map = map1;
+    }
+
+    rc = libxl_bitmap_alloc(ctx, and_map, small_map->size * 8);
+    if (rc)
+        goto out;
+
+    /* 
+     *  If bitmaps aren't same size, their 'and' will be size of
+     *  smaller bit map
+     */
+    for (i = 0; i < and_map->size; i++)
+        and_map->map[i] = (large_map->map[i] & small_map->map[i]);
+
+out: 
+    GC_FREE;
+    return rc;
+}
+
 int libxl_bitmap_count_set(const libxl_bitmap *bitmap)
 {
     int i, nr_set_bits = 0;
diff --git a/tools/libxl/libxl_utils.h b/tools/libxl/libxl_utils.h
index acacdd9..a128a7c 100644
--- a/tools/libxl/libxl_utils.h
+++ b/tools/libxl/libxl_utils.h
@@ -90,6 +90,13 @@ int libxl_bitmap_test(const libxl_bitmap *bitmap, int bit);
 void libxl_bitmap_set(libxl_bitmap *bitmap, int bit);
 void libxl_bitmap_reset(libxl_bitmap *bitmap, int bit);
 int libxl_bitmap_count_set(const libxl_bitmap *cpumap);
+/* Or and and functions for two bitmaps */
+int libxl_bitmap_or(libxl_ctx *ctx, libxl_bitmap *or_map,
+                    const libxl_bitmap *map1, 
+                    const libxl_bitmap *map2); 
+int libxl_bitmap_and(libxl_ctx *ctx, libxl_bitmap *and_map,
+                     const libxl_bitmap *map1, 
+                     const libxl_bitmap *map2);
 char *libxl_bitmap_to_hex_string(libxl_ctx *ctx, const libxl_bitmap *cpumap);
 static inline void libxl_bitmap_set_any(libxl_bitmap *bitmap)
 {
-- 
1.9.1


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