Move to babeltrace namespace

[babeltrace.git] / include / babeltrace / align.h

diff --git a/include/babeltrace/align.h b/include/babeltrace/align.h
new file mode 100644 (file)
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--- /dev/null
+++ b/include/babeltrace/align.h
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+#ifndef _BABELTRACE_ALIGN_H
+#define _BABELTRACE_ALIGN_H
+
+/*
+ * BabelTrace align.h - alignment header
+ *
+ * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <ctf/compiler.h>
+
+#define ALIGN(x, a)            __ALIGN_MASK(x, (typeof(x))(a) - 1)
+#define __ALIGN_MASK(x, mask)  (((x) + (mask)) & ~(mask))
+#define PTR_ALIGN(p, a)                ((typeof(p)) ALIGN((unsigned long) (p), a))
+#define ALIGN_FLOOR(x, a)      __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
+#define __ALIGN_FLOOR_MASK(x, mask)    ((x) & ~(mask))
+#define PTR_ALIGN_FLOOR(p, a) \
+                       ((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
+#define IS_ALIGNED(x, a)       (((x) & ((typeof(x)) (a) - 1)) == 0)
+
+/*
+ * Align pointer on natural object alignment.
+ */
+#define object_align(obj)      PTR_ALIGN(obj, __alignof__(*(obj)))
+#define object_align_floor(obj)        PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))
+
+/**
+ * offset_align - Calculate the offset needed to align an object on its natural
+ *                alignment towards higher addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be added to align towards higher
+ * addresses.
+ */
+#define offset_align(align_drift, alignment)                                  \
+       ({                                                                     \
+               MAYBE_BUILD_BUG_ON((alignment) == 0                            \
+                                  || ((alignment) & ((alignment) - 1)));      \
+               (((alignment) - (align_drift)) & ((alignment) - 1));           \
+       })
+
+/**
+ * offset_align_floor - Calculate the offset needed to align an object
+ *                      on its natural alignment towards lower addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be substracted to align towards lower addresses.
+ */
+#define offset_align_floor(align_drift, alignment)                            \
+       ({                                                                     \
+               MAYBE_BUILD_BUG_ON((alignment) == 0                            \
+                                  || ((alignment) & ((alignment) - 1)));      \
+               (((align_drift) - (alignment)) & ((alignment) - 1);            \
+       })
+
+#endif /* _BABELTRACE_ALIGN_H */