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[lttngtop.git] / lib / babeltrace / align.h

diff --git a/lib/babeltrace/align.h b/lib/babeltrace/align.h
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+#ifndef _BABELTRACE_ALIGN_H
+#define _BABELTRACE_ALIGN_H
+
+/*
+ * BabelTrace align.h - alignment header
+ *
+ * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * 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.
+ */
+
+#include <babeltrace/compiler.h>
+#include <unistd.h>
+#include <limits.h>
+
+#ifndef PAGE_SIZE              /* Cygwin limits.h defines its own PAGE_SIZE */
+#define PAGE_SIZE              sysconf(_SC_PAGE_SIZE)
+#endif
+
+#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 */