JavaScriptCore-1218.tar.gz

[apple/javascriptcore.git] / runtime / PropertyOffset.h

diff --git a/runtime/PropertyOffset.h b/runtime/PropertyOffset.h
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+/*
+ * Copyright (C) 2012 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef PropertyOffset_h
+#define PropertyOffset_h
+
+#include <wtf/Platform.h>
+#include <wtf/StdLibExtras.h>
+
+namespace JSC {
+
+typedef int PropertyOffset;
+
+static const PropertyOffset invalidOffset = -1;
+static const PropertyOffset firstOutOfLineOffset = 100;
+
+// Declare all of the functions because they tend to do forward calls.
+inline void checkOffset(PropertyOffset);
+inline void checkOffset(PropertyOffset, int inlineCapacity);
+inline void validateOffset(PropertyOffset);
+inline void validateOffset(PropertyOffset, int inlineCapacity);
+inline bool isValidOffset(PropertyOffset);
+inline bool isInlineOffset(PropertyOffset);
+inline bool isOutOfLineOffset(PropertyOffset);
+inline size_t offsetInInlineStorage(PropertyOffset);
+inline size_t offsetInOutOfLineStorage(PropertyOffset);
+inline size_t offsetInRespectiveStorage(PropertyOffset);
+inline size_t numberOfOutOfLineSlotsForLastOffset(PropertyOffset);
+inline size_t numberOfSlotsForLastOffset(PropertyOffset, int inlineCapacity);
+
+inline void checkOffset(PropertyOffset offset)
+{
+    UNUSED_PARAM(offset);
+    ASSERT(offset >= invalidOffset);
+}
+
+inline void checkOffset(PropertyOffset offset, int inlineCapacity)
+{
+    UNUSED_PARAM(offset);
+    UNUSED_PARAM(inlineCapacity);
+    ASSERT(offset >= invalidOffset);
+    ASSERT(offset == invalidOffset
+        || offset < inlineCapacity
+        || isOutOfLineOffset(offset));
+}
+
+inline void validateOffset(PropertyOffset offset)
+{
+    checkOffset(offset);
+    ASSERT(isValidOffset(offset));
+}
+
+inline void validateOffset(PropertyOffset offset, int inlineCapacity)
+{
+    checkOffset(offset, inlineCapacity);
+    ASSERT(isValidOffset(offset));
+}
+
+inline bool isValidOffset(PropertyOffset offset)
+{
+    checkOffset(offset);
+    return offset != invalidOffset;
+}
+
+inline bool isInlineOffset(PropertyOffset offset)
+{
+    checkOffset(offset);
+    return offset < firstOutOfLineOffset;
+}
+
+inline bool isOutOfLineOffset(PropertyOffset offset)
+{
+    checkOffset(offset);
+    return !isInlineOffset(offset);
+}
+
+inline size_t offsetInInlineStorage(PropertyOffset offset)
+{
+    validateOffset(offset);
+    ASSERT(isInlineOffset(offset));
+    return offset;
+}
+
+inline size_t offsetInOutOfLineStorage(PropertyOffset offset)
+{
+    validateOffset(offset);
+    ASSERT(isOutOfLineOffset(offset));
+    return -static_cast<ptrdiff_t>(offset - firstOutOfLineOffset) - 1;
+}
+
+inline size_t offsetInRespectiveStorage(PropertyOffset offset)
+{
+    if (isInlineOffset(offset))
+        return offsetInInlineStorage(offset);
+    return offsetInOutOfLineStorage(offset);
+}
+
+inline size_t numberOfOutOfLineSlotsForLastOffset(PropertyOffset offset)
+{
+    checkOffset(offset);
+    if (offset < firstOutOfLineOffset)
+        return 0;
+    return offset - firstOutOfLineOffset + 1;
+}
+
+inline size_t numberOfSlotsForLastOffset(PropertyOffset offset, int inlineCapacity)
+{
+    checkOffset(offset, inlineCapacity);
+    if (offset < inlineCapacity)
+        return offset + 1;
+    return inlineCapacity + numberOfOutOfLineSlotsForLastOffset(offset);
+}
+
+inline PropertyOffset offsetForPropertyNumber(int propertyNumber, int inlineCapacity)
+{
+    PropertyOffset offset = propertyNumber;
+    if (offset >= inlineCapacity) {
+        offset += firstOutOfLineOffset;
+        offset -= inlineCapacity;
+    }
+    return offset;
+}
+
+} // namespace JSC
+
+#endif // PropertyOffset_h