--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/oops/arrayOop.hpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,70 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// arrayOopDesc is the abstract baseclass for all arrays.
+
+class arrayOopDesc : public oopDesc {
+ friend class VMStructs;
+ private:
+ int _length; // number of elements in the array
+
+ public:
+ // Interpreter/Compiler offsets
+ static int length_offset_in_bytes() { return offset_of(arrayOopDesc, _length); }
+ static int base_offset_in_bytes(BasicType type) { return header_size(type) * HeapWordSize; }
+
+ // Returns the address of the first element.
+ void* base(BasicType type) const { return (void*) (((intptr_t) this) + base_offset_in_bytes(type)); }
+
+ // Tells whether index is within bounds.
+ bool is_within_bounds(int index) const { return 0 <= index && index < length(); }
+
+ // Accessores for instance variable
+ int length() const { return _length; }
+ void set_length(int length) { _length = length; }
+
+ // Header size computation.
+ // Should only be called with constants as argument (will not constant fold otherwise)
+ static int header_size(BasicType type) {
+ return Universe::element_type_should_be_aligned(type)
+ ? align_object_size(sizeof(arrayOopDesc)/HeapWordSize)
+ : sizeof(arrayOopDesc)/HeapWordSize;
+ }
+
+ // This method returns the maximum length that can passed into
+ // typeArrayOop::object_size(scale, length, header_size) without causing an
+ // overflow. We substract an extra 2*wordSize to guard against double word
+ // alignments. It gets the scale from the type2aelembytes array.
+ static int32_t max_array_length(BasicType type) {
+ assert(type >= 0 && type < T_CONFLICT, "wrong type");
+ assert(type2aelembytes[type] != 0, "wrong type");
+ // We use max_jint, since object_size is internally represented by an 'int'
+ // This gives us an upper bound of max_jint words for the size of the oop.
+ int32_t max_words = (max_jint - header_size(type) - 2);
+ int elembytes = (type == T_OBJECT) ? T_OBJECT_aelem_bytes : type2aelembytes[type];
+ jlong len = ((jlong)max_words * HeapWordSize) / elembytes;
+ return (len > max_jint) ? max_jint : (int32_t)len;
+ }
+
+};