| /* |
| * 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; |
| } |
| |
| }; |