/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "oops/arrayOop.hpp"

#ifndef PRODUCT

#include "utilities/globalDefinitions.hpp"
// Unit tests

bool arrayOopDesc::check_overflow(BasicType type) {
  int32_t length = max_array_length(type);
  size_t bytes_per_element = type2aelembytes(type);
  size_t bytes = (size_t)length * bytes_per_element + header_size_in_bytes();
  return (bytes - header_size_in_bytes()) / bytes_per_element == (size_t)length;
}

// The old implementation of max_array_length. For 64-bit platforms the old
// and new implementations should return the same value.
int32_t arrayOopDesc::old_max_array_length(BasicType type) {
   const int bytes_per_element = type2aelembytes(type);
    if (bytes_per_element < HeapWordSize) {
      return max_jint;
    }
    const int32_t max_words = align_size_down(max_jint, MinObjAlignment);
    const int32_t max_element_words = max_words - header_size(type);
    const int32_t words_per_element = bytes_per_element >> LogHeapWordSize;
    return max_element_words / words_per_element;
}

bool arrayOopDesc::test_max_array_length() {
  tty->print_cr("test_max_array_length");
  
  assert(check_overflow(T_BOOLEAN), "size_t overflow for boolean array");
  assert(check_overflow(T_CHAR), "size_t overflow for char array");
  assert(check_overflow(T_FLOAT), "size_t overflow for float array");
  assert(check_overflow(T_DOUBLE), "size_t overflow for double array");
  assert(check_overflow(T_BYTE), "size_t overflow for byte array");
  assert(check_overflow(T_SHORT), "size_t overflow for short array");
  assert(check_overflow(T_INT), "size_t overflow for int array");
  assert(check_overflow(T_LONG), "size_t overflow for long array");
  assert(check_overflow(T_OBJECT), "size_t overflow for object array");
  assert(check_overflow(T_ARRAY), "size_t overflow for array array");
  assert(check_overflow(T_NARROWOOP), "size_t overflow for narrowOop array");

  // T_VOID and T_ADDRESS are not supported by max_array_length()

#ifdef _LP64
  assert(max_array_length(T_BOOLEAN) == old_max_array_length(T_BOOLEAN), "calculation changed for boolean");
  assert(max_array_length(T_CHAR) == old_max_array_length(T_CHAR), "calculation changed for char");
  assert(max_array_length(T_FLOAT) == old_max_array_length(T_FLOAT), "calculation changed for float");
  assert(max_array_length(T_DOUBLE) == old_max_array_length(T_DOUBLE), "calculation changed for double");
  assert(max_array_length(T_BYTE) == old_max_array_length(T_BYTE), "calculation changed for byte");
  assert(max_array_length(T_SHORT) == old_max_array_length(T_SHORT), "calculation changed for short");
  assert(max_array_length(T_INT) == old_max_array_length(T_INT), "calculation changed for int");
  assert(max_array_length(T_LONG) == old_max_array_length(T_LONG), "calculation changed for long");
  assert(max_array_length(T_OBJECT) == old_max_array_length(T_OBJECT), "calculation changed for object");
  assert(max_array_length(T_ARRAY) == old_max_array_length(T_ARRAY), "calculation changed for array");
  assert(max_array_length(T_NARROWOOP) == old_max_array_length(T_NARROWOOP), "calculation changed for narrowOop");
#endif

  return true;
}


#endif //PRODUCT