/*

 * Copyright (c) 1997, 2016, 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 "classfile/classFileStream.hpp"

#include "classfile/classLoader.hpp"

#include "classfile/dictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "memory/resourceArea.hpp"

const bool ClassFileStream::verify = true;

const bool ClassFileStream::no_verification = false;

void ClassFileStream::truncated_file_error(TRAPS) const {

  THROW_MSG(vmSymbols::java_lang_ClassFormatError(), "Truncated class file");

}

ClassFileStream::ClassFileStream(const u1* buffer,

                                 int length,

                                 const char* source,

                                 bool verify_stream) :

  _buffer_start(buffer),

  _buffer_end(buffer + length),

  _current(buffer),

  _source(source),

  _need_verify(verify_stream) {}

const u1* ClassFileStream::clone_buffer() const {

  u1* const new_buffer_start = NEW_RESOURCE_ARRAY(u1, length());

  memcpy(new_buffer_start, _buffer_start, length());

  return new_buffer_start;

}

const char* const ClassFileStream::clone_source() const {

  const char* const src = source();

  char* source_copy = NULL;

  if (src != NULL) {

    size_t source_len = strlen(src);

    source_copy = NEW_RESOURCE_ARRAY(char, source_len + 1);

    strncpy(source_copy, src, source_len + 1);

  }

  return source_copy;

}

// Caller responsible for ResourceMark

// clone stream with a rewound position

const ClassFileStream* ClassFileStream::clone() const {

  const u1* const new_buffer_start = clone_buffer();

  return new ClassFileStream(new_buffer_start,

                             length(),

                             clone_source(),

                             need_verify());

}

u1 ClassFileStream::get_u1(TRAPS) const {

  if (_need_verify) {

    guarantee_more(1, CHECK_0);

  } else {

    assert(1 <= _buffer_end - _current, "buffer overflow");

  }

  return *_current++;

}

u2 ClassFileStream::get_u2(TRAPS) const {

  if (_need_verify) {

    guarantee_more(2, CHECK_0);

  } else {

    assert(2 <= _buffer_end - _current, "buffer overflow");

  }

  const u1* tmp = _current;

  _current += 2;

  return Bytes::get_Java_u2((address)tmp);

}

u4 ClassFileStream::get_u4(TRAPS) const {

  if (_need_verify) {

    guarantee_more(4, CHECK_0);

  } else {

    assert(4 <= _buffer_end - _current, "buffer overflow");

  }

  const u1* tmp = _current;

  _current += 4;

  return Bytes::get_Java_u4((address)tmp);

}

u8 ClassFileStream::get_u8(TRAPS) const {

  if (_need_verify) {

    guarantee_more(8, CHECK_0);

  } else {

    assert(8 <= _buffer_end - _current, "buffer overflow");

  }

  const u1* tmp = _current;

  _current += 8;

  return Bytes::get_Java_u8((address)tmp);

}

void ClassFileStream::skip_u1(int length, TRAPS) const {

  if (_need_verify) {

    guarantee_more(length, CHECK);

  }

  _current += length;

}

void ClassFileStream::skip_u2(int length, TRAPS) const {

  if (_need_verify) {

    guarantee_more(length * 2, CHECK);

  }

  _current += length * 2;

}

void ClassFileStream::skip_u4(int length, TRAPS) const {

  if (_need_verify) {

    guarantee_more(length * 4, CHECK);

  }

  _current += length * 4;

}

uint64_t ClassFileStream::compute_fingerprint() const {

  int classfile_size = length();

  int classfile_crc = ClassLoader::crc32(0, (const char*)buffer(), length());

  uint64_t fingerprint = (uint64_t(classfile_size) << 32) | uint64_t(uint32_t(classfile_crc));

  assert(fingerprint != 0, "must not be zero");

  return fingerprint;

}