1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classFileStream.hpp"
  27 #include "classfile/vmSymbols.hpp"
  28 #include "memory/resourceArea.hpp"
  29 
  30 const bool ClassFileStream::verify = true;
  31 const bool ClassFileStream::no_verification = false;
  32 
  33 void ClassFileStream::truncated_file_error(TRAPS) const {
  34   THROW_MSG(vmSymbols::java_lang_ClassFormatError(), "Truncated class file");
  35 }
  36 
  37 ClassFileStream::ClassFileStream(const u1* buffer,
  38                                  int length,
  39                                  const char* source,
  40                                  bool verify_stream) :
  41   _buffer_start(buffer),
  42   _buffer_end(buffer + length),
  43   _current(buffer),
  44   _source(source),
  45   _need_verify(verify_stream) {}
  46 
  47 const u1* ClassFileStream::clone_buffer() const {
  48   u1* const new_buffer_start = NEW_RESOURCE_ARRAY(u1, length());
  49   memcpy(new_buffer_start, _buffer_start, length());
  50   return new_buffer_start;
  51 }
  52 
  53 const char* const ClassFileStream::clone_source() const {
  54   const char* const src = source();
  55   char* source_copy = NULL;
  56   if (src != NULL) {
  57     size_t source_len = strlen(src);
  58     source_copy = NEW_RESOURCE_ARRAY(char, source_len + 1);
  59     strncpy(source_copy, src, source_len + 1);
  60   }
  61   return source_copy;
  62 }
  63 
  64 // Caller responsible for ResourceMark
  65 // clone stream with a rewound position
  66 const ClassFileStream* ClassFileStream::clone() const {
  67   const u1* const new_buffer_start = clone_buffer();
  68   return new ClassFileStream(new_buffer_start,
  69                              length(),
  70                              clone_source(),
  71                              need_verify());
  72 }
  73 
  74 u1 ClassFileStream::get_u1(TRAPS) const {
  75   if (_need_verify) {
  76     guarantee_more(1, CHECK_0);
  77   } else {
  78     assert(1 <= _buffer_end - _current, "buffer overflow");
  79   }
  80   return *_current++;
  81 }
  82 
  83 u2 ClassFileStream::get_u2(TRAPS) const {
  84   if (_need_verify) {
  85     guarantee_more(2, CHECK_0);
  86   } else {
  87     assert(2 <= _buffer_end - _current, "buffer overflow");
  88   }
  89   const u1* tmp = _current;
  90   _current += 2;
  91   return Bytes::get_Java_u2((address)tmp);
  92 }
  93 
  94 u4 ClassFileStream::get_u4(TRAPS) const {
  95   if (_need_verify) {
  96     guarantee_more(4, CHECK_0);
  97   } else {
  98     assert(4 <= _buffer_end - _current, "buffer overflow");
  99   }
 100   const u1* tmp = _current;
 101   _current += 4;
 102   return Bytes::get_Java_u4((address)tmp);
 103 }
 104 
 105 u8 ClassFileStream::get_u8(TRAPS) const {
 106   if (_need_verify) {
 107     guarantee_more(8, CHECK_0);
 108   } else {
 109     assert(8 <= _buffer_end - _current, "buffer overflow");
 110   }
 111   const u1* tmp = _current;
 112   _current += 8;
 113   return Bytes::get_Java_u8((address)tmp);
 114 }
 115 
 116 void ClassFileStream::skip_u1(int length, TRAPS) const {
 117   if (_need_verify) {
 118     guarantee_more(length, CHECK);
 119   }
 120   _current += length;
 121 }
 122 
 123 void ClassFileStream::skip_u2(int length, TRAPS) const {
 124   if (_need_verify) {
 125     guarantee_more(length * 2, CHECK);
 126   }
 127   _current += length * 2;
 128 }
 129 
 130 void ClassFileStream::skip_u4(int length, TRAPS) const {
 131   if (_need_verify) {
 132     guarantee_more(length * 4, CHECK);
 133   }
 134   _current += length * 4;
 135 }