1 /*
   2  * Copyright (c) 1997, 2019, 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 
  29 void ClassFileStream::truncated_file_error(TRAPS) {
  30   THROW_MSG(vmSymbols::java_lang_ClassFormatError(), "Truncated class file");
  31 }
  32 
  33 ClassFileStream::ClassFileStream(u1* buffer, int length, const char* source) {
  34   _buffer_start = buffer;
  35   _buffer_end   = buffer + length;
  36   _current      = buffer;
  37   _source       = source;
  38   _need_verify  = false;
  39 }
  40 
  41 const u1* ClassFileStream::clone_buffer() const {
  42   u1* const new_buffer_start = NEW_RESOURCE_ARRAY(u1, length());
  43   memcpy(new_buffer_start, _buffer_start, length());
  44   return new_buffer_start;
  45 }
  46 
  47 const char* const ClassFileStream::clone_source() const {
  48   const char* const src = source();
  49   char* source_copy = NULL;
  50   if (src != NULL) {
  51     size_t source_len = strlen(src);
  52     source_copy = NEW_RESOURCE_ARRAY(char, source_len + 1);
  53     strncpy(source_copy, src, source_len + 1);
  54   }
  55   return source_copy;
  56 }
  57 
  58 // Caller responsible for ResourceMark
  59 // clone stream with a rewound position
  60 const ClassFileStream* ClassFileStream::clone() const {
  61   const u1* const new_buffer_start = clone_buffer();
  62   return new ClassFileStream(const_cast<u1*>(new_buffer_start),
  63                              length(),
  64                              clone_source()/*,
  65                              need_verify()*/);
  66 }
  67 
  68 u1 ClassFileStream::get_u1(TRAPS) {
  69   if (_need_verify) {
  70     guarantee_more(1, CHECK_0);
  71   } else {
  72     assert(1 <= _buffer_end - _current, "buffer overflow");
  73   }
  74   return *_current++;
  75 }
  76 
  77 u2 ClassFileStream::get_u2(TRAPS) {
  78   if (_need_verify) {
  79     guarantee_more(2, CHECK_0);
  80   } else {
  81     assert(2 <= _buffer_end - _current, "buffer overflow");
  82   }
  83   u1* tmp = _current;
  84   _current += 2;
  85   return Bytes::get_Java_u2(tmp);
  86 }
  87 
  88 u4 ClassFileStream::get_u4(TRAPS) {
  89   if (_need_verify) {
  90     guarantee_more(4, CHECK_0);
  91   } else {
  92     assert(4 <= _buffer_end - _current, "buffer overflow");
  93   }
  94   u1* tmp = _current;
  95   _current += 4;
  96   return Bytes::get_Java_u4(tmp);
  97 }
  98 
  99 u8 ClassFileStream::get_u8(TRAPS) {
 100   if (_need_verify) {
 101     guarantee_more(8, CHECK_0);
 102   } else {
 103     assert(8 <= _buffer_end - _current, "buffer overflow");
 104   }
 105   u1* tmp = _current;
 106   _current += 8;
 107   return Bytes::get_Java_u8(tmp);
 108 }
 109 
 110 void ClassFileStream::skip_u1(int length, TRAPS) {
 111   if (_need_verify) {
 112     guarantee_more(length, CHECK);
 113   }
 114   _current += length;
 115 }
 116 
 117 void ClassFileStream::skip_u2(int length, TRAPS) {
 118   if (_need_verify) {
 119     guarantee_more(length * 2, CHECK);
 120   }
 121   _current += length * 2;
 122 }
 123 
 124 void ClassFileStream::skip_u4(int length, TRAPS) {
 125   if (_need_verify) {
 126     guarantee_more(length * 4, CHECK);
 127   }
 128   _current += length * 4;
 129 }