1 /*
   2  * Copyright (c) 1997, 2014, 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 #ifndef SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP
  26 #define SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP
  27 
  28 #include "utilities/top.hpp"
  29 #ifdef TARGET_ARCH_x86
  30 # include "bytes_x86.hpp"
  31 #endif
  32 #ifdef TARGET_ARCH_sparc
  33 # include "bytes_sparc.hpp"
  34 #endif
  35 #ifdef TARGET_ARCH_zero
  36 # include "bytes_zero.hpp"
  37 #endif
  38 #ifdef TARGET_ARCH_arm
  39 # include "bytes_arm.hpp"
  40 #endif
  41 #ifdef TARGET_ARCH_ppc
  42 # include "bytes_ppc.hpp"
  43 #endif
  44 #ifdef TARGET_ARCH_aarch32
  45 # include "bytes_aarch32.hpp"
  46 #endif
  47 
  48 // Input stream for reading .class file
  49 //
  50 // The entire input stream is present in a buffer allocated by the caller.
  51 // The caller is responsible for deallocating the buffer and for using
  52 // ResourceMarks appropriately when constructing streams.
  53 
  54 class ClassFileStream: public ResourceObj {
  55  private:
  56   u1*   _buffer_start; // Buffer bottom
  57   u1*   _buffer_end;   // Buffer top (one past last element)
  58   u1*   _current;      // Current buffer position
  59   const char* _source; // Source of stream (directory name, ZIP/JAR archive name)
  60   bool  _need_verify;  // True if verification is on for the class file
  61 
  62   void truncated_file_error(TRAPS);
  63  public:
  64   // Constructor
  65   ClassFileStream(u1* buffer, int length, const char* source);
  66 
  67   // Buffer access
  68   u1* buffer() const           { return _buffer_start; }
  69   int length() const           { return _buffer_end - _buffer_start; }
  70   u1* current() const          { return _current; }
  71   void set_current(u1* pos)    { _current = pos; }
  72   const char* source() const   { return _source; }
  73   void set_verify(bool flag)   { _need_verify = flag; }
  74 
  75   void check_truncated_file(bool b, TRAPS) {
  76     if (b) {
  77       truncated_file_error(THREAD);
  78     }
  79   }
  80 
  81   void guarantee_more(int size, TRAPS) {
  82     size_t remaining = (size_t)(_buffer_end - _current);
  83     unsigned int usize = (unsigned int)size;
  84     check_truncated_file(usize > remaining, CHECK);
  85   }
  86 
  87   // Read u1 from stream
  88   u1 get_u1(TRAPS);
  89   u1 get_u1_fast() {
  90     return *_current++;
  91   }
  92 
  93   // Read u2 from stream
  94   u2 get_u2(TRAPS);
  95   u2 get_u2_fast() {
  96     u2 res = Bytes::get_Java_u2(_current);
  97     _current += 2;
  98     return res;
  99   }
 100 
 101   // Read u4 from stream
 102   u4 get_u4(TRAPS);
 103   u4 get_u4_fast() {
 104     u4 res = Bytes::get_Java_u4(_current);
 105     _current += 4;
 106     return res;
 107   }
 108 
 109   // Read u8 from stream
 110   u8 get_u8(TRAPS);
 111   u8 get_u8_fast() {
 112     u8 res = Bytes::get_Java_u8(_current);
 113     _current += 8;
 114     return res;
 115   }
 116 
 117   // Get direct pointer into stream at current position.
 118   // Returns NULL if length elements are not remaining. The caller is
 119   // responsible for calling skip below if buffer contents is used.
 120   u1* get_u1_buffer() {
 121     return _current;
 122   }
 123 
 124   u2* get_u2_buffer() {
 125     return (u2*) _current;
 126   }
 127 
 128   // Skip length u1 or u2 elements from stream
 129   void skip_u1(int length, TRAPS);
 130   void skip_u1_fast(int length) {
 131     _current += length;
 132   }
 133 
 134   void skip_u2(int length, TRAPS);
 135   void skip_u2_fast(int length) {
 136     _current += 2 * length;
 137   }
 138 
 139   void skip_u4(int length, TRAPS);
 140   void skip_u4_fast(int length) {
 141     _current += 4 * length;
 142   }
 143 
 144   // Tells whether eos is reached
 145   bool at_eos() const          { return _current == _buffer_end; }
 146 };
 147 
 148 #endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP