classFileStream.hpp revision 2273:1d1603768966 
1/*
2 * Copyright (c) 1997, 2011, 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
45// Input stream for reading .class file
46//
47// The entire input stream is present in a buffer allocated by the caller.
48// The caller is responsible for deallocating the buffer and for using
49// ResourceMarks appropriately when constructing streams.
50
51class ClassFileStream: public ResourceObj {
52 private:
53  u1*   _buffer_start; // Buffer bottom
54  u1*   _buffer_end;   // Buffer top (one past last element)
55  u1*   _current;      // Current buffer position
56  char* _source;       // Source of stream (directory name, ZIP/JAR archive name)
57  bool  _need_verify;  // True if verification is on for the class file
58
59  void truncated_file_error(TRAPS);
60 public:
61  // Constructor
62  ClassFileStream(u1* buffer, int length, char* source);
63
64  // Buffer access
65  u1* buffer() const           { return _buffer_start; }
66  int length() const           { return _buffer_end - _buffer_start; }
67  u1* current() const          { return _current; }
68  void set_current(u1* pos)    { _current = pos; }
69  char* source() const         { return _source; }
70  void set_verify(bool flag)   { _need_verify = flag; }
71
72  void check_truncated_file(bool b, TRAPS) {
73    if (b) {
74      truncated_file_error(THREAD);
75    }
76  }
77
78  void guarantee_more(int size, TRAPS) {
79    size_t remaining = (size_t)(_buffer_end - _current);
80    unsigned int usize = (unsigned int)size;
81    check_truncated_file(usize > remaining, CHECK);
82  }
83
84  // Read u1 from stream
85  u1 get_u1(TRAPS);
86  u1 get_u1_fast() {
87    return *_current++;
88  }
89
90  // Read u2 from stream
91  u2 get_u2(TRAPS);
92  u2 get_u2_fast() {
93    u2 res = Bytes::get_Java_u2(_current);
94    _current += 2;
95    return res;
96  }
97
98  // Read u4 from stream
99  u4 get_u4(TRAPS);
100  u4 get_u4_fast() {
101    u4 res = Bytes::get_Java_u4(_current);
102    _current += 4;
103    return res;
104  }
105
106  // Read u8 from stream
107  u8 get_u8(TRAPS);
108  u8 get_u8_fast() {
109    u8 res = Bytes::get_Java_u8(_current);
110    _current += 8;
111    return res;
112  }
113
114  // Get direct pointer into stream at current position.
115  // Returns NULL if length elements are not remaining. The caller is
116  // responsible for calling skip below if buffer contents is used.
117  u1* get_u1_buffer() {
118    return _current;
119  }
120
121  u2* get_u2_buffer() {
122    return (u2*) _current;
123  }
124
125  // Skip length u1 or u2 elements from stream
126  void skip_u1(int length, TRAPS);
127  void skip_u1_fast(int length) {
128    _current += length;
129  }
130
131  void skip_u2(int length, TRAPS);
132  void skip_u2_fast(int length) {
133    _current += 2 * length;
134  }
135
136  // Tells whether eos is reached
137  bool at_eos() const          { return _current == _buffer_end; }
138};
139
140#endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP
141