1 /*
2 * Copyright (c) 1997, 2015, 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
51 class 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 const 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
61 #if INCLUDE_JFR
62 u1* clone_buffer() const;
63 const char* const clone_source() const;
64 #endif
65
66 public:
67 // Constructor
68 ClassFileStream(u1* buffer, int length, const char* source, bool need_verify = false);
69
70 // Buffer access
71 u1* buffer() const { return _buffer_start; }
72 int length() const { return _buffer_end - _buffer_start; }
73 u1* current() const { return _current; }
74 void set_current(u1* pos) { _current = pos; }
75 // for relative positioning
76 juint current_offset() const {
77 return (juint)(_current - _buffer_start);
78 }
79 const char* source() const { return _source; }
80 void set_verify(bool flag) { _need_verify = flag; }
81
82 void check_truncated_file(bool b, TRAPS) {
83 if (b) {
84 truncated_file_error(THREAD);
85 }
86 }
87
88 void guarantee_more(int size, TRAPS) {
89 size_t remaining = (size_t)(_buffer_end - _current);
90 unsigned int usize = (unsigned int)size;
91 check_truncated_file(usize > remaining, CHECK);
92 }
93
94 // Read u1 from stream
95 u1 get_u1(TRAPS);
96 u1 get_u1_fast() {
97 return *_current++;
98 }
99
100 // Read u2 from stream
101 u2 get_u2(TRAPS);
102 u2 get_u2_fast() {
103 u2 res = Bytes::get_Java_u2(_current);
104 _current += 2;
105 return res;
106 }
107
108 // Read u4 from stream
109 u4 get_u4(TRAPS);
110 u4 get_u4_fast() {
111 u4 res = Bytes::get_Java_u4(_current);
112 _current += 4;
113 return res;
114 }
115
116 // Read u8 from stream
117 u8 get_u8(TRAPS);
118 u8 get_u8_fast() {
119 u8 res = Bytes::get_Java_u8(_current);
120 _current += 8;
121 return res;
122 }
123
124 // Get direct pointer into stream at current position.
125 // Returns NULL if length elements are not remaining. The caller is
126 // responsible for calling skip below if buffer contents is used.
127 u1* get_u1_buffer() {
128 return _current;
129 }
130
131 u2* get_u2_buffer() {
132 return (u2*) _current;
133 }
134
135 // Skip length u1 or u2 elements from stream
136 void skip_u1(int length, TRAPS);
137 void skip_u1_fast(int length) {
138 _current += length;
139 }
140
141 void skip_u2(int length, TRAPS);
142 void skip_u2_fast(int length) {
143 _current += 2 * length;
144 }
145
146 void skip_u4(int length, TRAPS);
147 void skip_u4_fast(int length) {
148 _current += 4 * length;
149 }
150
151 // Tells whether eos is reached
152 bool at_eos() const { return _current == _buffer_end; }
153
154 #if INCLUDE_JFR
155 ClassFileStream* clone() const;
156
157 bool need_verify() const { return _need_verify; }
158 #endif
159 };
160
161 #endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP