1 /*
2 * Copyright (c) 1997, 2010, 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
39 // Input stream for reading .class file
40 //
41 // The entire input stream is present in a buffer allocated by the caller.
42 // The caller is responsible for deallocating the buffer and for using
43 // ResourceMarks appropriately when constructing streams.
44
45 class ClassFileStream: public ResourceObj {
46 private:
47 u1* _buffer_start; // Buffer bottom
48 u1* _buffer_end; // Buffer top (one past last element)
49 u1* _current; // Current buffer position
50 char* _source; // Source of stream (directory name, ZIP/JAR archive name)
51 bool _need_verify; // True if verification is on for the class file
52
53 void truncated_file_error(TRAPS);
54 public:
55 // Constructor
56 ClassFileStream(u1* buffer, int length, char* source);
57
58 // Buffer access
59 u1* buffer() const { return _buffer_start; }
60 int length() const { return _buffer_end - _buffer_start; }
61 u1* current() const { return _current; }
62 void set_current(u1* pos) { _current = pos; }
63 char* source() const { return _source; }
64 void set_verify(bool flag) { _need_verify = flag; }
65
66 void check_truncated_file(bool b, TRAPS) {
67 if (b) {
68 truncated_file_error(THREAD);
69 }
70 }
71
72 void guarantee_more(int size, TRAPS) {
73 size_t remaining = (size_t)(_buffer_end - _current);
74 unsigned int usize = (unsigned int)size;
75 check_truncated_file(usize > remaining, CHECK);
76 }
77
78 // Read u1 from stream
79 u1 get_u1(TRAPS);
80 u1 get_u1_fast() {
81 return *_current++;
82 }
83
84 // Read u2 from stream
85 u2 get_u2(TRAPS);
86 u2 get_u2_fast() {
87 u2 res = Bytes::get_Java_u2(_current);
88 _current += 2;
89 return res;
90 }
91
92 // Read u4 from stream
93 u4 get_u4(TRAPS);
94 u4 get_u4_fast() {
95 u4 res = Bytes::get_Java_u4(_current);
96 _current += 4;
97 return res;
98 }
99
100 // Read u8 from stream
101 u8 get_u8(TRAPS);
102 u8 get_u8_fast() {
103 u8 res = Bytes::get_Java_u8(_current);
104 _current += 8;
105 return res;
106 }
107
108 // Get direct pointer into stream at current position.
109 // Returns NULL if length elements are not remaining. The caller is
110 // responsible for calling skip below if buffer contents is used.
111 u1* get_u1_buffer() {
112 return _current;
113 }
114
115 u2* get_u2_buffer() {
116 return (u2*) _current;
117 }
118
119 // Skip length u1 or u2 elements from stream
120 void skip_u1(int length, TRAPS);
121 void skip_u1_fast(int length) {
122 _current += length;
123 }
124
125 void skip_u2(int length, TRAPS);
126 void skip_u2_fast(int length) {
127 _current += 2 * length;
128 }
129
130 // Tells whether eos is reached
131 bool at_eos() const { return _current == _buffer_end; }
132 };
133
134 #endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP