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
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 public:
61 // Constructor
62 ClassFileStream(u1* buffer, int length, const 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 const 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 void skip_u4(int length, TRAPS);
137 void skip_u4_fast(int length) {
138 _current += 4 * length;
139 }
140
141 // Tells whether eos is reached
142 bool at_eos() const { return _current == _buffer_end; }
143 };
144
145 #endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP