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 "memory/allocation.hpp" 29 #include "utilities/bytes.hpp" 30 #include "utilities/exceptions.hpp" 31 32 // Input stream for reading .class file 33 // 34 // The entire input stream is present in a buffer allocated by the caller. 35 // The caller is responsible for deallocating the buffer and for using 36 // ResourceMarks appropriately when constructing streams. 37 38 class ClassPathEntry; 39 40 class ClassFileStream: public ResourceObj { 41 private: 42 const u1* const _buffer_start; // Buffer bottom 43 const u1* const _buffer_end; // Buffer top (one past last element) 44 mutable const u1* _current; // Current buffer position 45 const char* const _source; // Source of stream (directory name, ZIP/JAR archive name) 46 bool _need_verify; // True if verification is on for the class file 47 48 void truncated_file_error(TRAPS) const ; 49 50 protected: 51 const u1* clone_buffer() const; 52 const char* const clone_source() const; 53 54 public: 55 static const bool no_verification; 56 static const bool verify; 57 58 ClassFileStream(const u1* buffer, 59 int length, 60 const char* source, 61 bool verify_stream = verify); // to be verified by default 62 63 virtual const ClassFileStream* clone() const; 64 65 // Buffer access buffer() const66 const u1* buffer() const { return _buffer_start; } length() const67 int length() const { return _buffer_end - _buffer_start; } current() const68 const u1* current() const { return _current; } set_current(const u1 * pos) const69 void set_current(const u1* pos) const { 70 assert(pos >= _buffer_start && pos <= _buffer_end, "invariant"); 71 _current = pos; 72 } 73 74 // for relative positioning current_offset() const75 juint current_offset() const { 76 return (juint)(_current - _buffer_start); 77 } source() const78 const char* source() const { return _source; } need_verify() const79 bool need_verify() const { return _need_verify; } set_verify(bool flag)80 void set_verify(bool flag) { _need_verify = flag; } 81 check_truncated_file(bool b,TRAPS) const82 void check_truncated_file(bool b, TRAPS) const { 83 if (b) { 84 truncated_file_error(THREAD); 85 } 86 } 87 guarantee_more(int size,TRAPS) const88 void guarantee_more(int size, TRAPS) const { 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) const; get_u1_fast() const96 u1 get_u1_fast() const { 97 return *_current++; 98 } 99 100 // Read u2 from stream 101 u2 get_u2(TRAPS) const; get_u2_fast() const102 u2 get_u2_fast() const { 103 u2 res = Bytes::get_Java_u2((address)_current); 104 _current += 2; 105 return res; 106 } 107 108 // Read u4 from stream 109 u4 get_u4(TRAPS) const; get_u4_fast() const110 u4 get_u4_fast() const { 111 u4 res = Bytes::get_Java_u4((address)_current); 112 _current += 4; 113 return res; 114 } 115 116 // Read u8 from stream 117 u8 get_u8(TRAPS) const; get_u8_fast() const118 u8 get_u8_fast() const { 119 u8 res = Bytes::get_Java_u8((address)_current); 120 _current += 8; 121 return res; 122 } 123 124 // Skip length u1 or u2 elements from stream 125 void skip_u1(int length, TRAPS) const; skip_u1_fast(int length) const126 void skip_u1_fast(int length) const { 127 _current += length; 128 } 129 130 void skip_u2(int length, TRAPS) const; skip_u2_fast(int length) const131 void skip_u2_fast(int length) const { 132 _current += 2 * length; 133 } 134 135 void skip_u4(int length, TRAPS) const; skip_u4_fast(int length) const136 void skip_u4_fast(int length) const { 137 _current += 4 * length; 138 } 139 140 // Tells whether eos is reached at_eos() const141 bool at_eos() const { return _current == _buffer_end; } 142 143 uint64_t compute_fingerprint() const; 144 }; 145 146 #endif // SHARE_VM_CLASSFILE_CLASSFILESTREAM_HPP 147