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_CODE_COMPRESSEDSTREAM_HPP 26 #define SHARE_VM_CODE_COMPRESSEDSTREAM_HPP 27 28 #include "memory/allocation.hpp" 29 30 // Simple interface for filing out and filing in basic types 31 // Used for writing out and reading in debugging information. 32 33 class CompressedStream : public ResourceObj { 34 friend class VMStructs; 35 protected: 36 u_char* _buffer; 37 int _position; 38 39 enum { 40 // Constants for UNSIGNED5 coding of Pack200 41 lg_H = 6, H = 1<<lg_H, // number of high codes (64) 42 L = (1<<BitsPerByte)-H, // number of low codes (192) 43 MAX_i = 4 // bytes are numbered in (0..4), max 5 bytes 44 }; 45 46 // these inlines are defined only in compressedStream.cpp 47 static inline juint encode_sign(jint value); // for Pack200 SIGNED5 48 static inline jint decode_sign(juint value); // for Pack200 SIGNED5 49 static inline juint reverse_int(juint bits); // to trim trailing float 0's 50 51 public: 52 CompressedStream(u_char* buffer, int position = 0) { 53 _buffer = buffer; 54 _position = position; 55 } 56 57 u_char* buffer() const { return _buffer; } 58 59 // Positioning 60 int position() const { return _position; } 61 void set_position(int position) { _position = position; } 62 }; 63 64 65 class CompressedReadStream : public CompressedStream { 66 private: 67 inline u_char read() { return _buffer[_position++]; } 68 69 jint read_int_mb(jint b0); // UNSIGNED5 coding, 2-5 byte cases 70 71 public: 72 CompressedReadStream(u_char* buffer, int position = 0) 73 : CompressedStream(buffer, position) {} 74 75 jboolean read_bool() { return (jboolean) read(); } 76 jbyte read_byte() { return (jbyte ) read(); } 77 jchar read_char() { return (jchar ) read_int(); } 78 jshort read_short() { return (jshort ) read_signed_int(); } 79 jint read_int() { jint b0 = read(); 80 if (b0 < L) return b0; 81 else return read_int_mb(b0); 82 } 83 jint read_signed_int(); 84 jfloat read_float(); // jfloat_cast(reverse_int(read_int())) 85 jdouble read_double(); // jdouble_cast(2*reverse_int(read_int)) 86 jlong read_long(); // jlong_from(2*read_signed_int()) 87 }; 88 89 90 class CompressedWriteStream : public CompressedStream { 91 private: 92 bool full() { 93 return _position >= _size; 94 } 95 void store(u_char b) { 96 _buffer[_position++] = b; 97 } 98 void write(u_char b) { 99 if (full()) grow(); 100 store(b); 101 } 102 void grow(); 103 104 void write_int_mb(jint value); // UNSIGNED5 coding, 1-5 byte cases 105 106 protected: 107 int _size; 108 109 public: 110 CompressedWriteStream(int initial_size); 111 CompressedWriteStream(u_char* buffer, int initial_size, int position = 0) 112 : CompressedStream(buffer, position) { _size = initial_size; } 113 114 void write_bool(jboolean value) { write(value); } 115 void write_byte(jbyte value) { write(value); } 116 void write_char(jchar value) { write_int(value); } 117 void write_short(jshort value) { write_signed_int(value); } 118 void write_int(jint value) { if ((juint)value < L && !full()) 119 store((u_char)value); 120 else write_int_mb(value); } 121 void write_signed_int(jint value); // write_int(encode_sign(value)) 122 void write_float(jfloat value); // write_int(reverse_int(jint_cast(v))) 123 void write_double(jdouble value); // write_int(reverse_int(<low,high>)) 124 void write_long(jlong value); // write_signed_int(<low,high>) 125 }; 126 127 #endif // SHARE_VM_CODE_COMPRESSEDSTREAM_HPP