compressedStream.hpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1997, 2005, 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// Simple interface for filing out and filing in basic types 26// Used for writing out and reading in debugging information. 27 28class CompressedStream : public ResourceObj { 29 friend class VMStructs; 30 protected: 31 u_char* _buffer; 32 int _position; 33 34 enum { 35 // Constants for UNSIGNED5 coding of Pack200 36 lg_H = 6, H = 1<<lg_H, // number of high codes (64) 37 L = (1<<BitsPerByte)-H, // number of low codes (192) 38 MAX_i = 4 // bytes are numbered in (0..4), max 5 bytes 39 }; 40 41 // these inlines are defined only in compressedStream.cpp 42 static inline juint encode_sign(jint value); // for Pack200 SIGNED5 43 static inline jint decode_sign(juint value); // for Pack200 SIGNED5 44 static inline juint reverse_int(juint bits); // to trim trailing float 0's 45 46 public: 47 CompressedStream(u_char* buffer, int position = 0) { 48 _buffer = buffer; 49 _position = position; 50 } 51 52 u_char* buffer() const { return _buffer; } 53 54 // Positioning 55 int position() const { return _position; } 56 void set_position(int position) { _position = position; } 57}; 58 59 60class CompressedReadStream : public CompressedStream { 61 private: 62 inline u_char read() { return _buffer[_position++]; } 63 64 jint read_int_mb(jint b0); // UNSIGNED5 coding, 2-5 byte cases 65 66 public: 67 CompressedReadStream(u_char* buffer, int position = 0) 68 : CompressedStream(buffer, position) {} 69 70 jboolean read_bool() { return (jboolean) read(); } 71 jbyte read_byte() { return (jbyte ) read(); } 72 jchar read_char() { return (jchar ) read_int(); } 73 jshort read_short() { return (jshort ) read_signed_int(); } 74 jint read_int() { jint b0 = read(); 75 if (b0 < L) return b0; 76 else return read_int_mb(b0); 77 } 78 jint read_signed_int(); 79 jfloat read_float(); // jfloat_cast(reverse_int(read_int())) 80 jdouble read_double(); // jdouble_cast(2*reverse_int(read_int)) 81 jlong read_long(); // jlong_from(2*read_signed_int()) 82}; 83 84 85class CompressedWriteStream : public CompressedStream { 86 private: 87 bool full() { 88 return _position >= _size; 89 } 90 void store(u_char b) { 91 _buffer[_position++] = b; 92 } 93 void write(u_char b) { 94 if (full()) grow(); 95 store(b); 96 } 97 void grow(); 98 99 void write_int_mb(jint value); // UNSIGNED5 coding, 1-5 byte cases 100 101 protected: 102 int _size; 103 104 public: 105 CompressedWriteStream(int initial_size); 106 CompressedWriteStream(u_char* buffer, int initial_size, int position = 0) 107 : CompressedStream(buffer, position) { _size = initial_size; } 108 109 void write_bool(jboolean value) { write(value); } 110 void write_byte(jbyte value) { write(value); } 111 void write_char(jchar value) { write_int(value); } 112 void write_short(jshort value) { write_signed_int(value); } 113 void write_int(jint value) { if ((juint)value < L && !full()) 114 store((u_char)value); 115 else write_int_mb(value); } 116 void write_signed_int(jint value); // write_int(encode_sign(value)) 117 void write_float(jfloat value); // write_int(reverse_int(jint_cast(v))) 118 void write_double(jdouble value); // write_int(reverse_int(<low,high>)) 119 void write_long(jlong value); // write_signed_int(<low,high>) 120}; 121