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comparison src/share/vm/code/compressedStream.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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children c18cbe5936b8
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-1:000000000000 0:a61af66fc99e
1 /*
2 * Copyright 1997-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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
28 class 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
60 class 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
85 class 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 };