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src/share/vm/code/compressedStream.hpp@e9ff18c4ace7 (annotated)

src/share/vm/code/compressedStream.hpp

Wed, 02 Jun 2010 22:45:42 -0700

author

jrose

date

Wed, 02 Jun 2010 22:45:42 -0700

changeset 1934

e9ff18c4ace7

parent 1907

c18cbe5936b8

child 2314

f95d63e2154a

permissions

-rw-r--r--

Merge

duke@435	1	/*
trims@1907	2	* Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// Simple interface for filing out and filing in basic types
duke@435	26	// Used for writing out and reading in debugging information.
duke@435	27
duke@435	28	class CompressedStream : public ResourceObj {
duke@435	29	friend class VMStructs;
duke@435	30	protected:
duke@435	31	u_char* _buffer;
duke@435	32	int _position;
duke@435	33
duke@435	34	enum {
duke@435	35	// Constants for UNSIGNED5 coding of Pack200
duke@435	36	lg_H = 6, H = 1<<lg_H, // number of high codes (64)
duke@435	37	L = (1<<BitsPerByte)-H, // number of low codes (192)
duke@435	38	MAX_i = 4 // bytes are numbered in (0..4), max 5 bytes
duke@435	39	};
duke@435	40
duke@435	41	// these inlines are defined only in compressedStream.cpp
duke@435	42	static inline juint encode_sign(jint value); // for Pack200 SIGNED5
duke@435	43	static inline jint decode_sign(juint value); // for Pack200 SIGNED5
duke@435	44	static inline juint reverse_int(juint bits); // to trim trailing float 0's
duke@435	45
duke@435	46	public:
duke@435	47	CompressedStream(u_char* buffer, int position = 0) {
duke@435	48	_buffer = buffer;
duke@435	49	_position = position;
duke@435	50	}
duke@435	51
duke@435	52	u_char* buffer() const { return _buffer; }
duke@435	53
duke@435	54	// Positioning
duke@435	55	int position() const { return _position; }
duke@435	56	void set_position(int position) { _position = position; }
duke@435	57	};
duke@435	58
duke@435	59
duke@435	60	class CompressedReadStream : public CompressedStream {
duke@435	61	private:
duke@435	62	inline u_char read() { return _buffer[_position++]; }
duke@435	63
duke@435	64	jint read_int_mb(jint b0); // UNSIGNED5 coding, 2-5 byte cases
duke@435	65
duke@435	66	public:
duke@435	67	CompressedReadStream(u_char* buffer, int position = 0)
duke@435	68	: CompressedStream(buffer, position) {}
duke@435	69
duke@435	70	jboolean read_bool() { return (jboolean) read(); }
duke@435	71	jbyte read_byte() { return (jbyte ) read(); }
duke@435	72	jchar read_char() { return (jchar ) read_int(); }
duke@435	73	jshort read_short() { return (jshort ) read_signed_int(); }
duke@435	74	jint read_int() { jint b0 = read();
duke@435	75	if (b0 < L) return b0;
duke@435	76	else return read_int_mb(b0);
duke@435	77	}
duke@435	78	jint read_signed_int();
duke@435	79	jfloat read_float(); // jfloat_cast(reverse_int(read_int()))
duke@435	80	jdouble read_double(); // jdouble_cast(2*reverse_int(read_int))
duke@435	81	jlong read_long(); // jlong_from(2*read_signed_int())
duke@435	82	};
duke@435	83
duke@435	84
duke@435	85	class CompressedWriteStream : public CompressedStream {
duke@435	86	private:
duke@435	87	bool full() {
duke@435	88	return _position >= _size;
duke@435	89	}
duke@435	90	void store(u_char b) {
duke@435	91	_buffer[_position++] = b;
duke@435	92	}
duke@435	93	void write(u_char b) {
duke@435	94	if (full()) grow();
duke@435	95	store(b);
duke@435	96	}
duke@435	97	void grow();
duke@435	98
duke@435	99	void write_int_mb(jint value); // UNSIGNED5 coding, 1-5 byte cases
duke@435	100
duke@435	101	protected:
duke@435	102	int _size;
duke@435	103
duke@435	104	public:
duke@435	105	CompressedWriteStream(int initial_size);
duke@435	106	CompressedWriteStream(u_char* buffer, int initial_size, int position = 0)
duke@435	107	: CompressedStream(buffer, position) { _size = initial_size; }
duke@435	108
duke@435	109	void write_bool(jboolean value) { write(value); }
duke@435	110	void write_byte(jbyte value) { write(value); }
duke@435	111	void write_char(jchar value) { write_int(value); }
duke@435	112	void write_short(jshort value) { write_signed_int(value); }
duke@435	113	void write_int(jint value) { if ((juint)value < L && !full())
duke@435	114	store((u_char)value);
duke@435	115	else write_int_mb(value); }
duke@435	116	void write_signed_int(jint value); // write_int(encode_sign(value))
duke@435	117	void write_float(jfloat value); // write_int(reverse_int(jint_cast(v)))
duke@435	118	void write_double(jdouble value); // write_int(reverse_int(<low,high>))
duke@435	119	void write_long(jlong value); // write_signed_int(<low,high>)
duke@435	120	};