1 /* 2 * Copyright (c) 2001, 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, 20 * CA 94065 USA or visit www.oracle.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 #ifndef _BUFFER_ 26 #define _BUFFER_ 27 28 // A Buffer is the backing store for the IOBuf abstraction and 29 // supports producer-consumer filling and draining. 30 31 class Buffer { 32 public: 33 Buffer(int bufSize); 34 ~Buffer(); 35 36 char* fillPos(); // Position of the place where buffer should be filled 37 int remaining(); // Number of bytes that can be placed starting at fillPos 38 int size(); // Size of the buffer 39 // Move up fill position by amount (decreases remaining()); returns 40 // false if not enough space 41 bool incrFillPos(int amt); 42 43 // Read single byte (0..255); returns -1 if no data available. 44 int readByte(); 45 // Read multiple bytes, non-blocking (this buffer does not define a 46 // fill mechanism), into provided buffer. Returns number of bytes read. 47 int readBytes(char* buf, int len); 48 49 // Access to drain position. Be very careful using this. 50 char* drainPos(); 51 int drainRemaining(); 52 bool incrDrainPos(int amt); 53 54 // Compact buffer, removing already-consumed input. This must be 55 // called periodically to yield the illusion of an infinite buffer. 56 void compact(); 57 58 private: 59 Buffer(const Buffer&); 60 Buffer& operator=(const Buffer&); 61 62 char* buf; 63 int sz; 64 int fill; 65 int drain; 66 }; 67 68 #endif // #defined _BUFFER_