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1 /*
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2 * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #ifndef _BUFFER_
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26 #define _BUFFER_
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27
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28 // A Buffer is the backing store for the IOBuf abstraction and
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29 // supports producer-consumer filling and draining.
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30
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31 class Buffer {
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32 public:
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33 Buffer(int bufSize);
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34 ~Buffer();
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35
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36 char* fillPos(); // Position of the place where buffer should be filled
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37 int remaining(); // Number of bytes that can be placed starting at fillPos
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38 int size(); // Size of the buffer
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39 // Move up fill position by amount (decreases remaining()); returns
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40 // false if not enough space
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41 bool incrFillPos(int amt);
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42
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43 // Read single byte (0..255); returns -1 if no data available.
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44 int readByte();
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45 // Read multiple bytes, non-blocking (this buffer does not define a
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46 // fill mechanism), into provided buffer. Returns number of bytes read.
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47 int readBytes(char* buf, int len);
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48
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49 // Access to drain position. Be very careful using this.
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50 char* drainPos();
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51 int drainRemaining();
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52 bool incrDrainPos(int amt);
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53
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54 // Compact buffer, removing already-consumed input. This must be
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55 // called periodically to yield the illusion of an infinite buffer.
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56 void compact();
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57
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58 private:
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59 Buffer(const Buffer&);
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60 Buffer& operator=(const Buffer&);
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61
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62 char* buf;
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63 int sz;
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64 int fill;
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65 int drain;
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66 };
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67
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68 #endif // #defined _BUFFER_
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