Mercurial > jhg

annotate src/com/tmate/hgkit/fs/ByteArrayDataAccess.java @ 159:f5aed108754e wrap-data-access

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Approach with DataAccess instead of plain byte[] was merged into default branch
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Wed, 09 Mar 2011 13:28:02 +0100
parents 9429c7bd1920
children
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51
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Artem Tikhomirov <tikhomirov.artem@gmail.com>
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1 /*
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2 * Copyright (c) 2011 Artem Tikhomirov
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3 */
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4 package com.tmate.hgkit.fs;
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5
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6 import java.io.IOException;
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7
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8 /**
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9 *
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10 * @author artem
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11 */
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12 public class ByteArrayDataAccess extends DataAccess {
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13
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14 private final byte[] data;
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15 private final int offset;
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16 private final int length;
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17 private int pos;
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18
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19 public ByteArrayDataAccess(byte[] data) {
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20 this(data, 0, data.length);
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21 }
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22
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23 public ByteArrayDataAccess(byte[] data, int offset, int length) {
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24 this.data = data;
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25 this.offset = offset;
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26 this.length = length;
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27 pos = 0;
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28 }
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29
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30 @Override
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31 public byte readByte() throws IOException {
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32 if (pos >= length) {
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33 throw new IOException();
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34 }
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35 return data[offset + pos++];
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36 }
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37 @Override
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38 public void readBytes(byte[] buf, int off, int len) throws IOException {
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39 if (len > (this.length - pos)) {
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40 throw new IOException();
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41 }
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42 System.arraycopy(data, pos, buf, off, len);
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43 pos += len;
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44 }
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45
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46 @Override
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47 public void reset() {
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48 pos = 0;
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49 }
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50 @Override
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51 public long length() {
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52 return length;
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53 }
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54 @Override
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55 public void seek(long offset) {
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56 pos = (int) offset;
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57 }
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58 @Override
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59 public void skip(int bytes) throws IOException {
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60 seek(pos + bytes);
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61 }
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62 @Override
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63 public boolean isEmpty() {
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64 return pos >= length;
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65 }
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66
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67 //
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68
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69 // when byte[] needed from DA, we may save few cycles and some memory giving this (otherwise unsafe) access to underlying data
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70 @Override
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71 public byte[] byteArray() {
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72 return data;
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73 }
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74 }