svn-gvsig-desktop / branches / Mobile_Compatible_Hito_1 / libFMap_mobile_shp_driver / src-comp / org / gvsig / datasources / impljme / BufferedBigByteBufferJME.java @ 21865
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1 | 21865 | jldominguez | package org.gvsig.datasources.impljme; |
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2 | |||
3 | import java.io.IOException; |
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4 | import java.nio.ByteBuffer; |
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5 | import java.nio.ByteOrder; |
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6 | |||
7 | import org.apache.log4j.Logger; |
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8 | import org.gvsig.datasources.common.IBigByteBuffer; |
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9 | import org.gvsig.datasources.common.IByteBuffer; |
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10 | import org.gvsig.datasources.common.IRandomFileChannel; |
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11 | |||
12 | /**
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13 | * This class implements the IBigByteBuffer for JME. As the desktop version,
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14 | * it keeps a small buffer in memory, by using the classes ByteBufferJME
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15 | * and RandomFileChannelJME.
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16 | *
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17 | * @see org.gvsig.datasources.impljme.ByteBufferJME
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18 | * @see org.gvsig.datasources.impljme.RandomFileChannelJME
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19 | *
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20 | * @author jldominguez
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21 | *
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22 | */
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23 | public class BufferedBigByteBufferJME implements IBigByteBuffer { |
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24 | |||
25 | private static Logger logger = Logger.getLogger(BufferedBigByteBufferJME.class); |
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26 | |||
27 | /**
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28 | * Memory buffer size
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29 | */
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30 | public static long DEFAULT_SIZE = 4*1024; // 8 Kbytes |
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31 | |||
32 | private ByteBufferJME theBuffer = null; |
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33 | |||
34 | private RandomFileChannelJME fc;
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35 | private long minAbs, maxAbs, posAbs; |
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36 | private int minRel, maxRel, posRel; |
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37 | private long sizeChunk, amountMem; |
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38 | private long fileSize; |
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39 | private int mode; |
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40 | |||
41 | public BufferedBigByteBufferJME(IRandomFileChannel ch, int acc_mode) { |
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42 | |||
43 | amountMem = DEFAULT_SIZE; |
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44 | fc = (RandomFileChannelJME) ch; |
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45 | try {
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46 | fileSize = fc.size(); |
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47 | mode = acc_mode; |
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48 | sizeChunk = Math.min(fc.size(), amountMem);
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49 | } catch (IOException e) { |
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50 | logger.error("While instantiating: " + e.getMessage());
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51 | } |
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52 | |||
53 | theBuffer = (ByteBufferJME) Impl.allocateDirect((int) sizeChunk);
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54 | |||
55 | byte[] aux = new byte[(int) sizeChunk]; |
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56 | |||
57 | fc.getAsIs(aux); |
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58 | |||
59 | theBuffer.put(aux); |
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60 | |||
61 | theBuffer.position(0);
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62 | minAbs = 0;
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63 | maxAbs = sizeChunk; |
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64 | } |
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65 | |||
66 | /**
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67 | * Checks the position and loads the data if necessary.
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68 | *
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69 | * @throws IOException
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70 | */
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71 | private void prepareBuffer(long posActual, int numBytesToRead) |
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72 | { |
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73 | long desiredPos = posActual + numBytesToRead;
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74 | if ((desiredPos > maxAbs) || (posActual < minAbs)) {
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75 | |||
76 | // logger.debug("Se ha pedido fuera del buffer: Tenemos: ["
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77 | // + minAbs + " , " + maxAbs + "], Se pide hasta: " + desiredPos);
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78 | // Quiero leer fuera:
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79 | sizeChunk = Math.min(fileSize-posActual, amountMem);
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80 | try {
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81 | mapFrom(posActual); |
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82 | } catch (IOException e) { |
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83 | e.printStackTrace(); |
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84 | } |
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85 | } else {
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86 | theBuffer.position((int) (posActual - minAbs));
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87 | // System.out.println("NOT setting in buffer");
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88 | } |
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89 | // Dejamos posAbs apuntando a donde va a quedar
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90 | // "a priori", antes de leer de verdad, que se hace
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91 | // al salir de esta funci?n.
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92 | posAbs = desiredPos; |
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93 | } |
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94 | |||
95 | |||
96 | |||
97 | /**
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98 | * @param posActual
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99 | * @throws IOException
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100 | */
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101 | private IByteBuffer mapFrom(long newPos) throws IOException { |
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102 | ByteOrder lastOrder = theBuffer.order();
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103 | // bb = fc.map(mode, newPos, sizeChunk);
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104 | fc.position((int) newPos);
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105 | // bb = ByteBuffer.wrap(buff);
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106 | // bb = ByteBuffer.allocate((int)sizeChunk);
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107 | theBuffer.position(0);
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108 | |||
109 | byte[] newbuf = new byte[(int) sizeChunk]; |
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110 | fc.getAsIs(newbuf); |
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111 | |||
112 | theBuffer = new ByteBufferJME(newbuf);
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113 | // System.out.println("Mapeo desde " + newPos + " con sizeChunk= " + sizeChunk + " numRead = " + numRead);
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114 | minAbs = newPos; |
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115 | maxAbs = sizeChunk + newPos; |
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116 | theBuffer.order(lastOrder); |
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117 | return theBuffer;
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118 | } |
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119 | |||
120 | |||
121 | |||
122 | public void position(long p) { |
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123 | |||
124 | prepareBuffer(p, 0);
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125 | int relPos = (int) (p - minAbs); |
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126 | if (relPos < 0) { |
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127 | System.out.println("Position=" + p); |
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128 | } |
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129 | } |
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130 | |||
131 | public int position() { |
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132 | // TODO Auto-generated method stub
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133 | return (int) posAbs; |
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134 | } |
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135 | |||
136 | public byte get() { |
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137 | prepareBuffer(posAbs, 1);
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138 | return theBuffer.get();
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139 | } |
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140 | |||
141 | public byte getByte(int ind) { |
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142 | prepareBuffer(ind, 1);
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143 | return theBuffer.get(ind - (int) minAbs); |
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144 | } |
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145 | |||
146 | public int getInt() { |
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147 | prepareBuffer(posAbs, 4);
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148 | return theBuffer.getInt();
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149 | } |
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150 | |||
151 | public short getShort() { |
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152 | prepareBuffer(posAbs, 2);
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153 | return theBuffer.getShort();
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154 | } |
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155 | |||
156 | public int getInt(int index) { |
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157 | prepareBuffer(index, 4);
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158 | return theBuffer.getInt(index - (int) minAbs); |
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159 | } |
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160 | |||
161 | public void get(byte[] out) { |
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162 | prepareBuffer(posAbs, out.length); |
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163 | theBuffer.get(out); |
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164 | } |
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165 | |||
166 | public double getDouble() { |
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167 | prepareBuffer(posAbs, 8);
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168 | return theBuffer.getDouble();
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169 | } |
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170 | |||
171 | public void order(ByteOrder o) { |
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172 | theBuffer.order(o); |
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173 | } |
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174 | |||
175 | } |