1 | /* |
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2 | * RandomAccessCharacterFile.java |
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3 | * |
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4 | * Copyright (C) 2008 Hideo at Yokohama |
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5 | * Copyright (C) 2008-2009 Erik Huelsmann |
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6 | * $Id: RandomAccessCharacterFile.java 15387 2020-10-01 22:29:11Z mevenson $ |
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7 | * |
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8 | * This program is free software; you can redistribute it and/or |
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9 | * modify it under the terms of the GNU General Public License |
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10 | * as published by the Free Software Foundation; either version 2 |
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11 | * of the License, or (at your option) any later version. |
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12 | * |
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13 | * This program is distributed in the hope that it will be useful, |
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | * GNU General Public License for more details. |
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17 | * |
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18 | * You should have received a copy of the GNU General Public License |
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19 | * along with this program; if not, write to the Free Software |
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20 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, . |
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21 | * |
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22 | * As a special exception, the copyright holders of this library give you |
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23 | * permission to link this library with independent modules to produce an |
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24 | * executable, regardless of the license terms of these independent |
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25 | * modules, and to copy and distribute the resulting executable under |
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26 | * terms of your choice, provided that you also meet, for each linked |
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27 | * independent module, the terms and conditions of the license of that |
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28 | * module. An independent module is a module which is not derived from |
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29 | * or based on this library. If you modify this library, you may extend |
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30 | * this exception to your version of the library, but you are not |
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31 | * obligated to do so. If you do not wish to do so, delete this |
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32 | * exception statement from your version. |
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33 | */ |
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34 | |
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35 | package org.armedbear.lisp.util; |
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36 | |
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37 | import java.io.IOException; |
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38 | import java.io.PushbackInputStream; |
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39 | import java.io.OutputStream; |
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40 | import java.io.RandomAccessFile; |
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41 | import java.io.PushbackReader; |
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42 | import java.io.Reader; |
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43 | import java.io.StringReader; |
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44 | import java.io.Writer; |
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45 | import java.nio.ByteBuffer; |
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46 | import java.nio.CharBuffer; |
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47 | import java.nio.channels.FileChannel; |
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48 | import java.nio.charset.Charset; |
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49 | import java.nio.charset.CharsetDecoder; |
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50 | import java.nio.charset.CharsetEncoder; |
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51 | import java.nio.charset.CoderMalfunctionError; |
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52 | import java.nio.charset.CoderResult; |
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53 | import java.nio.charset.CodingErrorAction; |
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54 | import java.nio.charset.UnsupportedCharsetException; |
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55 | |
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56 | import org.armedbear.lisp.Debug; |
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57 | |
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58 | import static org.armedbear.lisp.Lisp.error; |
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59 | |
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60 | import org.armedbear.lisp.SimpleError; |
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61 | import org.armedbear.lisp.SimpleString; |
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62 | |
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63 | public class RandomAccessCharacterFile { |
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64 | |
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65 | private class RandomAccessInputStream extends PushbackInputStream { |
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66 | |
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67 | public RandomAccessInputStream() { |
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68 | super(null); |
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69 | } |
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70 | |
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71 | private byte[] read_buf = new byte[1]; |
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72 | |
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73 | @Override |
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74 | public final int read() throws IOException { |
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75 | int len = read(read_buf); |
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76 | if (len == 1) { |
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77 | // byte is signed, char is unsigned, int is signed. |
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78 | // buf can hold 0xff, we want it as 0xff in int, not -1. |
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79 | return 0xff & (int) read_buf[0]; |
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80 | } else { |
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81 | return -1; |
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82 | } |
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83 | // ### BUG: 'int read()' is to return a *codepoint*, |
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84 | // not the half of a surrogate pair! |
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85 | } |
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86 | |
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87 | @Override |
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88 | public final int read(byte[] b, int off, int len) throws IOException { |
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89 | return RandomAccessCharacterFile.this.read(b, off, len); |
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90 | } |
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91 | |
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92 | @Override |
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93 | public final void unread(int b) throws IOException { |
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94 | RandomAccessCharacterFile.this.unreadByte((byte)b); |
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95 | } |
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96 | |
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97 | @Override |
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98 | public final void unread(byte[] b, int off, int len) throws IOException { |
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99 | for (int i = 0; i < len; i++) |
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100 | this.unread(b[off+i]); |
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101 | } |
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102 | |
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103 | @Override |
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104 | public final void unread(byte[] b) throws IOException { |
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105 | this.unread(b, 0, b.length); |
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106 | } |
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107 | |
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108 | @Override |
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109 | public final int available() throws IOException { |
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110 | return (int)(RandomAccessCharacterFile.this.length() |
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111 | - RandomAccessCharacterFile.this.position()); |
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112 | } |
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113 | |
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114 | @Override |
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115 | public final synchronized void mark(int readlimit) { |
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116 | } |
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117 | |
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118 | @Override |
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119 | public final boolean markSupported() { |
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120 | return false; |
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121 | } |
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122 | |
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123 | @Override |
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124 | public final synchronized void reset() throws IOException { |
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125 | throw new IOException("Operation not supported"); |
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126 | } |
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127 | |
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128 | @Override |
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129 | public final long skip(long n) throws IOException { |
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130 | RandomAccessCharacterFile.this.position(RandomAccessCharacterFile.this.position()+n); |
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131 | return n; |
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132 | } |
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133 | |
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134 | @Override |
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135 | public final int read(byte[] b) throws IOException { |
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136 | return this.read(b, 0, b.length); |
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137 | } |
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138 | |
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139 | @Override |
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140 | public final void close() throws IOException { |
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141 | RandomAccessCharacterFile.this.close(); |
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142 | } |
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143 | } |
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144 | |
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145 | private class RandomAccessOutputStream extends OutputStream { |
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146 | |
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147 | RandomAccessOutputStream() { |
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148 | } |
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149 | |
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150 | private byte[] buf = new byte[1]; |
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151 | public final void write(int b) throws IOException { |
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152 | buf[0] = (byte)b; |
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153 | RandomAccessCharacterFile.this.write(buf, 0, 1); |
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154 | } |
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155 | |
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156 | @Override |
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157 | public final void write(byte[] b) throws IOException { |
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158 | RandomAccessCharacterFile.this.write(b, 0, b.length); |
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159 | } |
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160 | |
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161 | @Override |
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162 | public final void write(byte[] b, int off, int len) throws IOException { |
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163 | RandomAccessCharacterFile.this.write(b, off, len); |
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164 | } |
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165 | |
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166 | @Override |
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167 | public final void flush() throws IOException { |
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168 | RandomAccessCharacterFile.this.flush(); |
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169 | } |
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170 | |
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171 | @Override |
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172 | public final void close() throws IOException { |
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173 | RandomAccessCharacterFile.this.close(); |
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174 | } |
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175 | } |
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176 | |
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177 | // dummy reader which we need to call the Pushback constructor |
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178 | // because a null value won't work |
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179 | static Reader staticReader = new StringReader(""); |
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180 | |
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181 | private class RandomAccessReader extends PushbackReader { |
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182 | |
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183 | RandomAccessReader() { |
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184 | // because we override all methods of Pushbackreader, |
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185 | // staticReader will never be referenced |
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186 | super(staticReader); |
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187 | } |
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188 | |
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189 | @Override |
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190 | public final void close() throws IOException { |
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191 | RandomAccessCharacterFile.this.close(); |
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192 | } |
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193 | |
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194 | private char[] read_buf = new char[1]; |
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195 | |
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196 | @Override |
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197 | public final int read() throws IOException { |
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198 | int n = this.read(read_buf); |
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199 | |
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200 | if (n == 1) |
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201 | return read_buf[0]; |
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202 | else |
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203 | return -1; |
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204 | // ### BUG: 'int read()' is to return a codepoint! |
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205 | // not the half of a surrogate pair! |
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206 | } |
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207 | |
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208 | @Override |
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209 | public final void unread(int c) throws IOException { |
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210 | RandomAccessCharacterFile.this.unreadChar((char)c); |
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211 | } |
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212 | |
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213 | @Override |
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214 | public final void unread(char[] cbuf, int off, int len) throws IOException { |
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215 | for (int i = 0; i < len; i++) |
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216 | this.unread(cbuf[off+i]); |
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217 | } |
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218 | |
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219 | @Override |
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220 | public final void unread(char[] cbuf) throws IOException { |
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221 | this.unread(cbuf, 0, cbuf.length); |
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222 | } |
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223 | |
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224 | @Override |
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225 | public final int read(CharBuffer target) throws IOException { |
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226 | //FIXME: to be implemented |
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227 | throw new IOException("Not implemented"); |
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228 | } |
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229 | |
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230 | @Override |
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231 | public final int read(char[] cbuf) throws IOException { |
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232 | return RandomAccessCharacterFile.this.read(cbuf, 0, cbuf.length); |
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233 | } |
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234 | |
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235 | @Override |
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236 | public final int read(char[] cb, int off, int len) throws IOException { |
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237 | return RandomAccessCharacterFile.this.read(cb, off, len); |
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238 | } |
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239 | |
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240 | @Override |
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241 | public final boolean ready() throws IOException { |
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242 | return true; |
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243 | } |
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244 | } |
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245 | |
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246 | private class RandomAccessWriter extends Writer { |
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247 | |
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248 | RandomAccessWriter() { |
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249 | } |
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250 | |
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251 | public final void close() throws IOException { |
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252 | RandomAccessCharacterFile.this.close(); |
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253 | } |
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254 | |
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255 | public final void flush() throws IOException { |
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256 | RandomAccessCharacterFile.this.flush(); |
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257 | } |
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258 | |
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259 | @Override |
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260 | public final void write(char[] cb, int off, int len) throws IOException { |
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261 | RandomAccessCharacterFile.this.write(cb, off, len); |
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262 | } |
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263 | |
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264 | } |
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265 | |
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266 | |
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267 | final static int BUFSIZ = 4*1024; // setting this to a small value like 8 is helpful for testing. |
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268 | |
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269 | private RandomAccessWriter writer; |
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270 | private RandomAccessReader reader; |
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271 | private RandomAccessInputStream inputStream; |
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272 | private RandomAccessOutputStream outputStream; |
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273 | private FileChannel fcn; |
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274 | |
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275 | private Charset cset; |
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276 | private CharsetEncoder cenc; |
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277 | private CharsetDecoder cdec; |
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278 | |
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279 | /** |
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280 | * bbuf is treated as a cache of the file content. |
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281 | * If it points to somewhere in the middle of the file, it holds the copy of the file content, |
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282 | * even when you are writing a large chunk of data. If you write in the middle of a file, |
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283 | * bbuf first gets filled with contents of the data, and only after that any new data is |
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284 | * written on bbuf. |
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285 | * The exception is when you are appending data at the end of the file. |
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286 | */ |
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287 | private ByteBuffer bbuf; |
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288 | private boolean bbufIsDirty; /* whether bbuf holds data that must be written. */ |
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289 | private boolean bbufIsReadable; /* whether bbuf.remaining() contains readable content. */ |
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290 | private long bbufpos; /* where the beginning of bbuf is pointing in the file now. */ |
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291 | |
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292 | public RandomAccessCharacterFile(RandomAccessFile raf, String encoding) throws IOException { |
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293 | |
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294 | fcn = raf.getChannel(); |
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295 | |
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296 | setEncoding(encoding); |
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297 | bbuf = ByteBuffer.allocate(BUFSIZ); |
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298 | |
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299 | // there is no readable data available in the buffers. |
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300 | ((java.nio.Buffer)bbuf).flip(); |
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301 | |
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302 | // there is no write pending data in the buffers. |
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303 | bbufIsDirty = false; |
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304 | |
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305 | bbufIsReadable = true; |
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306 | |
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307 | bbufpos = fcn.position(); |
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308 | |
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309 | reader = new RandomAccessReader(); |
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310 | writer = new RandomAccessWriter(); |
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311 | inputStream = new RandomAccessInputStream(); |
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312 | outputStream = new RandomAccessOutputStream(); |
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313 | } |
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314 | |
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315 | public void setEncoding(String encoding) { |
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316 | if (encoding == null) { |
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317 | cset = Charset.defaultCharset(); |
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318 | } else { |
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319 | try { |
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320 | cset = Charset.forName(encoding); |
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321 | } catch (UnsupportedCharsetException e) { |
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322 | error(new SimpleError("Undefined encoding: " + encoding)); |
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323 | } |
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324 | } |
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325 | cdec = cset.newDecoder(); |
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326 | cdec.onMalformedInput(CodingErrorAction.REPLACE); |
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327 | cdec.onUnmappableCharacter(CodingErrorAction.REPLACE); |
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328 | cenc = cset.newEncoder(); |
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329 | } |
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330 | |
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331 | public Writer getWriter() { |
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332 | return writer; |
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333 | } |
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334 | |
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335 | public PushbackReader getReader() { |
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336 | return reader; |
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337 | } |
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338 | |
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339 | public PushbackInputStream getInputStream() { |
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340 | return inputStream; |
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341 | } |
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342 | |
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343 | public OutputStream getOutputStream() { |
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344 | return outputStream; |
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345 | } |
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346 | |
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347 | public final void close() throws IOException { |
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348 | internalFlush(true); |
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349 | fcn.close(); |
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350 | } |
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351 | |
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352 | public final void flush() throws IOException { |
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353 | internalFlush(false); |
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354 | } |
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355 | |
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356 | private final boolean ensureReadBbuf(boolean force) throws IOException { |
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357 | boolean bufReady = true; |
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358 | |
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359 | if ((bbuf.remaining() == 0) || force || ! bbufIsReadable) { |
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360 | // need to read from the file. |
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361 | |
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362 | if (bbufIsDirty) { |
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363 | flushBbuf(false); |
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364 | ((java.nio.Buffer)bbuf).clear(); |
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365 | bbufIsReadable = false; |
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366 | } else { |
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367 | int bbufEnd = bbufIsReadable |
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368 | ? ((java.nio.Buffer)bbuf).limit() |
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369 | : ((java.nio.Buffer)bbuf).position(); |
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370 | fcn.position(bbufpos + bbufEnd); |
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371 | bbufpos += ((java.nio.Buffer)bbuf).position(); |
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372 | if (bbufIsReadable) { |
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373 | bbuf.compact(); |
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374 | bbufIsReadable = false; |
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375 | } else //must discard the junk bytes after ((java.nio.Buffer)bbuf).position() |
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376 | ((java.nio.Buffer)bbuf).clear(); |
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377 | } |
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378 | |
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379 | bufReady = (fcn.read(bbuf) != -1); |
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380 | ((java.nio.Buffer)bbuf).flip(); |
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381 | bbufIsReadable = true; |
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382 | } |
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383 | |
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384 | return bufReady; |
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385 | } |
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386 | |
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387 | |
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388 | final int read(char[] cb, int off, int len) throws IOException { |
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389 | CharBuffer cbuf = CharBuffer.wrap(cb, off, len); |
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390 | cdec.reset(); |
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391 | boolean decodeWasUnderflow = false; |
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392 | boolean atEof = false; |
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393 | while ((cbuf.remaining() > 0) && ! atEof) { |
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394 | int oldRemaining = cbuf.remaining(); |
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395 | atEof = ! ensureReadBbuf(decodeWasUnderflow); |
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396 | CoderResult r; |
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397 | try { |
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398 | r = cdec.decode(bbuf, cbuf, atEof ); |
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399 | } catch (IllegalStateException e) { |
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400 | throw new IOException("CharsetDecoder failed", e); |
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401 | } catch (CoderMalfunctionError e) { |
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402 | throw new IOException("CharsetDecoder malfunction", e); |
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403 | } |
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404 | |
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405 | if (oldRemaining == cbuf.remaining() |
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406 | && CoderResult.OVERFLOW == r) { |
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407 | // if this happens, the decoding failed |
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408 | // but the bufs didn't advance. Advance |
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409 | // them manually and do manual replacing, |
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410 | // otherwise we loop endlessly. This occurs |
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411 | // at least when parsing latin1 files with |
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412 | // lowercase o-umlauts in them |
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413 | // Note that this is at the moment copy-paste |
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414 | // with DecodingReader.read() |
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415 | cbuf.put('?'); |
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416 | bbuf.get(); |
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417 | } |
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418 | decodeWasUnderflow = (CoderResult.UNDERFLOW == r); |
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419 | } |
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420 | if (cbuf.remaining() == len) { |
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421 | return -1; |
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422 | } else { |
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423 | return len - cbuf.remaining(); |
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424 | } |
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425 | } |
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426 | |
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427 | final void write(char[] cb, int off, int len) throws IOException { |
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428 | CharBuffer cbuf = CharBuffer.wrap(cb, off, len); |
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429 | encodeAndWrite(cbuf, false, false); |
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430 | } |
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431 | |
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432 | private final void internalFlush(boolean endOfFile) throws IOException { |
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433 | if (endOfFile) { |
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434 | CharBuffer cbuf = CharBuffer.allocate(0); |
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435 | encodeAndWrite(cbuf, true, endOfFile); |
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436 | } else { |
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437 | flushBbuf(false); |
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438 | } |
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439 | } |
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440 | |
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441 | private final void encodeAndWrite(CharBuffer cbuf, boolean flush, |
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442 | boolean endOfFile) throws IOException { |
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443 | while (cbuf.remaining() > 0) { |
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444 | CoderResult r = cenc.encode(cbuf, bbuf, endOfFile); |
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445 | bbufIsDirty = true; |
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446 | if (CoderResult.OVERFLOW == r || bbuf.remaining() == 0) { |
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447 | flushBbuf(false); |
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448 | ((java.nio.Buffer)bbuf).clear(); |
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449 | bbufIsReadable = false; |
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450 | } |
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451 | if (r.isUnmappable()) { |
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452 | throw new RACFUnmappableCharacterException(((java.nio.Buffer)cbuf).position(), |
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453 | cbuf.charAt(((java.nio.Buffer)cbuf).position()), |
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454 | cset.name()); |
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455 | } |
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456 | if (r.isMalformed()) { |
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457 | // We don't really expect Malformed, but not handling it |
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458 | // will cause an infinite loop if we don't... |
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459 | throw new RACFMalformedInputException(((java.nio.Buffer)cbuf).position(), |
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460 | cbuf.charAt(((java.nio.Buffer)cbuf).position()), |
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461 | cset.name()); |
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462 | } |
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463 | // UNDERFLOW is the normal condition where cbuf runs out |
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464 | // before bbuf is filled. |
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465 | } |
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466 | if (((java.nio.Buffer)bbuf).position() > 0 && bbufIsDirty && flush) { |
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467 | flushBbuf(false); |
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468 | } |
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469 | } |
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470 | |
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471 | public final void position(long newPosition) throws IOException { |
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472 | flushBbuf(true); |
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473 | long bbufend = bbufpos // in case bbuf is readable, its contents is valid |
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474 | + (bbufIsReadable |
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475 | ? ((java.nio.Buffer)bbuf).limit() |
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476 | : ((java.nio.Buffer)bbuf).position()); // beyond position() |
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477 | if (newPosition >= bbufpos && newPosition < bbufend) { |
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478 | // near seek. within existing data of bbuf. |
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479 | if (!bbufIsReadable) { //rewinding. keep tail buffered. |
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480 | ((java.nio.Buffer)bbuf).limit(((java.nio.Buffer)bbuf).position()); |
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481 | bbufIsReadable = true; |
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482 | } |
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483 | ((java.nio.Buffer)bbuf).position((int)(newPosition - bbufpos)); |
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484 | } else { |
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485 | fcn.position(newPosition); |
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486 | // far seek; discard the buffer (it's already cleared) |
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487 | ((java.nio.Buffer)bbuf).clear(); |
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488 | ((java.nio.Buffer)bbuf).flip(); // "there is no useful data on this buffer yet." |
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489 | bbufIsReadable = true; |
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490 | bbufpos = newPosition; |
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491 | } |
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492 | } |
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493 | |
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494 | public final long position() throws IOException { |
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495 | return bbufpos + ((java.nio.Buffer)bbuf).position(); // the logical position within the file. |
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496 | } |
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497 | |
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498 | public final long length() throws IOException { |
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499 | flushBbuf(true); |
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500 | return fcn.size(); |
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501 | } |
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502 | |
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503 | final void flushBbuf(boolean commitOnly) throws IOException { |
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504 | if (commitOnly && !bbufIsDirty) |
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505 | return; |
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506 | //otherwise, we do at least need to increase bbufpos |
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507 | |
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508 | fcn.position(bbufpos); |
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509 | |
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510 | // if the buffer is dirty, the modifications have to be |
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511 | // before position(): before re-positioning, this.position() |
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512 | // calls this function. |
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513 | if (commitOnly) { |
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514 | ByteBuffer dup = bbuf.duplicate(); |
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515 | ((java.nio.Buffer)dup).flip(); |
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516 | fcn.write(dup); |
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517 | //ideally, should restore fcn.position(). but don't for performance. |
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518 | // fcn.position(fcn.position()-dup.position()); |
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519 | bbufIsDirty = false; //this fixed stas's bug, but not mine. |
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520 | return; |
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521 | } |
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522 | |
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523 | if (bbufIsDirty) { |
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524 | ((java.nio.Buffer)bbuf).flip(); |
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525 | fcn.write(bbuf); |
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526 | } |
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527 | |
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528 | bbufpos += ((java.nio.Buffer)bbuf).position(); |
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529 | ((java.nio.Buffer)bbuf).clear(); |
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530 | ((java.nio.Buffer)bbuf).flip(); // there's no useable data in this buffer |
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531 | bbufIsDirty = false; |
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532 | bbufIsReadable = true; |
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533 | } |
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534 | |
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535 | public final int read(byte[] b, int off, int len) throws IOException { |
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536 | int pos = off; |
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537 | boolean atEof = false; |
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538 | while (pos - off < len && ! atEof) { |
---|
539 | |
---|
540 | atEof = ! ensureReadBbuf(false); |
---|
541 | int want = Math.min(off + len - pos, bbuf.remaining()); |
---|
542 | bbuf.get(b, pos, want); |
---|
543 | pos += want; |
---|
544 | } |
---|
545 | return pos - off; |
---|
546 | } |
---|
547 | |
---|
548 | // a method corresponding to the good ol' ungetc in C. |
---|
549 | // This function may fail when using (combined) character codes that use |
---|
550 | // escape sequences to switch between sub-codes. |
---|
551 | // ASCII, ISO-8859 series, any 8bit code are OK, all unicode variations are OK, |
---|
552 | // but applications of the ISO-2022 encoding framework can have trouble. |
---|
553 | // Example of such code is ISO-2022-JP which is used in Japanese e-mail. |
---|
554 | private CharBuffer singleCharBuf; |
---|
555 | private ByteBuffer shortByteBuf; |
---|
556 | public final void unreadChar(char c) throws IOException { |
---|
557 | // algorithm : |
---|
558 | // 1. encode c into bytes, to find out how many bytes it corresponds to |
---|
559 | // 2. move the position backwards that many bytes. |
---|
560 | // ** we stop here. Don't bother to write the bytes to the buffer, |
---|
561 | // assuming that it is the same as the original data. |
---|
562 | // If we allow to write back different characters, the buffer must get 'dirty' |
---|
563 | // but that would require read/write permissions on files you use unreadChar, |
---|
564 | // even if you are just reading for some tokenizer. |
---|
565 | // |
---|
566 | // So we don't do the following. |
---|
567 | // 3. write the bytes. |
---|
568 | // 4. move the position back again. |
---|
569 | if (singleCharBuf == null) { |
---|
570 | singleCharBuf = CharBuffer.allocate(1); |
---|
571 | shortByteBuf = ByteBuffer.allocate((int)cenc.maxBytesPerChar()); |
---|
572 | } |
---|
573 | ((java.nio.Buffer)singleCharBuf).clear(); |
---|
574 | singleCharBuf.append(c); |
---|
575 | ((java.nio.Buffer)singleCharBuf).flip(); |
---|
576 | ((java.nio.Buffer)shortByteBuf).clear(); |
---|
577 | cenc.encode(singleCharBuf, shortByteBuf, false); |
---|
578 | int n = ((java.nio.Buffer)shortByteBuf).position(); |
---|
579 | long pos = position() - n; |
---|
580 | position(pos); |
---|
581 | } |
---|
582 | |
---|
583 | public final void unreadByte(byte b) throws IOException { |
---|
584 | long pos = position() - 1; |
---|
585 | position(pos); |
---|
586 | } |
---|
587 | |
---|
588 | final void write(byte[] b, int off, int len) throws IOException { |
---|
589 | int pos = off; |
---|
590 | while (pos < off + len) { |
---|
591 | if (bbuf.remaining() == 0) { |
---|
592 | flushBbuf(false); |
---|
593 | ((java.nio.Buffer)bbuf).clear(); |
---|
594 | bbufIsReadable = false; |
---|
595 | } |
---|
596 | int thisBatchLen = Math.min(off + len - pos, bbuf.remaining()); |
---|
597 | bbuf.put(b, pos, thisBatchLen); |
---|
598 | pos += thisBatchLen; |
---|
599 | bbufIsDirty = true; |
---|
600 | } |
---|
601 | } |
---|
602 | } |
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