Using FastJar to read the content table of JAR files emul
authorJaroslav Tulach <jaroslav.tulach@apidesign.org>
Sun, 10 Feb 2013 12:14:40 +0100
branchemul
changeset 706a48961ff3e6b
parent 705 6de8252246b5
child 707 a9187d4aaa6b
Using FastJar to read the content table of JAR files
emul/mini/src/main/java/org/apidesign/bck2brwsr/emul/zip/FastJar.java
vm/src/main/java/org/apidesign/vm4brwsr/Zips.java
vmtest/src/test/java/org/apidesign/bck2brwsr/vmtest/impl/ZipEntryTest.java
     1.1 --- a/emul/mini/src/main/java/org/apidesign/bck2brwsr/emul/zip/FastJar.java	Sun Feb 10 09:51:22 2013 +0100
     1.2 +++ b/emul/mini/src/main/java/org/apidesign/bck2brwsr/emul/zip/FastJar.java	Sun Feb 10 12:14:40 2013 +0100
     1.3 @@ -28,17 +28,12 @@
     1.4   *
     1.5   * Portions Copyrighted 2007 Sun Microsystems, Inc.
     1.6   */
     1.7 -package org.netbeans.modules.java.source.parsing;
     1.8 +package org.apidesign.bck2brwsr.emul.zip;
     1.9  
    1.10 -import java.io.File;
    1.11 +import java.io.ByteArrayInputStream;
    1.12  import java.io.IOException;
    1.13  import java.io.InputStream;
    1.14 -import java.io.RandomAccessFile;
    1.15 -import java.util.Date;
    1.16 -import java.util.LinkedList;
    1.17 -import java.util.List;
    1.18  import java.util.zip.ZipEntry;
    1.19 -import java.util.zip.ZipFile;
    1.20  import java.util.zip.ZipInputStream;
    1.21  
    1.22  /**
    1.23 @@ -46,78 +41,28 @@
    1.24   * @author Tomas Zezula
    1.25   */
    1.26  public final class FastJar {
    1.27 +    private final byte[] arr;
    1.28  
    1.29 -    private FastJar() {
    1.30 +    public FastJar(byte[] arr) {
    1.31 +        this.arr = arr;
    1.32      }
    1.33      
    1.34      
    1.35      private static final int GIVE_UP = 1<<16;
    1.36 -    
    1.37 -    
    1.38 -    private static class RandomAccessFileInputStream extends InputStream {
    1.39 -        
    1.40 -        private final RandomAccessFile b;
    1.41 -        private final long len;
    1.42 -        
    1.43 -        public RandomAccessFileInputStream (RandomAccessFile b) throws IOException {
    1.44 -            assert b != null;
    1.45 -            this.b = b;
    1.46 -            this.len = b.length();
    1.47 -        }
    1.48 -        
    1.49 -        public RandomAccessFileInputStream (RandomAccessFile b, long len) throws IOException {
    1.50 -            assert b != null;
    1.51 -            assert len >=0;
    1.52 -            this.b = b;
    1.53 -            this.len = b.getFilePointer()+len;
    1.54 -        }
    1.55 -    
    1.56 -        public int read (byte[] data, int offset, int size) throws IOException {
    1.57 -            int rem = available();
    1.58 -            if (rem == 0) {
    1.59 -                return -1;
    1.60 -            }
    1.61 -            int rlen;
    1.62 -            if (size<rem) {
    1.63 -                rlen = size;
    1.64 -            }
    1.65 -            else {
    1.66 -                rlen = rem;
    1.67 -            }
    1.68 -            return this.b.read(data, offset, rlen);
    1.69 -        }
    1.70  
    1.71 -        public int read() throws java.io.IOException {
    1.72 -            if (available()==0) {
    1.73 -                return -1;
    1.74 -            }
    1.75 -            else {
    1.76 -                return b.readByte();
    1.77 -            }
    1.78 -        }
    1.79 -        
    1.80 -        public int available () throws IOException {
    1.81 -             return (int) (len - this.b.getFilePointer());
    1.82 -        }
    1.83 -        
    1.84 -        public void close () throws IOException {
    1.85 -            b.close ();
    1.86 -        }
    1.87 -    }
    1.88 -    
    1.89      public static final  class Entry {
    1.90          
    1.91          public final String name;
    1.92          final long offset;
    1.93          private final long dosTime;
    1.94          
    1.95 -        public Entry (String name, long offset, long time) {
    1.96 +        Entry (String name, long offset, long time) {
    1.97              assert name != null;
    1.98              this.name = name;
    1.99              this.offset = offset;
   1.100              this.dosTime = time;
   1.101          }        
   1.102 -        
   1.103 +/*        
   1.104          public long getTime () {
   1.105              Date d = new Date((int)(((dosTime >> 25) & 0x7f) + 80),
   1.106                      (int)(((dosTime >> 21) & 0x0f) - 1),
   1.107 @@ -127,120 +72,94 @@
   1.108                      (int)((dosTime << 1) & 0x3e));
   1.109              return d.getTime();
   1.110          }
   1.111 +        */
   1.112      }
   1.113      
   1.114 -    public static InputStream getInputStream (final File file, final Entry e) throws IOException {
   1.115 -        return getInputStream(file, e.offset);
   1.116 +    public InputStream getInputStream (final Entry e) throws IOException {
   1.117 +        return getInputStream(arr, e.offset);
   1.118      }
   1.119      
   1.120 -    static InputStream getInputStream (final File file, final long offset) throws IOException {
   1.121 -        RandomAccessFile  f = new RandomAccessFile (file, "r");     //NOI18N
   1.122 -        f.seek (offset);
   1.123 -        ZipInputStream in = new ZipInputStream (new RandomAccessFileInputStream (f));
   1.124 +    private static InputStream getInputStream (byte[] arr, final long offset) throws IOException {
   1.125 +        ByteArrayInputStream is = new ByteArrayInputStream(arr);
   1.126 +        is.skip(offset);
   1.127 +        ZipInputStream in = new ZipInputStream (is);
   1.128          ZipEntry e = in.getNextEntry();
   1.129          if (e != null && e.getCrc() == 0L && e.getMethod() == ZipEntry.STORED) {
   1.130 -            long cp = f.getFilePointer();
   1.131 -            in.close();
   1.132 -            f = new RandomAccessFile (file, "r");     //NOI18N
   1.133 -            f.seek (cp);
   1.134 -            return new RandomAccessFileInputStream (f, e.getSize());
   1.135 +            int cp = arr.length - is.available();
   1.136 +            return new ByteArrayInputStream(arr, cp, (int)e.getSize());
   1.137          }
   1.138          return in;
   1.139      }
   1.140      
   1.141 -    static ZipEntry getZipEntry (final File file, final long offset) throws IOException {
   1.142 -        RandomAccessFile  f = new RandomAccessFile (file, "r");     //NOI18N
   1.143 -        try {
   1.144 -            f.seek (offset);
   1.145 -            ZipInputStream in = new ZipInputStream (new RandomAccessFileInputStream (f));
   1.146 -            try {
   1.147 -                return in.getNextEntry();
   1.148 -            } finally {
   1.149 -                in.close();
   1.150 +    public Entry[] list() throws IOException {
   1.151 +        final int size = arr.length;
   1.152 +
   1.153 +        int at = size - ZipInputStream.ENDHDR;
   1.154 +
   1.155 +        byte[] data = new byte[ZipInputStream.ENDHDR];        
   1.156 +        int giveup = 0;
   1.157 +
   1.158 +        do {
   1.159 +            org.apidesign.bck2brwsr.emul.lang.System.arraycopy(arr, at, data, 0, data.length);
   1.160 +            at--;
   1.161 +            giveup++;
   1.162 +            if (giveup > GIVE_UP) {
   1.163 +                throw new IOException ();
   1.164              }
   1.165 -        } finally {
   1.166 -            f.close ();
   1.167 +        } while (getsig(data) != ZipInputStream.ENDSIG);
   1.168 +
   1.169 +
   1.170 +        final long censize = endsiz(data);
   1.171 +        final long cenoff  = endoff(data);
   1.172 +        at = (int) cenoff;                                                     
   1.173 +
   1.174 +        Entry[] result = new Entry[0];
   1.175 +        int cenread = 0;
   1.176 +        data = new byte[ZipInputStream.CENHDR];
   1.177 +        while (cenread < censize) {
   1.178 +            org.apidesign.bck2brwsr.emul.lang.System.arraycopy(arr, at, data, 0, data.length);
   1.179 +            at += data.length;
   1.180 +            if (getsig(data) != ZipInputStream.CENSIG) {
   1.181 +                throw new IOException("No central table");          //NOI18N
   1.182 +            }
   1.183 +            int cennam = cennam(data);
   1.184 +            int cenext = cenext(data);
   1.185 +            int cencom = cencom(data);
   1.186 +            long lhoff = cenoff(data);
   1.187 +            long centim = centim(data);
   1.188 +            String name = new String(arr, at, cennam, "UTF-8");
   1.189 +            at += cennam;
   1.190 +            int seekby = cenext+cencom;
   1.191 +            int cendatalen = ZipInputStream.CENHDR + cennam + seekby;
   1.192 +            cenread+=cendatalen;
   1.193 +            result = addEntry(result, new Entry(name,lhoff, centim));
   1.194 +            at += seekby;
   1.195          }
   1.196 +        return result;
   1.197      }
   1.198  
   1.199 -    public static Iterable<? extends Entry> list(File f) throws IOException {
   1.200 -        RandomAccessFile b = new RandomAccessFile (f,"r");      //NOI18N
   1.201 -        try {
   1.202 -            final long size = (int) b.length();
   1.203 -            b.seek (size-ZipFile.ENDHDR);                                           
   1.204 -
   1.205 -            byte[] data = new byte[ZipFile.ENDHDR];        
   1.206 -            int giveup = 0;
   1.207 -
   1.208 -            do {
   1.209 -                if (b.read(data, 0, ZipFile.ENDHDR)!=ZipFile.ENDHDR) {
   1.210 -                    throw new IOException ();
   1.211 -                }
   1.212 -                b.seek(b.getFilePointer()-(ZipFile.ENDHDR+1));
   1.213 -                giveup++;
   1.214 -                if (giveup > GIVE_UP) {
   1.215 -                    throw new IOException ();
   1.216 -                }
   1.217 -            } while (getsig(data) != ZipFile.ENDSIG);
   1.218 -
   1.219 -
   1.220 -            final long censize = endsiz(data);
   1.221 -            final long cenoff  = endoff(data);
   1.222 -            b.seek (cenoff);                                                        
   1.223 -
   1.224 -            List<Entry> result = new LinkedList<Entry>();
   1.225 -            int cenread = 0;
   1.226 -            data = new byte[ZipFile.CENHDR];
   1.227 -            while (cenread < censize) {
   1.228 -                if (b.read(data, 0, ZipFile.CENHDR)!=ZipFile.CENHDR) {
   1.229 -                    throw new IOException ("No central table");         //NOI18N
   1.230 -                }             
   1.231 -                if (getsig(data) != ZipFile.CENSIG) {
   1.232 -                    throw new IOException("No central table");          //NOI18N
   1.233 -                }
   1.234 -                int cennam = cennam(data);
   1.235 -                int cenext = cenext(data);
   1.236 -                int cencom = cencom(data);
   1.237 -                long lhoff = cenoff(data);
   1.238 -                long centim = centim(data);
   1.239 -                String name = name(b, cennam);
   1.240 -                int seekby = cenext+cencom;
   1.241 -                int cendatalen = ZipFile.CENHDR + cennam + seekby;
   1.242 -                cenread+=cendatalen;
   1.243 -                result.add(new Entry(name,lhoff, centim));
   1.244 -                seekBy(b,seekby);
   1.245 -            }
   1.246 -            return result;
   1.247 -        } finally {
   1.248 -            b.close();
   1.249 -        }
   1.250 -    }
   1.251 -
   1.252 -    private static final String name(final RandomAccessFile b, final int cennam) throws IOException {
   1.253 -	byte[] name = new byte[cennam];
   1.254 -	b.read(name, 0, cennam);
   1.255 -	return new String(name, "UTF-8");       //NOI18N
   1.256 +    private Entry[] addEntry(Entry[] result, Entry entry) {
   1.257 +        Entry[] e = new Entry[result.length + 1];
   1.258 +        e[result.length] = entry;
   1.259 +        org.apidesign.bck2brwsr.emul.lang.System.arraycopy(result, 0, e, 0, result.length);
   1.260 +        return e;
   1.261      }
   1.262  
   1.263      private static final long getsig(final byte[] b) throws IOException {return get32(b,0);}
   1.264 -    private static final long endsiz(final byte[] b) throws IOException {return get32(b,ZipFile.ENDSIZ);}
   1.265 -    private static final long endoff(final byte[] b) throws IOException {return get32(b,ZipFile.ENDOFF);}
   1.266 -    private static final long  cenlen(final byte[] b) throws IOException {return get32(b,ZipFile.CENLEN);}
   1.267 -    private static final long  censiz(final byte[] b) throws IOException {return get32(b,ZipFile.CENSIZ);}
   1.268 -    private static final long centim(final byte[] b) throws IOException {return get32(b,ZipFile.CENTIM);}
   1.269 -    private static final int  cennam(final byte[] b) throws IOException {return get16(b,ZipFile.CENNAM);}
   1.270 -    private static final int  cenext(final byte[] b) throws IOException {return get16(b,ZipFile.CENEXT);}
   1.271 -    private static final int  cencom(final byte[] b) throws IOException {return get16(b,ZipFile.CENCOM);}
   1.272 -    private static final long cenoff (final byte[] b) throws IOException {return get32(b,ZipFile.CENOFF);}
   1.273 -    private static final int lochow(final byte[] b) throws IOException {return get16(b,ZipFile.LOCHOW);}
   1.274 -    private static final int locname(final byte[] b) throws IOException {return get16(b,ZipFile.LOCNAM);}
   1.275 -    private static final int locext(final byte[] b) throws IOException {return get16(b,ZipFile.LOCEXT);}
   1.276 -    private static final long locsiz(final byte[] b) throws IOException {return get32(b,ZipFile.LOCSIZ);}
   1.277 +    private static final long endsiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.ENDSIZ);}
   1.278 +    private static final long endoff(final byte[] b) throws IOException {return get32(b,ZipInputStream.ENDOFF);}
   1.279 +    private static final long  cenlen(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENLEN);}
   1.280 +    private static final long  censiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENSIZ);}
   1.281 +    private static final long centim(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENTIM);}
   1.282 +    private static final int  cennam(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENNAM);}
   1.283 +    private static final int  cenext(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENEXT);}
   1.284 +    private static final int  cencom(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENCOM);}
   1.285 +    private static final long cenoff (final byte[] b) throws IOException {return get32(b,ZipInputStream.CENOFF);}
   1.286 +    private static final int lochow(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCHOW);}
   1.287 +    private static final int locname(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCNAM);}
   1.288 +    private static final int locext(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCEXT);}
   1.289 +    private static final long locsiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.LOCSIZ);}
   1.290      
   1.291 -    private static final void seekBy(final RandomAccessFile b, int offset) throws IOException {
   1.292 -        b.seek(b.getFilePointer() + offset);
   1.293 -    }
   1.294 -
   1.295      private static final int get16(final byte[] b, int off) throws IOException {        
   1.296          final int b1 = b[off];
   1.297  	final int b2 = b[off+1];
     2.1 --- a/vm/src/main/java/org/apidesign/vm4brwsr/Zips.java	Sun Feb 10 09:51:22 2013 +0100
     2.2 +++ b/vm/src/main/java/org/apidesign/vm4brwsr/Zips.java	Sun Feb 10 12:14:40 2013 +0100
     2.3 @@ -19,17 +19,25 @@
     2.4  
     2.5  import java.io.ByteArrayInputStream;
     2.6  import java.io.IOException;
     2.7 +import java.io.InputStream;
     2.8  import java.net.URL;
     2.9 -import java.util.zip.ZipEntry;
    2.10 -import java.util.zip.ZipInputStream;
    2.11  import org.apidesign.bck2brwsr.core.JavaScriptBody;
    2.12 +import org.apidesign.bck2brwsr.emul.zip.FastJar;
    2.13  
    2.14  /** Conversion from classpath to load function.
    2.15   *
    2.16   * @author Jaroslav Tulach <jtulach@netbeans.org>
    2.17   */
    2.18  final class Zips {
    2.19 -    private Zips() {
    2.20 +    private final FastJar fj;
    2.21 +
    2.22 +    private Zips(String path, byte[] zipData) throws IOException {
    2.23 +        long bef = currentTimeMillis();
    2.24 +        fj = new FastJar(zipData);
    2.25 +        for (FastJar.Entry e : fj.list()) {
    2.26 +            putRes(e.name, e);
    2.27 +        }
    2.28 +        log("Iterating thru " + path + " took " + (currentTimeMillis() - bef) + "ms");
    2.29      }
    2.30      
    2.31      public static void init() {
    2.32 @@ -64,38 +72,32 @@
    2.33          }
    2.34          return null;
    2.35      }
    2.36 +    
    2.37 +    @JavaScriptBody(args = { "msg" }, body = "console.log(msg.toString());")
    2.38 +    private static native void log(String msg);
    2.39 +
    2.40 +    private byte[] findRes(String res) throws IOException {
    2.41 +        Object arr = findResImpl(res);
    2.42 +        if (arr instanceof FastJar.Entry) {
    2.43 +            long bef = currentTimeMillis();
    2.44 +            InputStream zip = fj.getInputStream((FastJar.Entry)arr);
    2.45 +            arr = readFully(new byte[512], zip);
    2.46 +            putRes(res, arr);
    2.47 +            log("Reading " + res + " took " + (currentTimeMillis() - bef) + "ms");
    2.48 +        }
    2.49 +        return (byte[]) arr;
    2.50 +    }
    2.51  
    2.52      @JavaScriptBody(args = { "res" }, body = "var r = this[res]; return r ? r : null;")
    2.53 -    private native byte[] findRes(String res);
    2.54 +    private native Object findResImpl(String res);
    2.55  
    2.56      @JavaScriptBody(args = { "res", "arr" }, body = "this[res] = arr;")
    2.57 -    private native void putRes(String res, byte[] arr);
    2.58 +    private native void putRes(String res, Object arr);
    2.59      
    2.60      private static Zips toZip(String path) throws IOException {
    2.61          URL u = new URL(path);
    2.62 -        ZipInputStream zip = new ZipInputStream(u.openStream());
    2.63 -        Zips z = new Zips();
    2.64 -        for (;;) {
    2.65 -            ZipEntry entry = zip.getNextEntry();
    2.66 -            if (entry == null) {
    2.67 -                break;
    2.68 -            }
    2.69 -            byte[] arr = new byte[4096];
    2.70 -            int offset = 0;
    2.71 -            for (;;) {
    2.72 -                int len = zip.read(arr, offset, arr.length - offset);
    2.73 -                if (len == -1) {
    2.74 -                    break;
    2.75 -                }
    2.76 -                offset += len;
    2.77 -                if (offset == arr.length) {
    2.78 -                    enlargeArray(arr, arr.length + 4096);
    2.79 -                }
    2.80 -            }
    2.81 -            sliceArray(arr, offset);
    2.82 -            z.putRes(entry.getName(), arr);
    2.83 -        }
    2.84 -        return z;
    2.85 +        byte[] zipData = (byte[]) u.getContent(new Class[] { byte[].class });
    2.86 +        return new Zips(path, zipData);
    2.87      }
    2.88  
    2.89      private static String processClassPathAttr(final byte[] man, String url, Object[] classpath) throws IOException {
    2.90 @@ -132,6 +134,28 @@
    2.91  
    2.92      @JavaScriptBody(args = { "arr", "len" }, body = "arr.splice(len, arr.length - len);")
    2.93      private static native void sliceArray(byte[] arr, int len);
    2.94 +
    2.95 +    private static Object readFully(byte[] arr, InputStream zip) throws IOException {
    2.96 +        int offset = 0;
    2.97 +        for (;;) {
    2.98 +            int len = zip.read(arr, offset, arr.length - offset);
    2.99 +            if (len == -1) {
   2.100 +                break;
   2.101 +            }
   2.102 +            offset += len;
   2.103 +            if (offset == arr.length) {
   2.104 +                enlargeArray(arr, arr.length + 4096);
   2.105 +            }
   2.106 +        }
   2.107 +        sliceArray(arr, offset);
   2.108 +        return arr;
   2.109 +    }
   2.110 +
   2.111 +    private static long currentTimeMillis() {
   2.112 +        return (long)m();
   2.113 +    }
   2.114 +    @JavaScriptBody(args = {  }, body = "return window.performance.now();")
   2.115 +    private static native double m();
   2.116      
   2.117      
   2.118  }
     3.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     3.2 +++ b/vmtest/src/test/java/org/apidesign/bck2brwsr/vmtest/impl/ZipEntryTest.java	Sun Feb 10 12:14:40 2013 +0100
     3.3 @@ -0,0 +1,67 @@
     3.4 +/**
     3.5 + * Back 2 Browser Bytecode Translator
     3.6 + * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
     3.7 + *
     3.8 + * This program is free software: you can redistribute it and/or modify
     3.9 + * it under the terms of the GNU General Public License as published by
    3.10 + * the Free Software Foundation, version 2 of the License.
    3.11 + *
    3.12 + * This program is distributed in the hope that it will be useful,
    3.13 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    3.14 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    3.15 + * GNU General Public License for more details.
    3.16 + *
    3.17 + * You should have received a copy of the GNU General Public License
    3.18 + * along with this program. Look for COPYING file in the top folder.
    3.19 + * If not, see http://opensource.org/licenses/GPL-2.0.
    3.20 + */
    3.21 +package org.apidesign.bck2brwsr.vmtest.impl;
    3.22 +
    3.23 +import java.io.ByteArrayInputStream;
    3.24 +import java.io.IOException;
    3.25 +import java.io.InputStream;
    3.26 +import org.apidesign.bck2brwsr.emul.zip.FastJar;
    3.27 +import org.testng.annotations.Test;
    3.28 +import static org.testng.Assert.*;
    3.29 +
    3.30 +/**
    3.31 + *
    3.32 + * @author Jaroslav Tulach <jtulach@netbeans.org>
    3.33 + */
    3.34 +@GenerateZip(name = "five.zip", contents = {
    3.35 +    "1.txt", "one",
    3.36 +    "2.txt", "duo",
    3.37 +    "3.txt", "three",
    3.38 +    "4.txt", "four",
    3.39 +    "5.txt", "five"
    3.40 +})
    3.41 +public class ZipEntryTest {
    3.42 +    @Test
    3.43 +    public void readEntriesEffectively() throws IOException {
    3.44 +        InputStream is = ZipEntryTest.class.getResourceAsStream("five.zip");
    3.45 +        byte[] arr = new byte[is.available()];
    3.46 +        int len = is.read(arr);
    3.47 +        assertEquals(len, arr.length, "Read fully");
    3.48 +        
    3.49 +        FastJar fj = new FastJar(arr);
    3.50 +        FastJar.Entry[] entrs = fj.list();
    3.51 +        
    3.52 +        assertEquals(5, entrs.length, "Five entries");
    3.53 +        
    3.54 +        for (int i = 1; i <= 5; i++) {
    3.55 +            FastJar.Entry en = entrs[i - 1];
    3.56 +            assertEquals(en.name, i + ".txt");
    3.57 +//            assertEquals(cis.cnt, 0, "Content of the file should be skipped, not read");
    3.58 +        }
    3.59 +        
    3.60 +        assertContent("three", fj.getInputStream(entrs[3 - 1]), "read OK");
    3.61 +        assertContent("five", fj.getInputStream(entrs[5 - 1]), "read OK");
    3.62 +    }
    3.63 +
    3.64 +    private static void assertContent(String exp, InputStream is, String msg) throws IOException {
    3.65 +        byte[] arr = new byte[512];
    3.66 +        int len = is.read(arr);
    3.67 +        String s = new String(arr, 0, len);
    3.68 +        assertEquals(exp, s, msg);
    3.69 +    }
    3.70 +}