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  * General Public License Version 2 only ("GPL") or the Common

  * Development and Distribution License("CDDL") (collectively, the

  * "License"). You may not use this file except in compliance with the

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  * http://www.netbeans.org/cddl-gplv2.html

  * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

  * specific language governing permissions and limitations under the

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  * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

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  * Contributor(s):

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  * Portions Copyrighted 2007 Sun Microsystems, Inc.

  */

 package org.apidesign.bck2brwsr.emul.zip;

 import java.io.ByteArrayInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.lang.reflect.Method;

 import java.util.zip.ZipEntry;

 import java.util.zip.ZipInputStream;

 import org.apidesign.bck2brwsr.core.Exported;

 import org.apidesign.bck2brwsr.core.JavaScriptBody;

 /**

  *

  * @author Tomas Zezula

  */

 public final class FastJar {

     private final byte[] arr;

     public FastJar(byte[] arr) {

         this.arr = arr;

     }

     private static final int GIVE_UP = 1<<16;

     public static final  class Entry {

         public final String name;

         final long offset;

         private final long dosTime;

         Entry (String name, long offset, long time) {

             assert name != null;

             this.name = name;

             this.offset = offset;

             this.dosTime = time;

         }        

 /*        

         public long getTime () {

             Date d = new Date((int)(((dosTime >> 25) & 0x7f) + 80),

                     (int)(((dosTime >> 21) & 0x0f) - 1),

                     (int)((dosTime >> 16) & 0x1f),

                     (int)((dosTime >> 11) & 0x1f),

                     (int)((dosTime >> 5) & 0x3f),

                     (int)((dosTime << 1) & 0x3e));

             return d.getTime();

         }

         */

     }

     public InputStream getInputStream (final Entry e) throws IOException {

         return getInputStream(arr, e.offset);

     }

     private static InputStream getInputStream (byte[] arr, final long offset) throws IOException {

         ByteArrayInputStream is = new ByteArrayInputStream(arr);

         is.skip(offset);

         ZipInputStream in = new ZipInputStream (is);

         ZipEntry e = in.getNextEntry();

         if (e != null && e.getCrc() == 0L && e.getMethod() == ZipEntry.STORED) {

             int cp = arr.length - is.available();

             return new ByteArrayInputStream(arr, cp, (int)e.getSize());

         }

         return in;

     }

     public Entry[] list() throws IOException {

         final int size = arr.length;

         int at = size - ZipInputStream.ENDHDR;

         byte[] data = new byte[ZipInputStream.ENDHDR];        

         int giveup = 0;

         do {

             FastJar.arraycopy(arr, at, data, 0, data.length);

             at--;

             giveup++;

             if (giveup > GIVE_UP) {

                 throw new IOException ();

             }

         } while (getsig(data) != ZipInputStream.ENDSIG);

         final long censize = endsiz(data);

         final long cenoff  = endoff(data);

         at = (int) cenoff;                                                     

         Entry[] result = new Entry[0];

         int cenread = 0;

         data = new byte[ZipInputStream.CENHDR];

         while (cenread < censize) {

             FastJar.arraycopy(arr, at, data, 0, data.length);

             at += data.length;

             if (getsig(data) != ZipInputStream.CENSIG) {

                 throw new IOException("No central table");          //NOI18N

             }

             int cennam = cennam(data);

             int cenext = cenext(data);

             int cencom = cencom(data);

             long lhoff = cenoff(data);

             long centim = centim(data);

             String name = new String(arr, at, cennam, "UTF-8");

             at += cennam;

             int seekby = cenext+cencom;

             int cendatalen = ZipInputStream.CENHDR + cennam + seekby;

             cenread+=cendatalen;

             result = addEntry(result, new Entry(name,lhoff, centim));

             at += seekby;

         }

         return result;

     }

     private Entry[] addEntry(Entry[] result, Entry entry) {

         Entry[] e = new Entry[result.length + 1];

         e[result.length] = entry;

         FastJar.arraycopy(result, 0, e, 0, result.length);

         return e;

     }

     private static final long getsig(final byte[] b) throws IOException {return get32(b,0);}

     private static final long endsiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.ENDSIZ);}

     private static final long endoff(final byte[] b) throws IOException {return get32(b,ZipInputStream.ENDOFF);}

     private static final long  cenlen(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENLEN);}

     private static final long  censiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENSIZ);}

     private static final long centim(final byte[] b) throws IOException {return get32(b,ZipInputStream.CENTIM);}

     private static final int  cennam(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENNAM);}

     private static final int  cenext(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENEXT);}

     private static final int  cencom(final byte[] b) throws IOException {return get16(b,ZipInputStream.CENCOM);}

     private static final long cenoff (final byte[] b) throws IOException {return get32(b,ZipInputStream.CENOFF);}

     private static final int lochow(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCHOW);}

     private static final int locname(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCNAM);}

     private static final int locext(final byte[] b) throws IOException {return get16(b,ZipInputStream.LOCEXT);}

     private static final long locsiz(final byte[] b) throws IOException {return get32(b,ZipInputStream.LOCSIZ);}

     private static final int get16(final byte[] b, int off) throws IOException {        

         final int b1 = b[off];

 	final int b2 = b[off+1];

         return (b1 & 0xff) | ((b2 & 0xff) << 8);

     }

     private static final long get32(final byte[] b, int off) throws IOException {

 	final int s1 = get16(b, off);

 	final int s2 = get16(b, off+2);

         return s1 | ((long)s2 << 16);

     }

     @JavaScriptBody(args = {"value", "srcBegin", "dst", "dstBegin", "count"}, body

             = "if (srcBegin < dstBegin) {\n"

             + "    while (count-- > 0) {\n"

             + "        dst[dstBegin + count] = value[srcBegin + count];\n"

             + "    }\n"

             + "} else {\n"

             + "    while (count-- > 0) {\n"

             + "        dst[dstBegin++] = value[srcBegin++];\n"

             + "    }\n"

             + "}"

     )

     @Exported

     static void arraycopy(Object src, int srcBegin, Object dst, int dstBegin, int count) {

         try {

             Class<?> system = Class.forName("java.lang.System");

             Method m = system.getMethod("arraycopy", Object.class, int.class, Object.class, int.class, int.class);

             m.invoke(null, src, srcBegin, dst, dstBegin, count);

         } catch (Exception ex) {

             throw new IllegalStateException(ex);

         }

     }

 }