UBiDiProps.java

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 * (C) Copyright IBM Corp. and others, 1996-2009 - All Rights Reserved         *
 *                                                                             *
 * The original version of this source code and documentation is copyrighted   *
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*   file name:  UBiDiProps.java
*   encoding:   US-ASCII
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2005jan16
*   created by: Markus W. Scherer
*
*   Low-level Unicode bidi/shaping properties access.
*   Java port of ubidi_props.h/.c.
*/

package sun.text.normalizer;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.InputStream;
import java.io.IOException;

public final class UBiDiProps {
    // constructors etc. --------------------------------------------------- ***

    // port of ubidi_openProps()
    public UBiDiProps() throws IOException{
        InputStream is=ICUData.getStream(DATA_FILE_NAME);
        BufferedInputStream b=new BufferedInputStream(is, 4096 /* data buffer size */);
        readData(b);
        b.close();
        is.close();

    }

    private void readData(InputStream is) throws IOException {
        DataInputStream inputStream=new DataInputStream(is);

        // read the header
        ICUBinary.readHeader(inputStream, FMT, new IsAcceptable());

        // read indexes[]
        int i, count;
        count=inputStream.readInt();
        if(count<IX_INDEX_TOP) {
            throw new IOException("indexes[0] too small in "+DATA_FILE_NAME);
        }
        indexes=new int[count];

        indexes[0]=count;
        for(i=1; i<count; ++i) {
            indexes[i]=inputStream.readInt();
        }

        // read the trie
        trie=new CharTrie(inputStream, null);

        // read mirrors[]
        count=indexes[IX_MIRROR_LENGTH];
        if(count>0) {
            mirrors=new int[count];
            for(i=0; i<count; ++i) {
                mirrors[i]=inputStream.readInt();
            }
        }

        // read jgArray[]
        count=indexes[IX_JG_LIMIT]-indexes[IX_JG_START];
        jgArray=new byte[count];
        for(i=0; i<count; ++i) {
            jgArray[i]=inputStream.readByte();
        }
    }

    // implement ICUBinary.Authenticate
    private final class IsAcceptable implements ICUBinary.Authenticate {
        public boolean isDataVersionAcceptable(byte version[]) {
            return version[0]==1 &&
                   version[2]==Trie.INDEX_STAGE_1_SHIFT_ && version[3]==Trie.INDEX_STAGE_2_SHIFT_;
        }
    }

    // UBiDiProps singleton
    private static UBiDiProps gBdp=null;

    // port of ubidi_getSingleton()
    public static final synchronized UBiDiProps getSingleton() throws IOException {
        if(gBdp==null) {
            gBdp=new UBiDiProps();
        }
        return gBdp;
    }

    // UBiDiProps dummy singleton
    private static UBiDiProps gBdpDummy=null;

    private UBiDiProps(boolean makeDummy) { // ignore makeDummy, only creates a unique signature
        indexes=new int[IX_TOP];
        indexes[0]=IX_TOP;
        trie=new CharTrie(0, 0, null); // dummy trie, always returns 0
    }

    /**
     * Get a singleton dummy object, one that works with no real data.
     * This can be used when the real data is not available.
     * Using the dummy can reduce checks for available data after an initial failure.
     * Port of ucase_getDummy().
     */
    public static final synchronized UBiDiProps getDummy() {
        if(gBdpDummy==null) {
            gBdpDummy=new UBiDiProps(true);
        }
        return gBdpDummy;
    }

    public final int getClass(int c) {
        return getClassFromProps(trie.getCodePointValue(c));
    }

    // data members -------------------------------------------------------- ***
    private int indexes[];
    private int mirrors[];
    private byte jgArray[];

    private CharTrie trie;

    // data format constants ----------------------------------------------- ***
    private static final String DATA_FILE_NAME = "/sun/text/resources/ubidi.icu";

    /* format "BiDi" */
    private static final byte FMT[]={ 0x42, 0x69, 0x44, 0x69 };

    /* indexes into indexes[] */
    private static final int IX_INDEX_TOP=0;
    private static final int IX_MIRROR_LENGTH=3;

    private static final int IX_JG_START=4;
    private static final int IX_JG_LIMIT=5;

    private static final int IX_TOP=16;

    private static final int CLASS_MASK=    0x0000001f;

    private static final int getClassFromProps(int props) {
        return props&CLASS_MASK;
    }

}