jdbcblob.java

hsql是很有名的嵌入式数据库

            }

            return i + 1;
        }

        return -1;
    }

    /**
     * Retrieves the byte position in the <code>BLOB</code> value
     * designated by this <code>Blob</code> object at which
     * <code>pattern</code> begins.  The search begins at position
     * <code>start</code>.
     *
     * @param pattern the <code>Blob</code> object designating
     *      the <code>BLOB</code> value for which to search
     * @param start the position in the <code>BLOB</code> value
     *        at which to begin searching; the first position is 1
     * @return the position at which the pattern begins, else -1
     * @exception SQLException if there is an error accessing the
     *        <code>BLOB</code> value
     *
     * @since JDK 1.2, HSQLDB 1.7.2
     */
    public long position(final Blob pattern, long start) throws SQLException {

        final byte[] ldata = data;
        final int    dlen  = ldata.length;

        if (start > dlen || pattern == null) {
            return -1;
        } else if (start < 1) {
            start = 0;
        } else {
            start--;
        }

        final long plen = pattern.length();

        if (plen == 0 || start > ((long) dlen) - plen) {
            return -1;
        }

        // by now, we know plen <= Integer.MAX_VALUE
        final int iplen = (int) plen;
        byte[]    bap;

        if (pattern instanceof jdbcBlob) {
            bap = ((jdbcBlob) pattern).data;
        } else {
            bap = pattern.getBytes(1, iplen);
        }

        final int  stop = dlen - iplen;
        final byte b0   = bap[0];

        outer_loop:
        for (int i = (int) start; i <= stop; i++) {
            if (ldata[i] != b0) {
                continue;
            }

            int len     = iplen;
            int doffset = i;
            int poffset = 0;

            while (len-- > 0) {
                if (ldata[doffset++] != bap[poffset++]) {
                    continue outer_loop;
                }
            }

            return i + 1;
        }

        return -1;
    }

    // -------------------------- JDBC 3.0 -----------------------------------

    /**
     * Writes the given array of bytes to the <code>BLOB</code> value that
     * this <code>Blob</code> object represents, starting at position
     * <code>pos</code>, and returns the number of bytes written. <p>
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSLQDB 1.7.2 does not support this feature. <p>
     *
     * Calling this method always throws an <code>SQLException</code>.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param pos the position in the <code>BLOB</code> object at which
     *        to start writing
     * @param bytes the array of bytes to be written to the <code>BLOB</code>
     *        value that this <code>Blob</code> object represents
     * @return the number of bytes written
     * @exception SQLException if there is an error accessing the
     *            <code>BLOB</code> value
     * @see #getBytes
     *
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int setBytes(long pos, byte[] bytes) throws SQLException {
        throw Util.notSupported;
    }

    /**
     * Writes all or part of the given <code>byte</code> array to the
     * <code>BLOB</code> value that this <code>Blob</code> object represents
     * and returns the number of bytes written.
     * Writing starts at position <code>pos</code> in the <code>BLOB</code>
     * value; <code>len</code> bytes from the given byte array are written. <p>
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSLQDB 1.7.2 does not support this feature. <p>
     *
     * Calling this method always throws an <code>SQLException</code>.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param pos the position in the <code>BLOB</code> object at which
     *        to start writing
     * @param bytes the array of bytes to be written to this <code>BLOB</code>
     *        object
     * @param offset the offset into the array <code>bytes</code> at which
     *        to start reading the bytes to be set
     * @param len the number of bytes to be written to the <code>BLOB</code>
     *        value from the array of bytes <code>bytes</code>
     * @return the number of bytes written
     * @exception SQLException if there is an error accessing the
     *            <code>BLOB</code> value
     * @see #getBytes
     *
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int setBytes(long pos, byte[] bytes, int offset,
                        int len) throws SQLException {
        throw Util.notSupported;
    }

    /**
     * Retrieves a stream that can be used to write to the <code>BLOB</code>
     * value that this <code>Blob</code> object represents.  The stream begins
     * at position <code>pos</code>. <p>
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB 1.7.2 does not support this feature. <p>
     *
     * Calling this method always throws an <code>SQLException</code>.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param pos the position in the <code>BLOB</code> value at which
     *        to start writing
     * @return a <code>java.io.OutputStream</code> object to which data can
     *         be written
     * @exception SQLException if there is an error accessing the
     *            <code>BLOB</code> value
     * @see #getBinaryStream
     *
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public OutputStream setBinaryStream(long pos) throws SQLException {
        throw Util.notSupported;
    }

    /**
     * Truncates the <code>BLOB</code> value that this <code>Blob</code>
     * object represents to be <code>len</code> bytes in length.
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * This operation affects only the client-side value; it has no effect upon
     * the value as it is stored in the database.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param len the length, in bytes, to which the <code>BLOB</code> value
     *        that this <code>Blob</code> object represents should be truncated
     * @exception SQLException if there is an error accessing the
     *            <code>BLOB</code> value
     *
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public void truncate(final long len) throws SQLException {

        final byte[] ldata = data;

        if (len < 0 || len > ldata.length) {
            throw Util.sqlException(Trace.INVALID_JDBC_ARGUMENT,
                                    Long.toString(len));
        }

        if (len == ldata.length) {
            return;
        }

        byte[] newData = new byte[(int) len];

        System.arraycopy(ldata, 0, newData, 0, (int) len);

        data = newData;
    }

//    public static void main(String[] args) throws Exception {
//
//        System.out.println("--------------------------------");
//        System.out.println((new jdbcBlob(new byte[0])).position(new byte[]{1}, 1));
//        System.out.println((new jdbcBlob(new byte[]{1})).position(new byte[0], 1));
//        System.out.println((new jdbcBlob(new byte[]{1})).position((byte[])null, 1));
//
//        System.out.println("--------------------------------");
//        byte[] data1 = new byte[]{0,1,2,1,2,3,2,3,4,2,3,4,5,2,3,4,5,0,1,2,
//                                  1,2,3,2,3,4,2,3,4,5,2,3,4};
//        byte[] pattern = new byte[]{2,3,4,5};
//
//        jdbcBlob blob1 = new jdbcBlob(data1);
//        jdbcBlob blob2 = new jdbcBlob(pattern);
//
//        for (int i = -1; i <= data1.length + 1; i++) {
//            System.out.println(blob1.position(pattern, i));
//        }
//
//        System.out.println("--------------------------------");
//
//        for (int i = -1; i <= data1.length + 1; i++) {
//            System.out.println(blob1.position(blob2, i));
//        }
//
//        System.out.println("--------------------------------");
//
//        new jdbcBlob(null);
//    }
}