/* Copyright (c) 2001-2024, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */


package org.hsqldb.jdbc;

import java.io.InputStream;
import java.io.OutputStream;

import java.sql.Blob;
import java.sql.SQLException;

import org.hsqldb.HsqlException;
import org.hsqldb.SessionInterface;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.types.BlobDataID;
import org.hsqldb.types.BlobInputStream;

/**
 * A wrapper for HSQLDB BlobData objects.
 *
 * Instances of this class are returned by calls to ResultSet methods.
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.7.4
 * @since JDK 1.2, HSQLDB 2.0
 */
public class JDBCBlobClient implements Blob {

    /**
     * Returns the number of bytes in the {@code BLOB} value designated
     * by this {@code Blob} object.
     *
     * @return length of the {@code BLOB} in bytes
     * @throws SQLException if there is an error accessing the length of the
     *   {@code BLOB}
     */
    public synchronized long length() throws SQLException {

        checkClosed();

        try {
            return blob.length(session);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    /**
     * Retrieves all or part of the {@code BLOB} value that this
     * {@code Blob} object represents, as an array of bytes.
     *
     * @param pos the ordinal position of the first byte in the
     *   {@code BLOB} value to be extracted; the first byte is at
     *   position 1
     * @param length the number of consecutive bytes to be copied
     * @return a byte array containing up to {@code length} consecutive
     *   bytes from the {@code BLOB} value designated by this
     *   {@code Blob} object, starting with the byte at position
     *   {@code pos}
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized byte[] getBytes(
            long pos,
            int length)
            throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, pos - 1, length)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            return blob.getBytes(session, pos - 1, length);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    /**
     * Retrieves the {@code BLOB} value designated by this
     * {@code Blob} instance as a stream.
     *
     * @return a stream containing the {@code BLOB} data
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized InputStream getBinaryStream() throws SQLException {
        checkClosed();

        return new BlobInputStream(session, blob, 0, length());
    }

    /**
     * Retrieves the byte position at which the specified byte array
     * {@code pattern} begins within the {@code BLOB} value that
     * this {@code Blob} object represents.
     *
     * @param pattern the byte array for which to search
     * @param start the position at which to begin searching; the first
     *   position is 1
     * @return the position at which the pattern appears, else -1
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB}
     */
    public synchronized long position(
            byte[] pattern,
            long start)
            throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, start - 1, 0)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            long position = blob.position(session, pattern, start - 1);

            if (position >= 0) {
                position++;
            }

            return position;
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

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

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, start - 1, 0)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (pattern instanceof JDBCBlobClient) {
            BlobDataID searchClob = ((JDBCBlobClient) pattern).blob;

            try {
                long position = blob.position(session, searchClob, start - 1);

                if (position >= 0) {
                    position++;
                }

                return position;
            } catch (HsqlException e) {
                throw JDBCUtil.sqlException(e);
            }
        }

        if (!isInLimits(Integer.MAX_VALUE, 0, pattern.length())) {
            throw JDBCUtil.outOfRangeArgument();
        }

        byte[] bytePattern = pattern.getBytes(1, (int) pattern.length());

        return position(bytePattern, start);
    }

    /**
     * Writes the given array of bytes to the {@code BLOB} value that
     * this {@code Blob} object represents, starting at position
     * {@code pos}, and returns the number of bytes written.
     *
     * @param pos the position in the {@code BLOB} object at which to
     *   start writing
     * @param bytes the array of bytes to be written to the
     *   {@code BLOB} value that this {@code Blob} object
     *   represents
     * @return the number of bytes written
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized int setBytes(
            long pos,
            byte[] bytes)
            throws SQLException {
        return setBytes(pos, bytes, 0, bytes.length);
    }

    /**
     * Writes all or part of the given {@code byte} array to the
     * {@code BLOB} value that this {@code Blob} object represents
     * and returns the number of bytes written.
     *
     * @param pos the position in the {@code BLOB} object at which to
     *   start writing
     * @param bytes the array of bytes to be written to this
     *   {@code BLOB} object
     * @param offset the offset into the array {@code bytes} at which
     *   to start reading the bytes to be set
     * @param len the number of bytes to be written to the {@code BLOB}
     *   value from the array of bytes {@code bytes}
     * @return the number of bytes written
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized int setBytes(
            long pos,
            byte[] bytes,
            int offset,
            int len)
            throws SQLException {

        checkClosed();

        if (!isInLimits(bytes.length, offset, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (!isInLimits(Long.MAX_VALUE, pos - 1, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (!isWritable) {
            throw JDBCUtil.notUpdatableColumn();
        }

        try {
            startUpdate();
            blob.setBytes(session, pos - 1, bytes, offset, len);

            return len;
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    /**
     * Retrieves a stream that can be used to write to the {@code BLOB}
     * value that this {@code Blob} object represents.
     *
     * @param pos the position in the {@code BLOB} value at which to
     *   start writing
     * @return a {@code java.io.OutputStream} object to which data can
     *   be written
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized OutputStream setBinaryStream(
            long pos)
            throws SQLException {
        throw JDBCUtil.notSupported();
    }

    /**
     * Truncates the {@code BLOB} value that this {@code Blob}
     * object represents to be {@code len} bytes in length.
     *
     * @param len the length, in bytes, to which the {@code BLOB} value
     *   that this {@code Blob} object represents should be truncated
     * @throws SQLException if there is an error accessing the
     *   {@code BLOB} value
     */
    public synchronized void truncate(long len) throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, 0, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            blob.truncate(session, len);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    /**
     * This method frees the {@code Blob} object and releases the resources that
     * it holds. The object is invalid once the {@code free}
     * method is called.
     * <p>
     * After {@code free} has been called, any attempt to invoke a
     * method other than {@code free} will result in a {@code SQLException}
     * being thrown.  If {@code free} is called multiple times, the subsequent
     * calls to {@code free} are treated as a no-op.
     *
     * @throws SQLException if an error occurs releasing
     * the Blob's resources
     * @since JDK 1.6, HSQLDB 2.0
     */
    public synchronized void free() throws SQLException {
        isClosed = true;
    }

    /**
     * Returns an {@code InputStream} object that contains a partial {@code Blob} value,
     * starting  with the byte specified by pos, which is length bytes in length.
     *
     * @param pos the offset to the first byte of the partial value to be retrieved.
     *  The first byte in the {@code Blob} is at position 1
     * @param length the length in bytes of the partial value to be retrieved
     * @return {@code InputStream} through which the partial {@code Blob} value can be read.
     * @throws SQLException if pos is less than 1 or if pos is greater than the number of bytes
     * in the {@code Blob} or if pos + length is greater than the number of bytes
     * in the {@code Blob}
     *
     * @since JDK 1.6, HSQLDB 2.0
     */
    public synchronized InputStream getBinaryStream(
            long pos,
            long length)
            throws SQLException {

        checkClosed();

        if (!isInLimits(this.length(), pos - 1, length)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        return new BlobInputStream(session, blob, pos - 1, length);
    }

    //--
    BlobDataID       originalBlob;
    BlobDataID       blob;
    SessionInterface session;
    int              colIndex;
    private boolean  isClosed;
    private boolean  isWritable;
    JDBCResultSet    resultSet;

    public JDBCBlobClient(SessionInterface session, BlobDataID blob) {
        this.session = session;
        this.blob    = blob;
    }

    public boolean isClosed() {
        return isClosed;
    }

    public BlobDataID getBlob() {
        return blob;
    }

    public synchronized void setWritable(JDBCResultSet result, int index) {
        isWritable = true;
        resultSet  = result;
        colIndex   = index;
    }

    public synchronized void clearUpdates() {

        if (originalBlob != null) {
            blob         = originalBlob;
            originalBlob = null;
        }
    }

    private void startUpdate() throws SQLException {

        if (originalBlob != null) {
            return;
        }

        originalBlob = blob;
        blob         = (BlobDataID) blob.duplicate(session);

        resultSet.startUpdate(colIndex + 1);

        resultSet.preparedStatement.parameterValues[colIndex] = blob;
        resultSet.preparedStatement.parameterSet[colIndex]    = true;
        resultSet.isRowUpdated                                = true;
    }

    private void checkClosed() throws SQLException {
        if (isClosed) {
            throw JDBCUtil.sqlException(ErrorCode.X_0F502);
        }
    }

    static boolean isInLimits(long fullLength, long pos, long len) {
        return pos >= 0 && len >= 0 && pos + len <= fullLength;
    }
}
