/*-------------------------------------------------------------------------
*
* Copyright (c) 2003-2005, PostgreSQL Global Development Group
*
* IDENTIFICATION
*   $PostgreSQL: pgjdbc/org/postgresql/util/PGbytea.java,v 1.12 2005/01/11 08:25:49 jurka Exp $
*
*-------------------------------------------------------------------------
*/
package org.postgresql.util;

import java.sql.*;

/**
 * Converts to and from the postgresql bytea datatype used by the backend.
 */
public class PGbytea
{
    private static final int MAX_3_BUFF_SIZE = 2 * 1024 * 1024;

    /*
     * Converts a PG bytea raw value (i.e. the raw binary representation
     * of the bytea data type) into a java byte[]
     */
    public static byte[] toBytes(byte[] s) throws SQLException
    {
        if (s == null)
            return null;
        final int slength = s.length;
        byte[] buf = null;
        int correctSize = slength;
        if (slength > MAX_3_BUFF_SIZE)
        {
            // count backslash escapes, they will be either
            // backslashes or an octal escape \\ or \003
            //
            for (int i = 0; i < slength; ++i)
            {
                byte current = s[i];
                if (current == '\\')
                {
                    byte next = s[ ++i ];
                    if (next == '\\')
                    {
                        --correctSize;
                    }
                    else
                    {
                        correctSize -= 3;
                    }
                }
            }
            buf = new byte[correctSize];
        }
        else
        {
            buf = new byte[slength];
        }
        int bufpos = 0;
        int thebyte;
        byte nextbyte;
        byte secondbyte;
        for (int i = 0; i < slength; i++)
        {
            nextbyte = s[i];
            if (nextbyte == (byte)'\\')
            {
                secondbyte = s[++i];
                if (secondbyte == (byte)'\\')
                {
                    //escaped \
                    buf[bufpos++] = (byte)'\\';
                }
                else
                {
                    thebyte = (secondbyte - 48) * 64 + (s[++i] - 48) * 8 + (s[++i] - 48);
                    if (thebyte > 127)
                        thebyte -= 256;
                    buf[bufpos++] = (byte)thebyte;
                }
            }
            else
            {
                buf[bufpos++] = nextbyte;
            }
        }
        if (bufpos == correctSize)
        {
            return buf;
        }
        byte[] l_return = new byte[bufpos];
        System.arraycopy(buf, 0, l_return, 0, bufpos);
        return l_return;
    }

    /*
     * Converts a java byte[] into a PG bytea string (i.e. the text
     * representation of the bytea data type)
     */
    public static String toPGString(byte[] p_buf) throws SQLException
    {
        if (p_buf == null)
            return null;
        StringBuffer l_strbuf = new StringBuffer(2 * p_buf.length);
        for (int i = 0; i < p_buf.length; i++)
        {
            int l_int = (int)p_buf[i];
            if (l_int < 0)
            {
                l_int = 256 + l_int;
            }
            //we escape the same non-printable characters as the backend
            //we must escape all 8bit characters otherwise when convering
            //from java unicode to the db character set we may end up with
            //question marks if the character set is SQL_ASCII
            if (l_int < 040 || l_int > 0176)
            {
                //escape charcter with the form \000, but need two \\ because of
                //the parser
                l_strbuf.append("\\");
                l_strbuf.append((char)(((l_int >> 6) & 0x3) + 48));
                l_strbuf.append((char)(((l_int >> 3) & 0x7) + 48));
                l_strbuf.append((char)((l_int & 0x07) + 48));
            }
            else if (p_buf[i] == (byte)'\\')
            {
                //escape the backslash character as \\, but need four \\\\ because
                //of the parser
                l_strbuf.append("\\\\");
            }
            else
            {
                //other characters are left alone
                l_strbuf.append((char)p_buf[i]);
            }
        }
        return l_strbuf.toString();
    }
}

@@ -219,29 +219,29 @@
  1.1
-2
+3
  200
-5/01/11 08:25:49
+6/09/26 06:52:34
  jur
@@ -3646,24 +3646,29 @@
       //the 
+Java 
 parser%0A     
@@ -4080,16 +4080,21 @@
 /of the 
+Java 
 parser%0A 

Change the comments in org.postgresql.util.PGbytea to clarify that the backslashes are given twice as often as required by the backend because of how Java processes string literals (and not because of the backend's parser).