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/*-------------------------------------------------------------------------
*
* Copyright (c) 2003-2011, PostgreSQL Global Development Group
*
*
*-------------------------------------------------------------------------
*/
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;
// Starting with PG 9.0, a new hex format is supported
// that starts with "\x". Figure out which format we're
// dealing with here.
//
if (s.length < 2 || s[0] != '\\' || s[1] != 'x') {
return toBytesOctalEscaped(s);
}
return toBytesHexEscaped(s);
}
private static byte[] toBytesHexEscaped(byte[] s)
{
byte[] output = new byte[(s.length - 2) / 2];
for (int i=0; i<output.length; i++) {
byte b1 = gethex(s[2 + i*2]);
byte b2 = gethex(s[2 + i*2 + 1]);
output[i] = (byte)((b1 << 4) | b2);
}
return output;
}
private static byte gethex(byte b) {
// 0-9 == 48-57
if (b <= 57)
return (byte)(b - 48);
// a-f == 97-102
if (b >= 97)
return (byte)(b - 97 + 10);
// A-F == 65-70
return (byte)(b - 65 + 10);
}
private static byte[] toBytesOctalEscaped(byte[] s)
{
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 Java 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 Java parser
l_strbuf.append("\\\\");
}
else
{
//other characters are left alone
l_strbuf.append((char)p_buf[i]);
}
}
return l_strbuf.toString();
}
}
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