001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.directory.shared.ldap.model.schema.syntaxCheckers; 021 022import org.apache.directory.shared.ldap.model.constants.SchemaConstants; 023import org.apache.directory.shared.ldap.model.schema.SyntaxChecker; 024import org.slf4j.Logger; 025import org.slf4j.LoggerFactory; 026 027 028/** 029 * A SyntaxChecker which verifies that a value is a Jpeg according to RFC 4517. 030 * 031 * The JFIF (Jpeg File Interchange Format) specify that a jpeg image starts with 032 * the following bytes : 033 * 0xFF 0xD8 (SOI, Start Of Image) 034 * 0xFF 0xE0 (App0) 035 * 0xNN 0xNN (Header length) 036 * "JFIF\0" (JFIF string with an ending \0) 037 * some other bytes which are related to the image. 038 * 039 * We will check for those 11 bytes, except the length. 040 * 041 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 042 */ 043@SuppressWarnings("serial") 044public class JpegSyntaxChecker extends SyntaxChecker 045{ 046 /** A logger for this class */ 047 private static final Logger LOG = LoggerFactory.getLogger( JpegSyntaxChecker.class ); 048 049 /** 050 * Creates a new instance of JpegSyntaxChecker. 051 */ 052 public JpegSyntaxChecker() 053 { 054 super( SchemaConstants.JPEG_SYNTAX ); 055 } 056 057 058 /** 059 * {@inheritDoc} 060 */ 061 public boolean isValidSyntax( Object value ) 062 { 063 if ( value == null ) 064 { 065 LOG.debug( "Syntax invalid for 'null'" ); 066 return false; 067 } 068 069 // The value must be a byte array 070 if ( ! ( value instanceof byte[] ) ) 071 { 072 LOG.debug( "Syntax invalid for '{}'", value ); 073 return false; 074 } 075 076 byte[] bytes = (byte[])value; 077 078 // The header must be at least 11 bytes long 079 if ( bytes.length < 11 ) 080 { 081 LOG.debug( "Syntax invalid for '{}'", value ); 082 return false; 083 } 084 085 if ( ( bytes[0] == ( byte ) 0x00FF ) // SOI 086 && ( bytes[1] == ( byte ) 0x00D8 ) 087 && ( bytes[2] == ( byte ) 0x00FF ) // APP0 088 && ( bytes[3] == ( byte ) 0x00E0 ) 089 && ( bytes[6] == 'J' ) // JFIF 090 && ( bytes[7] == 'F' ) // JFIF 091 && ( bytes[8] == 'I' ) // JFIF 092 && ( bytes[9] == 'F' ) 093 && ( bytes[10] == 0x00 ) ) // \0 094 { 095 // Note : this is not because the header is correct 096 // that the file is a jpeg file. There are much more 097 // elements to check, but we are not writing a jpeg 098 // file checker... 099 LOG.debug( "Syntax valid for '{}'", value ); 100 return true; 101 } 102 103 LOG.debug( "Syntax invalid for '{}'", value ); 104 return false; 105 } 106}