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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.padaf.preflight.utils;
import static org.apache.padaf.preflight.ValidationConstants.ERROR_SYNTAX_STREAM_INVALID_FILTER;
import static org.apache.padaf.preflight.ValidationConstants.ERROR_SYNTAX_STREAM_UNDEFINED_FILTER;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_ASCII_85;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_ASCII_HEX;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_CCITTFF;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_DCT;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_FLATE_DECODE;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_LZW;
import static org.apache.padaf.preflight.ValidationConstants.INLINE_DICTIONARY_VALUE_FILTER_RUN;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_ASCII_85;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_ASCII_HEX;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_CCITTFF;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_DCT;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_FLATE_DECODE;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_JBIG;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_LZW;
import static org.apache.padaf.preflight.ValidationConstants.STREAM_DICTIONARY_VALUE_FILTER_RUN;
import java.util.List;
import org.apache.padaf.preflight.ValidationResult.ValidationError;
public class FilterHelper {
/**
* This method checks if the filter is authorized for a PDF/A file.
* According to the PDF/A-1 specification, only the LZW filter is forbidden due to
* Copyright compatibility. Because of the PDF/A is based on the PDF1.4 specification,
* all filters that aren't declared in the PDF Reference Third Edition are rejected.
*
* @param filter the filter to checks
* @param errors the list of validation errors
* @return true if the filter is authorized, false otherwise.
*/
public static boolean isAuthorizedFilter(String filter, List<ValidationError> errors) {
String errorCode = isAuthorizedFilter(filter);
if (errorCode != null) {
// --- LZW is forbidden.
if ( ERROR_SYNTAX_STREAM_INVALID_FILTER.equals(errorCode) ) {
errors.add(new ValidationError(ERROR_SYNTAX_STREAM_INVALID_FILTER, "LZWDecode is forbidden"));
return false;
} else {
errors.add(new ValidationError(ERROR_SYNTAX_STREAM_UNDEFINED_FILTER, "This filter isn't defined in the PDF Reference Third Edition : "+filter));
return false;
}
}
return true;
}
/**
* This method checks if the filter is authorized for a PDF/A file.
* According to the PDF/A-1 specification, only the LZW filter is forbidden due to
* Copyright compatibility. Because of the PDF/A is based on the PDF1.4 specification,
* all filters that aren't declared in the PDF Reference Third Edition are rejected.
*
* @param filter
* @return null if validation succeed, the errorCode if the validation failed
*/
public static String isAuthorizedFilter(String filter) {
if (filter != null) {
// --- LZW is forbidden.
if (STREAM_DICTIONARY_VALUE_FILTER_LZW.equals(filter) || INLINE_DICTIONARY_VALUE_FILTER_LZW.equals(filter) ) {
return ERROR_SYNTAX_STREAM_INVALID_FILTER;
}
// --- Filters declared in the PDF Reference for PDF 1.4
// --- Other Filters are considered as invalid to avoid not consistent behaviour
boolean definedFilter = STREAM_DICTIONARY_VALUE_FILTER_FLATE_DECODE.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_ASCII_HEX.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_ASCII_85.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_CCITTFF.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_DCT.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_JBIG.equals(filter);
definedFilter = definedFilter || STREAM_DICTIONARY_VALUE_FILTER_RUN.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_FLATE_DECODE.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_ASCII_HEX.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_ASCII_85.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_CCITTFF.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_DCT.equals(filter);
definedFilter = definedFilter || INLINE_DICTIONARY_VALUE_FILTER_RUN.equals(filter);
if (!definedFilter) {
return ERROR_SYNTAX_STREAM_UNDEFINED_FILTER;
}
}
return null;
}
}