org.jwat.common.NewlineParser Maven / Gradle / Ivy
/**
* Java Web Archive Toolkit - Software to read and validate ARC, WARC
* and GZip files. (http://jwat.org/)
* Copyright 2011-2012 Netarkivet.dk (http://netarkivet.dk/)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jwat.common;
import java.io.IOException;
/**
* A small class to detect and count occurrences of either LF or CRLF pairs in
* a push back input stream, one method each. Implemented as an object instance
* so the caller can access the status information.
*
* A misplaced CR or LF is reported when the character is in the wrong order or
* simply not expected. Example LFCR has both CR and LF misplaced. If we are
* looking for LF's a CRLF pair has a misplaced CR.
*
* @author nicl
*/
public class NewlineParser {
/** Did the reader detect a missing CR while parsing newlines. */
public boolean bMissingCr = false;
/** Did the reader detect a missing LF while parsing newlines. */
public boolean bMissingLf = false;
/** Did the reader detect a misplaced CR while parsing newlines. */
public boolean bMisplacedCr = false;
/** Did the reader detect a misplaced LF while parsing newlines. */
public boolean bMisplacedLf = false;
/**
* Looks forward in the input stream and counts the number of newlines
* found. Non newlines characters are pushed back onto the input stream.
* @param in data input stream
* @param diagnostics object used to report errors and/or warnings
* @return newlines found in input stream
* @throws IOException if an error occurs while reading data
*/
public int parseLFs(ByteCountingPushBackInputStream in, Diagnostics diagnostics) throws IOException {
bMissingCr = false;
bMissingLf = false;
bMisplacedCr = false;
bMisplacedLf = false;
int newlines = 0;
byte[] buffer = new byte[2];
boolean bLoop = true;
while (bLoop) {
int read = in.read(buffer);
switch (read) {
case 1:
if (buffer[0] == '\n') {
++newlines;
} else if ((buffer[0] == '\r')) {
++newlines;
bMissingLf = true;
bMisplacedCr = true;
} else {
in.unread(buffer[0]);
bLoop = false;
}
break;
case 2:
if (buffer[0] == '\n') {
if (buffer[1] == '\n') {
newlines += 2;
} else if (buffer[1] != '\r') {
++newlines;
in.unread(buffer[1]);
} else {
++newlines;
bMisplacedCr = true;
}
} else if (buffer[0] == '\r') {
if (buffer[1] == '\n') {
++newlines;
bMisplacedCr = true;
bMisplacedLf = true;
} else {
++newlines;
bMisplacedCr = true;
bMissingLf = true;
in.unread(buffer[1]);
}
} else {
in.unread(buffer);
bLoop = false;
}
break;
default:
bLoop = false;
break;
}
}
if (diagnostics != null) {
if (bMissingLf) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Missing LF", "Sequence of LFs"));
}
if (bMisplacedCr) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Misplaced CR", "Sequence of LFs"));
}
if (bMisplacedLf) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Misplaced LF", "Sequence of LFs"));
}
}
return newlines;
}
/**
* Looks forward in the input stream and counts the number of newlines
* found. Non newlines characters are pushed back onto the input stream.
* @param in data input stream
* @param diagnostics object used to report errors and/or warnings
* @return newlines found in input stream
* @throws IOException if an error occurs while reading data
*/
public int parseCRLFs(ByteCountingPushBackInputStream in, Diagnostics diagnostics) throws IOException {
bMissingCr = false;
bMissingLf = false;
bMisplacedCr = false;
bMisplacedLf = false;
int newlines = 0;
byte[] buffer = new byte[2];
boolean bLoop = true;
while (bLoop) {
int read = in.read(buffer);
// Switch on the number of bytes we were able to read (0-2).
switch (read) {
case 1:
if (buffer[0] == '\n') {
++newlines;
bMissingCr = true;
} else if ((buffer[0] == '\r')) {
++newlines;
bMissingLf = true;
} else {
in.unread(buffer[0]);
bLoop = false;
}
break;
case 2:
if (buffer[0] == '\r') {
if (buffer[1] == '\n') {
++newlines;
} else {
++newlines;
bMissingLf = true;
in.unread(buffer[1]);
}
} else if (buffer[0] == '\n') {
if (buffer[1] == '\r') {
++newlines;
bMisplacedCr = true;
bMisplacedLf = true;
} else {
++newlines;
bMissingCr = true;
in.unread(buffer[1]);
}
} else {
in.unread(buffer);
bLoop = false;
}
break;
default:
bLoop = false;
break;
}
}
if (diagnostics != null) {
if (bMissingCr) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Missing CR", "Sequence of CRLFs"));
}
if (bMissingLf) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Missing LF", "Sequence of CRLFs"));
}
if (bMisplacedCr) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Misplaced CR", "Sequence of CRLFs"));
}
if (bMisplacedLf) {
diagnostics.addWarning(new Diagnosis(DiagnosisType.ERROR_EXPECTED,
"Misplaced LF", "Sequence of CRLFs"));
}
}
return newlines;
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy