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package de.danoeh.antennapod.util.vorbiscommentreader;
import org.apache.commons.io.EndianUtils;
import org.apache.commons.io.IOUtils;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.Arrays;
public abstract class VorbisCommentReader {
/** Length of first page in an ogg file in bytes. */
private static final int FIRST_PAGE_LENGTH = 58;
private static final int SECOND_PAGE_MAX_LENGTH = 64 * 1024 * 1024;
private static final int PACKET_TYPE_IDENTIFICATION = 1;
private static final int PACKET_TYPE_COMMENT = 3;
/** Called when Reader finds identification header. */
public abstract void onVorbisCommentFound();
public abstract void onVorbisCommentHeaderFound(VorbisCommentHeader header);
/**
* Is called every time the Reader finds a content vector. The handler
* should return true if it wants to handle the content vector.
*/
public abstract boolean onContentVectorKey(String content);
/**
* Is called if onContentVectorKey returned true for the key.
*
* @throws VorbisCommentReaderException
*/
public abstract void onContentVectorValue(String key, String value)
throws VorbisCommentReaderException;
public abstract void onNoVorbisCommentFound();
public abstract void onEndOfComment();
public abstract void onError(VorbisCommentReaderException exception);
public void readInputStream(InputStream input)
throws VorbisCommentReaderException {
try {
// look for identification header
if (findIdentificationHeader(input)) {
onVorbisCommentFound();
input = new OggInputStream(input);
if (findCommentHeader(input)) {
VorbisCommentHeader commentHeader = readCommentHeader(input);
if (commentHeader != null) {
onVorbisCommentHeaderFound(commentHeader);
for (int i = 0; i < commentHeader
.getUserCommentLength(); i++) {
try {
long vectorLength = EndianUtils
.readSwappedUnsignedInteger(input);
String key = readContentVectorKey(input,
vectorLength).toLowerCase();
boolean readValue = onContentVectorKey(key);
if (readValue) {
String value = readUTF8String(
input,
(int) (vectorLength - key.length() - 1));
onContentVectorValue(key, value);
} else {
IOUtils.skipFully(input,
vectorLength - key.length() - 1);
}
} catch (IOException e) {
e.printStackTrace();
}
}
onEndOfComment();
}
} else {
onError(new VorbisCommentReaderException(
"No comment header found"));
}
} else {
onNoVorbisCommentFound();
}
} catch (IOException e) {
onError(new VorbisCommentReaderException(e));
}
}
private String readUTF8String(InputStream input, long length)
throws IOException {
byte[] buffer = new byte[(int) length];
IOUtils.readFully(input, buffer);
Charset charset = Charset.forName("UTF-8");
return charset.newDecoder().decode(ByteBuffer.wrap(buffer)).toString();
}
/**
* Looks for an identification header in the first page of the file. If an
* identification header is found, it will be skipped completely and the
* method will return true, otherwise false.
*
* @throws IOException
*/
private boolean findIdentificationHeader(InputStream input)
throws IOException {
byte[] buffer = new byte[FIRST_PAGE_LENGTH];
IOUtils.readFully(input, buffer);
int i;
for (i = 6; i < buffer.length; i++) {
if (buffer[i - 5] == 'v' && buffer[i - 4] == 'o'
&& buffer[i - 3] == 'r' && buffer[i - 2] == 'b'
&& buffer[i - 1] == 'i' && buffer[i] == 's'
&& buffer[i - 6] == PACKET_TYPE_IDENTIFICATION) {
return true;
}
}
return false;
}
private boolean findCommentHeader(InputStream input) throws IOException {
char[] buffer = new char["vorbis".length() + 1];
for (int bytesRead = 0; bytesRead < SECOND_PAGE_MAX_LENGTH; bytesRead++) {
char c = (char) input.read();
int dest = -1;
switch (c) {
case PACKET_TYPE_COMMENT:
dest = 0;
break;
case 'v':
dest = 1;
break;
case 'o':
dest = 2;
break;
case 'r':
dest = 3;
break;
case 'b':
dest = 4;
break;
case 'i':
dest = 5;
break;
case 's':
dest = 6;
break;
}
if (dest >= 0) {
buffer[dest] = c;
if (buffer[1] == 'v' && buffer[2] == 'o' && buffer[3] == 'r'
&& buffer[4] == 'b' && buffer[5] == 'i'
&& buffer[6] == 's' && buffer[0] == PACKET_TYPE_COMMENT) {
return true;
}
} else {
Arrays.fill(buffer, (char) 0);
}
}
return false;
}
private VorbisCommentHeader readCommentHeader(InputStream input)
throws IOException, VorbisCommentReaderException {
try {
long vendorLength = EndianUtils.readSwappedUnsignedInteger(input);
String vendorName = readUTF8String(input, vendorLength);
long userCommentLength = EndianUtils
.readSwappedUnsignedInteger(input);
return new VorbisCommentHeader(vendorName, userCommentLength);
} catch (UnsupportedEncodingException e) {
throw new VorbisCommentReaderException(e);
}
}
private String readContentVectorKey(InputStream input, long vectorLength)
throws IOException {
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < vectorLength; i++) {
char c = (char) input.read();
if (c == '=') {
return buffer.toString();
} else {
buffer.append(c);
}
}
return null; // no key found
}
}
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