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/*
* Copyright (C) 2013 Adrian Ulrich <adrian@blinkenlights.ch>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package github.daneren2005.dsub.util.tags;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.HashMap;
import java.util.ArrayList;
public class Common {
private static final int MAX_COMMENT_SIZE = 512;
/**
* Returns a 32bit int from given byte offset in LE
*/
public int b2le32(byte[] b, int off) {
int r = 0;
for(int i=0; i<4; i++) {
r |= ( b2u(b[off+i]) << (8*i) );
}
return r;
}
/**
* Same as b2le32 but reads from a RandomAccessFile instead of a buffer
*/
public int raf2le32(RandomAccessFile fh, long off) throws IOException {
byte[] scratch = new byte[4];
fh.seek(off);
fh.read(scratch);
return b2le32(scratch, 0);
}
public int b2be32(byte[] b, int off) {
return swap32(b2le32(b, off));
}
public int swap32(int i) {
return((i&0xff)<<24)+((i&0xff00)<<8)+((i&0xff0000)>>8)+((i>>24)&0xff);
}
/**
* Returns a 16bit int from given byte offset in LE
*/
public int b2le16(byte[] b, int off) {
return ( b2u(b[off]) | b2u(b[off+1]) << 8 );
}
/**
* convert 'byte' value into unsigned int
*/
public int b2u(byte x) {
return (x & 0xFF);
}
/**
* Printout debug message to STDOUT
*/
public void debug(String s) {
System.out.println("DBUG "+s);
}
/**
* Throws an exception, killing the parser
*/
public void xdie(String reason) throws IOException {
throw new IOException(reason);
}
public HashMap parse_vorbis_comment(RandomAccessFile fh, PageInfo.PageParser pp, long offset, long payload_len) throws IOException {
HashMap tags = new HashMap();
long last_byte = offset + payload_len;
// skip vendor string in format: [LEN][VENDOR_STRING] -> 4 = LEN = 32bit int
offset += 4 + raf2le32(fh, offset);
// we can now read the number of comments in this file, we will also
// adjust offset to point to the value after this 32bit int
int comments = raf2le32(fh, offset);
offset += 4;
for ( ; comments > 0; comments--) {
int comment_len = raf2le32(fh, offset);
offset += 4;
long can_read = last_byte - offset; // indicates the last byte of this page
int do_read = (int)(can_read > comment_len ? comment_len : can_read); // how much data is readable in this page
if (do_read >= 3) {
int bsize = (do_read > MAX_COMMENT_SIZE ? MAX_COMMENT_SIZE : do_read);
byte[] data = new byte[bsize];
fh.seek(offset);
fh.read(data);
String tag_raw = new String(data);
String[] tag_vec = tag_raw.split("=", 2);
String tag_key = tag_vec[0].toUpperCase();
addTagEntry(tags, tag_key, tag_vec[1]);
}
// set offset to begin of next tag (OR the end of this page!)
offset += do_read;
// We hit the end of a stream
// this is most likely due to the fact that we cropped do_read to not cross
// the page boundary -> we must now calculate the position of the next tag
if (offset == last_byte) {
int partial_cruft = comment_len - do_read; // how many bytes we did not read
while(partial_cruft > 0) {
PageInfo pi = pp.parse_stream_page(fh, last_byte);
if (pi.header_len <1 || pi.payload_len < 1)
xdie("Data from callback doesnt make much sense");
offset += pi.header_len; // move position behind page header
last_byte = offset + pi.payload_len; // and adjust the last byte to pos + payload_size
if (offset+partial_cruft < last_byte) {
offset += partial_cruft; // partial data ends in this block: just adjust the ofset
break;
} else {
// this page just contains data from the partial tag -> skip to next one
offset = last_byte;
partial_cruft -= pi.payload_len;
}
}
}
}
return tags;
}
public void addTagEntry(HashMap tags, String key, String value) {
if(tags.containsKey(key)) {
((ArrayList)tags.get(key)).add(value); // just add to existing vector
}
else {
ArrayList l = new ArrayList<String>();
l.add(value);
tags.put(key, l);
}
}
}
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