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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.Enumeration;
public class FlacFile extends Common implements PageInfo.PageParser {
private static final int FLAC_TYPE_STREAMINFO = 0; // Basic info about the stream
private static final int FLAC_TYPE_COMMENT = 4; // ID of 'VorbisComment's
public FlacFile() {
}
public HashMap getTags(RandomAccessFile s) throws IOException {
int xoff = 4; // skip file magic
int retry = 64;
boolean need_infos = true;
boolean need_tags = true;
HashMap infos = new HashMap();
HashMap tags = new HashMap();
for(; retry > 0; retry--) {
PageInfo pi = parse_stream_page(s, xoff);
if(pi.type == FLAC_TYPE_STREAMINFO) {
infos = parse_streaminfo_block(s, xoff+pi.header_len, pi.payload_len);
need_infos = false;
}
if(pi.type == FLAC_TYPE_COMMENT) {
tags = parse_vorbis_comment(s, this, xoff+pi.header_len, pi.payload_len);
need_tags = false;
}
if(pi.last_page == true || (need_tags == false && need_infos == false))
break; // eof reached
// else: calculate next offset
xoff += pi.header_len + pi.payload_len;
}
// Copy duration to final hashmap if found in infoblock
if(infos.containsKey("duration")) {
tags.put("duration", infos.get("duration"));
}
return tags;
}
/**
* Parses the metadata block at 'offset'
*/
public PageInfo parse_stream_page(RandomAccessFile s, long offset) throws IOException {
byte[] mb_head = new byte[4];
int stop_after = 0;
int block_type = 0;
int block_size = 0;
s.seek(offset);
if( s.read(mb_head) != 4 )
xdie("failed to read metadata block header");
block_size = b2be32(mb_head,0); // read whole header as 32 big endian
block_type = (block_size >> 24) & 127; // BIT 1-7 are the type
stop_after = (((block_size >> 24) & 128) > 0 ? 1 : 0 ); // BIT 0 indicates the last-block flag
block_size = (block_size & 0x00FFFFFF); // byte 1-7 are the size
PageInfo pi = new PageInfo();
pi.header_len = 4; // fixed size in flac
pi.payload_len = block_size;
pi.type = block_type;
pi.last_page = (stop_after != 0);
return pi;
}
/*
** Returns a hashma with parsed vorbis identification header data
**/
private HashMap parse_streaminfo_block(RandomAccessFile s, long offset, long pl_len) throws IOException {
HashMap id_hash = new HashMap();
byte[] buff = new byte[18];
if(pl_len >= buff.length) {
s.seek(offset);
s.read(buff);
id_hash.put("blocksize_minimal", (b2be32(buff, 0) >> 16));
id_hash.put("blocksize_maximal", (b2be32(buff, 0) & 0x0000FFFF));
id_hash.put("framesize_minimal", (b2be32(buff, 4) >> 8));
id_hash.put("framesize_maximal", (b2be32(buff, 7) >> 8));
id_hash.put("sampling_rate", (b2be32(buff, 10) >> 12));
id_hash.put("channels", ((b2be32(buff, 10) >> 9) & 7) + 1); // 3 bits
id_hash.put("num_samples", b2be32(buff, 14)); // fixme: this is actually 36 bit: the 4 hi bits are discarded due to java
if((Integer)id_hash.get("sampling_rate") > 0) {
int duration = (Integer)id_hash.get("num_samples") / (Integer)id_hash.get("sampling_rate");
id_hash.put("duration", (int)duration);
}
}
return id_hash;
}
}
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