85 lines
2.7 KiB
Java
85 lines
2.7 KiB
Java
/*
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* Copyright (C) 2013 Adrian Ulrich <adrian@blinkenlights.ch>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package net.nullsum.audinaut.util.tags;
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import java.io.IOException;
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import java.io.RandomAccessFile;
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import java.util.HashMap;
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class FlacFile extends Common {
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private static final int FLAC_TYPE_COMMENT = 4; // ID of 'VorbisComment's
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public FlacFile() {
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}
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public HashMap getTags(RandomAccessFile s) throws IOException {
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int xoff = 4; // skip file magic
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int retry = 64;
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int[] r;
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HashMap tags = new HashMap();
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for (; retry > 0; retry--) {
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r = parse_metadata_block(s, xoff);
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if (r[2] == FLAC_TYPE_COMMENT) {
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tags = parse_vorbis_comment(s, xoff + r[0], r[1]);
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break;
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}
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if (r[3] != 0)
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break; // eof reached
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// else: calculate next offset
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xoff += r[0] + r[1];
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}
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return tags;
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}
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/* Parses the metadata block at 'offset' and returns
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** [header_size, payload_size, type, stop_after]
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*/
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private int[] parse_metadata_block(RandomAccessFile s, long offset) throws IOException {
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int[] result = new int[4];
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byte[] mb_head = new byte[4];
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int stop_after;
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int block_type;
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int block_size;
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s.seek(offset);
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if (s.read(mb_head) != 4)
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xdie("failed to read metadata block header");
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block_size = b2be32(mb_head, 0); // read whole header as 32 big endian
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block_type = (block_size >> 24) & 127; // BIT 1-7 are the type
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stop_after = (((block_size >> 24) & 128) > 0 ? 1 : 0); // BIT 0 indicates the last-block flag
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block_size = (block_size & 0x00FFFFFF); // byte 1-7 are the size
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// debug("size="+block_size+", type="+block_type+", is_last="+stop_after);
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result[0] = 4; // hardcoded - only returned to be consistent with OGG parser
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result[1] = block_size;
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result[2] = block_type;
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result[3] = stop_after;
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return result;
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}
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}
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