content: /*
   * 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 net.nullsum.audinaut.util.tags;
  
  import java.io.IOException;
  import java.io.RandomAccessFile;
  import java.nio.charset.StandardCharsets;
  import java.util.HashMap;
  
  
  class LameHeader extends Common {
  
      public LameHeader() {
      }
  
      public HashMap getTags(RandomAccessFile s) throws IOException {
          return parseLameHeader(s, 0);
      }
  
      public HashMap parseLameHeader(RandomAccessFile s, long offset) throws IOException {
          HashMap tags = new HashMap();
          byte[] chunk = new byte[4];
  
          s.seek(offset + 0x24);
          s.read(chunk);
  
          String lameMark = new String(chunk, 0, chunk.length, StandardCharsets.ISO_8859_1);
  
          if (lameMark.equals("Info") || lameMark.equals("Xing")) {
              s.seek(offset + 0xAB);
              s.read(chunk);
  
              int raw = b2be32(chunk, 0);
              int gtrk_raw = raw >> 16;     /* first 16 bits are the raw track gain value */
              int galb_raw = raw & 0xFFFF;  /* the rest is for the album gain value       */
  
              float gtrk_val = (float) (gtrk_raw & 0x01FF) / 10;
              float galb_val = (float) (galb_raw & 0x01FF) / 10;
  
              gtrk_val = ((gtrk_raw & 0x0200) != 0 ? -1 * gtrk_val : gtrk_val);
              galb_val = ((galb_raw & 0x0200) != 0 ? -1 * galb_val : galb_val);
  
              if ((gtrk_raw & 0xE000) == 0x2000) {
                  addTagEntry(tags, "REPLAYGAIN_TRACK_GAIN", gtrk_val + " dB");
              }
              if ((gtrk_raw & 0xE000) == 0x4000) {
                  addTagEntry(tags, "REPLAYGAIN_ALBUM_GAIN", galb_val + " dB");
              }
  
          }
  
          return tags;
      }
  
  }
  