JDK14/Java14源码在线阅读

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.media.sound;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.sound.sampled.AudioFileFormat.Type;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;

/**
 * AIFF file reader and writer.
 *
 * @author Kara Kytle
 * @author Jan Borgersen
 * @author Florian Bomers
 */
public final class AiffFileReader extends SunFileReader {

    @Override
    StandardFileFormat getAudioFileFormatImpl(final InputStream stream)
            throws UnsupportedAudioFileException, IOException {
        DataInputStream dis = new DataInputStream(stream);

        AudioFormat format = null;

        // Read the magic number
        int magic = dis.readInt();

        // $$fb: fix for 4369044: javax.sound.sampled.AudioSystem.getAudioInputStream() works wrong with Cp037
        if (magic != AiffFileFormat.AIFF_MAGIC) {
            // not AIFF, throw exception
            throw new UnsupportedAudioFileException("not an AIFF file");
        }

        long /* unsigned 32bit */ frameLength = 0;
        int length = dis.readInt();
        int iffType = dis.readInt();

        final long totallength;
        if(length <= 0 ) {
            length = AudioSystem.NOT_SPECIFIED;
            totallength = AudioSystem.NOT_SPECIFIED;
        } else {
            totallength = length + 8;
        }

        // Is this an AIFC or just plain AIFF file.
        boolean aifc = false;
        // $$fb: fix for 4369044: javax.sound.sampled.AudioSystem.getAudioInputStream() works wrong with Cp037
        if (iffType ==  AiffFileFormat.AIFC_MAGIC) {
            aifc = true;
        }

        // Loop through the AIFF chunks until
        // we get to the SSND chunk.
        boolean ssndFound = false;
        while (!ssndFound) {
            // Read the chunk name
            int chunkName = dis.readInt();
            int chunkLen = dis.readInt();

            int chunkRead = 0;

            // Switch on the chunk name.
            switch (chunkName) {
            case AiffFileFormat.FVER_MAGIC:
                // Ignore format version for now.
                break;

            case AiffFileFormat.COMM_MAGIC:
                // AIFF vs. AIFC
                // $$fb: fix for 4399551: Repost of bug candidate: cannot replay aif file (Review ID: 108108)
                if ((!aifc && chunkLen < 18) || (aifc && chunkLen < 22)) {
                    throw new UnsupportedAudioFileException("Invalid AIFF/COMM chunksize");
                }
                // Read header info.
                int channels = dis.readUnsignedShort();
                if (channels <= 0) {
                    throw new UnsupportedAudioFileException("Invalid number of channels");
                }
                frameLength = dis.readInt() & 0xffffffffL; // numSampleFrames

                int sampleSizeInBits = dis.readUnsignedShort();
                if (sampleSizeInBits < 1 || sampleSizeInBits > 32) {
                    throw new UnsupportedAudioFileException("Invalid AIFF/COMM sampleSize");
                }
                float sampleRate = (float) read_ieee_extended(dis);
                chunkRead += (2 + 4 + 2 + 10);

                // If this is not AIFC then we assume it's
                // a linearly encoded file.
                AudioFormat.Encoding encoding = AudioFormat.Encoding.PCM_SIGNED;

                if (aifc) {
                    int enc = dis.readInt(); chunkRead += 4;
                    switch (enc) {
                    case AiffFileFormat.AIFC_PCM:
                        encoding = AudioFormat.Encoding.PCM_SIGNED;
                        break;
                    case AiffFileFormat.AIFC_ULAW:
                        encoding = AudioFormat.Encoding.ULAW;
                        sampleSizeInBits = 8; // Java Sound convention
                        break;
                    default:
                        throw new UnsupportedAudioFileException("Invalid AIFF encoding");
                    }
                }
                int frameSize = calculatePCMFrameSize(sampleSizeInBits, channels);
                //$fb what's that ??
                //if (sampleSizeInBits == 8) {
                //    encoding = AudioFormat.Encoding.PCM_SIGNED;
                //}
                format =  new AudioFormat(encoding, sampleRate,
                                          sampleSizeInBits, channels,
                                          frameSize, sampleRate, true);
                break;
            case AiffFileFormat.SSND_MAGIC:
                // Data chunk.
                int dataOffset = dis.readInt(); // for now unused in javasound
                int blocksize = dis.readInt();  // for now unused in javasound
                chunkRead += 8;
                ssndFound = true;
                break;
            } // switch
            // skip the remainder of this chunk
            if (!ssndFound) {
                int toSkip = chunkLen - chunkRead;
                if (toSkip > 0) {
                    dis.skipBytes(toSkip);
                }
            }
        } // while

        if (format == null) {
            throw new UnsupportedAudioFileException("missing COMM chunk");
        }
        Type type = aifc ? Type.AIFC : Type.AIFF;

        return new AiffFileFormat(type, totallength, format, frameLength);
    }

    // HELPER METHODS
    /**
     * read_ieee_extended
     * Extended precision IEEE floating-point conversion routine.
     * @argument DataInputStream
     * @return double
     * @exception IOException
     */
    private double read_ieee_extended(DataInputStream dis) throws IOException {

        double f = 0;
        int expon = 0;

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