audio/utilities/AudioExtent.cc

	AudioExtent.cc revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
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 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
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/*
 * Copyright (c) 1993-2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <AudioExtent.h>
#include <stdio.h>

// class AudioExtent methods


// class AudioExtent Constructor
AudioExtent::
AudioExtent(
    Audio*      obj,        // audio object to point to
    double      s,      // start time
    double      e):     // end time
    Audio("[extent]"), ref(obj)
{
    ref->Reference();       // reference audio object
    SetStart(s);            // set start/end times
    SetEnd(e);
}

// class AudioExtent Destructor
AudioExtent::
~AudioExtent()
{
    ref->Dereference();     // clear audio object reference
}

// Get referenced object
Audio* AudioExtent::
GetRef() const
{
    return (ref);
}

// Set referenced object
void AudioExtent::
SetRef(
    Audio*      r)      // new audio object
{
    if (ref == r)           // object is not changing
        return;
    ref->Dereference();     // dereference previous object
    if (r != 0) {
        ref = r;
        ref->Reference();   // reference new object
    } else {
        PrintMsg(_MGET_("AudioExtent:...NULL Audio object reference"),
            Fatal);
    }
}

// Get start time
Double AudioExtent::
GetStart() const
{
    return (start);
}

// Set start time
void AudioExtent::
SetStart(
    Double      s)      // start time, in seconds
{
    if (Undefined(s) || (s < 0.))
        start = 0.;
    else
        start = s;
}

// Get end time
Double AudioExtent::
GetEnd() const
{
    // If determinate endpoint, return it
    if (!Undefined(end))
        return (end);
    // Otherwise, return the endpoint of the underlying object
    return (ref->GetLength());
}

// Set end time
void AudioExtent::
SetEnd(
    Double      e)      // end time, in seconds
{
    Double      len;

    // If known endpoint and object has known size, do not exceed size
    if (!Undefined(e)) {
        len = ref->GetLength();
        if (!Undefined(len) && (e > len))
            e = len;
    }
    end = e;
}

// Get the length of an audio extent
Double AudioExtent::
GetLength() const
{
    Double      x;

    // If extent end is indeterminate, use the end of the target object
    x = GetEnd();
    // If the object length is indeterminate, then the length is
    if (Undefined(x))
        return (x);
    return (x - start);
}

// Construct a name for the list
char *AudioExtent::
GetName() const
{
    // XXX - construct a better name
    return (ref->GetName());
}

// Get the audio header for the current read position
AudioHdr AudioExtent::
GetHeader()
{
    return (ref->GetDHeader(ReadPosition() + start));
}

// Get the audio header for the given position
AudioHdr AudioExtent::
GetHeader(
    Double      pos)        // position
{
    return (ref->GetDHeader(pos + start));
}

// Copy data from extent into specified buffer.
// No data format translation takes place.
// The object's read position is not updated.
//
// Since the extent could refer to a list of extents of differing encodings,
// clients should always use GetHeader() in combination with ReadData()
AudioError AudioExtent::
ReadData(
    void*       buf,        // destination buffer address
    size_t&     len,        // buffer size (updated)
    Double&     pos)        // start position (updated)
{
    size_t      cnt;
    off_t       buflen;
    Double      off;
    Double      newpos;
    AudioError  err;

    // Save buffer size and zero transfer count
    cnt = len;
    len = 0;

    // Position must be valid
    if (Undefined(pos) || (pos < 0.) || ((int)cnt < 0))
        return (RaiseError(AUDIO_ERR_BADARG));

    // If the end is determinate, check start position and length
    off = pos + start;
    newpos = GetEnd();
    if (!Undefined(newpos)) {
        // If starting beyond eof, give up now
        if (off >= newpos) {
            err = AUDIO_EOF;
            err.sys = AUDIO_COPY_INPUT_EOF;
            return (err);
        }

        // If the read would extend beyond end-of-extent, shorten it
        buflen = GetHeader(pos).Time_to_Bytes((Double)(newpos - off));
        if (buflen == 0) {
            err = AUDIO_EOF;
            err.sys = AUDIO_COPY_INPUT_EOF;
            return (err);
        }
        if (buflen < cnt)
            cnt = (size_t)buflen;
    }
    // Zero-length reads are easy
    if (cnt == 0) {
        err = AUDIO_SUCCESS;
        err.sys = AUDIO_COPY_ZERO_LIMIT;
        return (err);
    }

    // Save the offset, read data, and update the returned position
    newpos = off;
    len = cnt;
    err = ref->ReadData(buf, len, newpos);
    pos = (newpos - start);     // XXX - calculate bytes and convert?
    return (err);
}

// Write to AudioExtent is (currently) prohibited
AudioError AudioExtent::
WriteData(
    void*,              // destination buffer address
    size_t&     len,        // buffer size (updated)
    Double&)            // start position (updated)
{
    len = 0;
    return (RaiseError(AUDIO_ERR_NOEFFECT));
}