audio/utilities/AudioPipe.cc

/*
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 * (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
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/*
 * Copyright (c) 1990-2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

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

#include <stdlib.h>
#include <unistd.h>
#include <AudioPipe.h>

// class AudioPipe methods


// Constructor with file descriptor, mode, and optional name
AudioPipe::
AudioPipe(
    const int       desc,       // file descriptor
    const FileAccess    acc,        // access mode
    const char      *name_local):   // name
    AudioUnixfile(name_local, acc)
{
    setfd(desc);
}

// The create routine for pipes writes a file header
AudioError AudioPipe::
Create()
{
    AudioError  err;

    // Was the header properly set?
    err = GetHeader().Validate();
    if (err != AUDIO_SUCCESS)
        return (RaiseError(err));

    // Open fd supplied by constructor
    if (!isfdset())
        return (RaiseError(AUDIO_ERR_NOEFFECT));

    // Write the file header with current (usually unknown) size
    err = encode_filehdr();
    if (err != AUDIO_SUCCESS) {
        (void) close(getfd());      // If error, remove file
        setfd(-1);
        return (err);
    }

    // Set the actual output length to zero
    setlength(0.);

    return (AUDIO_SUCCESS);
}

// The open routine for pipes decodes the header
AudioError AudioPipe::
Open()
{
    AudioError      err;

    // The constructor should have supplied a valid fd
    if (!isfdset())
        return (RaiseError(AUDIO_ERR_NOEFFECT));

    // Decode a file header
    err = decode_filehdr();
    if (err != AUDIO_SUCCESS) {
        (void) close(getfd());
        setfd(-1);
        return (err);
    }

    return (AUDIO_SUCCESS);
}

// Read data from underlying pipe into specified buffer.
// No data format translation takes place.
// Since there's no going back, the object's read position pointer is updated.
AudioError AudioPipe::
ReadData(
    void*       buf,        // destination buffer address
    size_t&     len,        // buffer length (updated)
    Double&     pos)        // start position (updated)
{
    AudioError  err;
    char        *tbuf;      // current buffer pointer
    size_t      remain;     // number of bytes remaining
    size_t      cnt;        // accumulated number of bytes read

    tbuf = (char *)buf;
    remain = len;
    cnt = 0;

    // Pipes return short reads.  If non-blocking i/o, try to read all.
    do {
        // Call the real routine
        err = AudioUnixfile::ReadData((void*)tbuf, remain, pos);

        // Update the object's read position
        if (!err) {
            (void) SetReadPosition(pos, Absolute);
            if (remain == 0)
                break;
            cnt += remain;
            tbuf += remain;
            remain = len - cnt;
        }
    } while (!err && (remain > 0) && GetBlocking());
    len = cnt;
    if (len > 0)
        return (AUDIO_SUCCESS);
    return (err);
}

// Write data to underlying file from specified buffer.
// No data format translation takes place.
// Since there's no going back, the object's write position pointer is updated.
AudioError AudioPipe::
WriteData(
    void*       buf,        // source buffer address
    size_t&     len,        // buffer length (updated)
    Double&     pos)        // start position (updated)
{
    AudioError  err;

    // Call the real routine
    err = AudioUnixfile::WriteData(buf, len, pos);

    // Update the object's write position
    if (err == AUDIO_SUCCESS)
        (void) SetWritePosition(pos, Absolute);
    return (err);
}