source: vbox/trunk/src/VBox/RDP/client-1.8.4/rdpsnd.c@ 88182

/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Sound Channel Process Functions
   Copyright 2006-2010 Pierre Ossman <[email protected]> for Cendio AB
   Copyright 2009-2011 Peter Astrand <[email protected]> for Cendio AB
   Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 2003-2008
   Copyright (C) GuoJunBo <[email protected]> 2003

   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/>.
*/

/*
 * Oracle GPL Disclaimer: For the avoidance of doubt, except that if any license choice
 * other than GPL or LGPL is available it will apply instead, Oracle elects to use only
 * the General Public License version 2 (GPLv2) at this time for any software where
 * a choice of GPL license versions is made available with the language indicating
 * that GPLv2 or any later version may be used, or where a choice of which version
 * of the GPL is applied is otherwise unspecified.
 */

#include <assert.h>

#include "rdesktop.h"
#include "rdpsnd.h"
#include "rdpsnd_dsp.h"

#define RDPSND_CLOSE            1
#define RDPSND_WRITE            2
#define RDPSND_SET_VOLUME       3
#define RDPSND_UNKNOWN4         4
#define RDPSND_COMPLETION       5
#define RDPSND_PING                     6
#define RDPSND_NEGOTIATE        7

#define RDPSND_REC_NEGOTIATE    39
#define RDPSND_REC_START                40
#define RDPSND_REC_STOP                 41
#define RDPSND_REC_DATA                 42
#define RDPSND_REC_SET_VOLUME   43

/* Special flag for RDPSND recording extension,
   not defined in MS specs.

   See doc/rdpsnd-rec.txt for more information.
*/
#define RDPSND_FLAG_RECORD              0x00800000

#define MAX_FORMATS             10
#define MAX_QUEUE               50

extern RD_BOOL g_rdpsnd;

static VCHANNEL *rdpsnd_channel;
static VCHANNEL *rdpsnddbg_channel;
static struct audio_driver *drivers = NULL;
struct audio_driver *current_driver = NULL;

static RD_BOOL rdpsnd_negotiated;
static RD_BOOL rdpsnd_rec_negotiated;

static RD_BOOL device_open;
static RD_BOOL rec_device_open;

static RD_WAVEFORMATEX formats[MAX_FORMATS];
static unsigned int format_count;
static unsigned int current_format;

static RD_WAVEFORMATEX rec_formats[MAX_FORMATS];
static unsigned int rec_format_count;
static unsigned int rec_current_format;

unsigned int queue_hi, queue_lo, queue_pending;
struct audio_packet packet_queue[MAX_QUEUE];

static char record_buffer[8192];
static uint32 record_buffer_size;

static uint8 packet_opcode;
static struct stream packet;

void (*wave_out_play) (void);

static void rdpsnd_queue_write(STREAM s, uint16 tick, uint8 index);
static void rdpsnd_queue_init(void);
static void rdpsnd_queue_clear(void);
static void rdpsnd_queue_complete_pending(void);
static long rdpsnd_queue_next_completion(void);

static STREAM
rdpsnd_init_packet(uint16 type, uint16 size)
{
        STREAM s;

        s = channel_init(rdpsnd_channel, size + 4);
        out_uint16_le(s, type);
        out_uint16_le(s, size);
        return s;
}

static void
rdpsnd_send(STREAM s)
{
        channel_send(s, rdpsnd_channel);
}

static void
rdpsnd_send_completion(uint16 tick, uint8 packet_index)
{
        STREAM s;

        s = rdpsnd_init_packet(RDPSND_COMPLETION, 4);
        out_uint16_le(s, tick);
        out_uint8(s, packet_index);
        out_uint8(s, 0);
        s_mark_end(s);
        rdpsnd_send(s);

        DEBUG_SOUND(("RDPSND: -> RDPSND_COMPLETION(tick: %u, index: %u)\n",
                     (unsigned) tick, (unsigned) packet_index));
}

static void
rdpsnd_flush_record(void)
{
        STREAM s;
        unsigned int chunk_size;
        char *data;

        if (record_buffer_size == 0)
                return;

        assert(record_buffer_size <= sizeof(record_buffer));

        data = record_buffer;

        /*
         * Microsoft's RDP server keeps dropping chunks, so we need to
         * transmit everything inside one channel fragment or we risk
         * making the rdpsnd server go out of sync with the byte stream.
         */
        while (record_buffer_size)
        {
                if (record_buffer_size < 1596)
                        chunk_size = record_buffer_size;
                else
                        chunk_size = 1596;

                s = rdpsnd_init_packet(RDPSND_REC_DATA, chunk_size);
                out_uint8p(s, data, chunk_size);

                s_mark_end(s);
                rdpsnd_send(s);

                data = data + chunk_size;
                record_buffer_size -= chunk_size;

                DEBUG_SOUND(("RDPSND: -> RDPSND_REC_DATA(length: %u)\n", (unsigned) chunk_size));
        }

        record_buffer_size = 0;
}

static void
rdpsnd_clear_record(void)
{
        /*
         * Silently drop everything we have in the record buffer as
         * we've somehow gotten a reset in regard to the server.
         */
        record_buffer_size = 0;
}

void
rdpsnd_record(const void *data, unsigned int size)
{
        uint32 remain, chunk;

        assert(rec_device_open);

        while (size)
        {
                remain = sizeof(record_buffer) - record_buffer_size;

                if (size >= remain)
                        chunk = remain;
                else
                        chunk = size;

                memcpy(record_buffer + record_buffer_size, data, chunk);

#ifdef B_ENDIAN
                if (current_driver->need_byteswap_on_be)
                        rdpsnd_dsp_swapbytes(record_buffer + record_buffer_size,
                                             chunk, &rec_formats[rec_current_format]);
#endif

                record_buffer_size += chunk;

                data = (const char *) data + chunk;
                size -= chunk;

                if (record_buffer_size == sizeof(record_buffer))
                        rdpsnd_flush_record();
        }
}

static RD_BOOL
rdpsnd_auto_select(void)
{
        static RD_BOOL failed = False;

        if (!failed)
        {
                current_driver = drivers;
                while (current_driver != NULL)
                {
                        DEBUG(("trying %s...\n", current_driver->name));
                        if (current_driver->wave_out_open())
                        {
                                DEBUG(("selected %s\n", current_driver->name));
                                current_driver->wave_out_close();
                                return True;
                        }
                        current_driver = current_driver->next;
                }

                warning("no working audio-driver found\n");
                failed = True;
                current_driver = NULL;
        }

        return False;
}

static void
rdpsnd_process_negotiate(STREAM in)
{
        uint16 in_format_count, i;
        uint8 pad;
        uint16 version;
        RD_WAVEFORMATEX *format;
        STREAM out;
        RD_BOOL device_available = False;
        int readcnt;
        int discardcnt;

        in_uint8s(in, 14);      /* initial bytes not valid from server */
        in_uint16_le(in, in_format_count);
        in_uint8(in, pad);
        in_uint16_le(in, version);
        in_uint8s(in, 1);       /* padding */

        DEBUG_SOUND(("RDPSND: RDPSND_NEGOTIATE(formats: %d, pad: 0x%02x, version: %x)\n",
                     (int) in_format_count, (unsigned) pad, (unsigned) version));

        if (rdpsnd_negotiated)
        {
                error("RDPSND: Extra RDPSND_NEGOTIATE in the middle of a session\n");
                /* Do a complete reset of the sound state */
                rdpsnd_reset_state();
        }

        if (!current_driver && g_rdpsnd)
                device_available = rdpsnd_auto_select();

        if (current_driver && !device_available && current_driver->wave_out_open())
        {
                current_driver->wave_out_close();
                device_available = True;
        }

        format_count = 0;
        if (s_check_rem(in, 18 * in_format_count))
        {
                for (i = 0; i < in_format_count; i++)
                {
                        format = &formats[format_count];
                        in_uint16_le(in, format->wFormatTag);
                        in_uint16_le(in, format->nChannels);
                        in_uint32_le(in, format->nSamplesPerSec);
                        in_uint32_le(in, format->nAvgBytesPerSec);
                        in_uint16_le(in, format->nBlockAlign);
                        in_uint16_le(in, format->wBitsPerSample);
                        in_uint16_le(in, format->cbSize);

                        /* read in the buffer of unknown use */
                        readcnt = format->cbSize;
                        discardcnt = 0;
                        if (format->cbSize > MAX_CBSIZE)
                        {
                                fprintf(stderr, "cbSize too large for buffer: %d\n",
                                        format->cbSize);
                                readcnt = MAX_CBSIZE;
                                discardcnt = format->cbSize - MAX_CBSIZE;
                        }
                        in_uint8a(in, format->cb, readcnt);
                        in_uint8s(in, discardcnt);

                        if (current_driver && current_driver->wave_out_format_supported(format))
                        {
                                format_count++;
                                if (format_count == MAX_FORMATS)
                                        break;
                        }
                }
        }

        out = rdpsnd_init_packet(RDPSND_NEGOTIATE | 0x200, 20 + 18 * format_count);

        uint32 flags = TSSNDCAPS_VOLUME;

        /* if sound is enabled, set snd caps to alive to enable
           transmision of audio from server */
        if (g_rdpsnd)
        {
                flags |= TSSNDCAPS_ALIVE;
                flags |= RDPSND_FLAG_RECORD;
        }
        out_uint32_le(out, flags);      /* TSSNDCAPS flags */

        out_uint32(out, 0xffffffff);    /* volume */
        out_uint32(out, 0);     /* pitch */
        out_uint16(out, 0);     /* UDP port */

        out_uint16_le(out, format_count);
        out_uint8(out, 0);      /* padding */
        out_uint16_le(out, 2);  /* version */
        out_uint8(out, 0);      /* padding */

        for (i = 0; i < format_count; i++)
        {
                format = &formats[i];
                out_uint16_le(out, format->wFormatTag);
                out_uint16_le(out, format->nChannels);
                out_uint32_le(out, format->nSamplesPerSec);
                out_uint32_le(out, format->nAvgBytesPerSec);
                out_uint16_le(out, format->nBlockAlign);
                out_uint16_le(out, format->wBitsPerSample);
                out_uint16(out, 0);     /* cbSize */
        }

        s_mark_end(out);

        DEBUG_SOUND(("RDPSND: -> RDPSND_NEGOTIATE(formats: %d)\n", (int) format_count));

        rdpsnd_send(out);

        rdpsnd_negotiated = True;
}

static void
rdpsnd_process_ping(STREAM in)
{
        uint16 tick;
        STREAM out;
        struct stream packet = *in;

        if (!s_check_rem(in, 4))
        {
                rdp_protocol_error("rdpsnd_process_training(), consume of training data from stream would overrun", &packet);
        }

        in_uint16_le(in, tick);

        DEBUG_SOUND(("RDPSND: RDPSND_PING(tick: 0x%04x)\n", (unsigned) tick));

        out = rdpsnd_init_packet(RDPSND_PING | 0x2300, 4);
        out_uint16_le(out, tick);
        out_uint16_le(out, 0);
        s_mark_end(out);
        rdpsnd_send(out);

        DEBUG_SOUND(("RDPSND: -> (tick: 0x%04x)\n", (unsigned) tick));
}

static void
rdpsnd_process_rec_negotiate(STREAM in)
{
        uint16 in_format_count, i;
        uint16 version;
        RD_WAVEFORMATEX *format;
        STREAM out;
        RD_BOOL device_available = False;
        int readcnt;
        int discardcnt;

        in_uint8s(in, 8);       /* initial bytes not valid from server */
        in_uint16_le(in, in_format_count);
        in_uint16_le(in, version);

        DEBUG_SOUND(("RDPSND: RDPSND_REC_NEGOTIATE(formats: %d, version: %x)\n",
                     (int) in_format_count, (unsigned) version));

        if (rdpsnd_rec_negotiated)
        {
                error("RDPSND: Extra RDPSND_REC_NEGOTIATE in the middle of a session\n");
                /* Do a complete reset of the sound state */
                rdpsnd_reset_state();
        }

        if (!current_driver)
                device_available = rdpsnd_auto_select();

        if (current_driver && !device_available && current_driver->wave_in_open
            && current_driver->wave_in_open())
        {
                current_driver->wave_in_close();
                device_available = True;
        }

        rec_format_count = 0;
        if (s_check_rem(in, 18 * in_format_count))
        {
                for (i = 0; i < in_format_count; i++)
                {
                        format = &rec_formats[rec_format_count];
                        in_uint16_le(in, format->wFormatTag);
                        in_uint16_le(in, format->nChannels);
                        in_uint32_le(in, format->nSamplesPerSec);
                        in_uint32_le(in, format->nAvgBytesPerSec);
                        in_uint16_le(in, format->nBlockAlign);
                        in_uint16_le(in, format->wBitsPerSample);
                        in_uint16_le(in, format->cbSize);

                        /* read in the buffer of unknown use */
                        readcnt = format->cbSize;
                        discardcnt = 0;
                        if (format->cbSize > MAX_CBSIZE)
                        {
                                fprintf(stderr, "cbSize too large for buffer: %d\n",
                                        format->cbSize);
                                readcnt = MAX_CBSIZE;
                                discardcnt = format->cbSize - MAX_CBSIZE;
                        }
                        in_uint8a(in, format->cb, readcnt);
                        in_uint8s(in, discardcnt);

                        if (current_driver && current_driver->wave_in_format_supported
                            && current_driver->wave_in_format_supported(format))
                        {
                                rec_format_count++;
                                if (rec_format_count == MAX_FORMATS)
                                        break;
                        }
                }
        }

        out = rdpsnd_init_packet(RDPSND_REC_NEGOTIATE, 12 + 18 * rec_format_count);
        out_uint32_le(out, 0x00000000); /* flags */
        out_uint32_le(out, 0xffffffff); /* volume */
        out_uint16_le(out, rec_format_count);
        out_uint16_le(out, 1);  /* version */

        for (i = 0; i < rec_format_count; i++)
        {
                format = &rec_formats[i];
                out_uint16_le(out, format->wFormatTag);
                out_uint16_le(out, format->nChannels);
                out_uint32_le(out, format->nSamplesPerSec);
                out_uint32_le(out, format->nAvgBytesPerSec);
                out_uint16_le(out, format->nBlockAlign);
                out_uint16_le(out, format->wBitsPerSample);
                out_uint16(out, 0);     /* cbSize */
        }

        s_mark_end(out);

        DEBUG_SOUND(("RDPSND: -> RDPSND_REC_NEGOTIATE(formats: %d)\n", (int) rec_format_count));

        rdpsnd_send(out);

        rdpsnd_rec_negotiated = True;
}

static void
rdpsnd_process_packet(uint8 opcode, STREAM s)
{
        uint16 vol_left, vol_right;
        static uint16 tick, format;
        static uint8 packet_index;

        switch (opcode)
        {
                case RDPSND_WRITE:
                        in_uint16_le(s, tick);
                        in_uint16_le(s, format);
                        in_uint8(s, packet_index);
                        in_uint8s(s, 3);
                        DEBUG_SOUND(("RDPSND: RDPSND_WRITE(tick: %u, format: %u, index: %u, data: %u bytes)\n", (unsigned) tick, (unsigned) format, (unsigned) packet_index, (unsigned) s->size - 8));

                        if (format >= MAX_FORMATS)
                        {
                                error("RDPSND: Invalid format index\n");
                                break;
                        }

                        if (!device_open || (format != current_format))
                        {
                                /*
                                 * If we haven't selected a device by now, then either
                                 * we've failed to find a working device, or the server
                                 * is sending bogus RDPSND_WRITE.
                                 */
                                if (!current_driver)
                                {
                                        rdpsnd_send_completion(tick, packet_index);
                                        break;
                                }
                                if (!device_open && !current_driver->wave_out_open())
                                {
                                        rdpsnd_send_completion(tick, packet_index);
                                        break;
                                }
                                if (!current_driver->wave_out_set_format(&formats[format]))
                                {
                                        rdpsnd_send_completion(tick, packet_index);
                                        current_driver->wave_out_close();
                                        device_open = False;
                                        break;
                                }
                                device_open = True;
                                current_format = format;
                        }

                        rdpsnd_queue_write(rdpsnd_dsp_process
                                           (s->p, s->end - s->p, current_driver,
                                            &formats[current_format]), tick, packet_index);
                        return;
                        break;
                case RDPSND_CLOSE:
                        DEBUG_SOUND(("RDPSND: RDPSND_CLOSE()\n"));
                        if (device_open)
                                current_driver->wave_out_close();
                        device_open = False;
                        break;
                case RDPSND_NEGOTIATE:
                        rdpsnd_process_negotiate(s);
                        break;
                case RDPSND_PING:
                        rdpsnd_process_ping(s);
                        break;
                case RDPSND_SET_VOLUME:
                        in_uint16_le(s, vol_left);
                        in_uint16_le(s, vol_right);
                        DEBUG_SOUND(("RDPSND: RDPSND_VOLUME(left: 0x%04x (%u %%), right: 0x%04x (%u %%))\n", (unsigned) vol_left, (unsigned) vol_left / 655, (unsigned) vol_right, (unsigned) vol_right / 655));
                        if (device_open)
                                current_driver->wave_out_volume(vol_left, vol_right);
                        break;
                case RDPSND_REC_NEGOTIATE:
                        rdpsnd_process_rec_negotiate(s);
                        break;
                case RDPSND_REC_START:
                        in_uint16_le(s, format);
                        DEBUG_SOUND(("RDPSND: RDPSND_REC_START(format: %u)\n", (unsigned) format));

                        if (format >= MAX_FORMATS)
                        {
                                error("RDPSND: Invalid format index\n");
                                break;
                        }

                        if (rec_device_open)
                        {
                                error("RDPSND: Multiple RDPSND_REC_START\n");
                                break;
                        }

                        if (!current_driver->wave_in_open())
                                break;

                        if (!current_driver->wave_in_set_format(&rec_formats[format]))
                        {
                                error("RDPSND: Device not accepting format\n");
                                current_driver->wave_in_close();
                                break;
                        }
                        rec_current_format = format;
                        rec_device_open = True;
                        break;
                case RDPSND_REC_STOP:
                        DEBUG_SOUND(("RDPSND: RDPSND_REC_STOP()\n"));
                        rdpsnd_flush_record();
                        if (rec_device_open)
                                current_driver->wave_in_close();
                        rec_device_open = False;
                        break;
                case RDPSND_REC_SET_VOLUME:
                        in_uint16_le(s, vol_left);
                        in_uint16_le(s, vol_right);
                        DEBUG_SOUND(("RDPSND: RDPSND_REC_VOLUME(left: 0x%04x (%u %%), right: 0x%04x (%u %%))\n", (unsigned) vol_left, (unsigned) vol_left / 655, (unsigned) vol_right, (unsigned) vol_right / 655));
                        if (rec_device_open)
                                current_driver->wave_in_volume(vol_left, vol_right);
                        break;
                default:
                        unimpl("RDPSND packet type %x\n", opcode);
                        break;
        }
}

static void
rdpsnd_process(STREAM s)
{
        uint16 len;

        while (!s_check_end(s))
        {
                /* New packet */
                if (packet.size == 0)
                {
                        if ((s->end - s->p) < 4)
                        {
                                error("RDPSND: Split at packet header. Things will go south from here...\n");
                                return;
                        }
                        in_uint8(s, packet_opcode);
                        in_uint8s(s, 1);        /* Padding */
                        in_uint16_le(s, len);

                        DEBUG_SOUND(("RDPSND: == Opcode %x Length: %d ==\n",
                                     (int) packet_opcode, (int) len));

                        packet.p = packet.data;
                        packet.end = packet.data + len;
                        packet.size = len;
                }
                else
                {
                        len = MIN(s->end - s->p, packet.end - packet.p);

                        /* Microsoft's server is so broken it's not even funny... */
                        if (packet_opcode == RDPSND_WRITE)
                        {
                                if ((packet.p - packet.data) < 12)
                                        len = MIN(len, 12 - (packet.p - packet.data));
                                else if ((packet.p - packet.data) == 12)
                                {
                                        DEBUG_SOUND(("RDPSND: Eating 4 bytes of %d bytes...\n",
                                                     len));
                                        in_uint8s(s, 4);
                                        len -= 4;
                                }
                        }

                        in_uint8a(s, packet.p, len);
                        packet.p += len;
                }

                /* Packet fully assembled */
                if (packet.p == packet.end)
                {
                        packet.p = packet.data;
                        rdpsnd_process_packet(packet_opcode, &packet);
                        packet.size = 0;
                }
        }
}

static RD_BOOL
rdpsnddbg_line_handler(const char *line, void *data)
{
#ifdef WITH_DEBUG_SOUND
        fprintf(stderr, "SNDDBG: %s\n", line);
#endif
        return True;
}

static void
rdpsnddbg_process(STREAM s)
{
        unsigned int pkglen;
        static char *rest = NULL;
        char *buf;

        if (!s_check(s))
        {
                rdp_protocol_error("rdpsnddbg_process(), stream is in unstable state", s);
        }

        pkglen = s->end - s->p;
        /* str_handle_lines requires null terminated strings */
        buf = (char *) xmalloc(pkglen + 1);
        STRNCPY(buf, (char *) s->p, pkglen + 1);

        str_handle_lines(buf, &rest, rdpsnddbg_line_handler, NULL);

        xfree(buf);
}

static void
rdpsnd_register_drivers(char *options)
{
        struct audio_driver **reg;

        /* The order of registrations define the probe-order
           when opening the device for the first time */
        reg = &drivers;
#if defined(RDPSND_ALSA)
        *reg = alsa_register(options);
        assert(*reg);
        reg = &((*reg)->next);
#endif
#if defined(RDPSND_SUN)
        *reg = sun_register(options);
        assert(*reg);
        reg = &((*reg)->next);
#endif
#if defined(RDPSND_OSS)
        *reg = oss_register(options);
        assert(*reg);
        reg = &((*reg)->next);
#endif
#if defined(RDPSND_SGI)
        *reg = sgi_register(options);
        assert(*reg);
        reg = &((*reg)->next);
#endif
#if defined(RDPSND_LIBAO)
        *reg = libao_register(options);
        assert(*reg);
        reg = &((*reg)->next);
#endif
        *reg = NULL;
}

RD_BOOL
rdpsnd_init(char *optarg)
{
        struct audio_driver *pos;
        char *driver = NULL, *options = NULL;

        drivers = NULL;

        packet.data = (uint8 *) xmalloc(65536);
        packet.p = packet.end = packet.data;
        packet.size = 0;

        rdpsnd_channel =
                channel_register("rdpsnd", CHANNEL_OPTION_INITIALIZED | CHANNEL_OPTION_ENCRYPT_RDP,
                                 rdpsnd_process);

        rdpsnddbg_channel =
                channel_register("snddbg", CHANNEL_OPTION_INITIALIZED | CHANNEL_OPTION_ENCRYPT_RDP,
                                 rdpsnddbg_process);

        if ((rdpsnd_channel == NULL) || (rdpsnddbg_channel == NULL))
        {
                error("channel_register\n");
                return False;
        }

        rdpsnd_queue_init();

        if (optarg != NULL && strlen(optarg) > 0)
        {
                driver = options = optarg;

                while (*options != '\0' && *options != ':')
                        options++;

                if (*options == ':')
                {
                        *options = '\0';
                        options++;
                }

                if (*options == '\0')
                        options = NULL;
        }

        rdpsnd_register_drivers(options);

        if (!driver)
                return True;

        pos = drivers;
        while (pos != NULL)
        {
                if (!strcmp(pos->name, driver))
                {
                        DEBUG(("selected %s\n", pos->name));
                        current_driver = pos;
                        return True;
                }
                pos = pos->next;
        }
        return False;
}

void
rdpsnd_reset_state(void)
{
        if (device_open)
                current_driver->wave_out_close();
        device_open = False;
        rdpsnd_queue_clear();
        rdpsnd_negotiated = False;

        if (rec_device_open)
                current_driver->wave_in_close();
        rec_device_open = False;
        rdpsnd_clear_record();
        rdpsnd_rec_negotiated = False;
}


void
rdpsnd_show_help(void)
{
        struct audio_driver *pos;

        rdpsnd_register_drivers(NULL);

        pos = drivers;
        while (pos != NULL)
        {
                fprintf(stderr, "                     %s:\t%s\n", pos->name, pos->description);
                pos = pos->next;
        }
}

void
rdpsnd_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv)
{
        long next_pending;

        if (device_open || rec_device_open)
                current_driver->add_fds(n, rfds, wfds, tv);

        next_pending = rdpsnd_queue_next_completion();
        if (next_pending >= 0)
        {
                long cur_timeout;

                cur_timeout = tv->tv_sec * 1000000 + tv->tv_usec;
                if (cur_timeout > next_pending)
                {
                        tv->tv_sec = next_pending / 1000000;
                        tv->tv_usec = next_pending % 1000000;
                }
        }
}

void
rdpsnd_check_fds(fd_set * rfds, fd_set * wfds)
{
        rdpsnd_queue_complete_pending();

        if (device_open || rec_device_open)
                current_driver->check_fds(rfds, wfds);
}

static void
rdpsnd_queue_write(STREAM s, uint16 tick, uint8 index)
{
        struct audio_packet *packet = &packet_queue[queue_hi];
        unsigned int next_hi = (queue_hi + 1) % MAX_QUEUE;

        if (next_hi == queue_pending)
        {
                error("No space to queue audio packet\n");
                return;
        }

        queue_hi = next_hi;

        packet->s = *s;
        packet->tick = tick;
        packet->index = index;

        gettimeofday(&packet->arrive_tv, NULL);
}

struct audio_packet *
rdpsnd_queue_current_packet(void)
{
        return &packet_queue[queue_lo];
}

RD_BOOL
rdpsnd_queue_empty(void)
{
        return (queue_lo == queue_hi);
}

static void
rdpsnd_queue_init(void)
{
        queue_pending = queue_lo = queue_hi = 0;
}

static void
rdpsnd_queue_clear(void)
{
        struct audio_packet *packet;

        /* Go through everything, not just the pending packets */
        while (queue_pending != queue_hi)
        {
                packet = &packet_queue[queue_pending];
                xfree(packet->s.data);
                queue_pending = (queue_pending + 1) % MAX_QUEUE;
        }

        /* Reset everything back to the initial state */
        queue_pending = queue_lo = queue_hi = 0;
}

void
rdpsnd_queue_next(unsigned long completed_in_us)
{
        struct audio_packet *packet;

        assert(!rdpsnd_queue_empty());

        packet = &packet_queue[queue_lo];

        gettimeofday(&packet->completion_tv, NULL);

        packet->completion_tv.tv_usec += completed_in_us;
        packet->completion_tv.tv_sec += packet->completion_tv.tv_usec / 1000000;
        packet->completion_tv.tv_usec %= 1000000;

        queue_lo = (queue_lo + 1) % MAX_QUEUE;

        rdpsnd_queue_complete_pending();
}

int
rdpsnd_queue_next_tick(void)
{
        if (((queue_lo + 1) % MAX_QUEUE) != queue_hi)
        {
                return packet_queue[(queue_lo + 1) % MAX_QUEUE].tick;
        }
        else
        {
                return (packet_queue[queue_lo].tick + 65535) % 65536;
        }
}

static void
rdpsnd_queue_complete_pending(void)
{
        struct timeval now;
        long elapsed;
        struct audio_packet *packet;

        gettimeofday(&now, NULL);

        while (queue_pending != queue_lo)
        {
                packet = &packet_queue[queue_pending];

                if (now.tv_sec < packet->completion_tv.tv_sec)
                        break;

                if ((now.tv_sec == packet->completion_tv.tv_sec) &&
                    (now.tv_usec < packet->completion_tv.tv_usec))
                        break;

                elapsed = (packet->completion_tv.tv_sec - packet->arrive_tv.tv_sec) * 1000000 +
                        (packet->completion_tv.tv_usec - packet->arrive_tv.tv_usec);
                elapsed /= 1000;

                xfree(packet->s.data);
                rdpsnd_send_completion((packet->tick + elapsed) % 65536, packet->index);
                queue_pending = (queue_pending + 1) % MAX_QUEUE;
        }
}

static long
rdpsnd_queue_next_completion(void)
{
        struct audio_packet *packet;
        long remaining;
        struct timeval now;

        if (queue_pending == queue_lo)
                return -1;

        gettimeofday(&now, NULL);

        packet = &packet_queue[queue_pending];

        remaining = (packet->completion_tv.tv_sec - now.tv_sec) * 1000000 +
                (packet->completion_tv.tv_usec - now.tv_usec);

        if (remaining < 0)
                return 0;

        return remaining;
}