mixer.c

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/*              DirectSound
 *
 * Copyright 1998 Marcus Meissner
 * Copyright 1998 Rob Riggs
 * Copyright 2000-2002 TransGaming Technologies, Inc.
 * Copyright 2007 Peter Dons Tychsen
 * Copyright 2007 Maarten Lankhorst
 * Copyright 2011 Owen Rudge for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include "dsound_private.h"
 
void DSOUND_RecalcVolPan(PDSVOLUMEPAN volpan)
{
    double temp;
    TRACE("(%p)\n",volpan);
 
    TRACE("Vol=%d Pan=%d\n", volpan->lVolume, volpan->lPan);
    /* the AmpFactors are expressed in 16.16 fixed point */
    volpan->dwVolAmpFactor = (ULONG) (pow(2.0, volpan->lVolume / 600.0) * 0xffff);
    /* FIXME: dwPan{Left|Right}AmpFactor */
 
    /* FIXME: use calculated vol and pan ampfactors */
    temp = (double) (volpan->lVolume - (volpan->lPan > 0 ? volpan->lPan : 0));
    volpan->dwTotalLeftAmpFactor = (ULONG) (pow(2.0, temp / 600.0) * 0xffff);
    temp = (double) (volpan->lVolume + (volpan->lPan < 0 ? volpan->lPan : 0));
    volpan->dwTotalRightAmpFactor = (ULONG) (pow(2.0, temp / 600.0) * 0xffff);
 
    TRACE("left = %x, right = %x\n", volpan->dwTotalLeftAmpFactor, volpan->dwTotalRightAmpFactor);
}
 
void DSOUND_AmpFactorToVolPan(PDSVOLUMEPAN volpan)
{
    double left,right;
    TRACE("(%p)\n",volpan);
 
    TRACE("left=%x, right=%x\n",volpan->dwTotalLeftAmpFactor,volpan->dwTotalRightAmpFactor);
    if (volpan->dwTotalLeftAmpFactor==0)
        left=-10000;
    else
        left=600 * log(((double)volpan->dwTotalLeftAmpFactor) / 0xffff) / log(2);
    if (volpan->dwTotalRightAmpFactor==0)
        right=-10000;
    else
        right=600 * log(((double)volpan->dwTotalRightAmpFactor) / 0xffff) / log(2);
    if (left<right)
    {
        volpan->lVolume=right;
        volpan->dwVolAmpFactor=volpan->dwTotalRightAmpFactor;
    }
    else
    {
        volpan->lVolume=left;
        volpan->dwVolAmpFactor=volpan->dwTotalLeftAmpFactor;
    }
    if (volpan->lVolume < -10000)
        volpan->lVolume=-10000;
    volpan->lPan=right-left;
    if (volpan->lPan < -10000)
        volpan->lPan=-10000;
 
    TRACE("Vol=%d Pan=%d\n", volpan->lVolume, volpan->lPan);
}
 
DWORD DSOUND_bufpos_to_mixpos(const DirectSoundDevice* device, DWORD pos)
{
    DWORD ret = pos * 32 / device->pwfx->wBitsPerSample;
    if (device->pwfx->wBitsPerSample == 32)
        ret *= 2;
    return ret;
}
 
/* NOTE: Not all secpos have to always be mapped to a bufpos, other way around is always the case
 * DWORD64 is used here because a single DWORD wouldn't be big enough to fit the freqAcc for big buffers
 */
DWORD DSOUND_secpos_to_bufpos(const IDirectSoundBufferImpl *dsb, DWORD secpos, DWORD secmixpos, DWORD* overshot)
{
    DWORD64 framelen = secpos / dsb->pwfx->nBlockAlign;
    DWORD64 freqAdjust = dsb->freqAdjust;
    DWORD64 acc, freqAcc;
 
    if (secpos < secmixpos)
        freqAcc = dsb->freqAccNext;
    else freqAcc = dsb->freqAcc;
    acc = (framelen << DSOUND_FREQSHIFT) + (freqAdjust - 1 - freqAcc);
    acc /= freqAdjust;
    if (overshot)
    {
        DWORD64 oshot = acc * freqAdjust + freqAcc;
        assert(oshot >= framelen << DSOUND_FREQSHIFT);
        oshot -= framelen << DSOUND_FREQSHIFT;
        *overshot = (DWORD)oshot;
        assert(*overshot < dsb->freqAdjust);
    }
    return (DWORD)acc * dsb->device->pwfx->nBlockAlign;
}
 
static DWORD DSOUND_bufpos_to_secpos(const IDirectSoundBufferImpl *dsb, DWORD bufpos)
{
    DWORD oAdv = dsb->device->pwfx->nBlockAlign, iAdv = dsb->pwfx->nBlockAlign, pos;
    DWORD64 framelen;
    DWORD64 acc;
 
    framelen = bufpos/oAdv;
    acc = framelen * (DWORD64)dsb->freqAdjust + (DWORD64)dsb->freqAccNext;
    acc = acc >> DSOUND_FREQSHIFT;
    pos = (DWORD)acc * iAdv;
    if (pos >= dsb->buflen)
        /* Because of differences between freqAcc and freqAccNext, this might happen */
        pos = dsb->buflen - iAdv;
    TRACE("Converted %d/%d to %d/%d\n", bufpos, dsb->tmp_buffer_len, pos, dsb->buflen);
    return pos;
}
 
static void DSOUND_RecalcFreqAcc(IDirectSoundBufferImpl *dsb)
{
    if (!dsb->freqneeded) return;
    dsb->freqAcc = dsb->freqAccNext;
    dsb->tmp_buffer_len = DSOUND_secpos_to_bufpos(dsb, dsb->buflen, 0, &dsb->freqAccNext);
    TRACE("New freqadjust: %04x, new buflen: %d\n", dsb->freqAccNext, dsb->tmp_buffer_len);
}
 
void DSOUND_RecalcFormat(IDirectSoundBufferImpl *dsb)
{
    BOOL needremix = TRUE, needresample = (dsb->freq != dsb->device->pwfx->nSamplesPerSec);
    DWORD bAlign = dsb->pwfx->nBlockAlign, pAlign = dsb->device->pwfx->nBlockAlign;
    WAVEFORMATEXTENSIBLE *pwfxe;
    BOOL ieee = FALSE;
 
    TRACE("(%p)\n",dsb);
 
    pwfxe = (WAVEFORMATEXTENSIBLE *) dsb->pwfx;
 
    if ((pwfxe->Format.wFormatTag == WAVE_FORMAT_IEEE_FLOAT) || ((pwfxe->Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE)
        && (IsEqualGUID(&pwfxe->SubFormat, &KSDATAFORMAT_SUBTYPE_IEEE_FLOAT))))
        ieee = TRUE;
 
    /* calculate the 10ms write lead */
    dsb->writelead = (dsb->freq / 100) * dsb->pwfx->nBlockAlign;
 
    if ((dsb->pwfx->wBitsPerSample == dsb->device->pwfx->wBitsPerSample) &&
        (dsb->pwfx->nChannels == dsb->device->pwfx->nChannels) && !needresample && !ieee)
        needremix = FALSE;
    HeapFree(GetProcessHeap(), 0, dsb->tmp_buffer);
    dsb->tmp_buffer = NULL;
    dsb->max_buffer_len = dsb->freqAcc = dsb->freqAccNext = 0;
    dsb->freqneeded = needresample;
 
    if (ieee)
        dsb->convert = convertbpp[4][dsb->device->pwfx->wBitsPerSample/8 - 1];
    else
        dsb->convert = convertbpp[dsb->pwfx->wBitsPerSample/8 - 1][dsb->device->pwfx->wBitsPerSample/8 - 1];
 
    dsb->resampleinmixer = FALSE;
 
    if (needremix)
    {
        if (needresample)
            DSOUND_RecalcFreqAcc(dsb);
        else
            dsb->tmp_buffer_len = dsb->buflen / bAlign * pAlign;
        dsb->max_buffer_len = dsb->tmp_buffer_len;
        if ((dsb->max_buffer_len <= dsb->device->buflen || dsb->max_buffer_len < ds_snd_shadow_maxsize * 1024 * 1024) && ds_snd_shadow_maxsize >= 0)
            dsb->tmp_buffer = HeapAlloc(GetProcessHeap(), 0, dsb->max_buffer_len);
        if (dsb->tmp_buffer)
            FillMemory(dsb->tmp_buffer, dsb->tmp_buffer_len, dsb->device->pwfx->wBitsPerSample == 8 ? 128 : 0);
        else
            dsb->resampleinmixer = TRUE;
    }
    else dsb->max_buffer_len = dsb->tmp_buffer_len = dsb->buflen;
    dsb->buf_mixpos = DSOUND_secpos_to_bufpos(dsb, dsb->sec_mixpos, 0, NULL);
}
 
void DSOUND_CheckEvent(const IDirectSoundBufferImpl *dsb, DWORD playpos, int len)
{
    int         i;
    DWORD           offset;
    LPDSBPOSITIONNOTIFY event;
    TRACE("(%p,%d)\n",dsb,len);
 
    if (dsb->nrofnotifies == 0)
        return;
 
    TRACE("(%p) buflen = %d, playpos = %d, len = %d\n",
        dsb, dsb->buflen, playpos, len);
    for (i = 0; i < dsb->nrofnotifies ; i++) {
        event = dsb->notifies + i;
        offset = event->dwOffset;
        TRACE("checking %d, position %d, event = %p\n",
            i, offset, event->hEventNotify);
        /* DSBPN_OFFSETSTOP has to be the last element. So this is */
        /* OK. [Inside DirectX, p274] */
        /* Windows does not seem to enforce this, and some apps rely */
        /* on that, so we can't stop there. */
        /*  */
        /* This also means we can't sort the entries by offset, */
        /* because DSBPN_OFFSETSTOP == -1 */
        if (offset == DSBPN_OFFSETSTOP) {
            if (dsb->state == STATE_STOPPED) {
                SetEvent(event->hEventNotify);
                TRACE("signalled event %p (%d)\n", event->hEventNotify, i);
            }
                        continue;
        }
        if ((playpos + len) >= dsb->buflen) {
            if ((offset < ((playpos + len) % dsb->buflen)) ||
                (offset >= playpos)) {
                TRACE("signalled event %p (%d)\n", event->hEventNotify, i);
                SetEvent(event->hEventNotify);
            }
        } else {
            if ((offset >= playpos) && (offset < (playpos + len))) {
                TRACE("signalled event %p (%d)\n", event->hEventNotify, i);
                SetEvent(event->hEventNotify);
            }
        }
    }
}
 
static inline void cp_fields(const IDirectSoundBufferImpl *dsb, const BYTE *ibuf, BYTE *obuf,
        UINT istride, UINT ostride, UINT count, UINT freqAcc, UINT adj)
{
    DirectSoundDevice *device = dsb->device;
    INT istep = dsb->pwfx->wBitsPerSample / 8, ostep = device->pwfx->wBitsPerSample / 8;
 
    if (device->pwfx->nChannels == dsb->pwfx->nChannels ||
        (device->pwfx->nChannels == 2 && dsb->pwfx->nChannels == 6) ||
        (device->pwfx->nChannels == 8 && dsb->pwfx->nChannels == 2) ||
        (device->pwfx->nChannels == 6 && dsb->pwfx->nChannels == 2)) {
        dsb->convert(ibuf, obuf, istride, ostride, count, freqAcc, adj);
        if (device->pwfx->nChannels == 2 || dsb->pwfx->nChannels == 2)
            dsb->convert(ibuf + istep, obuf + ostep, istride, ostride, count, freqAcc, adj);
        return;
    }
 
    if (device->pwfx->nChannels == 1 && dsb->pwfx->nChannels == 2)
    {
        dsb->convert(ibuf, obuf, istride, ostride, count, freqAcc, adj);
        return;
    }
 
    if (device->pwfx->nChannels == 2 && dsb->pwfx->nChannels == 1)
    {
        dsb->convert(ibuf, obuf, istride, ostride, count, freqAcc, adj);
        dsb->convert(ibuf, obuf + ostep, istride, ostride, count, freqAcc, adj);
        return;
    }
 
    WARN("Unable to remap channels: device=%u, buffer=%u\n", device->pwfx->nChannels,
            dsb->pwfx->nChannels);
}
 
static inline DWORD DSOUND_BufPtrDiff(DWORD buflen, DWORD ptr1, DWORD ptr2)
{
/* If these asserts fail, the problem is not here, but in the underlying code */
    assert(ptr1 < buflen);
    assert(ptr2 < buflen);
    if (ptr1 >= ptr2) {
        return ptr1 - ptr2;
    } else {
        return buflen + ptr1 - ptr2;
    }
}
void DSOUND_MixToTemporary(const IDirectSoundBufferImpl *dsb, DWORD writepos, DWORD len, BOOL inmixer)
{
    INT size;
    BYTE    *ibp, *obp, *obp_begin;
    INT iAdvance = dsb->pwfx->nBlockAlign;
    INT oAdvance = dsb->device->pwfx->nBlockAlign;
    DWORD freqAcc, target_writepos = 0, overshot, maxlen;
 
    /* We resample only when needed */
    if ((dsb->tmp_buffer && inmixer) || (!dsb->tmp_buffer && !inmixer) || dsb->resampleinmixer != inmixer)
        return;
 
    assert(writepos + len <= dsb->buflen);
    if (inmixer && writepos + len < dsb->buflen)
        len += dsb->pwfx->nBlockAlign;
 
    maxlen = DSOUND_secpos_to_bufpos(dsb, len, 0, NULL);
 
    ibp = dsb->buffer->memory + writepos;
    if (!inmixer)
        obp_begin = dsb->tmp_buffer;
    else if (dsb->device->tmp_buffer_len < maxlen || !dsb->device->tmp_buffer)
    {
        dsb->device->tmp_buffer_len = maxlen;
        if (dsb->device->tmp_buffer)
            dsb->device->tmp_buffer = HeapReAlloc(GetProcessHeap(), 0, dsb->device->tmp_buffer, maxlen);
        else
            dsb->device->tmp_buffer = HeapAlloc(GetProcessHeap(), 0, maxlen);
        obp_begin = dsb->device->tmp_buffer;
    }
    else
        obp_begin = dsb->device->tmp_buffer;
 
    TRACE("(%p, %p)\n", dsb, ibp);
    size = len / iAdvance;
 
    /* Check for same sample rate */
    if (dsb->freq == dsb->device->pwfx->nSamplesPerSec) {
        TRACE("(%p) Same sample rate %d = primary %d\n", dsb,
            dsb->freq, dsb->device->pwfx->nSamplesPerSec);
        obp = obp_begin;
        if (!inmixer)
             obp += writepos/iAdvance*oAdvance;
 
        cp_fields(dsb, ibp, obp, iAdvance, oAdvance, size, 0, 1 << DSOUND_FREQSHIFT);
        return;
    }
 
    /* Mix in different sample rates */
    TRACE("(%p) Adjusting frequency: %d -> %d\n", dsb, dsb->freq, dsb->device->pwfx->nSamplesPerSec);
 
    target_writepos = DSOUND_secpos_to_bufpos(dsb, writepos, dsb->sec_mixpos, &freqAcc);
    overshot = freqAcc >> DSOUND_FREQSHIFT;
    if (overshot)
    {
        if (overshot >= size)
            return;
        size -= overshot;
        writepos += overshot * iAdvance;
        if (writepos >= dsb->buflen)
            return;
        ibp = dsb->buffer->memory + writepos;
        freqAcc &= (1 << DSOUND_FREQSHIFT) - 1;
        TRACE("Overshot: %d, freqAcc: %04x\n", overshot, freqAcc);
    }
 
    if (!inmixer)
        obp = obp_begin + target_writepos;
    else obp = obp_begin;
 
    /* FIXME: Small problem here when we're overwriting buf_mixpos, it then STILL uses old freqAcc, not sure if it matters or not */
    cp_fields(dsb, ibp, obp, iAdvance, oAdvance, size, freqAcc, dsb->freqAdjust);
}
 
static LPBYTE DSOUND_MixerVol(const IDirectSoundBufferImpl *dsb, INT len)
{
    INT i;
    BYTE    *bpc;
    INT16   *bps, *mems;
    DWORD vLeft, vRight;
    INT nChannels = dsb->device->pwfx->nChannels;
    LPBYTE mem = (dsb->tmp_buffer ? dsb->tmp_buffer : dsb->buffer->memory) + dsb->buf_mixpos;
 
    if (dsb->resampleinmixer)
        mem = dsb->device->tmp_buffer;
 
    TRACE("(%p,%d)\n",dsb,len);
    TRACE("left = %x, right = %x\n", dsb->volpan.dwTotalLeftAmpFactor,
        dsb->volpan.dwTotalRightAmpFactor);
 
    if ((!(dsb->dsbd.dwFlags & DSBCAPS_CTRLPAN) || (dsb->volpan.lPan == 0)) &&
        (!(dsb->dsbd.dwFlags & DSBCAPS_CTRLVOLUME) || (dsb->volpan.lVolume == 0)) &&
         !(dsb->dsbd.dwFlags & DSBCAPS_CTRL3D))
        return NULL; /* Nothing to do */
 
    if (nChannels != 1 && nChannels != 2)
    {
        FIXME("There is no support for %d channels\n", nChannels);
        return NULL;
    }
 
    if (dsb->device->pwfx->wBitsPerSample != 8 && dsb->device->pwfx->wBitsPerSample != 16)
    {
        FIXME("There is no support for %d bpp\n", dsb->device->pwfx->wBitsPerSample);
        return NULL;
    }
 
    if (dsb->device->tmp_buffer_len < len || !dsb->device->tmp_buffer)
    {
        /* If we just resampled in DSOUND_MixToTemporary, we shouldn't need to resize here */
        assert(!dsb->resampleinmixer);
        dsb->device->tmp_buffer_len = len;
        if (dsb->device->tmp_buffer)
            dsb->device->tmp_buffer = HeapReAlloc(GetProcessHeap(), 0, dsb->device->tmp_buffer, len);
        else
            dsb->device->tmp_buffer = HeapAlloc(GetProcessHeap(), 0, len);
    }
 
    bpc = dsb->device->tmp_buffer;
    bps = (INT16 *)bpc;
    mems = (INT16 *)mem;
    vLeft = dsb->volpan.dwTotalLeftAmpFactor;
    if (nChannels > 1)
        vRight = dsb->volpan.dwTotalRightAmpFactor;
    else
        vRight = vLeft;
 
    switch (dsb->device->pwfx->wBitsPerSample) {
    case 8:
        /* 8-bit WAV is unsigned, but we need to operate */
        /* on signed data for this to work properly */
        for (i = 0; i < len-1; i+=2) {
            *(bpc++) = (((*(mem++) - 128) * vLeft) >> 16) + 128;
            *(bpc++) = (((*(mem++) - 128) * vRight) >> 16) + 128;
        }
        if (len % 2 == 1 && nChannels == 1)
            *(bpc++) = (((*(mem++) - 128) * vLeft) >> 16) + 128;
        break;
    case 16:
        /* 16-bit WAV is signed -- much better */
        for (i = 0; i < len-3; i += 4) {
            *(bps++) = (*(mems++) * vLeft) >> 16;
            *(bps++) = (*(mems++) * vRight) >> 16;
        }
        if (len % 4 == 2 && nChannels == 1)
            *(bps++) = ((INT)*(mems++) * vLeft) >> 16;
        break;
    }
    return dsb->device->tmp_buffer;
}
 
static DWORD DSOUND_MixInBuffer(IDirectSoundBufferImpl *dsb, DWORD writepos, DWORD fraglen)
{
    INT len = fraglen, ilen;
    BYTE *ibuf = (dsb->tmp_buffer ? dsb->tmp_buffer : dsb->buffer->memory) + dsb->buf_mixpos, *volbuf;
    DWORD oldpos, mixbufpos;
 
    TRACE("buf_mixpos=%d/%d sec_mixpos=%d/%d\n", dsb->buf_mixpos, dsb->tmp_buffer_len, dsb->sec_mixpos, dsb->buflen);
    TRACE("(%p,%d,%d)\n",dsb,writepos,fraglen);
 
    assert(dsb->buf_mixpos + len <= dsb->tmp_buffer_len);
 
    if (len % dsb->device->pwfx->nBlockAlign) {
        INT nBlockAlign = dsb->device->pwfx->nBlockAlign;
        ERR("length not a multiple of block size, len = %d, block size = %d\n", len, nBlockAlign);
        len -= len % nBlockAlign; /* data alignment */
    }
 
    /* Resample buffer to temporary buffer specifically allocated for this purpose, if needed */
    DSOUND_MixToTemporary(dsb, dsb->sec_mixpos, DSOUND_bufpos_to_secpos(dsb, dsb->buf_mixpos+len) - dsb->sec_mixpos, TRUE);
    if (dsb->resampleinmixer)
        ibuf = dsb->device->tmp_buffer;
 
    /* Apply volume if needed */
    volbuf = DSOUND_MixerVol(dsb, len);
    if (volbuf)
        ibuf = volbuf;
 
    mixbufpos = DSOUND_bufpos_to_mixpos(dsb->device, writepos);
    /* Now mix the temporary buffer into the devices main buffer */
    if ((writepos + len) <= dsb->device->buflen)
        dsb->device->mixfunction(ibuf, dsb->device->mix_buffer + mixbufpos, len);
    else
    {
        DWORD todo = dsb->device->buflen - writepos;
        dsb->device->mixfunction(ibuf, dsb->device->mix_buffer + mixbufpos, todo);
        dsb->device->mixfunction(ibuf + todo, dsb->device->mix_buffer, len - todo);
    }
 
    oldpos = dsb->sec_mixpos;
    dsb->buf_mixpos += len;
 
    if (dsb->buf_mixpos >= dsb->tmp_buffer_len) {
        if (dsb->buf_mixpos > dsb->tmp_buffer_len)
            ERR("Mixpos (%u) past buflen (%u), capping...\n", dsb->buf_mixpos, dsb->tmp_buffer_len);
        if (dsb->playflags & DSBPLAY_LOOPING) {
            dsb->buf_mixpos -= dsb->tmp_buffer_len;
        } else if (dsb->buf_mixpos >= dsb->tmp_buffer_len) {
            dsb->buf_mixpos = dsb->sec_mixpos = 0;
            dsb->state = STATE_STOPPED;
        }
        DSOUND_RecalcFreqAcc(dsb);
    }
 
    dsb->sec_mixpos = DSOUND_bufpos_to_secpos(dsb, dsb->buf_mixpos);
    ilen = DSOUND_BufPtrDiff(dsb->buflen, dsb->sec_mixpos, oldpos);
    /* check for notification positions */
    if (dsb->dsbd.dwFlags & DSBCAPS_CTRLPOSITIONNOTIFY &&
        dsb->state != STATE_STARTING) {
        DSOUND_CheckEvent(dsb, oldpos, ilen);
    }
 
    /* increase mix position */
    dsb->primary_mixpos += len;
    if (dsb->primary_mixpos >= dsb->device->buflen)
        dsb->primary_mixpos -= dsb->device->buflen;
    return len;
}
 
static DWORD DSOUND_MixOne(IDirectSoundBufferImpl *dsb, DWORD writepos, DWORD mixlen)
{
    /* The buffer's primary_mixpos may be before or after the device
     * buffer's mixpos, but both must be ahead of writepos. */
    DWORD primary_done;
 
    TRACE("(%p,%d,%d)\n",dsb,writepos,mixlen);
    TRACE("writepos=%d, buf_mixpos=%d, primary_mixpos=%d, mixlen=%d\n", writepos, dsb->buf_mixpos, dsb->primary_mixpos, mixlen);
    TRACE("looping=%d, leadin=%d, buflen=%d\n", dsb->playflags, dsb->leadin, dsb->tmp_buffer_len);
 
    /* If leading in, only mix about 20 ms, and 'skip' mixing the rest, for more fluid pointer advancement */
    if (dsb->leadin && dsb->state == STATE_STARTING)
    {
        if (mixlen > 2 * dsb->device->fraglen)
        {
            dsb->primary_mixpos += mixlen - 2 * dsb->device->fraglen;
            dsb->primary_mixpos %= dsb->device->buflen;
        }
    }
    dsb->leadin = FALSE;
 
    /* calculate how much pre-buffering has already been done for this buffer */
    primary_done = DSOUND_BufPtrDiff(dsb->device->buflen, dsb->primary_mixpos, writepos);
 
    /* sanity */
    if(mixlen < primary_done)
    {
        /* Should *NEVER* happen */
        ERR("Fatal error. Under/Overflow? primary_done=%d, mixpos=%d/%d (%d/%d), primary_mixpos=%d, writepos=%d, mixlen=%d\n", primary_done,dsb->buf_mixpos,dsb->tmp_buffer_len,dsb->sec_mixpos, dsb->buflen, dsb->primary_mixpos, writepos, mixlen);
        dsb->primary_mixpos = writepos + mixlen;
        dsb->primary_mixpos %= dsb->device->buflen;
        return mixlen;
    }
 
    /* take into account already mixed data */
    mixlen -= primary_done;
 
    TRACE("primary_done=%d, mixlen (primary) = %i\n", primary_done, mixlen);
 
    if (!mixlen)
        return primary_done;
 
    /* First try to mix to the end of the buffer if possible
     * Theoretically it would allow for better optimization
    */
    if (mixlen + dsb->buf_mixpos >= dsb->tmp_buffer_len)
    {
        DWORD newmixed, mixfirst = dsb->tmp_buffer_len - dsb->buf_mixpos;
        newmixed = DSOUND_MixInBuffer(dsb, dsb->primary_mixpos, mixfirst);
        mixlen -= newmixed;
 
        if (dsb->playflags & DSBPLAY_LOOPING)
            while (newmixed && mixlen)
            {
                mixfirst = (dsb->tmp_buffer_len < mixlen ? dsb->tmp_buffer_len : mixlen);
                newmixed = DSOUND_MixInBuffer(dsb, dsb->primary_mixpos, mixfirst);
                mixlen -= newmixed;
            }
    }
    else DSOUND_MixInBuffer(dsb, dsb->primary_mixpos, mixlen);
 
    /* re-calculate the primary done */
    primary_done = DSOUND_BufPtrDiff(dsb->device->buflen, dsb->primary_mixpos, writepos);
 
    TRACE("new primary_mixpos=%d, total mixed data=%d\n", dsb->primary_mixpos, primary_done);
 
    /* Report back the total prebuffered amount for this buffer */
    return primary_done;
}
 
static DWORD DSOUND_MixToPrimary(const DirectSoundDevice *device, DWORD writepos, DWORD mixlen, BOOL recover, BOOL *all_stopped)
{
    INT i, len;
    DWORD minlen = 0;
    IDirectSoundBufferImpl  *dsb;
 
    /* unless we find a running buffer, all have stopped */
    *all_stopped = TRUE;
 
    TRACE("(%d,%d,%d)\n", writepos, mixlen, recover);
    for (i = 0; i < device->nrofbuffers; i++) {
        dsb = device->buffers[i];
 
        TRACE("MixToPrimary for %p, state=%d\n", dsb, dsb->state);
 
        if (dsb->buflen && dsb->state && !dsb->hwbuf) {
            TRACE("Checking %p, mixlen=%d\n", dsb, mixlen);
            RtlAcquireResourceShared(&dsb->lock, TRUE);
            /* if buffer is stopping it is stopped now */
            if (dsb->state == STATE_STOPPING) {
                dsb->state = STATE_STOPPED;
                DSOUND_CheckEvent(dsb, 0, 0);
            } else if (dsb->state != STATE_STOPPED) {
 
                /* if recovering, reset the mix position */
                if ((dsb->state == STATE_STARTING) || recover) {
                    dsb->primary_mixpos = writepos;
                }
 
                /* if the buffer was starting, it must be playing now */
                if (dsb->state == STATE_STARTING)
                    dsb->state = STATE_PLAYING;
 
                /* mix next buffer into the main buffer */
                len = DSOUND_MixOne(dsb, writepos, mixlen);
 
                if (!minlen) minlen = len;
 
                /* record the minimum length mixed from all buffers */
                /* we only want to return the length which *all* buffers have mixed */
                else if (len) minlen = (len < minlen) ? len : minlen;
 
                *all_stopped = FALSE;
            }
            RtlReleaseResource(&dsb->lock);
        }
    }
 
    TRACE("Mixed at least %d from all buffers\n", minlen);
    return minlen;
}
 
static void DSOUND_WaveQueue(DirectSoundDevice *device, BOOL force)
{
    DWORD prebuf_frags, wave_writepos, wave_fragpos, i;
    TRACE("(%p)\n", device);
 
    /* calculate the current wave frag position */
    wave_fragpos = (device->pwplay + device->pwqueue) % device->helfrags;
 
    /* calculate the current wave write position */
    wave_writepos = wave_fragpos * device->fraglen;
 
    TRACE("wave_fragpos = %i, wave_writepos = %i, pwqueue = %i, prebuf = %i\n",
        wave_fragpos, wave_writepos, device->pwqueue, device->prebuf);
 
    if (!force)
    {
        /* check remaining prebuffered frags */
        prebuf_frags = device->mixpos / device->fraglen;
        if (prebuf_frags == device->helfrags)
            --prebuf_frags;
        TRACE("wave_fragpos = %d, mixpos_frags = %d\n", wave_fragpos, prebuf_frags);
        if (prebuf_frags < wave_fragpos)
            prebuf_frags += device->helfrags;
        prebuf_frags -= wave_fragpos;
        TRACE("wanted prebuf_frags = %d\n", prebuf_frags);
    }
    else
        /* buffer the maximum amount of frags */
        prebuf_frags = device->prebuf;
 
    /* limit to the queue we have left */
    if ((prebuf_frags + device->pwqueue) > device->prebuf)
        prebuf_frags = device->prebuf - device->pwqueue;
 
    TRACE("prebuf_frags = %i\n", prebuf_frags);
 
    /* adjust queue */
    device->pwqueue += prebuf_frags;
 
    /* get out of CS when calling the wave system */
    LeaveCriticalSection(&(device->mixlock));
    /* **** */
 
    /* queue up the new buffers */
    for(i=0; i<prebuf_frags; i++){
        TRACE("queueing wave buffer %i\n", wave_fragpos);
        waveOutWrite(device->hwo, &device->pwave[wave_fragpos], sizeof(WAVEHDR));
        wave_fragpos++;
        wave_fragpos %= device->helfrags;
    }
 
    /* **** */
    EnterCriticalSection(&(device->mixlock));
 
    TRACE("queue now = %i\n", device->pwqueue);
}
 
static void DSOUND_PerformMix(DirectSoundDevice *device)
{
    TRACE("(%p)\n", device);
 
    /* **** */
    EnterCriticalSection(&(device->mixlock));
 
    if (device->priolevel != DSSCL_WRITEPRIMARY) {
        BOOL recover = FALSE, all_stopped = FALSE;
        DWORD playpos, writepos, writelead, maxq, frag, prebuff_max, prebuff_left, size1, size2, mixplaypos, mixplaypos2;
        LPVOID buf1, buf2;
        BOOL lock = (device->hwbuf && !(device->drvdesc.dwFlags & DSDDESC_DONTNEEDPRIMARYLOCK));
        int nfiller;
 
        /* the sound of silence */
        nfiller = device->pwfx->wBitsPerSample == 8 ? 128 : 0;
 
        /* get the position in the primary buffer */
        if (DSOUND_PrimaryGetPosition(device, &playpos, &writepos) != 0){
            LeaveCriticalSection(&(device->mixlock));
            return;
        }
 
        TRACE("primary playpos=%d, writepos=%d, clrpos=%d, mixpos=%d, buflen=%d\n",
              playpos,writepos,device->playpos,device->mixpos,device->buflen);
        assert(device->playpos < device->buflen);
 
        mixplaypos = DSOUND_bufpos_to_mixpos(device, device->playpos);
        mixplaypos2 = DSOUND_bufpos_to_mixpos(device, playpos);
 
        /* calc maximum prebuff */
        prebuff_max = (device->prebuf * device->fraglen);
        if (!device->hwbuf && playpos + prebuff_max >= device->helfrags * device->fraglen)
            prebuff_max += device->buflen - device->helfrags * device->fraglen;
 
        /* check how close we are to an underrun. It occurs when the writepos overtakes the mixpos */
        prebuff_left = DSOUND_BufPtrDiff(device->buflen, device->mixpos, playpos);
        writelead = DSOUND_BufPtrDiff(device->buflen, writepos, playpos);
 
        /* check for underrun. underrun occurs when the write position passes the mix position
         * also wipe out just-played sound data */
        if((prebuff_left > prebuff_max) || (device->state == STATE_STOPPED) || (device->state == STATE_STARTING)){
            if (device->state == STATE_STOPPING || device->state == STATE_PLAYING)
                WARN("Probable buffer underrun\n");
            else TRACE("Buffer starting or buffer underrun\n");
 
            /* recover mixing for all buffers */
            recover = TRUE;
 
            /* reset mix position to write position */
            device->mixpos = writepos;
 
            ZeroMemory(device->mix_buffer, device->mix_buffer_len);
            ZeroMemory(device->buffer, device->buflen);
        } else if (playpos < device->playpos) {
            buf1 = device->buffer + device->playpos;
            buf2 = device->buffer;
            size1 = device->buflen - device->playpos;
            size2 = playpos;
            FillMemory(device->mix_buffer + mixplaypos, device->mix_buffer_len - mixplaypos, 0);
            FillMemory(device->mix_buffer, mixplaypos2, 0);
            if (lock)
                IDsDriverBuffer_Lock(device->hwbuf, &buf1, &size1, &buf2, &size2, device->playpos, size1+size2, 0);
            FillMemory(buf1, size1, nfiller);
            if (playpos && (!buf2 || !size2))
                FIXME("%d: (%d, %d)=>(%d, %d) There should be an additional buffer here!!\n", __LINE__, device->playpos, device->mixpos, playpos, writepos);
            FillMemory(buf2, size2, nfiller);
            if (lock)
                IDsDriverBuffer_Unlock(device->hwbuf, buf1, size1, buf2, size2);
        } else {
            buf1 = device->buffer + device->playpos;
            buf2 = NULL;
            size1 = playpos - device->playpos;
            size2 = 0;
            FillMemory(device->mix_buffer + mixplaypos, mixplaypos2 - mixplaypos, 0);
            if (lock)
                IDsDriverBuffer_Lock(device->hwbuf, &buf1, &size1, &buf2, &size2, device->playpos, size1+size2, 0);
            FillMemory(buf1, size1, nfiller);
            if (buf2 && size2)
            {
                FIXME("%d: There should be no additional buffer here!!\n", __LINE__);
                FillMemory(buf2, size2, nfiller);
            }
            if (lock)
                IDsDriverBuffer_Unlock(device->hwbuf, buf1, size1, buf2, size2);
        }
        device->playpos = playpos;
 
        /* find the maximum we can prebuffer from current write position */
        maxq = (writelead < prebuff_max) ? (prebuff_max - writelead) : 0;
 
        TRACE("prebuff_left = %d, prebuff_max = %dx%d=%d, writelead=%d\n",
            prebuff_left, device->prebuf, device->fraglen, prebuff_max, writelead);
 
        if (lock)
            IDsDriverBuffer_Lock(device->hwbuf, &buf1, &size1, &buf2, &size2, writepos, maxq, 0);
 
        /* do the mixing */
        frag = DSOUND_MixToPrimary(device, writepos, maxq, recover, &all_stopped);
 
        if (frag + writepos > device->buflen)
        {
            DWORD todo = device->buflen - writepos;
            device->normfunction(device->mix_buffer + DSOUND_bufpos_to_mixpos(device, writepos), device->buffer + writepos, todo);
            device->normfunction(device->mix_buffer, device->buffer, frag - todo);
        }
        else
            device->normfunction(device->mix_buffer + DSOUND_bufpos_to_mixpos(device, writepos), device->buffer + writepos, frag);
 
        /* update the mix position, taking wrap-around into account */
        device->mixpos = writepos + frag;
        device->mixpos %= device->buflen;
 
        if (lock)
        {
            DWORD frag2 = (frag > size1 ? frag - size1 : 0);
            frag -= frag2;
            if (frag2 > size2)
            {
                FIXME("Buffering too much! (%d, %d, %d, %d)\n", maxq, frag, size2, frag2 - size2);
                frag2 = size2;
            }
            IDsDriverBuffer_Unlock(device->hwbuf, buf1, frag, buf2, frag2);
        }
 
        /* update prebuff left */
        prebuff_left = DSOUND_BufPtrDiff(device->buflen, device->mixpos, playpos);
 
        /* check if have a whole fragment */
        if (prebuff_left >= device->fraglen){
 
            /* update the wave queue if using wave system */
            if (!device->hwbuf)
                DSOUND_WaveQueue(device, FALSE);
 
            /* buffers are full. start playing if applicable */
            if(device->state == STATE_STARTING){
                TRACE("started primary buffer\n");
                if(DSOUND_PrimaryPlay(device) != DS_OK){
                    WARN("DSOUND_PrimaryPlay failed\n");
                }
                else{
                    /* we are playing now */
                    device->state = STATE_PLAYING;
                }
            }
 
            /* buffers are full. start stopping if applicable */
            if(device->state == STATE_STOPPED){
                TRACE("restarting primary buffer\n");
                if(DSOUND_PrimaryPlay(device) != DS_OK){
                    WARN("DSOUND_PrimaryPlay failed\n");
                }
                else{
                    /* start stopping again. as soon as there is no more data, it will stop */
                    device->state = STATE_STOPPING;
                }
            }
        }
 
        /* if device was stopping, its for sure stopped when all buffers have stopped */
        else if((all_stopped != FALSE) && (device->state == STATE_STOPPING)){
            TRACE("All buffers have stopped. Stopping primary buffer\n");
            device->state = STATE_STOPPED;
 
            /* stop the primary buffer now */
            DSOUND_PrimaryStop(device);
        }
 
    } else {
 
        /* update the wave queue if using wave system */
        if (!device->hwbuf)
            DSOUND_WaveQueue(device, TRUE);
        else
            /* Keep alsa happy, which needs GetPosition called once every 10 ms */
            IDsDriverBuffer_GetPosition(device->hwbuf, NULL, NULL);
 
        /* in the DSSCL_WRITEPRIMARY mode, the app is totally in charge... */
        if (device->state == STATE_STARTING) {
            if (DSOUND_PrimaryPlay(device) != DS_OK)
                WARN("DSOUND_PrimaryPlay failed\n");
            else
                device->state = STATE_PLAYING;
        }
        else if (device->state == STATE_STOPPING) {
            if (DSOUND_PrimaryStop(device) != DS_OK)
                WARN("DSOUND_PrimaryStop failed\n");
            else
                device->state = STATE_STOPPED;
        }
    }
 
    LeaveCriticalSection(&(device->mixlock));
    /* **** */
}
 
void CALLBACK DSOUND_timer(UINT timerID, UINT msg, DWORD_PTR dwUser,
                           DWORD_PTR dw1, DWORD_PTR dw2)
{
    DirectSoundDevice * device = (DirectSoundDevice*)dwUser;
    DWORD start_time =  GetTickCount();
    DWORD end_time;
    TRACE("(%d,%d,0x%lx,0x%lx,0x%lx)\n",timerID,msg,dwUser,dw1,dw2);
    TRACE("entering at %d\n", start_time);
 
    if (DSOUND_renderer[device->drvdesc.dnDevNode] != device) {
        ERR("dsound died without killing us?\n");
        timeKillEvent(timerID);
        timeEndPeriod(DS_TIME_RES);
        return;
    }
 
    RtlAcquireResourceShared(&(device->buffer_list_lock), TRUE);
 
    if (device->ref)
        DSOUND_PerformMix(device);
 
    RtlReleaseResource(&(device->buffer_list_lock));
 
    end_time = GetTickCount();
    TRACE("completed processing at %d, duration = %d\n", end_time, end_time - start_time);
}
 
void CALLBACK DSOUND_callback(HWAVEOUT hwo, UINT msg, DWORD_PTR dwUser, DWORD_PTR dw1, DWORD_PTR dw2)
{
    DirectSoundDevice * device = (DirectSoundDevice*)dwUser;
    TRACE("(%p,%x,%lx,%lx,%lx)\n",hwo,msg,dwUser,dw1,dw2);
    TRACE("entering at %d, msg=%08x(%s)\n", GetTickCount(), msg,
        msg==MM_WOM_DONE ? "MM_WOM_DONE" : msg==MM_WOM_CLOSE ? "MM_WOM_CLOSE" : 
        msg==MM_WOM_OPEN ? "MM_WOM_OPEN" : "UNKNOWN");
 
    /* check if packet completed from wave driver */
    if (msg == MM_WOM_DONE) {
 
        /* **** */
        EnterCriticalSection(&(device->mixlock));
 
        TRACE("done playing primary pos=%d\n", device->pwplay * device->fraglen);
 
        /* update playpos */
        device->pwplay++;
        device->pwplay %= device->helfrags;
 
        /* sanity */
        if(device->pwqueue == 0){
            ERR("Wave queue corrupted!\n");
        }
 
        /* update queue */
        device->pwqueue--;
 
        LeaveCriticalSection(&(device->mixlock));
        /* **** */
    }
    TRACE("completed\n");
}