- Remove some unneeded files

- Mass rename .c to .cpp

svn-id: r38227

1 files changed, 988 insertions, 0 deletions

diff --git a/engines/sci/sfx/mixer/soft.cpp b/engines/sci/sfx/mixer/soft.cpp
new file mode 100644
index 0000000000..d71567a209
--- /dev/null
+++ b/engines/sci/sfx/mixer/soft.cpp
@@ -0,0 +1,988 @@
+/***************************************************************************
+ mixer.c Copyright (C) 2003 Christoph Reichenbach
+
+
+ This program may be modified and copied freely according to the terms of
+ the GNU general public license (GPL), as long as the above copyright
+ notice and the licensing information contained herein are preserved.
+
+ Please refer to www.gnu.org for licensing details.
+
+ This work is provided AS IS, without warranty of any kind, expressed or
+ implied, including but not limited to the warranties of merchantibility,
+ noninfringement, and fitness for a specific purpose. The author will not
+ be held liable for any damage caused by this work or derivatives of it.
+
+ By using this source code, you agree to the licensing terms as stated
+ above.
+
+
+ Please contact the maintainer for bug reports or inquiries.
+
+ Current Maintainer:
+
+    Christoph Reichenbach (CR) <jameson@linuxgames.com>
+
+***************************************************************************/
+
+#include "../mixer.h"
+#include "sci/include/sci_memory.h"
+
+/* Max. number of microseconds in difference allowed between independent audio streams */
+#define TIMESTAMP_MAX_ALLOWED_DELTA 2000
+
+/*#define DEBUG 3*/
+/* Set DEBUG to one of the following:
+** anything -- high-level debugging (feed subscriptions/deletions etc.)
+**     >= 1 -- rough input and output analysis (once per call)
+**     >= 2 -- more detailed input analysis (once per call and feed)
+**     >= 3 -- fully detailed input and output analysis (once per frame and feed)
+*/
+
+/*#define DEBUG 0*/
+
+#define MIN_DELTA_OBSERVATIONS 100 /* Number of times the mixer is called before it starts trying to improve latency */
+#define MAX_DELTA_OBSERVATIONS 1000000 /* Number of times the mixer is called before we assume we truly understand timing */
+
+static int diagnosed_too_slow = 0;
+
+static volatile int mixer_lock = 0;
+
+/*#define DEBUG_LOCKS*/
+#ifdef DEBUG_LOCKS
+#  define DEBUG_ACQUIRE fprintf(stderr, "[ -LOCK -] ACKQ %d: %d\n", __LINE__, mixer_lock)
+#  define DEBUG_WAIT fprintf(stderr, "[ -LOCK -] WAIT %d: %d\n", __LINE__, mixer_lock);
+#  define DEBUG_RELEASE ; fprintf(stderr, "[ -LOCK -] REL %d: %d\n", __LINE__, mixer_lock);
+#else
+#  define DEBUG_ACQUIRE
+#  define DEBUG_WAIT
+#  define DEBUG_RELEASE
+#endif
+
+#define ACQUIRE_LOCK() ++mixer_lock; while (mixer_lock != 1) { DEBUG_WAIT sci_sched_yield(); } DEBUG_ACQUIRE
+#define RELEASE_LOCK() --mixer_lock DEBUG_RELEASE
+
+struct mixer_private {
+	byte *outbuf; /* Output buffer to write to the PCM device next time */
+	sfx_timestamp_t outbuf_timestamp; /* Timestamp associated with the output buffer */
+	int have_outbuf_timestamp; /* Whether we really _have_ an associated timestamp */
+	byte *writebuf; /* Buffer we're supposed to write to */
+	gint32 *compbuf_l, *compbuf_r; /* Intermediate buffers for computation */
+	int lastbuf_len; /* Number of frames stored in the last buffer */
+
+	long skew; /* Millisecond relative to which we compute time. This is the millisecond
+		   ** part of the first time we emitted sound, to simplify some computations.  */
+	long lsec; /* Last point in time we updated buffers, if any (seconds since the epoch) */
+	int played_this_second; /* Number of frames emitted so far in second lsec */
+
+	int max_delta; /* maximum observed time delta (using 'frames' as a metric unit) */
+	int delta_observations; /* Number of times we played; confidence measure for max_delta */
+
+	/* Pause data */
+	int paused;
+};
+
+#define P ((struct mixer_private *)(self->private_bits))
+
+
+static int
+mix_init(sfx_pcm_mixer_t *self, sfx_pcm_device_t *device)
+{
+	self->dev = device;
+	self->private_bits /* = P */ = sci_malloc(sizeof(struct mixer_private));
+	P->outbuf = P->writebuf = NULL;
+	P->lastbuf_len = 0;
+	P->compbuf_l = (gint32*)sci_malloc(sizeof(gint32) * device->buf_size);
+	P->compbuf_r = (gint32*)sci_malloc(sizeof(gint32) * device->buf_size);
+	P->played_this_second = 0;
+	P->paused = 0;
+#ifdef DEBUG
+	sciprintf("[soft-mixer] Initialised device %s v%s (%d Hz, %d/%x)\n",
+		  device->name, device->version,
+		  device->conf.rate, device->conf.stereo, device->conf.format);
+#endif
+	return SFX_OK;
+}
+
+static inline unsigned int
+gcd(unsigned int a, unsigned int b)
+{
+	if (a == b)
+		return a;
+
+	if (a < b) {
+		unsigned int c = b % a;
+
+		if (!c)
+			return a;
+
+		return gcd(c, a);
+	} else
+		return gcd(b, a);
+}
+
+static sfx_pcm_urat_t
+urat(unsigned int nom, unsigned int denom)
+{
+	sfx_pcm_urat_t rv;
+	unsigned int g;
+
+	rv.val = nom / denom;
+	nom -= rv.val * denom;
+	if (nom == 0)
+		g = 1;
+	else
+		g = gcd(nom, denom);
+
+	rv.nom = nom / g;
+	rv.den = denom / g;
+
+	return rv;
+}
+
+static void
+mix_subscribe(sfx_pcm_mixer_t *self, sfx_pcm_feed_t *feed)
+{
+	sfx_pcm_feed_state_t *fs;
+	ACQUIRE_LOCK();
+	if (!self->feeds) {
+		self->feeds_allocd = 2;
+		self->feeds = (sfx_pcm_feed_state_t*)sci_malloc(sizeof(sfx_pcm_feed_state_t)
+					 * self->feeds_allocd);
+	} else if (self->feeds_allocd == self->feeds_nr) {
+		self->feeds_allocd += 2;
+		self->feeds = (sfx_pcm_feed_state_t*)sci_realloc(self->feeds,
+					  sizeof(sfx_pcm_feed_state_t)
+					  * self->feeds_allocd);
+	}
+
+	fs = self->feeds + self->feeds_nr++;
+	fs->feed = feed;
+
+	feed->frame_size = SFX_PCM_FRAME_SIZE(feed->conf);
+
+	/*	fs->buf_size = (self->dev->buf_size
+			  * (feed->conf.rate
+			     + self->dev->conf.rate - 1))
+		/ self->dev->conf.rate;
+	*/
+	/* For the sake of people without 64 bit CPUs: */
+	fs->buf_size = 2 + /* Additional safety */
+		(self->dev->buf_size *
+			(1 + (feed->conf.rate / self->dev->conf.rate)));
+fprintf(stderr, " ---> %d/%d/%d/%d = %d\n",
+	self->dev->buf_size,
+	feed->conf.rate,
+	self->dev->conf.rate,
+	feed->frame_size,
+	fs->buf_size);
+
+	fs->buf = (byte*)sci_malloc(fs->buf_size * feed->frame_size);
+fprintf(stderr, " ---> --> %d for %p at %p\n", fs->buf_size * feed->frame_size, (void *)fs, (void *)fs->buf);
+{int i; for (i = 0; i < fs->buf_size * feed->frame_size; i++)
+fs->buf[i] = 0xa5; }
+	fs->scount = urat(0, 1);
+	fs->spd = urat(feed->conf.rate, self->dev->conf.rate);
+	fs->scount.den = fs->spd.den;
+	fs->ch_old.left = 0;
+	fs->ch_old.right = 0;
+	fs->ch_new.left = 0;
+	fs->ch_new.right = 0;
+	fs->mode = SFX_PCM_FEED_MODE_ALIVE;
+
+	/* If the feed can't provide us with timestamps, we don't need to wait for it to do so */
+	fs->pending_review = (feed->get_timestamp)? 1 : 0;
+
+	fs->frame_bufstart = 0;
+
+#ifdef DEBUG
+	sciprintf("[soft-mixer] Subscribed %s-%x (%d Hz, %d/%x) at %d+%d/%d, buffer size %d\n",
+		  feed->debug_name, feed->debug_nr, feed->conf.rate, feed->conf.stereo, feed->conf.format,
+		  fs->spd.val, fs->spd.nom, fs->spd.den, fs->buf_size);
+#endif
+	RELEASE_LOCK();
+}
+
+
+static void
+_mix_unsubscribe(sfx_pcm_mixer_t *self, sfx_pcm_feed_t *feed)
+{
+	int i;
+#ifdef DEBUG
+	sciprintf("[soft-mixer] Unsubscribing %s-%x\n", feed->debug_name, feed->debug_nr);
+#endif
+	for (i = 0; i < self->feeds_nr; i++) {
+		sfx_pcm_feed_state_t *fs = self->feeds + i;
+
+		if (fs->feed == feed) {
+			feed->destroy(feed);
+
+			if (fs->buf)
+				sci_free(fs->buf);
+
+			self->feeds_nr--;
+
+			/* Copy topmost into deleted so that we don't have any holes */
+			if (i != self->feeds_nr)
+				self->feeds[i] = self->feeds[self->feeds_nr];
+
+			if (self->feeds_allocd > 8 && self->feeds_allocd > (self->feeds_nr << 1)) {
+				/* Limit memory waste */
+				self->feeds_allocd >>= 1;
+				self->feeds
+					= (sfx_pcm_feed_state_t*)sci_realloc(self->feeds,
+						      sizeof(sfx_pcm_feed_state_t)
+						      * self->feeds_allocd);
+			}
+
+			for (i = 0; i < self->feeds_nr; i++)
+				fprintf(stderr, "  Feed #%d: %s-%x\n",
+					i, self->feeds[i].feed->debug_name,
+					self->feeds[i].feed->debug_nr);
+
+			return;
+		}
+	}
+
+	fprintf(stderr, "[sfx-mixer] Assertion failed: Deleting invalid feed %p out of %d\n", 
+		(void *)feed, self->feeds_nr);
+
+	BREAKPOINT();
+}
+
+static void
+mix_unsubscribe(sfx_pcm_mixer_t *self, sfx_pcm_feed_t *feed)
+{
+	ACQUIRE_LOCK();
+	_mix_unsubscribe(self, feed);
+	RELEASE_LOCK();
+}
+
+
+static void
+mix_exit(sfx_pcm_mixer_t *self)
+{
+	ACQUIRE_LOCK();
+	while (self->feeds_nr)
+		_mix_unsubscribe(self, self->feeds[0].feed);
+
+	if (P->outbuf)
+		sci_free(P->outbuf);
+	if (P->writebuf)
+		sci_free(P->writebuf);
+
+	if (P->compbuf_l)
+		sci_free(P->compbuf_l);
+	if (P->compbuf_l)
+		sci_free(P->compbuf_r);
+
+	sci_free(P);
+	self->private_bits /* = P */ = NULL;
+	RELEASE_LOCK();
+
+#ifdef DEBUG
+	sciprintf("[soft-mixer] Uninitialising mixer\n");
+#endif
+}
+
+
+#define LIMIT_16_BITS(v)			\
+		if (v < -32767)			\
+			v = -32768;		\
+		else if (v > 32766)		\
+			v = 32767
+
+static inline void
+mix_compute_output(sfx_pcm_mixer_t *self, int outplen)
+{
+	int frame_i;
+	sfx_pcm_config_t conf = self->dev->conf;
+	int use_16 = conf.format & SFX_PCM_FORMAT_16;
+	int bias = conf.format & ~SFX_PCM_FORMAT_LMASK;
+	byte *lchan, *rchan = NULL;
+	/* Don't see how this could possibly wind up being
+	** used w/o initialisation, but you never know... */
+	gint32 *lsrc = P->compbuf_l;
+	gint32 *rsrc = P->compbuf_r;
+	int frame_size = SFX_PCM_FRAME_SIZE(conf);
+
+
+	if (!P->writebuf)
+		P->writebuf = (byte*)sci_malloc(self->dev->buf_size * frame_size + 4);
+
+	if (conf.stereo) {
+		if (conf.stereo == SFX_PCM_STEREO_RL) {
+			lchan = P->writebuf + ((use_16)? 2 : 1);
+			rchan = P->writebuf;
+		} else {
+			lchan = P->writebuf;
+			rchan = P->writebuf + ((use_16)? 2 : 1);
+		}
+	} else
+		lchan = P->writebuf;
+
+
+	for (frame_i = 0; frame_i < outplen; frame_i++) {
+		int left = *lsrc++;
+		int right = *rsrc++;
+
+		if (conf.stereo) {
+			LIMIT_16_BITS(left);
+			LIMIT_16_BITS(right);
+
+			if (!use_16) {
+				left >>= 8;
+				right >>= 8;
+			}
+
+			left += bias;
+			right += bias;
+
+			if (use_16) {
+				if (SFX_PCM_FORMAT_LE == (conf.format & SFX_PCM_FORMAT_ENDIANNESS)) {
+					lchan[0] = left & 0xff;
+					lchan[1] = (left >> 8) & 0xff;
+					rchan[0] = right & 0xff;
+					rchan[1] = (right >> 8) & 0xff;
+				} else {
+					lchan[1] = left & 0xff;
+					lchan[0] = (left >> 8) & 0xff;
+					rchan[1] = right & 0xff;
+					rchan[0] = (right >> 8) & 0xff;
+				}
+
+				lchan += 4;
+				rchan += 4;
+			} else {
+				*lchan = left & 0xff;
+				*rchan = right & 0xff;
+
+				lchan += 2;
+				rchan += 2;
+			}
+
+		} else {
+			left += right;
+			left >>= 1;
+			LIMIT_16_BITS(left);
+			if (!use_16)
+				left >>= 8;
+
+			left += bias;
+
+			if (use_16) {
+				if (SFX_PCM_FORMAT_LE == (conf.format & SFX_PCM_FORMAT_ENDIANNESS)) {
+					lchan[0] = left & 0xff;
+					lchan[1] = (left >> 8) & 0xff;
+				} else {
+					lchan[1] = left & 0xff;
+					lchan[0] = (left >> 8) & 0xff;
+				}
+
+				lchan += 2;
+			} else {
+				*lchan = left & 0xff;
+				lchan += 1;
+			}
+		}
+	}
+}
+
+static inline void
+mix_swap_buffers(sfx_pcm_mixer_t *self)
+{ /* Swap buffers */
+	byte *tmp = P->outbuf;
+	P->outbuf = P->writebuf;
+	P->writebuf = tmp;
+}
+
+
+#define FRAME_OFFSET(usecs) \
+			((usecs >> 7) /* approximate, since uint32 is too small */ \
+			 * ((long) self->dev->conf.rate)) \
+			/ (1000000L >> 7)
+
+static inline int
+mix_compute_buf_len(sfx_pcm_mixer_t *self, int *skip_frames)
+     /* Computes the number of frames we ought to write. It tries to minimise the number,
+     ** in order to reduce latency. */
+     /* It sets 'skip_frames' to the number of frames to assume lost by latency, effectively
+     ** skipping them.  */
+{
+	int free_frames;
+	int played_frames = 0; /* since the last call */
+	long secs, usecs;
+	int frame_pos;
+	int result_frames;
+
+	sci_gettime(&secs, &usecs);
+
+	if (!P->outbuf) {
+		/* Called for the first time ever? */
+		P->skew = usecs;
+		P->lsec = secs;
+		P->max_delta = 0;
+		P->delta_observations = 0;
+		P->played_this_second = 0;
+		*skip_frames = 0;
+		return self->dev->buf_size;
+	}
+
+	/*	fprintf(stderr, "[%d:%d]S%d ", secs, usecs, P->skew);*/
+
+	if (P->skew > usecs) {
+		secs--;
+		usecs += (1000000 - P->skew);
+	}
+	else
+		usecs -= P->skew;
+
+	frame_pos = FRAME_OFFSET(usecs);
+
+	played_frames = frame_pos - P->played_this_second
+		+ ((secs - P->lsec) * self->dev->conf.rate);
+	/*
+	fprintf(stderr, "%d:%d - %d:%d  => %d\n", secs, frame_pos,
+		P->lsec, P->played_this_second, played_frames);
+	*/
+
+	if (played_frames > self->dev->buf_size)
+		played_frames = self->dev->buf_size;
+
+	/*
+	fprintf(stderr, "Between %d:? offset=%d and %d:%d offset=%d: Played %d at %d\n", P->lsec, P->played_this_second,
+	secs, usecs, frame_pos, played_frames, self->dev->conf.rate);
+	*/
+
+
+	if (played_frames > P->max_delta)
+		P->max_delta = played_frames;
+
+	free_frames = played_frames;
+
+	if (free_frames > self->dev->buf_size) {
+		if (!diagnosed_too_slow) {
+			sciprintf("[sfx-mixer] Your timer is too slow for your PCM output device (%d/%d), free=%d.\n"
+				  "[sfx-mixer] You might want to try changing the device, timer, or mixer, if possible.\n",
+				  played_frames, self->dev->buf_size, free_frames);
+		}
+		diagnosed_too_slow = 1;
+
+		*skip_frames = free_frames - self->dev->buf_size;
+		free_frames = self->dev->buf_size;
+	} else
+		*skip_frames = 0;
+
+	++P->delta_observations;
+	if (P->delta_observations > MAX_DELTA_OBSERVATIONS)
+		P->delta_observations = MAX_DELTA_OBSERVATIONS;
+
+/* 	/\* Disabled, broken *\/ */
+/* 	if (0 && P->delta_observations > MIN_DELTA_OBSERVATIONS) { /\* Start improving after a while *\/ */
+/* 		int diff = self->dev->conf.rate - P->max_delta; */
+
+/* 		/\* log-approximate P->max_delta over time *\/ */
+/* 		recommended_frames = P->max_delta + */
+/* 			((diff * MIN_DELTA_OBSERVATIONS) / P->delta_observations); */
+/* /\* WTF? *\/ */
+/* 	} else */
+/* 		recommended_frames = self->dev->buf_size; /\* Initially, keep the buffer full *\/ */
+
+#if (DEBUG >= 1)
+	sciprintf("[soft-mixer] played since last time: %d, recommended: %d, free: %d\n",
+		  played_frames, recommended_frames, free_frames);
+#endif
+
+	result_frames = free_frames;
+
+	if (result_frames < 0)
+		result_frames = 0;
+
+	P->played_this_second += result_frames;
+	while (P->played_this_second >= self->dev->conf.rate) {
+		/* Won't normally happen more than once */
+		P->played_this_second -= self->dev->conf.rate;
+		P->lsec++;
+	}
+
+	if (result_frames > self->dev->buf_size) {
+		fprintf(stderr, "[soft-mixer] Internal assertion failed: frames-to-write %d > %d\n",
+			result_frames, self->dev->buf_size);
+	}
+	return result_frames;
+}
+
+
+
+#define READ_NEW_VALUES() \
+		if (frames_left > 0) {						\
+			if (bias) { /* unsigned data */					\
+				if (!use_16) {						\
+					c_new.left = (*lsrc) << 8;			\
+					c_new.right = (*rsrc) << 8;			\
+				} else {						\
+					if (conf.format & SFX_PCM_FORMAT_LE) {		\
+						c_new.left = lsrc[0] | lsrc[1] << 8;	\
+						c_new.right = rsrc[0] | rsrc[1] << 8;	\
+					} else {					\
+						c_new.left = lsrc[1] | lsrc[0] << 8;	\
+						c_new.right = rsrc[1] | rsrc[0] << 8;	\
+					}						\
+				}							\
+			} else { /* signed data */							\
+				if (!use_16) {								\
+					c_new.left = (*((signed char *)lsrc)) << 8;			\
+					c_new.right = (*((signed char *)rsrc)) << 8;			\
+				} else {								\
+					if (conf.format & SFX_PCM_FORMAT_LE) {				\
+						c_new.left = lsrc[0] | ((signed char *)lsrc)[1] << 8;	\
+						c_new.right = rsrc[0] | ((signed char *)rsrc)[1] << 8;	\
+					} else {							\
+						c_new.left = lsrc[1] | ((signed char *)lsrc)[0] << 8;	\
+						c_new.right = rsrc[1] | ((signed char *)rsrc)[0] << 8;	\
+					}								\
+				}									\
+			}										\
+										\
+			c_new.left -= bias;					\
+			c_new.right -= bias;					\
+										\
+			lsrc += frame_size;					\
+			rsrc += frame_size;					\
+		} else {							\
+			c_new.left = c_new.right = 0;				\
+			break;							\
+		}
+
+
+static volatile int xx_offset;
+static volatile int xx_size;
+
+static void
+mix_compute_input_linear(sfx_pcm_mixer_t *self, int add_result,
+			 int len, sfx_timestamp_t *ts, sfx_timestamp_t base_ts)
+     /* if add_result is non-zero, P->outbuf should be added to rather than overwritten. */
+     /* base_ts is the timestamp for the first frame */
+{
+	sfx_pcm_feed_state_t *fs = self->feeds + add_result;
+	sfx_pcm_feed_t *f = fs->feed;
+	sfx_pcm_config_t conf = f->conf;
+	int use_16 = conf.format & SFX_PCM_FORMAT_16;
+	gint32 *lchan = P->compbuf_l;
+	gint32 *rchan = P->compbuf_r;
+	int frame_size = f->frame_size;
+	byte *wr_dest = fs->buf + (frame_size * fs->frame_bufstart);
+	byte *lsrc = fs->buf;
+	byte *rsrc = fs->buf;
+	/* Location to write to */
+	int frames_nr;
+	int bias = (conf.format & ~SFX_PCM_FORMAT_LMASK)? 0x8000 : 0;
+	/* We use this only on a 16 bit level here */
+
+	/* The two most extreme source frames we consider for a
+	** destination frame  */
+	struct twochannel_data c_old = fs->ch_old;
+	struct twochannel_data c_new = fs->ch_new;
+
+	int frames_read = 0;
+	int frames_left;
+	int write_offset; /* Iterator for translation */
+	int delay_frames = 0; /* Number of frames (dest buffer) at the beginning we skip */
+
+	/* First, compute the number of frames we want to retreive */
+	frames_nr = fs->spd.val * len;
+	/* A little complicated since we must consider partial frames */
+	frames_nr += (fs->spd.nom * len
+		       + (fs->scount.den - fs->scount.nom) /* remember that we may have leftovers */
+		       + (fs->spd.den - 1 /* round up */)
+		       )
+		/ fs->spd.den;
+
+	ts->secs = -1;
+
+	if (frames_nr > fs->buf_size) {
+		fprintf(stderr, "%d (%d*%d + somethign) bytes, but only %d allowed!!!!!\n",
+			frames_nr * f->frame_size,
+			fs->spd.val, len,
+			fs->buf_size);
+		BREAKPOINT();
+	}
+
+	if (fs->pending_review) {
+		int newmode = PCM_FEED_EMPTY; /* empty unless a get_timestamp() tells otherwise */
+
+		RELEASE_LOCK();
+		/* Retrieve timestamp */
+		if (f->get_timestamp)
+			newmode = f->get_timestamp(f, ts);
+		ACQUIRE_LOCK();
+
+		fs = self->feeds + add_result;
+		/* Reset in case of status update */
+
+		switch (newmode) {
+
+		case PCM_FEED_TIMESTAMP: {
+			/* Compute the number of frames the returned timestamp is in the future: */
+			delay_frames =
+				sfx_timestamp_frame_diff(sfx_timestamp_renormalise(*ts, base_ts.frame_rate),
+							  base_ts);
+
+			if (delay_frames <= 0)
+				/* Start ASAP, even if it's too late */
+				delay_frames = 0;
+			else
+				if (delay_frames > len)
+					delay_frames = len;
+			fs->pending_review = 0;
+		}
+			break;
+
+		case PCM_FEED_EMPTY:
+			fs->mode = SFX_PCM_FEED_MODE_DEAD;
+
+			/* ...fall through... */
+
+		case PCM_FEED_IDLE:
+			/* Clear audio buffer, if neccessary, and return */
+			if (!add_result) {
+				memset(P->compbuf_l, 0, sizeof(gint32) * len);
+				memset(P->compbuf_r, 0, sizeof(gint32) * len);
+			}
+			return;
+
+		default:
+			fprintf(stderr, "[soft-mixer] Fatal: Invalid mode returned by PCM feed %s-%d's get_timestamp(): %d\n",
+				f->debug_name, f->debug_nr, newmode);
+			exit(1);
+		}
+	}
+
+	RELEASE_LOCK();
+	/* Make sure we have sufficient information */
+	if (frames_nr > delay_frames + fs->frame_bufstart)
+		frames_read =
+			f->poll(f, wr_dest,
+				frames_nr
+				- delay_frames
+				- fs->frame_bufstart);
+
+	ACQUIRE_LOCK();
+	fs = self->feeds + add_result;
+
+	frames_read += fs->frame_bufstart;
+	frames_left = frames_read;
+
+	/* Reset in case of status update */
+
+	/* Skip at the beginning: */
+	if (delay_frames) {
+		if (!add_result) {
+			memset(lchan, 0, sizeof(gint32) * delay_frames);
+			memset(rchan, 0, sizeof(gint32) * delay_frames);
+		}
+		lchan += delay_frames;
+		rchan += delay_frames;
+
+		len -= delay_frames;
+	}
+
+
+#if (DEBUG >= 2)
+	sciprintf("[soft-mixer] Examining %s-%x (frame size %d); read %d/%d/%d, re-using %d frames\n",
+		  f->debug_name, f->debug_nr, frame_size, frames_read, frames_nr,
+		  fs->buf_size, fs->frame_bufstart);
+#endif
+
+
+	if (conf.stereo == SFX_PCM_STEREO_LR)
+		rsrc += (use_16)? 2 : 1;
+	else if (conf.stereo == SFX_PCM_STEREO_RL)
+		lsrc += (use_16)? 2 : 1;
+	/* Otherwise, we let both point to the same place */
+
+#if (DEBUG >= 2)
+	sciprintf("[soft-mixer] Stretching theoretical %d (physical %d) results to %d\n", frames_nr, frames_left, len);
+#endif
+	for (write_offset = 0; write_offset < len; write_offset++) {
+		int leftsum = 0; /* Sum of any complete frames we used */
+		int rightsum = 0;
+
+		int left; /* Sum of the two most extreme source frames
+			  ** we considered, i.e. the oldest and newest
+			  ** one corresponding to the output frame we are
+			  ** computing  */
+		int right;
+
+		int frame_steps = fs->spd.val;
+		int j;
+
+		if (fs->scount.nom >= fs->scount.den) {
+			fs->scount.nom -= fs->scount.den; /* Ensure fractional part < 1 */
+			++frame_steps;
+		}
+		if (frame_steps)
+			c_old = c_new;
+
+#if 0
+		if (write_offset == 0) {
+			READ_NEW_VALUES();
+			--frames_left;
+#if (DEBUG >= 3)
+			sciprintf("[soft-mixer] Initial read %d:%d\n", c_new.left, c_new.right);
+#endif
+			c_old = c_new;
+			}
+#endif
+
+		for (j = 0; j < frame_steps; j++) {
+			READ_NEW_VALUES();
+			--frames_left;
+#if (DEBUG >= 3)
+			sciprintf("[soft-mixer] Step %d/%d made %d:%d\n", j, frame_steps, c_new.left, c_new.right);
+#endif
+
+			/* The last frame will be subject to the fractional
+			** part analysis, so we add it to 'left' and 'right'
+			** later-- all others are added to (leftsum, rightsum).
+			*/
+			if (j+1 < frame_steps) {
+				leftsum += c_new.left;
+				rightsum += c_new.right;
+			}
+		}
+
+		left = c_new.left * fs->scount.nom
+			+ c_old.left * (fs->scount.den - fs->scount.nom);
+		right = c_new.right * fs->scount.nom
+			+ c_old.right * (fs->scount.den - fs->scount.nom);
+
+		/* Normalise */
+		left  /= fs->spd.den;
+		right /= fs->spd.den;
+
+
+		leftsum += left;
+		rightsum += right;
+
+
+		/* Make sure to divide by the number of frames we added here */
+		if (frame_steps > 1) {
+			leftsum  /= (frame_steps);
+			rightsum /= (frame_steps);
+		}
+
+
+#if (DEBUG >= 3)
+		sciprintf("[soft-mixer] Ultimate result: %d:%d (frac %d:%d)\n", leftsum, rightsum, left, right);
+#endif
+
+		if (add_result) {
+			*(lchan++) += leftsum;
+			*(rchan++) += rightsum;
+		} else {
+			*(lchan++) = leftsum;
+			*(rchan++) = rightsum;
+		}
+
+		fs->scount.nom += fs->spd.nom; /* Count up fractional part */
+	}
+
+	fs->ch_old = c_old;
+	fs->ch_new = c_new;
+
+	/* If neccessary, zero out the rest */
+	if (write_offset < len && !add_result) {
+		memset(lchan, 0, sizeof(gint32) * (len - write_offset));
+		memset(rchan, 0, sizeof(gint32) * (len - write_offset));
+	}
+
+	/* Save whether we have a partial frame still stored */
+	fs->frame_bufstart = frames_left;
+
+	if (frames_left) {
+		xx_offset = ((frames_read - frames_left) * f->frame_size);
+		xx_size = frames_left * f->frame_size;
+		if (xx_offset + xx_size
+		    >= fs->buf_size * f->frame_size) {
+			fprintf(stderr, "offset %d >= max %d!\n",
+				(xx_offset + xx_size), fs->buf_size * f->frame_size);
+			BREAKPOINT();
+		}
+
+		memmove(fs->buf,
+			fs->buf + ((frames_read - frames_left) * f->frame_size),
+			frames_left * f->frame_size);
+	}
+#if (DEBUG >= 2)
+	sciprintf("[soft-mixer] Leaving %d over\n", fs->frame_bufstart);
+#endif
+
+	if (frames_read + delay_frames < frames_nr) {
+		if (f->get_timestamp) /* Can resume? */
+			fs->pending_review = 1;
+		else
+			fs->mode = SFX_PCM_FEED_MODE_DEAD; /* Done. */
+	}
+}
+
+static int
+mix_process_linear(sfx_pcm_mixer_t *self)
+{
+ACQUIRE_LOCK();
+{
+	int src_i; /* source feed index counter */
+	int frames_skip; /* Number of frames to discard, rather than to emit */
+	int buflen = mix_compute_buf_len(self, &frames_skip); /* Compute # of frames we must compute and write */
+	int fake_buflen;
+	int timestamp_max_delta = 0;
+	int have_timestamp = 0;
+	sfx_timestamp_t start_timestamp; /* The timestamp at which the first frame will be played */
+	sfx_timestamp_t min_timestamp;
+	sfx_timestamp_t timestamp;
+
+	if (self->dev->get_output_timestamp)
+		start_timestamp = self->dev->get_output_timestamp(self->dev);
+	else {
+		long sec, usec;
+		sci_gettime(&sec, &usec);
+		start_timestamp = sfx_new_timestamp(sec, usec, self->dev->conf.rate);
+	}
+
+	if ((P->outbuf) && (P->lastbuf_len)) {
+		sfx_timestamp_t ts;
+		int rv;
+
+		if (P->have_outbuf_timestamp) {
+			ts = sfx_timestamp_renormalise(P->outbuf_timestamp, self->dev->conf.rate);
+		}
+
+		rv = self->dev->output(self->dev, P->outbuf,
+					   P->lastbuf_len,
+					   (P->have_outbuf_timestamp)? &ts : NULL);
+
+		if (rv == SFX_ERROR) {
+			RELEASE_LOCK();
+			return rv; /* error */
+		}
+	}
+
+#if (DEBUG >= 1)
+	if (self->feeds_nr)
+		sciprintf("[soft-mixer] Mixing %d output frames on %d input feeds\n", buflen, self->feeds_nr);
+#endif
+	if (self->feeds_nr && !P->paused) {
+		/* Below, we read out all feeds in case we have to skip frames first, then get the
+		** most current sound. 'fake_buflen' is either the actual buflen (for the last iteration)
+		** or a fraction of the buf length to discard.  */
+		do {
+			if (frames_skip) {
+				if (frames_skip > self->dev->buf_size)
+					fake_buflen = self->dev->buf_size;
+				else
+					fake_buflen = frames_skip;
+
+				frames_skip -= fake_buflen;
+			} else {
+				fake_buflen = buflen;
+				frames_skip = -1; /* Mark us as being completely done */
+			}
+
+			for (src_i = 0; src_i < self->feeds_nr; src_i++) {
+				mix_compute_input_linear(self, src_i,
+							 fake_buflen, &timestamp,
+							 start_timestamp);
+
+				if (timestamp.secs >= 0) {
+					if (have_timestamp) {
+						int diff = sfx_timestamp_usecs_diff(min_timestamp, timestamp);
+						if (diff > 0) {
+							/* New earlier timestamp */
+							timestamp = min_timestamp;
+							timestamp_max_delta += diff;
+						} else if (diff > timestamp_max_delta)
+							timestamp_max_delta = diff;
+						/* New max delta for timestamp */
+					} else {
+						min_timestamp = timestamp;
+						have_timestamp = 1;
+					}
+				}
+			}
+			/* Destroy all feeds we finished */
+			for (src_i = 0; src_i < self->feeds_nr; src_i++)
+				if (self->feeds[src_i].mode == SFX_PCM_FEED_MODE_DEAD)
+					_mix_unsubscribe(self, self->feeds[src_i].feed);
+		} while (frames_skip >= 0);
+
+	} else { /* Zero it out */
+		memset(P->compbuf_l, 0, sizeof(gint32) * buflen);
+		memset(P->compbuf_r, 0, sizeof(gint32) * buflen);
+	}
+
+#if (DEBUG >= 1)
+	if (self->feeds_nr)
+		sciprintf("[soft-mixer] Done mixing for this session, the result will be our next output buffer\n");
+#endif
+
+#if (DEBUG >= 3)
+	if (self->feeds_nr) {
+		int i;
+		sciprintf("[soft-mixer] Intermediate representation:\n");
+		for (i = 0; i < buflen; i++)
+			sciprintf("[soft-mixer] Offset %d:\t[%04x:%04x]\t%d:%d\n", i,
+				  P->compbuf_l[i] & 0xffff, P->compbuf_r[i] & 0xffff,
+				  P->compbuf_l[i], P->compbuf_r[i]);
+	}
+#endif
+
+	if (timestamp_max_delta > TIMESTAMP_MAX_ALLOWED_DELTA)
+		sciprintf("[soft-mixer] Warning: Difference in timestamps between audio feeds is %d us\n", timestamp_max_delta);
+
+	mix_compute_output(self, buflen);
+	P->lastbuf_len = buflen;
+
+	/* Finalize */
+	mix_swap_buffers(self);
+	if (have_timestamp)
+		P->outbuf_timestamp = sfx_timestamp_add(min_timestamp,
+							timestamp_max_delta >> 1);
+	P->have_outbuf_timestamp = have_timestamp;
+
+}	RELEASE_LOCK();
+	return SFX_OK;
+}
+
+static void
+mix_pause(sfx_pcm_mixer_t *self)
+{
+	ACQUIRE_LOCK();
+	P->paused = 1;
+	RELEASE_LOCK();
+}
+
+static void
+mix_resume(sfx_pcm_mixer_t *self)
+{
+	ACQUIRE_LOCK();
+	P->paused = 0;
+	RELEASE_LOCK();
+}
+
+sfx_pcm_mixer_t sfx_pcm_mixer_soft_linear = {
+	"soft-linear",
+	"0.1",
+
+	mix_init,
+	mix_exit,
+	mix_subscribe,
+	mix_pause,
+	mix_resume,
+	mix_process_linear,
+
+	0,
+	0,
+	NULL,
+	NULL,
+	NULL
+};