/*	buffer.c: output buffer	copyright 1997-2006 by the mpg123 project - free software under the terms of the LGPL 2.1	see COPYING and AUTHORS files in distribution or http://mpg123.de	initially written by Oliver Fromme	I (ThOr) am reviewing this file at about the same daytime as Oliver's timestamp here:	Mon Apr 14 03:53:18 MET DST 1997	- dammed night coders;-)*/#include <stdlib.h>#include <errno.h>#include "config.h"#include "mpg123.h"int outburst = MAXOUTBURST;static int intflag = FALSE;static int usr1flag = FALSE;static void catch_interrupt (void){	intflag = TRUE;}static void catch_usr1 (void){	usr1flag = TRUE;}/* Interfaces to writer process */extern void buffer_sig(int signal, int block);void buffer_ignore_lowmem(void){#ifndef NOXFERMEM	if (!buffermem)		return;	if(buffermem->wakeme[XF_READER])		xfermem_putcmd(buffermem->fd[XF_WRITER], XF_CMD_WAKEUP);#endif}void buffer_end(void){#ifndef NOXFERMEM	if (!buffermem)		return;	xfermem_putcmd(buffermem->fd[XF_WRITER], XF_CMD_TERMINATE);#endif}void buffer_resync(void){	buffer_sig(SIGINT, TRUE);}void buffer_reset(void){	buffer_sig(SIGUSR1, TRUE);}void buffer_start(void){	buffer_sig(SIGCONT, FALSE);}void buffer_stop(void){	buffer_sig(SIGSTOP, FALSE);}extern int buffer_pid;void buffer_sig(int signal, int block){	#ifndef NOXFERMEM	if (!buffermem)		return;	kill(buffer_pid, signal);		if (!block)		return;	if(xfermem_block(XF_WRITER, buffermem) != XF_CMD_WAKEUP) 		perror("Could not resync/reset buffers");#endif		return;}#ifndef NOXFERMEMvoid buffer_loop(struct audio_info_struct *ai, sigset_t *oldsigset){	int bytes;	int my_fd = buffermem->fd[XF_READER];	txfermem *xf = buffermem;	int done = FALSE;	int preload;	catchsignal (SIGINT, catch_interrupt);	catchsignal (SIGUSR1, catch_usr1);	sigprocmask (SIG_SETMASK, oldsigset, NULL);	if (param.outmode == DECODE_AUDIO) {		if (audio_open(ai) < 0) {			perror("audio");			exit(1);		}	}	/* Fill complete buffer on first run before starting to play.	 * Live mp3 streams constantly approach buffer underrun otherwise. [dk]	 */	preload = xf->size;	for (;;) {		if (intflag) {			intflag = FALSE;			if (param.outmode == DECODE_AUDIO)				audio_queueflush (ai);			xf->readindex = xf->freeindex;			if (xf->wakeme[XF_WRITER])				xfermem_putcmd(my_fd, XF_CMD_WAKEUP);		}		if (usr1flag) {			usr1flag = FALSE;			/*   close and re-open in order to flush			 *   the device's internal buffer before			 *   changing the sample rate.   [OF]			 */			/* writer must block when sending SIGUSR1			 * or we will lose all data processed 			 * in the meantime! [dk]			 */			xf->readindex = xf->freeindex;			/* We've nailed down the new starting location -			 * writer is now safe to go on. [dk]			 */			if (xf->wakeme[XF_WRITER])				xfermem_putcmd(my_fd, XF_CMD_WAKEUP);			if (param.outmode == DECODE_AUDIO) {				audio_close (ai);				ai->rate = xf->buf[0]; 				ai->channels = xf->buf[1]; 				ai->format = xf->buf[2];				if (audio_open(ai) < 0) {					perror("audio");					exit(1);				}			}		}		if ( (bytes = xfermem_get_usedspace(xf)) < outburst ) {			/* if we got a buffer underrun we first			 * fill 1/8 of the buffer before continue/start			 * playing */			if (preload < xf->size>>3)				preload = xf->size>>3;			if(preload < outburst)				preload = outburst;		}		if(bytes < preload) {			int cmd;			if (done && !bytes) { 				break;			}						if(!done) {				/* Don't spill into errno check below. */				errno = 0;				cmd = xfermem_block(XF_READER, xf);				switch(cmd) {					/* More input pending. */					case XF_CMD_WAKEUP_INFO:						continue;					/* Yes, we know buffer is low but					 * know we don't care.					 */					case XF_CMD_WAKEUP:						break;	/* Proceed playing. */					case XF_CMD_TERMINATE:						/* Proceed playing without 						 * blocking any further.						 */						done=TRUE;						break;					case -1:						if(errno==EINTR)							continue;						if(errno)							perror("Yuck! Error in buffer handling...");						done = TRUE;						xf->readindex = xf->freeindex;						xfermem_putcmd(xf->fd[XF_READER], XF_CMD_TERMINATE);						break;					default:						fprintf(stderr, "\nEh!? Received unknown command 0x%x in buffer process. Tell Daniel!\n", cmd);				}			}		}		/* Hack! The writer issues XF_CMD_WAKEUP when first adjust 		 * audio settings. We do not want to lower the preload mark		 * just yet!		 */		if (!bytes)			continue;		preload = outburst; /* set preload to lower mark */		if (bytes > xf->size - xf->readindex)			bytes = xf->size - xf->readindex;		if (bytes > outburst)			bytes = outburst;		if (param.outmode == DECODE_FILE)			bytes = write(OutputDescriptor, xf->data + xf->readindex, bytes);		else if (param.outmode == DECODE_AUDIO)			bytes = audio_play_samples(ai,				(unsigned char *) (xf->data + xf->readindex), bytes);		if(bytes < 0) {			bytes = 0;			if(errno != EINTR) {				perror("Ouch ... error while writing audio data: ");				/*				 * done==TRUE tells writer process to stop				 * sending data. There might be some latency				 * involved when resetting readindex to 				 * freeindex so we might need more than one				 * cycle to terminate. (The number of cycles				 * should be finite unless I managed to mess				 * up something. ;-) [dk]				 */				done = TRUE;					xf->readindex = xf->freeindex;				xfermem_putcmd(xf->fd[XF_READER], XF_CMD_TERMINATE);			}		}		xf->readindex = (xf->readindex + bytes) % xf->size;		if (xf->wakeme[XF_WRITER])			xfermem_putcmd(my_fd, XF_CMD_WAKEUP);	}	if (param.outmode == DECODE_AUDIO)		audio_close (ai);}#endif/* EOF */