Ringbuf lib now supports optional highwater semaphore (used to control output

block size average).

src/sbbs3/main.cpp

@@ -1209,6 +1209,8 @@ void output_thread(void* arg)
 
 		if(!avail) {
 			sem_wait(&sbbs->outbuf.sem);
+			if(sbbs->outbuf.highwater_mark)
+				sem_trywait_block(&sbbs->outbuf.highwater_sem,startup->outbuf_drain_timeout);
 			continue; 
 		}
 
@@ -2067,6 +2069,7 @@ bool sbbs_t::init()
 	}
 
     RingBufInit(&outbuf, IO_THREAD_BUF_SIZE);
+	outbuf.highwater_mark=startup->outbuf_highwater_mark;
 
 	if(cfg.node_num && client_socket!=INVALID_SOCKET) {
 
@@ -3457,6 +3460,7 @@ void DLLCALL bbs_thread(void* arg)
 #ifdef JAVASCRIPT
 	if(startup->js_max_bytes==0)			startup->js_max_bytes=JAVASCRIPT_MAX_BYTES;
 #endif
+	if(startup->outbuf_drain_timeout==0)	startup->outbuf_drain_timeout=10;
 
 	uptime=0;
 	served=0;

src/sbbs3/ringbuf.c

@@ -84,6 +84,7 @@ int RINGBUFCALL RingBufInit( RingBuf* rb, DWORD size
 #endif
 	)
 {
+	memset(rb,0,sizeof(RingBuf));
 	if((rb->pStart=(BYTE *)os_malloc(size+1))==NULL)
 		return(-1);
 #ifndef RINGBUF_USE_STD_RTL
@@ -95,6 +96,7 @@ int RINGBUFCALL RingBufInit( RingBuf* rb, DWORD size
     rb->size=size;
 #ifdef RINGBUF_SEM
 	sem_init(&rb->sem,0,0);
+	sem_init(&rb->highwater_sem,0,0);
 #endif
 #ifdef RINGBUF_MUTEX
 	pthread_mutex_init(&rb->mutex,NULL);
@@ -109,6 +111,7 @@ void RINGBUFCALL RingBufDispose( RingBuf* rb)
 #ifdef RINGBUF_SEM
 	sem_post(&rb->sem);		/* just incase someone's waiting */
 	sem_destroy(&rb->sem);
+	sem_destroy(&rb->highwater_sem);
 #endif
 #ifdef RINGBUF_MUTEX
 	pthread_mutex_destroy(&rb->mutex);
@@ -191,6 +194,8 @@ DWORD RINGBUFCALL RingBufWrite( RingBuf* rb, BYTE* src,  DWORD cnt )
 
 #ifdef RINGBUF_SEM
 	sem_post(&rb->sem);
+	if(rb->highwater_mark!=0 && RingBufFull(rb)>=rb->highwater_mark)
+		sem_post(&rb->highwater_sem);
 #endif
 #ifdef RINGBUF_MUTEX
 	pthread_mutex_unlock(&rb->mutex);

src/sbbs3/ringbuf.h

@@ -83,6 +83,8 @@ typedef struct {
     DWORD	size;
 #ifdef RINGBUF_SEM
 	sem_t	sem;			/* semaphore used to signal data waiting */
+	sem_t	highwater_sem;	/* semaphore used to signal highwater mark reached */
+	DWORD	highwater_mark;
 #endif
 #ifdef RINGBUF_MUTEX
 	pthread_mutex_t mutex;	/* mutex used to protect ring buffer pointers */

src/sbbs3/sbbs_ini.c

@@ -199,6 +199,11 @@ void sbbs_read_ini(
 	bbs->last_node
 		=iniReadShortInt(fp,section,"LastNode",4);
 
+	bbs->outbuf_highwater_mark
+		=iniReadShortInt(fp,section,"OutbufHighwaterMark",128);
+	bbs->outbuf_drain_timeout
+		=iniReadShortInt(fp,section,"OutbufDrainTimeout",10);
+
 	bbs->xtrn_polls_before_yield
 		=iniReadInteger(fp,section,"ExternalYield",10);
 	bbs->js_max_bytes