shithub: musw

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implement a primitive VLA to keep connection state.

--- a/dat.h

+++ b/dat.h

@@ -2,6 +2,7 @@

 typedef struct GameState GameState;

 typedef struct Derivative Derivative;

+typedef struct Conn Conn;

 struct GameState

 {

@@ -11,4 +12,11 @@

 struct Derivative

 {

 	double dx, dv;

+};

+

+struct Conn

+{

+	int *fds;

+	ulong off;

+	ulong cap;

 };

--- a/muswd.c

+++ b/muswd.c

@@ -9,8 +9,7 @@

 GameState state;

 double t, Δt;

-int *conns;

-int nconns;

+Conn conns;

 static long

 _iolisten(va_list *arg)

@@ -55,8 +54,15 @@

 			continue;

 		}

-		conns = erealloc(conns, ++nconns*sizeof(*conns));

-		conns[nconns-1] = dfd;

+		if(conns.off >= conns.cap){

+			conns.cap += 8;

+			conns.fds = erealloc(conns.fds, conns.cap*sizeof(*conns.fds));

+		}

+		conns.fds[conns.off++] = dfd;

+

+		if(debug)

+			fprint(2, "added conn %d for %lud conns at %lud max\n",

+				dfd, conns.off, conns.cap);

 	}

 }

@@ -89,9 +95,20 @@

 		then = now;

 		timeacc += frametime/1e9;

-		for(i = 0; i < nconns; i++)

-			fprint(conns[i], "state: x=%g v=%g\n", state.x, state.v);

+		for(i = 0; i < conns.off; i++)

+			if(fprint(conns.fds[i], "state: x=%g v=%g\n", state.x, state.v) < 0){

+				fprint(2, "client #%d hanged up\n", i+1);

+				if(conns.off < conns.cap-1)

+					memmove(&conns.fds[conns.off], &conns.fds[conns.off+1], conns.cap-conns.off - 1);

+				conns.off--;

+				if(debug)

+					fprint(2, "removed conn %d for %lud conns at %lud max\n",

+						i, conns.off, conns.cap);

+

+				i--;

+			}

+

 		while(timeacc >= Δt){

 			integrate(&state, t, Δt);

 			timeacc -= Δt;

@@ -128,6 +145,9 @@

 	acfd = announce("tcp!*!112", adir);

 	if(acfd < 0)

 		sysfatal("announce: %r");

+

+	conns.fds = emalloc(2*sizeof(*conns.fds));

+	conns.cap = 2;

 	threadcreate(threadlisten, adir, 4096);

 	threadcreate(threadsim, nil, 4096);