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implement Plumbmsg;
include "sys.m";
sys: Sys;
include "plumbmsg.m";
input: ref Sys->FD;
port: ref Sys->FD;
portname: string;
maxdatasize: int;
init(doinput: int, rcvport: string, maxdata: int): int
{
sys = load Sys Sys->PATH;
if(!doinput && rcvport == nil) # server, not client
return 1;
input = sys->open("/chan/plumb.input", Sys->OWRITE);
if(input == nil)
return -1;
if(rcvport == nil) # sending messages but never receiving them
return 1;
port = sys->open("/chan/plumb."+rcvport, Sys->OREAD);
if(port == nil){
input = nil;
return -1;
}
maxdatasize = maxdata;
portname = rcvport;
msg := ref Msg;
msg.src = portname;
msg.dst = "plumb";
msg.kind = "text";
msg.data = array of byte "start";
if(msg.send() < 0){
port = nil;
input = nil;
return -1;
}
return 1;
}
shutdown()
{
msg := ref Msg;
msg.src = portname;
msg.dst = "plumb";
msg.kind = "text";
msg.data = array of byte "stop";
msg.send();
}
Msg.send(msg: self ref Msg): int
{
hdr :=
msg.src+"\n"+
msg.dst+"\n"+
msg.dir+"\n"+
msg.kind+"\n"+
msg.attr+"\n"+
string len msg.data+"\n";
ahdr := array of byte hdr;
b := array[len ahdr+len msg.data] of byte;
b[0:] = ahdr;
b[len ahdr:] = msg.data;
return sys->write(input, b, len b);
}
Msg.recv(): ref Msg
{
b := array[maxdatasize+1000] of byte;
n := sys->read(port, b, len b);
if(n <= 0)
return nil;
return Msg.unpack(b[0:n]);
}
Msg.unpack(b: array of byte): ref Msg
{
(hdr, data) := unpack(b, 6);
if(hdr == nil)
return nil;
msg := ref Msg;
msg.src = hdr[0];
msg.dst = hdr[1];
msg.dir = hdr[2];
msg.kind = hdr[3];
msg.attr = hdr[4];
msg.data = data;
return msg;
}
Msg.pack(msg: self ref Msg): array of byte
{
hdr :=
msg.src+"\n"+
msg.dst+"\n"+
msg.dir+"\n"+
msg.kind+"\n"+
msg.attr+"\n"+
string len msg.data+"\n";
ahdr := array of byte hdr;
b := array[len ahdr+len msg.data] of byte;
b[0:] = ahdr;
b[len ahdr:] = msg.data;
return b;
}
# unpack message from array of bytes. last string in message
# is number of bytes in data portion of message
unpack(b: array of byte, ns: int): (array of string, array of byte)
{
i := 0;
a := array[ns] of string;
for(n:=0; n<ns; n++){
(i, a[n]) = unpackstring(b, i);
if(i < 0)
return (nil, nil);
}
nb := int a[ns-1];
if((len b)-i != nb){
sys->print("unpack: bad message format: wrong nbytes\n");
return (nil, nil);
}
# copy data so b can be reused or freed
data := array[nb] of byte;
data[0:] = b[i:];
return (a, data);
}
unpackstring(b: array of byte, i: int): (int, string)
{
starti := i;
while(i < len b){
if(b[i] == byte '\n')
return (i+1, string b[starti:i]);
i++;
}
return (-1, nil);
}
string2attrs(s: string): list of ref Attr
{
(nil, pairs) := sys->tokenize(s, "\t");
if(pairs == nil)
return nil;
attrs: list of ref Attr;
while(pairs != nil){
pair := hd pairs;
pairs = tl pairs;
a := ref Attr;
for(i:=0; i<len pair; i++)
if(pair[i] == '='){
a.name = pair[0:i];
if(++i < len pair)
a.val = pair[i:];
break;
}
attrs = a :: attrs;
}
return attrs;
}
attrs2string(l: list of ref Attr): string
{
s := "";
while(l != nil){
a := hd l;
l = tl l;
if(s == "")
s = a.name + "=" + a.val;
else
s += "\t" + a.name + "=" + a.val;
}
return s;
}
lookup(attrs: list of ref Attr, name: string): (int, string)
{
while(attrs != nil){
a := hd attrs;
attrs = tl attrs;
if(a.name == name)
return (1, a.val);
}
return (0, nil);
}
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