ls9-io.nw

Low-level input/output

<<ls9 macros>>=
#define printb(s)	prints((char *) s)
#define nl()		prints("\n")
@

<<ls9 globals>>=
FILE	*Ports[NPORTS];
byte	Port_flags[NPORTS];

full	Inport = 0,
	Outport = 1,
	Errport = 2;

full	Outstr = NIL;
size_t	Outmax = 0;
size_t	Outptr = 0;

char	*Instr = NULL;
int	Rejected = -1;
@

<<ls9 impl>>=
int readc(void) {
	int	c;

	if (Instr != NULL) {
		if (Rejected > -1) {
			c = Rejected;
			Rejected = -1;
			return c;
		}
		if (0 == *Instr) {
			return EOF;
		}
		else {
			return *Instr++;
		}
	}
	else {
		if (NULL == Ports[Inport]) {
			fatal("readc: input port is not open");
		}
		return getc(Ports[Inport]);
	}
}

void rejectc(int c) {
	if (Instr != NULL) {
		Rejected = c;
	}
	else {
		ungetc(c, Ports[Inport]);
	}
}

void flush(void) {
	if (fflush(Ports[Outport]))
		error("file write error, port",
			mkport(Outport, T_OUTPORT));
}

void blockwrite(char *s, size_t k) {
	full	n;

	if (1 == Plimit) return;
	if (Outstr != NIL) {
		while (Outptr + k >= Outmax) {
			n = mkstr(NULL, Outmax+1000);
			memcpy(string(n), string(Outstr), Outptr);
			Outmax += 1000;
			Outstr = n;
		}
		memcpy(&string(Outstr)[Outptr], s, k);
		Outptr += k;
		string(Outstr)[Outptr] = 0;
		return;
	}
	if (NULL == Ports[Outport])
		fatal("blockwrite: output port is not open");
	if (fwrite(s, 1, k, Ports[Outport]) != k)
		error("file write error, port",
			mkport(Outport, T_OUTPORT));
	if ((1 == Outport || 2 == Outport) && '\n' == s[k-1])
		flush();
	if (Plimit) {
		Plimit -= k;
		if (Plimit < 1) Plimit = 1;
	}
}

void writec(int c) {
	char	b[1];

	b[0] = (char)c;
	blockwrite(b, 1);
}

void prints(char *s) {
	blockwrite(s, strlen(s));
}
@

High-level port I/O

<<ls9 impl>>=
full newport(void) {
	full	i, n;

	for (n=0; n<2; n++) {
		for (i=0; i<NPORTS; i++) {
			if (NULL == Ports[i])
				return i;
		}
		if (0 == n) gc();
	}
	return NIL;
}

full open_inport(char *path) {
	full	i;

	i = newport();
	if (NIL == i) return NIL;
	Ports[i] = fopen(path, "r");
	if (NULL == Ports[i]) return NIL;
	return i;
}

full open_outport(char *path, int append) {
	full	i;

	i = newport();
	if (NIL == i) return NIL;
	Ports[i] = fopen(path, append? "a": "w");
	if (NULL == Ports[i]) return NIL;
	return i;
}

full set_inport(full port) {
	full	p = Inport;

	Inport = port;
	return p;
}

full set_outport(full port) {
	full	p = Outport;

	Outport = port;
	return p;
}

void close_port(full port) {
	if (port >= NPORTS) {
		return;
	}
	if (NULL == Ports[port]) {
		Port_flags[port] = 0;
		return;
	}
	fclose(Ports[port]);
	Ports[port] = NULL;
	Port_flags[port] = 0;
}

void reset_stdports(void) {
	clearerr(stdin);
	clearerr(stdout);
	clearerr(stderr);
	Inport = 0;
	Outport = 1;
	Errport = 2;
}

full lock_port(full port) {
	if (port >= NPORTS) {
		return NIL;
	}
	Port_flags[port] |= LOCK_TAG;
	return TRUE;
}

full unlock_port(full port) {
	if (port >= NPORTS) {
		return NIL;
	}
	Port_flags[port] &= (byte)~LOCK_TAG;
	return TRUE;
}
@