#include <stdio.h>
#include <unistd.h>	/* ioperm() */
#include <asm/io.h>

int portbase = 0;
unsigned char dlines = 0;	/* state of data lines */
unsigned char slines = 0;	/* status lines */
unsigned char clines = 0;	/* control lines */

/* enable: 0 disable line, 1 enable
 * line, no: e.g. 'D', '7' */
void doline(int enable,char line,char no) {
	int bit;

	switch (line) {
	case 'd': case 'D':
		if (no>='0' && no<='7') bit = no-'0';
		else {
			puts("invalid line number");
			return;
		}
		if (enable) dlines |= (1<<bit);
		else dlines &= ~(1<<bit);
		break;
	case 'c': case 'C':
		if (no>='0' && no<='3') bit = no-'0';
		else {
			puts("invalid line number");
			return;
		}
		if (bit != 2) enable = !enable;
		if (enable) clines |= (1<<bit);
		else clines &= ~(1<<bit);
		break;
	default:
		printf("I can't set line '%c'\n",line);
		return;
	}
}

void printline(int state,char *name) {
	if (state) printf("[%s]",name);
	else printf(" %s ",name);
}

void printd(unsigned char bits) {
	unsigned char mask = 1;
	int bit;

	for (bit = 0; bit < 8; bit++,mask<<=1)
		if (bits & mask) printf("[D%d]",bit);
		else printf(" D%d ",bit);
	putchar('\n');
}

void prints(unsigned char bits) {
	printline(bits & 8,"S3");
	printline(bits & 16,"S4");
	printline(bits & 32,"S5");
	printline(bits & 64,"S6");
	printline(!(bits & 128),"-S7");
	putchar('\n');
}

void printc(unsigned char bits) {
	printline(!(bits & 1),"-C0");
	printline(!(bits & 2),"-C1");
	printline(bits & 4,"C2");
	printline(!(bits & 8),"-C3");
	putchar('\n');
}

void help(void) {
	puts(	"Status output: [line] means that the line is high (+5V)\n"
		"Lines states are physical states, not logical.");
}

int main(int argc,char **argv) {
	char keybuff[80];

	while (!portbase) {
		puts("Choose parallel port: 0 lp0\t1 lpt1\t 2 lpt2");
		gets(keybuff);
		switch(keybuff[0]) {
		case '0': portbase = 0x3bc; break;
		case '1': portbase = 0x378; break;
		case '2': portbase = 0x278; break;
		}
	}

	printf("Using port base 0x%x\n",portbase);

	if (ioperm(portbase,3,1)) {
		perror("partest: trying to get port");
		puts("Check if you are root.");
		return 10;
	}

	dlines = inb(portbase);

	while (1) {
		outb(dlines,portbase);
		slines = inb(portbase+1);
		outb(clines,portbase+2);

		printf("Status:\t");
		printd(dlines);
		putchar('\t');
		printc(clines);
		putchar('\t');
		prints(slines);
		puts("Command?");
		puts("\t[+/-][line name]\te.g. +D0 enables D0 line");
		puts("\t? H\thelp");
		fflush(stdout);

		gets(keybuff);
		switch(keybuff[0]) {
		case '?': case 'h': case 'H': help(); break;
		case 'q': case 'Q':
			return 0;
		case '+': doline(1,keybuff[1],keybuff[2]); break;
		case '-': doline(0,keybuff[1],keybuff[2]); break;
		default: printf("I don't understand command '%c'\n",keybuff[0]);
			break;
		}
	}
}