#include <u.h>#include <libc.h>#include <ctype.h>#include <draw.h>#include <event.h> typedef struct Op Op;typedef struct Operator Operator;typedef struct Token Token;typedef struct Constant Constant;typedef struct Code Code; enum {	ONONE,	ONUMBER,	OVAR,	OUNARY,	OBINARY,}; struct Op {	int type;	union {		void (*f)(void);		double val;	};}; enum {	TNONE,	TNUMBER,	TVAR,	TOP,	TPARENL,	TPARENR,}; struct Token {	int type;	union {		Operator *op;		double val;	};	Token *next;}; double *stack, *sp;void add(void) { sp--; *sp += *(sp+1); }void sub(void) { sp--; *sp -= *(sp+1); }void mul(void) { sp--; *sp *= *(sp+1); }void div(void) { sp--; *sp /= *(sp+1); }void pot(void) { sp--; *sp = pow(*sp, *(sp+1)); }void osin(void) { *sp = sin(*sp); }void ocos(void) { *sp = cos(*sp); }void otan(void) { *sp = tan(*sp); }void oasin(void) { *sp = asin(*sp); }void oacos(void) { *sp = acos(*sp); }void oatan(void) { *sp = atan(*sp); }void osqrt(void) { *sp = sqrt(*sp); }void olog(void) { *sp = log10(*sp); }void oln(void) { *sp = log(*sp); } struct Operator {	char *s;	char type;	char rassoc;	short prec;	void (*f)(void);} ops[] = {	"+",	OBINARY,	0,	0,	add,	"-",	OBINARY,	0,	0,	sub,	"*",	OBINARY,	0,	100,	mul,	"/",	OBINARY,	0,	100,	div,	"^",	OBINARY,	1,	200,	pot,	"sin",	OUNARY,		0,	50,	osin,	"cos",	OUNARY,		0,	50,	ocos,	"tan",	OUNARY,		0,	50,	otan,	"asin",	OUNARY,		0,	50,	oasin,	"acos",	OUNARY,		0,	50,	oacos,	"atan",	OUNARY,		0,	50,	oatan,	"sqrt",	OUNARY,		0,	50,	osqrt,	"log",	OUNARY,		0,	50,	olog,	"ln",	OUNARY,		0,	50,	oln,}; struct Constant {	char *s;	double val;} consts[] = {	"pi",	3.14159265359,	"π",	3.14159265359,	"e",	2.71828182846,}; struct Code {	Op* p;	int len, cap;} *fns;int nfns; Token *opstackbot;double xmin = -10, xmax = 10;double ymin = -10, ymax = 10;Image *color;int cflag;char *imagedata;int picx = 640, picy = 480; void *emalloc(int size){	void *v;		v = mallocz(size, 1);	if(v == nil)		sysfatal("emalloc: %r");	setmalloctag(v, getcallerpc(&size));	return v;} voidaddop(Code *c, Op o){	if(c->len >= c->cap) {		c->cap += 32;		c->p = realloc(c->p, sizeof(Op) * c->cap);		if(c->p == nil)			sysfatal("realloc: %r");	}	c->p[c->len++] = o;} voidpush(Token *t){	t->next = opstackbot;	opstackbot = t;} voidpop(Code *c){	Token *t;	Op o;		t = opstackbot;	if(t == nil)		sysfatal("stack underflow");	opstackbot = t->next;	if(t->type != TOP)		sysfatal("non-operator pop");	o.type = t->op->type;	o.f = t->op->f;	addop(c, o);	free(t);} voidpopdel(void){	Token *t;		t = opstackbot;	opstackbot = t->next;	free(t);} Token *lex(char **s){	Token *t;	Operator *o;	Constant *c; 	while(isspace(**s))		(*s)++;	if(**s == 0)		return nil;		t = emalloc(sizeof(*t));	if(isdigit(**s)) {		t->type = TNUMBER;		t->val = strtod(*s, s);		return t;	}	if(**s == '(') {		t->type = TPARENL;		(*s)++;		return t;	}	if(**s == ')') {		t->type = TPARENR;		(*s)++;		return t;	}	if(**s == 'x') {		t->type = TVAR;		(*s)++;		return t;	}	for(o = ops; o < ops + nelem(ops); o++)		if(strncmp(*s, o->s, strlen(o->s)) == 0) {			t->type = TOP;			t->op = o;			*s += strlen(o->s);			return t;		}	for(c = consts; c < consts + nelem(consts); c++)		if(strncmp(*s, c->s, strlen(c->s)) == 0) {			t->type = TNUMBER;			t->val = c->val;			*s += strlen(c->s);			return t;		}	sysfatal("syntax error at %s", *s);	return nil;} voidparse(Code *c, char *s){	Token *t;	Op o;		while(t = lex(&s)) {		switch(t->type) {		case TNUMBER:			o.type = ONUMBER;			o.val = t->val;			addop(c, o);			free(t);			break;		case TVAR:			o.type = OVAR;			addop(c, o);			free(t);			break;		case TOP:			if(t->op->type == OBINARY)				while(opstackbot != nil && opstackbot->type == TOP &&					(opstackbot->op->prec > t->op->prec ||					t->op->rassoc && opstackbot->op->prec == t->op->prec))					pop(c);			push(t);			break;		case TPARENL:			push(t);			break;		case TPARENR:			while(opstackbot != nil && opstackbot->type == TOP)				pop(c);			if(opstackbot == nil)				sysfatal("mismatched parentheses");			popdel();			free(t);			break;		default:			sysfatal("unknown token type %d", t->type);		}	}	while(opstackbot != nil)		switch(opstackbot->type) {		case TOP:			pop(c);			break;		case TPARENL:			sysfatal("mismatched parentheses");		default:			sysfatal("syntax error");		}} intcalcstack(Code *c){	int cur, max;	Op *o;		cur = 0;	max = 0;	for(o = c->p; o < c->p + c->len; o++)		switch(o->type) {		case ONUMBER: case OVAR:			if(++cur > max)				max = cur;			break;		case OUNARY:			if(cur == 0)				sysfatal("syntax error");			break;		case OBINARY:			if(cur <= 1)				sysfatal("syntax error");			cur--;			break;		} 	if(cur != 1)		sysfatal("syntax error");	return max;} doublecalc(Code *c, double x){	Op *o;		sp = stack - 1;	for(o = c->p; o < c->p + c->len; o++)		switch(o->type) {		case ONUMBER:			*++sp = o->val;			break;		case OVAR:			*++sp = x;			break;		case OUNARY: case OBINARY:			o->f();		}	return *sp;} doubleconvx(Rectangle *r, int x){	return (xmax - xmin) * (x - r->min.x) / (r->max.x - r->min.x) + xmin;} intdeconvx(Rectangle *r, double dx){	return (dx - xmin) * (r->max.x - r->min.x) / (xmax - xmin) + r->min.x + 0.5;} doubleconvy(Rectangle *r, int y){	return (ymax - ymin) * (r->max.y - y) / (r->max.y - r->min.y) + ymin;} intdeconvy(Rectangle *r, double dy){	return (ymax - dy) * (r->max.y - r->min.y) / (ymax - ymin) + r->min.y + 0.5;} voidpixel(int x, int y){	char *p; 	if(cflag) {		if(x >= picx || y >= picy || x < 0 || y < 0)			return;		p = imagedata + (picx * y + x) * 3;		p[0] = p[1] = p[2] = 0;	} else		draw(screen, Rect(x, y, x + 1, y + 1), color, nil, ZP);} voiddrawinter(Code *co, Rectangle *r, double x1, double x2, int n){	double y1, y2;	int iy1, iy2;	int ix1, ix2; 	ix1 = deconvx(r, x1);	ix2 = deconvx(r, x2);	iy1 = iy2 = 0;	y1 = calc(co, x1);	if(!isNaN(y1)) {		iy1 = deconvy(r, y1);		pixel(ix1, iy1);	}	y2 = calc(co, x2);	if(!isNaN(y2)) {		iy2 = deconvy(r, y2);		pixel(ix2, iy2);	}	if(isNaN(y1) || isNaN(y2))		return;	if(n >= 10)		return;	if(iy2 >= iy1 - 1 && iy2 <= iy1 + 1)		return;	if(iy1 > r->max.y && iy2 > r->max.y)		return;	if(iy1 < r->min.y && iy2 < r->min.y)		return;	drawinter(co, r, x1, (x1 + x2) / 2, n + 1);	drawinter(co, r, (x1 + x2) / 2, x2, n + 1);} voiddrawgraph(Code *co, Rectangle *r){	int x;		for(x = r->min.x; x < r->max.x; x++)		drawinter(co, r, convx(r, x), convx(r, x + 1), 0);} voiddrawgraphs(void){	int i;		color = display->black;	for(i = 0; i < nfns; i++)		drawgraph(&fns[i], &screen->r);	flushimage(display, 1);} voidusage(void){	fprint(2, "usage: fplot [-c [-s size]] [-r range] functions ...\n");	exits("usage");} voidzoom(void){	Mouse m;	Rectangle r;	double xmin_, xmax_, ymin_, ymax_;		m.buttons = 7;	r = egetrect(1, &m);	if(r.min.x == 0 && r.min.y == 0 && r.max.x == 0 && r.max.y == 0)		return;	xmin_ = convx(&screen->r, r.min.x);	xmax_ = convx(&screen->r, r.max.x);	ymin_ = convy(&screen->r, r.max.y);	ymax_ = convy(&screen->r, r.min.y);	xmin = xmin_;	xmax = xmax_;	ymin = ymin_;	ymax = ymax_;	draw(screen, screen->r, display->white, nil, ZP);	drawgraphs();} voidparsefns(int n, char **s){	int i, max, cur; 	max = 0;	nfns = n;	fns = emalloc(sizeof(*fns) * n);	for(i = 0; i < nfns; i++) {		parse(&fns[i], s[i]);		cur = calcstack(&fns[i]);		if(cur > max)			max = cur;	}	stack = emalloc(sizeof(*stack) * max);} voidparserange(char *s){	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	xmin = strtod(s, &s);	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	xmax = strtod(s, &s);	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	ymin = strtod(s, &s);	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	ymax = strtod(s, &s);} voidparsesize(char *s){	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	picx = strtol(s, &s, 0);	while(*s && !isdigit(*s)) s++;	if(*s == 0) return;	picy = strtol(s, &s, 0);} voidmain(int argc, char **argv){	Event e;	Rectangle r;	int i; 	ARGBEGIN {	case 'r': parserange(EARGF(usage())); break;	case 's': parsesize(EARGF(usage())); break;	case 'c': cflag++; break;

Lines 1–500 of 543. Load more