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src/cmd/htmlroff/t1.c

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+#include "a.h"
+ 
+/*
+ * Section 1 - General Explanation.
+ */
+
+/* 1.3 - Numerical parameter input.  */
+char *units = "icPmnpuvx";
+int
+scale2units(char c)
+{
+	int x;
+	
+	switch(c){
+	case 'i':	/* inch */
+		return UPI;
+	case 'c':	/* centimeter */
+		return 0.3937008 * UPI;
+	case 'P':	/* pica = 1/6 inch */
+		return UPI / 6;
+	case 'm':	/* em = S points */
+		return UPI / 72.0 * getnr(L(".s"));
+	case 'n':	/* en = em/2 */
+		return UPI / 72.0 * getnr(L(".s")) / 2;
+	case 'p':	/* point = 1/72 inch */
+		return UPI / 72;
+	case 'u':	/* basic unit */
+		return 1;
+	case 'v':	/* vertical line space V */
+		x = getnr(L(".v"));
+		if(x == 0)
+			x = 12 * UPI / 72;
+		return x;
+	case 'x':	/* pixel (htmlroff addition) */
+		return UPX;
+	default:
+		return 1;
+	}
+}
+
+/* 1.4 - Numerical expressions. */
+int eval0(Rune**, int, int);
+int
+eval(Rune *s)
+{
+	return eval0(&s, 1, 1);
+}
+long
+runestrtol(Rune *a, Rune **p)
+{
+	long n;
+	
+	n = 0;
+	while('0' <= *a && *a <= '9'){
+		n = n*10 + *a-'0';
+		a++;
+	}
+	*p = a;
+	return n;
+}
+
+int
+evalscale(Rune *s, int c)
+{
+	return eval0(&s, scale2units(c), 1);
+}
+
+int
+eval0(Rune **pline, int scale, int recur)
+{
+	Rune *p;
+	int neg;
+	double f, p10;
+	int x, y;
+
+	neg = 0;
+	p = *pline;
+	while(*p == '-'){
+		neg = 1 - neg;
+		p++;
+	}
+	if(*p == '('){
+		p++;
+		x = eval0(&p, scale, 1);
+		if (*p != ')'){
+			*pline = p;
+			return x;
+		}
+		p++;
+	}else{
+		f = runestrtol(p, &p);
+		if(*p == '.'){
+			p10 = 1.0;
+			p++;
+			while('0' <= *p && *p <= '9'){
+				p10 /= 10;
+				f += p10*(*p++ - '0');
+			}
+		}
+		if(*p && strchr(units, *p)){
+			if(scale)
+				f *= scale2units(*p);
+			p++;
+		}else if(scale)
+			f *= scale;
+		x = f;
+	}
+	if(neg)
+		x = -x;
+	if(!recur){
+		*pline = p;
+		return x;
+	}
+	
+	while(*p){
+		switch(*p++) {
+		case '+':
+			x += eval0(&p, scale, 0);
+			continue;
+		case '-':
+			x -= eval0(&p, scale, 0);
+			continue;
+		case '*':
+			x *= eval0(&p, scale, 0);
+			continue;
+		case '/':
+			y = eval0(&p, scale, 0);
+			if (y == 0) {
+				fprint(2, "%L: divide by zero %S\n", p);
+				y = 1;
+			}
+			x /= y;
+			continue;
+		case '%':
+			y = eval0(&p, scale, 0);
+			if (!y) {
+				fprint(2, "%L: modulo by zero %S\n", p);
+				y = 1;
+			}
+			x %= y;
+			continue;
+		case '<':
+			if (*p == '=') {
+				p++;
+				x = x <= eval0(&p, scale, 0);
+				continue;
+			}
+			x = x < eval0(&p, scale, 0);
+			continue;
+		case '>':
+			if (*p == '=') {
+				p++;
+				x = x >= eval0(&p, scale, 0);
+				continue;
+			}
+			x = x > eval0(&p, scale, 0);
+			continue;
+		case '=':
+			if (*p == '=')
+				p++;
+			x = x == eval0(&p, scale, 0);
+			continue;
+		case '&':
+			x &= eval0(&p, scale, 0);
+			continue;
+		case ':':
+			x |= eval0(&p, scale, 0);
+			continue;
+		}
+	}
+	*pline = p;
+	return x;
+}
+
+void
+t1init(void)
+{
+	Tm tm;
+	
+	tm = *localtime(time(0));
+	nr(L("dw"), tm.wday+1);
+	nr(L("dy"), tm.mday);
+	nr(L("mo"), tm.mon);
+	nr(L("yr"), tm.year%100);
+}
+