1 files changed, 135 insertions, 0 deletions
diff --git a/src/cmd/eqn/paren.c b/src/cmd/eqn/paren.c
new file mode 100644
index 00000000..bb019bf7
--- /dev/null
+++ b/src/cmd/eqn/paren.c
@@ -0,0 +1,135 @@
+#include "e.h"
+
+#define abs(x) ((x) > 0 ? (x) : (-(x)))
+
+extern void brack(int, char *, char *, char *);
+
+void paren(int leftc, int p1, int rightc)
+{
+	int n, m, j;
+	double h1, b1;
+	double v, bv;	/* v = shift of inside, bv = shift of brackets */
+	extern double Parenbase, Parenshift, Parenheight;
+
+	bv = ttype == DEVPOST ? Parenshift : 0;	/* move brackets down this much */
+	h1 = eht[p1];
+	b1 = ebase[p1];
+	yyval = p1;
+	lfont[yyval] = rfont[yyval] = 0;
+	n = REL(h1,ps) + 0.99;	/* ceiling */
+	if (n < 2)
+		n = 1;
+	m = n - 2;
+	if (leftc == '{' || rightc == '}') {
+		n = n%2 ? n : ++n;
+		if (n < 3)
+			n = 3;
+		m = n-3;
+	}
+	eht[yyval] = EM((double) n + Parenheight, ps);
+	ebase[yyval] = eht[yyval]/2 - EM(Parenbase, ps);
+
+	/* try to cope with things that are badly centered */
+	/* (top heavy or bottom heavy) */
+	if (abs(h1/2 - b1) >= EM(0.5, ps))
+		v = REL(-ebase[yyval] + (eht[yyval]-h1)/2 + b1, ps);
+	else
+		v = 0;	/* don't shift it at all */
+
+	printf(".ds %d \\^", yyval);	/* was \| */
+	if (bv)
+		printf("\\v'%gm'", bv);
+	switch (leftc) {
+	case 'n':	/* nothing */
+	case '\0':
+		break;
+	case 'f':	/* floor */
+		if (n <= 1)
+			printf("\\(lf");
+		else
+			brack(m, "\\(bv", "\\(bv", "\\(lf");
+		break;
+	case 'c':	/* ceiling */
+		if (n <= 1)
+			printf("\\(lc");
+		else
+			brack(m, "\\(lc", "\\(bv", "\\(bv");
+		break;
+	case '{':
+		printf("\\b'\\(lt");
+		for(j = 0; j < m; j += 2) printf("\\(bv");
+		printf("\\(lk");
+		for(j = 0; j < m; j += 2) printf("\\(bv");
+		printf("\\(lb'");
+		break;
+	case '(':
+		brack(m, "\\(lt", "\\(bv", "\\(lb");
+		break;
+	case '[':
+		brack(m, "\\(lc", "\\(bv", "\\(lf");
+		break;
+	case '|':
+		brack(m, "|", "|", "|");
+		break;
+	default:
+		brack(m, (char *) &leftc, (char *) &leftc, (char *) &leftc);
+		break;
+	}
+	if (bv)
+		printf("\\v'%gm'", -bv);
+	if (v)
+		printf("\\v'%gm'\\*(%d\\v'%gm'", -v, p1, v);
+	else
+		printf("\\*(%d", p1);
+	if (rightc) {
+		if (bv)
+			printf("\\v'%gm'", bv);
+		switch (rightc) {
+		case 'f':	/* floor */
+			if (n <= 1)
+				printf("\\(rf");
+			else
+				brack(m, "\\(bv", "\\(bv", "\\(rf");
+			break;
+		case 'c':	/* ceiling */
+			if (n <= 1)
+				printf("\\(rc");
+			else
+				brack(m, "\\(rc", "\\(bv", "\\(bv");
+			break;
+		case '}':
+			printf("\\b'\\(rt");
+			for(j = 0; j < m; j += 2) printf("\\(bv");
+			printf("\\(rk");
+			for(j = 0; j < m; j += 2) printf("\\(bv");
+			printf("\\(rb'");
+			break;
+		case ']':
+			brack(m, "\\(rc", "\\(bv", "\\(rf");
+			break;
+		case ')':
+			brack(m, "\\(rt", "\\(bv", "\\(rb");
+			break;
+		case '|':
+			brack(m, "|", "|", "|");
+			break;
+		default:
+			brack(m, (char *) &rightc, (char *) &rightc, (char *) &rightc);
+			break;
+		}
+		if (bv)
+			printf("\\v'%gm'", -bv);
+	}
+	printf("\n");
+	dprintf(".\tcurly: h=%g b=%g n=%d v=%g l=%c, r=%c\n", 
+		eht[yyval], ebase[yyval], n, v, leftc, rightc);
+}
+
+void brack(int m, char *t, char *c, char *b)
+{
+	int j;
+	printf("\\b'%s", t);
+	for( j=0; j < m; j++)
+		printf("%s", c);
+	printf("%s'", b);
+}