From 63680c39395df87cb60cd6a096ffc48d72675b18 Mon Sep 17 00:00:00 2001
From: Ali Gholami Rudi <ali@rudi.ir>
Date: Wed, 9 Aug 2017 23:03:56 +0430
Subject: [PATCH] eqn: more comments

---
 box.c |  1 +
 eqn.c |  9 +++++++++
 tok.c | 22 ++++++++++------------
 3 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/box.c b/box.c
index 112fa3a..057a3f2 100644
--- a/box.c
+++ b/box.c
@@ -1,3 +1,4 @@
+/* equation boxes */
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/eqn.c b/eqn.c
index 389030a..c7f3b08 100644
--- a/eqn.c
+++ b/eqn.c
@@ -133,6 +133,7 @@ static int typenum(char *s)
 	return T_ORD;
 }
 
+/* read chartype command arguments and perform it */
 static void eqn_chartype(void)
 {
 	char gl[GNLEN], type[NMLEN];
@@ -142,6 +143,7 @@ static void eqn_chartype(void)
 		def_typeput(gl, typenum(type));
 }
 
+/* read breakcost command arguments and perform it */
 static void eqn_breakcost(void)
 {
 	char tok[NMLEN];
@@ -153,6 +155,7 @@ static void eqn_breakcost(void)
 		def_brcostput(type, cost);
 }
 
+/* read general eqn commands */
 static int eqn_commands(void)
 {
 	char var[LNLEN];
@@ -209,6 +212,7 @@ static int eqn_commands(void)
 	return 1;
 }
 
+/* read user-specified spaces */
 static int eqn_gaps(struct box *box, int szreg)
 {
 	if (!tok_jmp("~")) {
@@ -228,6 +232,7 @@ static int eqn_gaps(struct box *box, int szreg)
 	return 1;
 }
 
+/* return the font of the given token type */
 static char *tok_font(int tok, char *fn)
 {
 	if (fn && fn[0])
@@ -237,6 +242,7 @@ static char *tok_font(int tok, char *fn)
 	return grfont;
 }
 
+/* check the next token */
 static void tok_expect(char *s)
 {
 	if (tok_jmp(s)) {
@@ -246,6 +252,7 @@ static void tok_expect(char *s)
 	}
 }
 
+/* read pile command */
 static void eqn_pile(struct box *box, int sz0, char *fn0, int adj)
 {
 	struct box *pile[NPILES] = {NULL};
@@ -265,6 +272,7 @@ static void eqn_pile(struct box *box, int sz0, char *fn0, int adj)
 		box_free(pile[i]);
 }
 
+/* read matrix command */
 static void eqn_matrix(struct box *box, int sz0, char *fn0)
 {
 	struct box *cols[NPILES][NPILES] = {{NULL}};
@@ -309,6 +317,7 @@ static void eqn_matrix(struct box *box, int sz0, char *fn0)
 				box_free(cols[i][j]);
 }
 
+/* return nonzero if fn is italic */
 static int italic(char *fn)
 {
 	return (!strcmp("I", fn) || !strcmp("2", fn) ||
diff --git a/tok.c b/tok.c
index 319293f..7a09f5a 100644
--- a/tok.c
+++ b/tok.c
@@ -265,19 +265,17 @@ void tok_eqnout(char *s)
 /* return the length of a utf-8 character based on its first byte */
 static int utf8len(int c)
 {
-	if (c > 0 && c <= 0x7f)
+	if (~c & 0x80)
+		return c > 0;
+	if (~c & 0x40)
 		return 1;
-	if (c >= 0xfc)
-		return 6;
-	if (c >= 0xf8)
-		return 5;
-	if (c >= 0xf0)
-		return 4;
-	if (c >= 0xe0)
-		return 3;
-	if (c >= 0xc0)
+	if (~c & 0x20)
 		return 2;
-	return c != 0;
+	if (~c & 0x10)
+		return 3;
+	if (~c & 0x08)
+		return 4;
+	return 1;
 }
 
 /* return the type of a token */
@@ -425,7 +423,7 @@ int tok_type(void)
 	return tok[0] ? tok_curtype : 0;
 }
 
-/* return nonzero if current token is a chops the equation */
+/* return nonzero if current token chops the equation */
 int tok_chops(int soft)
 {
 	if (!tok_get() || tok_curtype == T_KEYWORD)
-- 
2.11.4.GIT