This patch address two problems.

1st one is relatively minor: according our own manpage, upper and lower
classes must be sorted, but currently not.

2nd one is serious:
	tr '[:lower:]' '[:upper:]'
	(and vice versa) currently works only if upper and lower classes
	have exact the same number of elements. When it is not true, like for
	many ISO8859-x locales which have bigger amount of lowercase letters,
	tr may do nasty things.

	See this page
	http://www.opengroup.org/onlinepubs/007908799/xcu/tr.html
	for detailed description of desired tr behaviour in such cases.

usr.bin/tr/extern.h

@@ -40,7 +40,8 @@
 
 typedef struct {
 	enum { STRING1, STRING2 } which;
-	enum { EOS, INFINITE, NORMAL, RANGE, SEQUENCE, SET } state;
+	enum { EOS, INFINITE, NORMAL, RANGE, SEQUENCE,
+	       SET, SET_UPPER, SET_LOWER } state;
 	int	 cnt;			/* character count */
 	int	 lastch;		/* last character */
 	int	equiv[NCHARS];		/* equivalence set */
@@ -49,3 +50,5 @@ typedef struct {
 } STR;
 
 int	 next(STR *);
+int charcoll(const void *, const void *);
+

usr.bin/tr/str.c

@@ -106,6 +106,8 @@ next(s)
 		}
 		return (1);
 	case SET:
+	case SET_UPPER:
+	case SET_LOWER:
 		if ((s->lastch = s->set[s->cnt++]) == OOBCH) {
 			s->state = NORMAL;
 			return (next(s));
@@ -194,7 +196,7 @@ genclass(s)
 {
 	int cnt, (*func)(int);
 	CLASS *cp, tmp;
-	int *p;
+	int *p, n;
 
 	tmp.name = s->str;
 	if ((cp = (CLASS *)bsearch(&tmp, classes, sizeof(classes) /
@@ -208,10 +210,18 @@ genclass(s)
 		if ((func)(cnt))
 			*p++ = cnt;
 	*p = OOBCH;
+	n = p - cp->set;
 
 	s->cnt = 0;
-	s->state = SET;
 	s->set = cp->set;
+	if (strcmp(s->str, "upper") == 0)
+		s->state = SET_UPPER;
+	else if (strcmp(s->str, "lower") == 0) {
+		s->state = SET_LOWER;
+	} else
+		s->state = SET;
+	if ((s->state == SET_LOWER || s->state == SET_UPPER) && n > 1)
+		mergesort(s->set, n, sizeof(*(s->set)), charcoll);
 }
 
 static int

usr.bin/tr/tr.c

@@ -101,7 +101,6 @@ static int string1[NCHARS] = {
 STR s1 = { STRING1, NORMAL, 0, OOBCH, { 0, OOBCH }, NULL, NULL };
 STR s2 = { STRING2, NORMAL, 0, OOBCH, { 0, OOBCH }, NULL, NULL };
 
-static int charcoll(const void *, const void *);
 static void setup(int *, char *, STR *, int, int);
 static void usage(void);
 
@@ -224,20 +223,55 @@ main(int argc, char **argv)
 	if (!next(&s2))
 		errx(1, "empty string2");
 
-	ch = s2.lastch;
+	/*
-	/* If string2 runs out of characters, use the last one specified. */
+	 * For -s result will contain only those characters defined
-	if (sflag)
+	 * as the second characters in each of the toupper or tolower
-		while (next(&s1)) {
+	 * pairs.
-			string1[s1.lastch] = ch = s2.lastch;
+	 */
-			string2[ch] = 1;
-			(void)next(&s2);
-		}
-	else
-		while (next(&s1)) {
-			string1[s1.lastch] = ch = s2.lastch;
-			(void)next(&s2);
-		}
 
+	/* If string2 runs out of characters, use the last one specified. */
+	while (next(&s1)) {
+	again:
+		if (s1.state == SET_LOWER &&
+		    s2.state == SET_UPPER &&
+		    s1.cnt == 1 && s2.cnt == 1) {
+			do {
+				string1[s1.lastch] = ch = toupper(s1.lastch);
+				if (sflag && isupper(ch))
+					string2[ch] = 1;
+				if (!next(&s1))
+					goto endloop;
+			} while (s1.state == SET_LOWER && s1.cnt > 1);
+			/* skip upper set */
+			do {
+				if (!next(&s2))
+					break;
+			} while (s2.state == SET_UPPER && s2.cnt > 1);
+			goto again;
+		} else if (s1.state == SET_UPPER &&
+			   s2.state == SET_LOWER &&
+			   s1.cnt == 1 && s2.cnt == 1) {
+			do {
+				string1[s1.lastch] = ch = tolower(s1.lastch);
+				if (sflag && islower(ch))
+					string2[ch] = 1;
+				if (!next(&s1))
+					goto endloop;
+			} while (s1.state == SET_UPPER && s1.cnt > 1);
+			/* skip lower set */
+			do {
+				if (!next(&s2))
+					break;
+			} while (s2.state == SET_LOWER && s2.cnt > 1);
+			goto again;
+		} else {
+			string1[s1.lastch] = s2.lastch;
+			if (sflag)
+				string2[s2.lastch] = 1;
+		}
+		(void)next(&s2);
+	}
+endloop:
 	if (cflag || Cflag) {
 		s2.str = argv[1];
 		s2.state = NORMAL;
@@ -294,15 +328,18 @@ setup(int *string, char *arg, STR *str, int cflag, int Cflag)
 			string[cnt] = !string[cnt] && ISCHAR(cnt);
 }
 
-static int
+int
 charcoll(const void *a, const void *b)
 {
-	char sa[2], sb[2];
+	static char sa[2], sb[2];
+	int r;
 
 	sa[0] = *(const int *)a;
 	sb[0] = *(const int *)b;
-	sa[1] = sb[1] = '\0';
+	r = strcoll(sa, sb);
-	return (strcoll(sa, sb));
+	if (r == 0)
+		r = *(const int *)a - *(const int *)b;
+	return (r);
 }
 
 static void