st.c: straight-forward comparison of characters

These functions are used in strcasehash, which is used to store encoding
names.  Encoding names often include hyphens (e.g. "UTF-8"), and
` '-' - 'A' ` is negative (cannot express in unsigned int).

Don't be tricky, just do what to do.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65621 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

st.c

@@ -2011,18 +2011,18 @@ strhash(st_data_t arg)
 int
 st_locale_insensitive_strcasecmp(const char *s1, const char *s2)
 {
-    unsigned int c1, c2;
+    char c1, c2;
 
     while (1) {
-        c1 = (unsigned char)*s1++;
-        c2 = (unsigned char)*s2++;
+        c1 = *s1++;
+        c2 = *s2++;
         if (c1 == '\0' || c2 == '\0') {
             if (c1 != '\0') return 1;
             if (c2 != '\0') return -1;
             return 0;
         }
-        if ((unsigned int)(c1 - 'A') <= ('Z' - 'A')) c1 += 'a' - 'A';
-        if ((unsigned int)(c2 - 'A') <= ('Z' - 'A')) c2 += 'a' - 'A';
+        if (('A' <= c1) && (c1 <= 'Z')) c1 += 'a' - 'A';
+        if (('A' <= c2) && (c2 <= 'Z')) c2 += 'a' - 'A';
         if (c1 != c2) {
             if (c1 > c2)
                 return 1;
@@ -2035,18 +2035,18 @@ st_locale_insensitive_strcasecmp(const char *s1, const char *s2)
 int
 st_locale_insensitive_strncasecmp(const char *s1, const char *s2, size_t n)
 {
-    unsigned int c1, c2;
+    char c1, c2;
 
     while (n--) {
-        c1 = (unsigned char)*s1++;
-        c2 = (unsigned char)*s2++;
+        c1 = *s1++;
+        c2 = *s2++;
         if (c1 == '\0' || c2 == '\0') {
             if (c1 != '\0') return 1;
             if (c2 != '\0') return -1;
             return 0;
         }
-        if ((unsigned int)(c1 - 'A') <= ('Z' - 'A')) c1 += 'a' - 'A';
-        if ((unsigned int)(c2 - 'A') <= ('Z' - 'A')) c2 += 'a' - 'A';
+        if (('A' <= c1) && (c1 <= 'Z')) c1 += 'a' - 'A';
+        if (('A' <= c2) && (c2 <= 'Z')) c2 += 'a' - 'A';
         if (c1 != c2) {
             if (c1 > c2)
                 return 1;