Remove unused single-byte char_is_cased() API.

https://postgr.es/m/450ceb6260cad30d7afdf155d991a9caafee7c0d.camel@j-davis.com

src/backend/utils/adt/pg_locale.c

@@ -1625,21 +1625,6 @@ pg_towlower(pg_wchar wc, pg_locale_t locale)
 		return locale->ctype->wc_tolower(wc, locale);
 }
 
-/*
- * char_is_cased()
- *
- * Fuzzy test of whether the given char is case-varying or not. The argument
- * is a single byte, so in a multibyte encoding, just assume any non-ASCII
- * char is case-varying.
- */
-bool
-char_is_cased(char ch, pg_locale_t locale)
-{
-	if (locale->ctype == NULL)
-		return (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z');
-	return locale->ctype->char_is_cased(ch, locale);
-}
-
 /*
  * Return required encoding ID for the given locale, or -1 if any encoding is
  * valid for the locale.

src/backend/utils/adt/pg_locale_builtin.c

@@ -191,13 +191,6 @@ wc_iscased_builtin(pg_wchar wc, pg_locale_t locale)
 	return pg_u_prop_cased(to_char32(wc));
 }
 
-static bool
-char_is_cased_builtin(char ch, pg_locale_t locale)
-{
-	return IS_HIGHBIT_SET(ch) ||
-		(ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z');
-}
-
 static pg_wchar
 wc_toupper_builtin(pg_wchar wc, pg_locale_t locale)
 {
@@ -225,7 +218,6 @@ static const struct ctype_methods ctype_methods_builtin = {
 	.wc_ispunct = wc_ispunct_builtin,
 	.wc_isspace = wc_isspace_builtin,
 	.wc_isxdigit = wc_isxdigit_builtin,
-	.char_is_cased = char_is_cased_builtin,
 	.wc_iscased = wc_iscased_builtin,
 	.wc_tolower = wc_tolower_builtin,
 	.wc_toupper = wc_toupper_builtin,

src/backend/utils/adt/pg_locale_icu.c

@@ -121,13 +121,6 @@ static int32_t u_strFoldCase_default(UChar *dest, int32_t destCapacity,
 									 const char *locale,
 									 UErrorCode *pErrorCode);
 
-static bool
-char_is_cased_icu(char ch, pg_locale_t locale)
-{
-	return IS_HIGHBIT_SET(ch) ||
-		(ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z');
-}
-
 /*
  * XXX: many of the functions below rely on casts directly from pg_wchar to
  * UChar32, which is correct for the UTF-8 encoding, but not in general.
@@ -244,7 +237,6 @@ static const struct ctype_methods ctype_methods_icu = {
 	.wc_ispunct = wc_ispunct_icu,
 	.wc_isspace = wc_isspace_icu,
 	.wc_isxdigit = wc_isxdigit_icu,
-	.char_is_cased = char_is_cased_icu,
 	.wc_iscased = wc_iscased_icu,
 	.wc_toupper = toupper_icu,
 	.wc_tolower = tolower_icu,

src/backend/utils/adt/pg_locale_libc.c

@@ -262,17 +262,6 @@ wc_iscased_libc_mb(pg_wchar wc, pg_locale_t locale)
 		iswlower_l((wint_t) wc, locale->lt);
 }
 
-static bool
-char_is_cased_libc(char ch, pg_locale_t locale)
-{
-	bool		is_multibyte = pg_database_encoding_max_length() > 1;
-
-	if (is_multibyte && IS_HIGHBIT_SET(ch))
-		return true;
-	else
-		return isalpha_l((unsigned char) ch, locale->lt);
-}
-
 static pg_wchar
 toupper_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
@@ -345,7 +334,6 @@ static const struct ctype_methods ctype_methods_libc_sb = {
 	.wc_ispunct = wc_ispunct_libc_sb,
 	.wc_isspace = wc_isspace_libc_sb,
 	.wc_isxdigit = wc_isxdigit_libc_sb,
-	.char_is_cased = char_is_cased_libc,
 	.wc_iscased = wc_iscased_libc_sb,
 	.wc_toupper = toupper_libc_sb,
 	.wc_tolower = tolower_libc_sb,
@@ -371,7 +359,6 @@ static const struct ctype_methods ctype_methods_libc_other_mb = {
 	.wc_ispunct = wc_ispunct_libc_sb,
 	.wc_isspace = wc_isspace_libc_sb,
 	.wc_isxdigit = wc_isxdigit_libc_sb,
-	.char_is_cased = char_is_cased_libc,
 	.wc_iscased = wc_iscased_libc_sb,
 	.wc_toupper = toupper_libc_sb,
 	.wc_tolower = tolower_libc_sb,
@@ -393,7 +380,6 @@ static const struct ctype_methods ctype_methods_libc_utf8 = {
 	.wc_ispunct = wc_ispunct_libc_mb,
 	.wc_isspace = wc_isspace_libc_mb,
 	.wc_isxdigit = wc_isxdigit_libc_mb,
-	.char_is_cased = char_is_cased_libc,
 	.wc_iscased = wc_iscased_libc_mb,
 	.wc_toupper = toupper_libc_mb,
 	.wc_tolower = tolower_libc_mb,

src/include/utils/pg_locale.h

@@ -125,9 +125,6 @@ struct ctype_methods
 	bool		(*wc_iscased) (pg_wchar wc, pg_locale_t locale);
 	pg_wchar	(*wc_toupper) (pg_wchar wc, pg_locale_t locale);
 	pg_wchar	(*wc_tolower) (pg_wchar wc, pg_locale_t locale);
-
-	/* required */
-	bool		(*char_is_cased) (char ch, pg_locale_t locale);
 };
 
 /*
@@ -178,7 +175,6 @@ extern pg_locale_t pg_newlocale_from_collation(Oid collid);
 
 extern char *get_collation_actual_version(char collprovider, const char *collcollate);
 
-extern bool char_is_cased(char ch, pg_locale_t locale);
 extern size_t pg_strlower(char *dst, size_t dstsize,
 						  const char *src, ssize_t srclen,
 						  pg_locale_t locale);