> I'm still inlined to think the method table is a good thing to do:
> 
> (a) The performance cases I tried seem implausibly bad -- running
> character classification patterns over large fields consisting only
> of
> codepoints over U+07FF.
> 
> (b) The method tables seem like a better code organization that
> separates the responsibilities of the provider from the calling code.
> It's also a requirement (or nearly so) if we want to provide some
> pluggability or support multiple library versions.
> 
> It would be good to hear from others on these points, though.

Attached v15. Just a rebase.

I'd still like some input here. We could either:

* commit this on the grounds that it's a desirable code improvement and
the worst-case regression isn't a major concern; or

* wait until v19 when we might have a more compelling use for the
method table (e.g. pluggable provider or multilib)

Regards,
        Jeff Davis

From 7abb1f6c9f8c845c20d6baf648e4bba075f4a3cb Mon Sep 17 00:00:00 2001
From: Jeff Davis <j...@j-davis.com>
Date: Fri, 29 Nov 2024 09:37:43 -0800
Subject: [PATCH v15 1/4] Control ctype behavior internally with a method
 table.

Previously, pattern matching and case mapping behavior branched based
on the provider.

Refactor to use a method table, which is less error-prone and easier
to hook.
---
 src/backend/regex/regc_pg_locale.c        | 377 +++++-----------------
 src/backend/utils/adt/like.c              |  22 +-
 src/backend/utils/adt/like_support.c      |   7 +-
 src/backend/utils/adt/pg_locale.c         | 121 +++----
 src/backend/utils/adt/pg_locale_builtin.c | 111 ++++++-
 src/backend/utils/adt/pg_locale_icu.c     | 116 ++++++-
 src/backend/utils/adt/pg_locale_libc.c    | 279 +++++++++++++---
 src/include/utils/pg_locale.h             |  52 +++
 src/tools/pgindent/typedefs.list          |   1 -
 9 files changed, 630 insertions(+), 456 deletions(-)

diff --git a/src/backend/regex/regc_pg_locale.c b/src/backend/regex/regc_pg_locale.c
index ed7411df83d..31b8f4a9478 100644
--- a/src/backend/regex/regc_pg_locale.c
+++ b/src/backend/regex/regc_pg_locale.c
@@ -63,18 +63,13 @@
  * NB: the coding here assumes pg_wchar is an unsigned type.
  */
 
-typedef enum
-{
-	PG_REGEX_STRATEGY_C,		/* C locale (encoding independent) */
-	PG_REGEX_STRATEGY_BUILTIN,	/* built-in Unicode semantics */
-	PG_REGEX_STRATEGY_LIBC_WIDE,	/* Use locale_t <wctype.h> functions */
-	PG_REGEX_STRATEGY_LIBC_1BYTE,	/* Use locale_t <ctype.h> functions */
-	PG_REGEX_STRATEGY_ICU,		/* Use ICU uchar.h functions */
-} PG_Locale_Strategy;
-
-static PG_Locale_Strategy pg_regex_strategy;
 static pg_locale_t pg_regex_locale;
 
+static struct pg_locale_struct dummy_c_locale = {
+	.collate_is_c = true,
+	.ctype_is_c = true,
+};
+
 /*
  * Hard-wired character properties for C locale
  */
@@ -231,7 +226,6 @@ void
 pg_set_regex_collation(Oid collation)
 {
 	pg_locale_t locale = 0;
-	PG_Locale_Strategy strategy;
 
 	if (!OidIsValid(collation))
 	{
@@ -252,8 +246,7 @@ pg_set_regex_collation(Oid collation)
 		 * catalog access is available, so we can't call
 		 * pg_newlocale_from_collation().
 		 */
-		strategy = PG_REGEX_STRATEGY_C;
-		locale = 0;
+		locale = &dummy_c_locale;
 	}
 	else
 	{
@@ -270,113 +263,41 @@ pg_set_regex_collation(Oid collation)
 			 * C/POSIX collations use this path regardless of database
 			 * encoding
 			 */
-			strategy = PG_REGEX_STRATEGY_C;
-			locale = 0;
-		}
-		else if (locale->provider == COLLPROVIDER_BUILTIN)
-		{
-			Assert(GetDatabaseEncoding() == PG_UTF8);
-			strategy = PG_REGEX_STRATEGY_BUILTIN;
-		}
-#ifdef USE_ICU
-		else if (locale->provider == COLLPROVIDER_ICU)
-		{
-			strategy = PG_REGEX_STRATEGY_ICU;
-		}
-#endif
-		else
-		{
-			Assert(locale->provider == COLLPROVIDER_LIBC);
-			if (GetDatabaseEncoding() == PG_UTF8)
-				strategy = PG_REGEX_STRATEGY_LIBC_WIDE;
-			else
-				strategy = PG_REGEX_STRATEGY_LIBC_1BYTE;
+			locale = &dummy_c_locale;
 		}
 	}
 
-	pg_regex_strategy = strategy;
 	pg_regex_locale = locale;
 }
 
 static int
 pg_wc_isdigit(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISDIGIT));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isdigit(c, !pg_regex_locale->info.builtin.casemap_full);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswdigit_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isdigit_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isdigit(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISDIGIT));
+	else
+		return pg_regex_locale->ctype->wc_isdigit(c, pg_regex_locale);
 }
 
 static int
 pg_wc_isalpha(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISALPHA));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isalpha(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswalpha_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isalpha_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isalpha(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISALPHA));
+	else
+		return pg_regex_locale->ctype->wc_isalpha(c, pg_regex_locale);
 }
 
 static int
 pg_wc_isalnum(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISALNUM));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isalnum(c, !pg_regex_locale->info.builtin.casemap_full);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswalnum_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isalnum_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isalnum(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISALNUM));
+	else
+		return pg_regex_locale->ctype->wc_isalnum(c, pg_regex_locale);
 }
 
 static int
@@ -391,219 +312,87 @@ pg_wc_isword(pg_wchar c)
 static int
 pg_wc_isupper(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISUPPER));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isupper(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswupper_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isupper_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isupper(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISUPPER));
+	else
+		return pg_regex_locale->ctype->wc_isupper(c, pg_regex_locale);
 }
 
 static int
 pg_wc_islower(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISLOWER));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_islower(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswlower_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					islower_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_islower(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISLOWER));
+	else
+		return pg_regex_locale->ctype->wc_islower(c, pg_regex_locale);
 }
 
 static int
 pg_wc_isgraph(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISGRAPH));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isgraph(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswgraph_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isgraph_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isgraph(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISGRAPH));
+	else
+		return pg_regex_locale->ctype->wc_isgraph(c, pg_regex_locale);
 }
 
 static int
 pg_wc_isprint(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISPRINT));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isprint(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswprint_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isprint_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isprint(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISPRINT));
+	else
+		return pg_regex_locale->ctype->wc_isprint(c, pg_regex_locale);
 }
 
 static int
 pg_wc_ispunct(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISPUNCT));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_ispunct(c, !pg_regex_locale->info.builtin.casemap_full);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswpunct_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					ispunct_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_ispunct(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISPUNCT));
+	else
+		return pg_regex_locale->ctype->wc_ispunct(c, pg_regex_locale);
 }
 
 static int
 pg_wc_isspace(pg_wchar c)
 {
-	switch (pg_regex_strategy)
-	{
-		case PG_REGEX_STRATEGY_C:
-			return (c <= (pg_wchar) 127 &&
-					(pg_char_properties[c] & PG_ISSPACE));
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return pg_u_isspace(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return iswspace_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			return (c <= (pg_wchar) UCHAR_MAX &&
-					isspace_l((unsigned char) c, pg_regex_locale->info.lt));
-			break;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_isspace(c);
-#endif
-			break;
-	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	if (pg_regex_locale->ctype_is_c)
+		return (c <= (pg_wchar) 127 &&
+				(pg_char_properties[c] & PG_ISSPACE));
+	else
+		return pg_regex_locale->ctype->wc_isspace(c, pg_regex_locale);
 }
 
 static pg_wchar
 pg_wc_toupper(pg_wchar c)
 {
-	switch (pg_regex_strategy)
+	if (pg_regex_locale->ctype_is_c)
 	{
-		case PG_REGEX_STRATEGY_C:
-			if (c <= (pg_wchar) 127)
-				return pg_ascii_toupper((unsigned char) c);
-			return c;
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return unicode_uppercase_simple(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return towupper_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			if (c <= (pg_wchar) UCHAR_MAX)
-				return toupper_l((unsigned char) c, pg_regex_locale->info.lt);
-			return c;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_toupper(c);
-#endif
-			break;
+		if (c <= (pg_wchar) 127)
+			return pg_ascii_toupper((unsigned char) c);
+		return c;
 	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	else
+		return pg_regex_locale->ctype->wc_toupper(c, pg_regex_locale);
 }
 
 static pg_wchar
 pg_wc_tolower(pg_wchar c)
 {
-	switch (pg_regex_strategy)
+	if (pg_regex_locale->ctype_is_c)
 	{
-		case PG_REGEX_STRATEGY_C:
-			if (c <= (pg_wchar) 127)
-				return pg_ascii_tolower((unsigned char) c);
-			return c;
-		case PG_REGEX_STRATEGY_BUILTIN:
-			return unicode_lowercase_simple(c);
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
-				return towlower_l((wint_t) c, pg_regex_locale->info.lt);
-			/* FALL THRU */
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-			if (c <= (pg_wchar) UCHAR_MAX)
-				return tolower_l((unsigned char) c, pg_regex_locale->info.lt);
-			return c;
-		case PG_REGEX_STRATEGY_ICU:
-#ifdef USE_ICU
-			return u_tolower(c);
-#endif
-			break;
+		if (c <= (pg_wchar) 127)
+			return pg_ascii_tolower((unsigned char) c);
+		return c;
 	}
-	return 0;					/* can't get here, but keep compiler quiet */
+	else
+		return pg_regex_locale->ctype->wc_tolower(c, pg_regex_locale);
 }
 
 
@@ -729,37 +518,25 @@ pg_ctype_get_cache(pg_wc_probefunc probefunc, int cclasscode)
 	 * would always be true for production values of MAX_SIMPLE_CHR, but it's
 	 * useful to allow it to be small for testing purposes.)
 	 */
-	switch (pg_regex_strategy)
+	if (pg_regex_locale->ctype_is_c)
 	{
-		case PG_REGEX_STRATEGY_C:
 #if MAX_SIMPLE_CHR >= 127
-			max_chr = (pg_wchar) 127;
-			pcc->cv.cclasscode = -1;
+		max_chr = (pg_wchar) 127;
+		pcc->cv.cclasscode = -1;
 #else
-			max_chr = (pg_wchar) MAX_SIMPLE_CHR;
+		max_chr = (pg_wchar) MAX_SIMPLE_CHR;
 #endif
-			break;
-		case PG_REGEX_STRATEGY_BUILTIN:
-			max_chr = (pg_wchar) MAX_SIMPLE_CHR;
-			break;
-		case PG_REGEX_STRATEGY_LIBC_WIDE:
-			max_chr = (pg_wchar) MAX_SIMPLE_CHR;
-			break;
-		case PG_REGEX_STRATEGY_LIBC_1BYTE:
-#if MAX_SIMPLE_CHR >= UCHAR_MAX
-			max_chr = (pg_wchar) UCHAR_MAX;
+	}
+	else
+	{
+		if (pg_regex_locale->ctype->max_chr != 0 &&
+			pg_regex_locale->ctype->max_chr <= MAX_SIMPLE_CHR)
+		{
+			max_chr = pg_regex_locale->ctype->max_chr;
 			pcc->cv.cclasscode = -1;
-#else
-			max_chr = (pg_wchar) MAX_SIMPLE_CHR;
-#endif
-			break;
-		case PG_REGEX_STRATEGY_ICU:
+		}
+		else
 			max_chr = (pg_wchar) MAX_SIMPLE_CHR;
-			break;
-		default:
-			Assert(false);
-			max_chr = 0;		/* can't get here, but keep compiler quiet */
-			break;
 	}
 
 	/*
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 7f4cf614585..4216ac17f43 100644
--- a/src/backend/utils/adt/like.c
+++ b/src/backend/utils/adt/like.c
@@ -98,7 +98,7 @@ SB_lower_char(unsigned char c, pg_locale_t locale)
 	else if (locale->is_default)
 		return pg_tolower(c);
 	else
-		return tolower_l(c, locale->info.lt);
+		return char_tolower(c, locale);
 }
 
 
@@ -209,7 +209,17 @@ Generic_Text_IC_like(text *str, text *pat, Oid collation)
 	 * way.
 	 */
 
-	if (pg_database_encoding_max_length() > 1 || (locale->provider == COLLPROVIDER_ICU))
+	if (locale->ctype_is_c ||
+		(char_tolower_enabled(locale) &&
+		 pg_database_encoding_max_length() == 1))
+	{
+		p = VARDATA_ANY(pat);
+		plen = VARSIZE_ANY_EXHDR(pat);
+		s = VARDATA_ANY(str);
+		slen = VARSIZE_ANY_EXHDR(str);
+		return SB_IMatchText(s, slen, p, plen, locale);
+	}
+	else
 	{
 		pat = DatumGetTextPP(DirectFunctionCall1Coll(lower, collation,
 													 PointerGetDatum(pat)));
@@ -224,14 +234,6 @@ Generic_Text_IC_like(text *str, text *pat, Oid collation)
 		else
 			return MB_MatchText(s, slen, p, plen, 0);
 	}
-	else
-	{
-		p = VARDATA_ANY(pat);
-		plen = VARSIZE_ANY_EXHDR(pat);
-		s = VARDATA_ANY(str);
-		slen = VARSIZE_ANY_EXHDR(str);
-		return SB_IMatchText(s, slen, p, plen, locale);
-	}
 }
 
 /*
diff --git a/src/backend/utils/adt/like_support.c b/src/backend/utils/adt/like_support.c
index 8fdc677371f..999f23f86d5 100644
--- a/src/backend/utils/adt/like_support.c
+++ b/src/backend/utils/adt/like_support.c
@@ -1495,13 +1495,8 @@ pattern_char_isalpha(char c, bool is_multibyte,
 {
 	if (locale->ctype_is_c)
 		return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
-	else if (is_multibyte && IS_HIGHBIT_SET(c))
-		return true;
-	else if (locale->provider != COLLPROVIDER_LIBC)
-		return IS_HIGHBIT_SET(c) ||
-			(c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
 	else
-		return isalpha_l((unsigned char) c, locale->info.lt);
+		return char_is_cased(c, locale);
 }
 
 
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 7d92f580a57..f26ce0e6cc7 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -100,31 +100,6 @@ extern pg_locale_t create_pg_locale_icu(Oid collid, MemoryContext context);
 extern pg_locale_t create_pg_locale_libc(Oid collid, MemoryContext context);
 extern char *get_collation_actual_version_libc(const char *collcollate);
 
-extern size_t strlower_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strfold_builtin(char *dst, size_t dstsize, const char *src,
-							  ssize_t srclen, pg_locale_t locale);
-
-extern size_t strlower_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strfold_icu(char *dst, size_t dstsize, const char *src,
-						  ssize_t srclen, pg_locale_t locale);
-
-extern size_t strlower_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-
 /* GUC settings */
 char	   *locale_messages;
 char	   *locale_monetary;
@@ -1236,6 +1211,9 @@ create_pg_locale(Oid collid, MemoryContext context)
 	Assert((result->collate_is_c && result->collate == NULL) ||
 		   (!result->collate_is_c && result->collate != NULL));
 
+	Assert((result->ctype_is_c && result->ctype == NULL) ||
+		   (!result->ctype_is_c && result->ctype != NULL));
+
 	datum = SysCacheGetAttr(COLLOID, tp, Anum_pg_collation_collversion,
 							&isnull);
 	if (!isnull)
@@ -1398,77 +1376,31 @@ size_t
 pg_strlower(char *dst, size_t dstsize, const char *src, ssize_t srclen,
 			pg_locale_t locale)
 {
-	if (locale->provider == COLLPROVIDER_BUILTIN)
-		return strlower_builtin(dst, dstsize, src, srclen, locale);
-#ifdef USE_ICU
-	else if (locale->provider == COLLPROVIDER_ICU)
-		return strlower_icu(dst, dstsize, src, srclen, locale);
-#endif
-	else if (locale->provider == COLLPROVIDER_LIBC)
-		return strlower_libc(dst, dstsize, src, srclen, locale);
-	else
-		/* shouldn't happen */
-		PGLOCALE_SUPPORT_ERROR(locale->provider);
-
-	return 0;					/* keep compiler quiet */
+	return locale->ctype->strlower(dst, dstsize, src, srclen, locale);
 }
 
 size_t
 pg_strtitle(char *dst, size_t dstsize, const char *src, ssize_t srclen,
 			pg_locale_t locale)
 {
-	if (locale->provider == COLLPROVIDER_BUILTIN)
-		return strtitle_builtin(dst, dstsize, src, srclen, locale);
-#ifdef USE_ICU
-	else if (locale->provider == COLLPROVIDER_ICU)
-		return strtitle_icu(dst, dstsize, src, srclen, locale);
-#endif
-	else if (locale->provider == COLLPROVIDER_LIBC)
-		return strtitle_libc(dst, dstsize, src, srclen, locale);
-	else
-		/* shouldn't happen */
-		PGLOCALE_SUPPORT_ERROR(locale->provider);
-
-	return 0;					/* keep compiler quiet */
+	return locale->ctype->strtitle(dst, dstsize, src, srclen, locale);
 }
 
 size_t
 pg_strupper(char *dst, size_t dstsize, const char *src, ssize_t srclen,
 			pg_locale_t locale)
 {
-	if (locale->provider == COLLPROVIDER_BUILTIN)
-		return strupper_builtin(dst, dstsize, src, srclen, locale);
-#ifdef USE_ICU
-	else if (locale->provider == COLLPROVIDER_ICU)
-		return strupper_icu(dst, dstsize, src, srclen, locale);
-#endif
-	else if (locale->provider == COLLPROVIDER_LIBC)
-		return strupper_libc(dst, dstsize, src, srclen, locale);
-	else
-		/* shouldn't happen */
-		PGLOCALE_SUPPORT_ERROR(locale->provider);
-
-	return 0;					/* keep compiler quiet */
+	return locale->ctype->strupper(dst, dstsize, src, srclen, locale);
 }
 
 size_t
 pg_strfold(char *dst, size_t dstsize, const char *src, ssize_t srclen,
 		   pg_locale_t locale)
 {
-	if (locale->provider == COLLPROVIDER_BUILTIN)
-		return strfold_builtin(dst, dstsize, src, srclen, locale);
-#ifdef USE_ICU
-	else if (locale->provider == COLLPROVIDER_ICU)
-		return strfold_icu(dst, dstsize, src, srclen, locale);
-#endif
-	/* for libc, just use strlower */
-	else if (locale->provider == COLLPROVIDER_LIBC)
-		return strlower_libc(dst, dstsize, src, srclen, locale);
+	if (locale->ctype->strfold)
+		return locale->ctype->strfold(dst, dstsize, src, srclen, locale);
 	else
-		/* shouldn't happen */
-		PGLOCALE_SUPPORT_ERROR(locale->provider);
-
-	return 0;					/* keep compiler quiet */
+		return locale->ctype->strlower(dst, dstsize, src, srclen, locale);
 }
 
 /*
@@ -1605,6 +1537,41 @@ pg_strnxfrm_prefix(char *dest, size_t destsize, const char *src,
 	return locale->collate->strnxfrm_prefix(dest, destsize, src, srclen, 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)
+{
+	return locale->ctype->char_is_cased(ch, locale);
+}
+
+/*
+ * char_tolower_enabled()
+ *
+ * Does the provider support char_tolower()?
+ */
+bool
+char_tolower_enabled(pg_locale_t locale)
+{
+	return (locale->ctype->char_tolower != NULL);
+}
+
+/*
+ * char_tolower()
+ *
+ * Convert char (single-byte encoding) to lowercase.
+ */
+char
+char_tolower(unsigned char ch, pg_locale_t locale)
+{
+	return locale->ctype->char_tolower(ch, locale);
+}
+
 /*
  * Return required encoding ID for the given locale, or -1 if any encoding is
  * valid for the locale.
diff --git a/src/backend/utils/adt/pg_locale_builtin.c b/src/backend/utils/adt/pg_locale_builtin.c
index 33ad20bbf07..23504be383a 100644
--- a/src/backend/utils/adt/pg_locale_builtin.c
+++ b/src/backend/utils/adt/pg_locale_builtin.c
@@ -25,15 +25,6 @@
 extern pg_locale_t create_pg_locale_builtin(Oid collid,
 											MemoryContext context);
 extern char *get_collation_actual_version_builtin(const char *collcollate);
-extern size_t strlower_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_builtin(char *dst, size_t dstsize, const char *src,
-							   ssize_t srclen, pg_locale_t locale);
-extern size_t strfold_builtin(char *dst, size_t dstsize, const char *src,
-							  ssize_t srclen, pg_locale_t locale);
-
 
 struct WordBoundaryState
 {
@@ -76,7 +67,7 @@ initcap_wbnext(void *state)
 	return wbstate->len;
 }
 
-size_t
+static size_t
 strlower_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
@@ -84,7 +75,7 @@ strlower_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 							locale->info.builtin.casemap_full);
 }
 
-size_t
+static size_t
 strtitle_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
@@ -101,7 +92,7 @@ strtitle_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 							initcap_wbnext, &wbstate);
 }
 
-size_t
+static size_t
 strupper_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
@@ -109,7 +100,7 @@ strupper_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 							locale->info.builtin.casemap_full);
 }
 
-size_t
+static size_t
 strfold_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				pg_locale_t locale)
 {
@@ -117,6 +108,98 @@ strfold_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 						   locale->info.builtin.casemap_full);
 }
 
+static bool
+wc_isdigit_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isdigit(wc, !locale->info.builtin.casemap_full);
+}
+
+static bool
+wc_isalpha_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isalpha(wc);
+}
+
+static bool
+wc_isalnum_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isalnum(wc, !locale->info.builtin.casemap_full);
+}
+
+static bool
+wc_isupper_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isupper(wc);
+}
+
+static bool
+wc_islower_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_islower(wc);
+}
+
+static bool
+wc_isgraph_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isgraph(wc);
+}
+
+static bool
+wc_isprint_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isprint(wc);
+}
+
+static bool
+wc_ispunct_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_ispunct(wc, !locale->info.builtin.casemap_full);
+}
+
+static bool
+wc_isspace_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return pg_u_isspace(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)
+{
+	return unicode_uppercase_simple(wc);
+}
+
+static pg_wchar
+wc_tolower_builtin(pg_wchar wc, pg_locale_t locale)
+{
+	return unicode_lowercase_simple(wc);
+}
+
+static const struct ctype_methods ctype_methods_builtin = {
+	.strlower = strlower_builtin,
+	.strtitle = strtitle_builtin,
+	.strupper = strupper_builtin,
+	.strfold = strfold_builtin,
+	.wc_isdigit = wc_isdigit_builtin,
+	.wc_isalpha = wc_isalpha_builtin,
+	.wc_isalnum = wc_isalnum_builtin,
+	.wc_isupper = wc_isupper_builtin,
+	.wc_islower = wc_islower_builtin,
+	.wc_isgraph = wc_isgraph_builtin,
+	.wc_isprint = wc_isprint_builtin,
+	.wc_ispunct = wc_ispunct_builtin,
+	.wc_isspace = wc_isspace_builtin,
+	.char_is_cased = char_is_cased_builtin,
+	.wc_tolower = wc_tolower_builtin,
+	.wc_toupper = wc_toupper_builtin,
+};
+
 pg_locale_t
 create_pg_locale_builtin(Oid collid, MemoryContext context)
 {
@@ -160,6 +243,8 @@ create_pg_locale_builtin(Oid collid, MemoryContext context)
 	result->deterministic = true;
 	result->collate_is_c = true;
 	result->ctype_is_c = (strcmp(locstr, "C") == 0);
+	if (!result->ctype_is_c)
+		result->ctype = &ctype_methods_builtin;
 
 	return result;
 }
diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index b0c73f2e43d..1cb24fadea2 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -48,19 +48,19 @@
 #define		TEXTBUFLEN			1024
 
 extern pg_locale_t create_pg_locale_icu(Oid collid, MemoryContext context);
-extern size_t strlower_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_icu(char *dst, size_t dstsize, const char *src,
-						   ssize_t srclen, pg_locale_t locale);
-extern size_t strfold_icu(char *dst, size_t dstsize, const char *src,
-						  ssize_t srclen, pg_locale_t locale);
 
 #ifdef USE_ICU
 
 extern UCollator *pg_ucol_open(const char *loc_str);
 
+static size_t strlower_icu(char *dst, size_t dstsize, const char *src,
+						   ssize_t srclen, pg_locale_t locale);
+static size_t strtitle_icu(char *dst, size_t dstsize, const char *src,
+						   ssize_t srclen, pg_locale_t locale);
+static size_t strupper_icu(char *dst, size_t dstsize, const char *src,
+						   ssize_t srclen, pg_locale_t locale);
+static size_t strfold_icu(char *dst, size_t dstsize, const char *src,
+						   ssize_t srclen, pg_locale_t locale);
 static int	strncoll_icu(const char *arg1, ssize_t len1,
 						 const char *arg2, ssize_t len2,
 						 pg_locale_t locale);
@@ -124,6 +124,25 @@ 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');
+}
+
+static pg_wchar
+toupper_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_toupper(wc);
+}
+
+static pg_wchar
+tolower_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_tolower(wc);
+}
+
 static const struct collate_methods collate_methods_icu = {
 	.strncoll = strncoll_icu,
 	.strnxfrm = strnxfrm_icu,
@@ -142,6 +161,78 @@ static const struct collate_methods collate_methods_icu_utf8 = {
 	.strxfrm_is_safe = true,
 };
 
+static bool
+wc_isdigit_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isdigit(wc);
+}
+
+static bool
+wc_isalpha_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isalpha(wc);
+}
+
+static bool
+wc_isalnum_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isalnum(wc);
+}
+
+static bool
+wc_isupper_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isupper(wc);
+}
+
+static bool
+wc_islower_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_islower(wc);
+}
+
+static bool
+wc_isgraph_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isgraph(wc);
+}
+
+static bool
+wc_isprint_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isprint(wc);
+}
+
+static bool
+wc_ispunct_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_ispunct(wc);
+}
+
+static bool
+wc_isspace_icu(pg_wchar wc, pg_locale_t locale)
+{
+	return u_isspace(wc);
+}
+
+static const struct ctype_methods ctype_methods_icu = {
+	.strlower = strlower_icu,
+	.strtitle = strtitle_icu,
+	.strupper = strupper_icu,
+	.strfold = strfold_icu,
+	.wc_isdigit = wc_isdigit_icu,
+	.wc_isalpha = wc_isalpha_icu,
+	.wc_isalnum = wc_isalnum_icu,
+	.wc_isupper = wc_isupper_icu,
+	.wc_islower = wc_islower_icu,
+	.wc_isgraph = wc_isgraph_icu,
+	.wc_isprint = wc_isprint_icu,
+	.wc_ispunct = wc_ispunct_icu,
+	.wc_isspace = wc_isspace_icu,
+	.char_is_cased = char_is_cased_icu,
+	.wc_toupper = toupper_icu,
+	.wc_tolower = tolower_icu,
+};
 #endif
 
 pg_locale_t
@@ -212,6 +303,7 @@ create_pg_locale_icu(Oid collid, MemoryContext context)
 		result->collate = &collate_methods_icu_utf8;
 	else
 		result->collate = &collate_methods_icu;
+	result->ctype = &ctype_methods_icu;
 
 	return result;
 #else
@@ -385,7 +477,7 @@ make_icu_collator(const char *iculocstr, const char *icurules)
 	}
 }
 
-size_t
+static size_t
 strlower_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			 pg_locale_t locale)
 {
@@ -405,7 +497,7 @@ strlower_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	return result_len;
 }
 
-size_t
+static size_t
 strtitle_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			 pg_locale_t locale)
 {
@@ -425,7 +517,7 @@ strtitle_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	return result_len;
 }
 
-size_t
+static size_t
 strupper_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			 pg_locale_t locale)
 {
@@ -445,7 +537,7 @@ strupper_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	return result_len;
 }
 
-size_t
+static size_t
 strfold_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			pg_locale_t locale)
 {
diff --git a/src/backend/utils/adt/pg_locale_libc.c b/src/backend/utils/adt/pg_locale_libc.c
index 8f9a8637897..1144c6ff304 100644
--- a/src/backend/utils/adt/pg_locale_libc.c
+++ b/src/backend/utils/adt/pg_locale_libc.c
@@ -43,13 +43,6 @@
 
 extern pg_locale_t create_pg_locale_libc(Oid collid, MemoryContext context);
 
-extern size_t strlower_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-extern size_t strtitle_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-extern size_t strupper_libc(char *dst, size_t dstsize, const char *src,
-							ssize_t srclen, pg_locale_t locale);
-
 static int	strncoll_libc(const char *arg1, ssize_t len1,
 						  const char *arg2, ssize_t len2,
 						  pg_locale_t locale);
@@ -86,6 +79,239 @@ static size_t strupper_libc_mb(char *dest, size_t destsize,
 							   const char *src, ssize_t srclen,
 							   pg_locale_t locale);
 
+static bool
+wc_isdigit_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isdigit_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isalpha_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isalpha_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isalnum_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isalnum_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isupper_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isupper_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_islower_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return islower_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isgraph_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isgraph_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isprint_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isprint_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_ispunct_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return ispunct_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isspace_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	return isspace_l((unsigned char) wc, locale->info.lt);
+}
+
+static bool
+wc_isdigit_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswdigit_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isalpha_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswalpha_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isalnum_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswalnum_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isupper_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswupper_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_islower_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswlower_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isgraph_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswgraph_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isprint_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswprint_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_ispunct_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswpunct_l((wint_t) wc, locale->info.lt);
+}
+
+static bool
+wc_isspace_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	return iswspace_l((wint_t) wc, locale->info.lt);
+}
+
+static char
+char_tolower_libc(unsigned char ch, pg_locale_t locale)
+{
+	Assert(pg_database_encoding_max_length() == 1);
+	return tolower_l(ch, locale->info.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->info.lt);
+}
+
+static pg_wchar
+toupper_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	Assert(GetDatabaseEncoding() != PG_UTF8);
+
+	if (wc <= (pg_wchar) UCHAR_MAX)
+		return toupper_l((unsigned char) wc, locale->info.lt);
+	else
+		return wc;
+}
+
+static pg_wchar
+toupper_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	Assert(GetDatabaseEncoding() == PG_UTF8);
+
+	if (sizeof(wchar_t) >= 4 || wc <= (pg_wchar) 0xFFFF)
+		return towupper_l((wint_t) wc, locale->info.lt);
+	else
+		return wc;
+}
+
+static pg_wchar
+tolower_libc_sb(pg_wchar wc, pg_locale_t locale)
+{
+	Assert(GetDatabaseEncoding() != PG_UTF8);
+
+	if (wc <= (pg_wchar) UCHAR_MAX)
+		return tolower_l((unsigned char) wc, locale->info.lt);
+	else
+		return wc;
+}
+
+static pg_wchar
+tolower_libc_mb(pg_wchar wc, pg_locale_t locale)
+{
+	Assert(GetDatabaseEncoding() == PG_UTF8);
+
+	if (sizeof(wchar_t) >= 4 || wc <= (pg_wchar) 0xFFFF)
+		return towlower_l((wint_t) wc, locale->info.lt);
+	else
+		return wc;
+}
+
+static const struct ctype_methods ctype_methods_libc_sb = {
+	.strlower = strlower_libc_sb,
+	.strtitle = strtitle_libc_sb,
+	.strupper = strupper_libc_sb,
+	.wc_isdigit = wc_isdigit_libc_sb,
+	.wc_isalpha = wc_isalpha_libc_sb,
+	.wc_isalnum = wc_isalnum_libc_sb,
+	.wc_isupper = wc_isupper_libc_sb,
+	.wc_islower = wc_islower_libc_sb,
+	.wc_isgraph = wc_isgraph_libc_sb,
+	.wc_isprint = wc_isprint_libc_sb,
+	.wc_ispunct = wc_ispunct_libc_sb,
+	.wc_isspace = wc_isspace_libc_sb,
+	.char_is_cased = char_is_cased_libc,
+	.char_tolower = char_tolower_libc,
+	.wc_toupper = toupper_libc_sb,
+	.wc_tolower = tolower_libc_sb,
+	.max_chr = UCHAR_MAX,
+};
+
+/*
+ * Non-UTF8 multibyte encodings use multibyte semantics for case mapping, but
+ * single-byte semantics for pattern matching.
+ */
+static const struct ctype_methods ctype_methods_libc_other_mb = {
+	.strlower = strlower_libc_mb,
+	.strtitle = strtitle_libc_mb,
+	.strupper = strupper_libc_mb,
+	.wc_isdigit = wc_isdigit_libc_sb,
+	.wc_isalpha = wc_isalpha_libc_sb,
+	.wc_isalnum = wc_isalnum_libc_sb,
+	.wc_isupper = wc_isupper_libc_sb,
+	.wc_islower = wc_islower_libc_sb,
+	.wc_isgraph = wc_isgraph_libc_sb,
+	.wc_isprint = wc_isprint_libc_sb,
+	.wc_ispunct = wc_ispunct_libc_sb,
+	.wc_isspace = wc_isspace_libc_sb,
+	.char_is_cased = char_is_cased_libc,
+	.char_tolower = char_tolower_libc,
+	.wc_toupper = toupper_libc_sb,
+	.wc_tolower = tolower_libc_sb,
+	.max_chr = UCHAR_MAX,
+};
+
+static const struct ctype_methods ctype_methods_libc_utf8 = {
+	.strlower = strlower_libc_mb,
+	.strtitle = strtitle_libc_mb,
+	.strupper = strupper_libc_mb,
+	.wc_isdigit = wc_isdigit_libc_mb,
+	.wc_isalpha = wc_isalpha_libc_mb,
+	.wc_isalnum = wc_isalnum_libc_mb,
+	.wc_isupper = wc_isupper_libc_mb,
+	.wc_islower = wc_islower_libc_mb,
+	.wc_isgraph = wc_isgraph_libc_mb,
+	.wc_isprint = wc_isprint_libc_mb,
+	.wc_ispunct = wc_ispunct_libc_mb,
+	.wc_isspace = wc_isspace_libc_mb,
+	.char_is_cased = char_is_cased_libc,
+	.char_tolower = char_tolower_libc,
+	.wc_toupper = toupper_libc_mb,
+	.wc_tolower = tolower_libc_mb,
+};
+
 static const struct collate_methods collate_methods_libc = {
 	.strncoll = strncoll_libc,
 	.strnxfrm = strnxfrm_libc,
@@ -120,36 +346,6 @@ static const struct collate_methods collate_methods_libc_win32_utf8 = {
 };
 #endif
 
-size_t
-strlower_libc(char *dst, size_t dstsize, const char *src,
-			  ssize_t srclen, pg_locale_t locale)
-{
-	if (pg_database_encoding_max_length() > 1)
-		return strlower_libc_mb(dst, dstsize, src, srclen, locale);
-	else
-		return strlower_libc_sb(dst, dstsize, src, srclen, locale);
-}
-
-size_t
-strtitle_libc(char *dst, size_t dstsize, const char *src,
-			  ssize_t srclen, pg_locale_t locale)
-{
-	if (pg_database_encoding_max_length() > 1)
-		return strtitle_libc_mb(dst, dstsize, src, srclen, locale);
-	else
-		return strtitle_libc_sb(dst, dstsize, src, srclen, locale);
-}
-
-size_t
-strupper_libc(char *dst, size_t dstsize, const char *src,
-			  ssize_t srclen, pg_locale_t locale)
-{
-	if (pg_database_encoding_max_length() > 1)
-		return strupper_libc_mb(dst, dstsize, src, srclen, locale);
-	else
-		return strupper_libc_sb(dst, dstsize, src, srclen, locale);
-}
-
 static size_t
 strlower_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
@@ -482,6 +678,15 @@ create_pg_locale_libc(Oid collid, MemoryContext context)
 #endif
 			result->collate = &collate_methods_libc;
 	}
+	if (!result->ctype_is_c)
+	{
+		if (GetDatabaseEncoding() == PG_UTF8)
+			result->ctype = &ctype_methods_libc_utf8;
+		else if (pg_database_encoding_max_length() > 1)
+			result->ctype = &ctype_methods_libc_other_mb;
+		else
+			result->ctype = &ctype_methods_libc_sb;
+	}
 
 	return result;
 }
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 0d5f0513ceb..cd2c812ae26 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -12,6 +12,8 @@
 #ifndef _PG_LOCALE_
 #define _PG_LOCALE_
 
+#include "mb/pg_wchar.h"
+
 #ifdef USE_ICU
 #include <unicode/ucol.h>
 #endif
@@ -77,6 +79,52 @@ struct collate_methods
 	bool		strxfrm_is_safe;
 };
 
+struct ctype_methods
+{
+	/* case mapping: LOWER()/INITCAP()/UPPER() */
+	size_t		(*strlower) (char *dest, size_t destsize,
+							 const char *src, ssize_t srclen,
+							 pg_locale_t locale);
+	size_t		(*strtitle) (char *dest, size_t destsize,
+							 const char *src, ssize_t srclen,
+							 pg_locale_t locale);
+	size_t		(*strupper) (char *dest, size_t destsize,
+							 const char *src, ssize_t srclen,
+							 pg_locale_t locale);
+	size_t		(*strfold) (char *dest, size_t destsize,
+							const char *src, ssize_t srclen,
+							pg_locale_t locale);
+
+	/* required */
+	bool		(*wc_isdigit) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isalpha) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isalnum) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isupper) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_islower) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isgraph) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isprint) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_ispunct) (pg_wchar wc, pg_locale_t locale);
+	bool		(*wc_isspace) (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);
+
+	/*
+	 * Optional. If defined, will only be called for single-byte encodings. If
+	 * not defined, or if the encoding is multibyte, will fall back to
+	 * pg_strlower().
+	 */
+	char		(*char_tolower) (unsigned char ch, pg_locale_t locale);
+
+	/*
+	 * For regex and pattern matching efficiency, the maximum char value
+	 * supported by the above methods. If zero, limit is set by regex code.
+	 */
+	pg_wchar	max_chr;
+};
+
 /*
  * We use a discriminated union to hold either a locale_t or an ICU collator.
  * pg_locale_t is occasionally checked for truth, so make it a pointer.
@@ -102,6 +150,7 @@ struct pg_locale_struct
 	bool		is_default;
 
 	const struct collate_methods *collate;	/* NULL if collate_is_c */
+	const struct ctype_methods *ctype;	/* NULL if ctype_is_c */
 
 	union
 	{
@@ -125,6 +174,9 @@ extern void init_database_collation(void);
 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 bool char_tolower_enabled(pg_locale_t locale);
+extern char char_tolower(unsigned char ch, pg_locale_t locale);
 extern size_t pg_strlower(char *dest, size_t destsize,
 						  const char *src, ssize_t srclen,
 						  pg_locale_t locale);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9a3bee93dec..594c98509c0 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1829,7 +1829,6 @@ PGTargetServerType
 PGTernaryBool
 PGTransactionStatusType
 PGVerbosity
-PG_Locale_Strategy
 PG_Lock_Status
 PG_init_t
 PGcancel
-- 
2.34.1

From 25e77e96f99412a4bf1a6d363bb5dbe8f914fbbf Mon Sep 17 00:00:00 2001
From: Jeff Davis <j...@j-davis.com>
Date: Mon, 7 Oct 2024 12:51:27 -0700
Subject: [PATCH v15 2/4] Remove provider field from pg_locale_t.

The behavior of pg_locale_t is entirely specified by methods, so a
separate provider field is no longer necessary.
---
 src/backend/utils/adt/pg_locale_builtin.c |  1 -
 src/backend/utils/adt/pg_locale_icu.c     | 11 -----------
 src/backend/utils/adt/pg_locale_libc.c    |  6 ------
 src/include/utils/pg_locale.h             |  1 -
 4 files changed, 19 deletions(-)

diff --git a/src/backend/utils/adt/pg_locale_builtin.c b/src/backend/utils/adt/pg_locale_builtin.c
index 23504be383a..bba98284e25 100644
--- a/src/backend/utils/adt/pg_locale_builtin.c
+++ b/src/backend/utils/adt/pg_locale_builtin.c
@@ -239,7 +239,6 @@ create_pg_locale_builtin(Oid collid, MemoryContext context)
 
 	result->info.builtin.locale = MemoryContextStrdup(context, locstr);
 	result->info.builtin.casemap_full = (strcmp(locstr, "PG_UNICODE_FAST") == 0);
-	result->provider = COLLPROVIDER_BUILTIN;
 	result->deterministic = true;
 	result->collate_is_c = true;
 	result->ctype_is_c = (strcmp(locstr, "C") == 0);
diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index 1cb24fadea2..f0068749471 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -295,7 +295,6 @@ create_pg_locale_icu(Oid collid, MemoryContext context)
 	result = MemoryContextAllocZero(context, sizeof(struct pg_locale_struct));
 	result->info.icu.locale = MemoryContextStrdup(context, iculocstr);
 	result->info.icu.ucol = collator;
-	result->provider = COLLPROVIDER_ICU;
 	result->deterministic = deterministic;
 	result->collate_is_c = false;
 	result->ctype_is_c = false;
@@ -572,8 +571,6 @@ strncoll_icu_utf8(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2
 	int			result;
 	UErrorCode	status;
 
-	Assert(locale->provider == COLLPROVIDER_ICU);
-
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	status = U_ZERO_ERROR;
@@ -601,8 +598,6 @@ strnxfrm_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	size_t		uchar_bsize;
 	Size		result_bsize;
 
-	Assert(locale->provider == COLLPROVIDER_ICU);
-
 	init_icu_converter();
 
 	ulen = uchar_length(icu_converter, src, srclen);
@@ -647,8 +642,6 @@ strnxfrm_prefix_icu_utf8(char *dest, size_t destsize,
 	uint32_t	state[2];
 	UErrorCode	status;
 
-	Assert(locale->provider == COLLPROVIDER_ICU);
-
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	uiter_setUTF8(&iter, src, srclen);
@@ -847,8 +840,6 @@ strncoll_icu(const char *arg1, ssize_t len1,
 			   *uchar2;
 	int			result;
 
-	Assert(locale->provider == COLLPROVIDER_ICU);
-
 	/* if encoding is UTF8, use more efficient strncoll_icu_utf8 */
 #ifdef HAVE_UCOL_STRCOLLUTF8
 	Assert(GetDatabaseEncoding() != PG_UTF8);
@@ -897,8 +888,6 @@ strnxfrm_prefix_icu(char *dest, size_t destsize,
 	size_t		uchar_bsize;
 	Size		result_bsize;
 
-	Assert(locale->provider == COLLPROVIDER_ICU);
-
 	/* if encoding is UTF8, use more efficient strnxfrm_prefix_icu_utf8 */
 	Assert(GetDatabaseEncoding() != PG_UTF8);
 
diff --git a/src/backend/utils/adt/pg_locale_libc.c b/src/backend/utils/adt/pg_locale_libc.c
index 1144c6ff304..1582f8cdd2a 100644
--- a/src/backend/utils/adt/pg_locale_libc.c
+++ b/src/backend/utils/adt/pg_locale_libc.c
@@ -662,7 +662,6 @@ create_pg_locale_libc(Oid collid, MemoryContext context)
 	loc = make_libc_collator(collate, ctype);
 
 	result = MemoryContextAllocZero(context, sizeof(struct pg_locale_struct));
-	result->provider = COLLPROVIDER_LIBC;
 	result->deterministic = true;
 	result->collate_is_c = (strcmp(collate, "C") == 0) ||
 		(strcmp(collate, "POSIX") == 0);
@@ -782,8 +781,6 @@ strncoll_libc(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2,
 	const char *arg2n;
 	int			result;
 
-	Assert(locale->provider == COLLPROVIDER_LIBC);
-
 	if (bufsize1 + bufsize2 > TEXTBUFLEN)
 		buf = palloc(bufsize1 + bufsize2);
 
@@ -838,8 +835,6 @@ strnxfrm_libc(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	size_t		bufsize = srclen + 1;
 	size_t		result;
 
-	Assert(locale->provider == COLLPROVIDER_LIBC);
-
 	if (srclen == -1)
 		return strxfrm_l(dest, src, destsize, locale->info.lt);
 
@@ -948,7 +943,6 @@ strncoll_libc_win32_utf8(const char *arg1, ssize_t len1, const char *arg2,
 	int			r;
 	int			result;
 
-	Assert(locale->provider == COLLPROVIDER_LIBC);
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	if (len1 == -1)
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index cd2c812ae26..f081091d200 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -143,7 +143,6 @@ struct ctype_methods
  */
 struct pg_locale_struct
 {
-	char		provider;
 	bool		deterministic;
 	bool		collate_is_c;
 	bool		ctype_is_c;
-- 
2.34.1

From babe04624ec0143794329950547ff9a4dda91990 Mon Sep 17 00:00:00 2001
From: Jeff Davis <j...@j-davis.com>
Date: Mon, 7 Oct 2024 13:36:44 -0700
Subject: [PATCH v15 3/4] Make provider data in pg_locale_t an opaque pointer.

---
 src/backend/utils/adt/pg_locale_builtin.c |  55 +++++--
 src/backend/utils/adt/pg_locale_icu.c     |  40 ++++--
 src/backend/utils/adt/pg_locale_libc.c    | 167 +++++++++++++++-------
 src/include/utils/pg_locale.h             |  17 +--
 4 files changed, 197 insertions(+), 82 deletions(-)

diff --git a/src/backend/utils/adt/pg_locale_builtin.c b/src/backend/utils/adt/pg_locale_builtin.c
index bba98284e25..f0462aa96aa 100644
--- a/src/backend/utils/adt/pg_locale_builtin.c
+++ b/src/backend/utils/adt/pg_locale_builtin.c
@@ -26,6 +26,12 @@ extern pg_locale_t create_pg_locale_builtin(Oid collid,
 											MemoryContext context);
 extern char *get_collation_actual_version_builtin(const char *collcollate);
 
+struct builtin_provider
+{
+	const char *locale;
+	bool		casemap_full;
+};
+
 struct WordBoundaryState
 {
 	const char *str;
@@ -71,14 +77,19 @@ static size_t
 strlower_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
 	return unicode_strlower(dest, destsize, src, srclen,
-							locale->info.builtin.casemap_full);
+							builtin->casemap_full);
 }
 
 static size_t
 strtitle_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
+	struct builtin_provider *builtin;
 	struct WordBoundaryState wbstate = {
 		.str = src,
 		.len = srclen,
@@ -87,8 +98,10 @@ strtitle_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 		.prev_alnum = false,
 	};
 
+	builtin = (struct builtin_provider *) locale->provider_data;
+
 	return unicode_strtitle(dest, destsize, src, srclen,
-							locale->info.builtin.casemap_full,
+							builtin->casemap_full,
 							initcap_wbnext, &wbstate);
 }
 
@@ -96,22 +109,34 @@ static size_t
 strupper_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
 	return unicode_strupper(dest, destsize, src, srclen,
-							locale->info.builtin.casemap_full);
+							builtin->casemap_full);
 }
 
 static size_t
 strfold_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				pg_locale_t locale)
 {
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
 	return unicode_strfold(dest, destsize, src, srclen,
-						   locale->info.builtin.casemap_full);
+						   builtin->casemap_full);
 }
 
 static bool
 wc_isdigit_builtin(pg_wchar wc, pg_locale_t locale)
 {
-	return pg_u_isdigit(wc, !locale->info.builtin.casemap_full);
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
+	return pg_u_isdigit(wc, !builtin->casemap_full);
 }
 
 static bool
@@ -123,7 +148,11 @@ wc_isalpha_builtin(pg_wchar wc, pg_locale_t locale)
 static bool
 wc_isalnum_builtin(pg_wchar wc, pg_locale_t locale)
 {
-	return pg_u_isalnum(wc, !locale->info.builtin.casemap_full);
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
+	return pg_u_isalnum(wc, !builtin->casemap_full);
 }
 
 static bool
@@ -153,7 +182,11 @@ wc_isprint_builtin(pg_wchar wc, pg_locale_t locale)
 static bool
 wc_ispunct_builtin(pg_wchar wc, pg_locale_t locale)
 {
-	return pg_u_ispunct(wc, !locale->info.builtin.casemap_full);
+	struct builtin_provider *builtin;
+
+	builtin = (struct builtin_provider *) locale->provider_data;
+
+	return pg_u_ispunct(wc, !builtin->casemap_full);
 }
 
 static bool
@@ -204,6 +237,7 @@ pg_locale_t
 create_pg_locale_builtin(Oid collid, MemoryContext context)
 {
 	const char *locstr;
+	struct builtin_provider *builtin;
 	pg_locale_t result;
 
 	if (collid == DEFAULT_COLLATION_OID)
@@ -237,8 +271,11 @@ create_pg_locale_builtin(Oid collid, MemoryContext context)
 
 	result = MemoryContextAllocZero(context, sizeof(struct pg_locale_struct));
 
-	result->info.builtin.locale = MemoryContextStrdup(context, locstr);
-	result->info.builtin.casemap_full = (strcmp(locstr, "PG_UNICODE_FAST") == 0);
+	builtin = MemoryContextAllocZero(context, sizeof(struct builtin_provider));
+	builtin->locale = MemoryContextStrdup(context, locstr);
+	builtin->casemap_full = (strcmp(locstr, "PG_UNICODE_FAST") == 0);
+	result->provider_data = (void *) builtin;
+
 	result->deterministic = true;
 	result->collate_is_c = true;
 	result->ctype_is_c = (strcmp(locstr, "C") == 0);
diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index f0068749471..19c51504f85 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -51,6 +51,12 @@ extern pg_locale_t create_pg_locale_icu(Oid collid, MemoryContext context);
 
 #ifdef USE_ICU
 
+struct icu_provider
+{
+	const char *locale;
+	UCollator  *ucol;
+};
+
 extern UCollator *pg_ucol_open(const char *loc_str);
 
 static size_t strlower_icu(char *dst, size_t dstsize, const char *src,
@@ -242,6 +248,7 @@ create_pg_locale_icu(Oid collid, MemoryContext context)
 	bool		deterministic;
 	const char *iculocstr;
 	const char *icurules = NULL;
+	struct icu_provider *icu;
 	UCollator  *collator;
 	pg_locale_t result;
 
@@ -293,8 +300,12 @@ create_pg_locale_icu(Oid collid, MemoryContext context)
 	collator = make_icu_collator(iculocstr, icurules);
 
 	result = MemoryContextAllocZero(context, sizeof(struct pg_locale_struct));
-	result->info.icu.locale = MemoryContextStrdup(context, iculocstr);
-	result->info.icu.ucol = collator;
+
+	icu = MemoryContextAllocZero(context, sizeof(struct icu_provider));
+	icu->locale = MemoryContextStrdup(context, iculocstr);
+	icu->ucol = collator;
+	result->provider_data = (void *) icu;
+
 	result->deterministic = deterministic;
 	result->collate_is_c = false;
 	result->ctype_is_c = false;
@@ -570,11 +581,12 @@ strncoll_icu_utf8(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2
 {
 	int			result;
 	UErrorCode	status;
+	struct icu_provider *icu = (struct icu_provider *) locale->provider_data;
 
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	status = U_ZERO_ERROR;
-	result = ucol_strcollUTF8(locale->info.icu.ucol,
+	result = ucol_strcollUTF8(icu->ucol,
 							  arg1, len1,
 							  arg2, len2,
 							  &status);
@@ -598,6 +610,8 @@ strnxfrm_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	size_t		uchar_bsize;
 	Size		result_bsize;
 
+	struct icu_provider *icu = (struct icu_provider *) locale->provider_data;
+
 	init_icu_converter();
 
 	ulen = uchar_length(icu_converter, src, srclen);
@@ -611,7 +625,7 @@ strnxfrm_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
 
 	ulen = uchar_convert(icu_converter, uchar, ulen + 1, src, srclen);
 
-	result_bsize = ucol_getSortKey(locale->info.icu.ucol,
+	result_bsize = ucol_getSortKey(icu->ucol,
 								   uchar, ulen,
 								   (uint8_t *) dest, destsize);
 
@@ -642,12 +656,14 @@ strnxfrm_prefix_icu_utf8(char *dest, size_t destsize,
 	uint32_t	state[2];
 	UErrorCode	status;
 
+	struct icu_provider *icu = (struct icu_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	uiter_setUTF8(&iter, src, srclen);
 	state[0] = state[1] = 0;	/* won't need that again */
 	status = U_ZERO_ERROR;
-	result = ucol_nextSortKeyPart(locale->info.icu.ucol,
+	result = ucol_nextSortKeyPart(icu->ucol,
 								  &iter,
 								  state,
 								  (uint8_t *) dest,
@@ -754,11 +770,13 @@ icu_convert_case(ICU_Convert_Func func, pg_locale_t mylocale,
 	UErrorCode	status;
 	int32_t		len_dest;
 
+	struct icu_provider *icu = (struct icu_provider *) mylocale->provider_data;
+
 	len_dest = len_source;		/* try first with same length */
 	*buff_dest = palloc(len_dest * sizeof(**buff_dest));
 	status = U_ZERO_ERROR;
 	len_dest = func(*buff_dest, len_dest, buff_source, len_source,
-					mylocale->info.icu.locale, &status);
+					icu->locale, &status);
 	if (status == U_BUFFER_OVERFLOW_ERROR)
 	{
 		/* try again with adjusted length */
@@ -766,7 +784,7 @@ icu_convert_case(ICU_Convert_Func func, pg_locale_t mylocale,
 		*buff_dest = palloc(len_dest * sizeof(**buff_dest));
 		status = U_ZERO_ERROR;
 		len_dest = func(*buff_dest, len_dest, buff_source, len_source,
-						mylocale->info.icu.locale, &status);
+						icu->locale, &status);
 	}
 	if (U_FAILURE(status))
 		ereport(ERROR,
@@ -840,6 +858,8 @@ strncoll_icu(const char *arg1, ssize_t len1,
 			   *uchar2;
 	int			result;
 
+	struct icu_provider *icu = (struct icu_provider *) locale->provider_data;
+
 	/* if encoding is UTF8, use more efficient strncoll_icu_utf8 */
 #ifdef HAVE_UCOL_STRCOLLUTF8
 	Assert(GetDatabaseEncoding() != PG_UTF8);
@@ -862,7 +882,7 @@ strncoll_icu(const char *arg1, ssize_t len1,
 	ulen1 = uchar_convert(icu_converter, uchar1, ulen1 + 1, arg1, len1);
 	ulen2 = uchar_convert(icu_converter, uchar2, ulen2 + 1, arg2, len2);
 
-	result = ucol_strcoll(locale->info.icu.ucol,
+	result = ucol_strcoll(icu->ucol,
 						  uchar1, ulen1,
 						  uchar2, ulen2);
 
@@ -888,6 +908,8 @@ strnxfrm_prefix_icu(char *dest, size_t destsize,
 	size_t		uchar_bsize;
 	Size		result_bsize;
 
+	struct icu_provider *icu = (struct icu_provider *) locale->provider_data;
+
 	/* if encoding is UTF8, use more efficient strnxfrm_prefix_icu_utf8 */
 	Assert(GetDatabaseEncoding() != PG_UTF8);
 
@@ -907,7 +929,7 @@ strnxfrm_prefix_icu(char *dest, size_t destsize,
 	uiter_setString(&iter, uchar, ulen);
 	state[0] = state[1] = 0;	/* won't need that again */
 	status = U_ZERO_ERROR;
-	result_bsize = ucol_nextSortKeyPart(locale->info.icu.ucol,
+	result_bsize = ucol_nextSortKeyPart(icu->ucol,
 										&iter,
 										state,
 										(uint8_t *) dest,
diff --git a/src/backend/utils/adt/pg_locale_libc.c b/src/backend/utils/adt/pg_locale_libc.c
index 1582f8cdd2a..d357962ebdf 100644
--- a/src/backend/utils/adt/pg_locale_libc.c
+++ b/src/backend/utils/adt/pg_locale_libc.c
@@ -1,3 +1,4 @@
+
 /*-----------------------------------------------------------------------
  *
  * PostgreSQL locale utilities for libc
@@ -41,6 +42,11 @@
  */
 #define		TEXTBUFLEN			1024
 
+struct libc_provider
+{
+	locale_t	lt;
+};
+
 extern pg_locale_t create_pg_locale_libc(Oid collid, MemoryContext context);
 
 static int	strncoll_libc(const char *arg1, ssize_t len1,
@@ -82,116 +88,154 @@ static size_t strupper_libc_mb(char *dest, size_t destsize,
 static bool
 wc_isdigit_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isdigit_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isdigit_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isalpha_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isalpha_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isalpha_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isalnum_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isalnum_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isalnum_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isupper_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isupper_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isupper_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_islower_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return islower_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return islower_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isgraph_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isgraph_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isgraph_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isprint_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isprint_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isprint_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_ispunct_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return ispunct_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return ispunct_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isspace_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
-	return isspace_l((unsigned char) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return isspace_l((unsigned char) wc, libc->lt);
 }
 
 static bool
 wc_isdigit_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswdigit_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswdigit_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isalpha_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswalpha_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswalpha_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isalnum_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswalnum_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswalnum_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isupper_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswupper_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswupper_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_islower_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswlower_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswlower_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isgraph_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswgraph_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswgraph_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isprint_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswprint_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswprint_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_ispunct_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswpunct_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswpunct_l((wint_t) wc, libc->lt);
 }
 
 static bool
 wc_isspace_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
-	return iswspace_l((wint_t) wc, locale->info.lt);
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
+	return iswspace_l((wint_t) wc, libc->lt);
 }
 
 static char
 char_tolower_libc(unsigned char ch, pg_locale_t locale)
 {
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(pg_database_encoding_max_length() == 1);
-	return tolower_l(ch, locale->info.lt);
+	return tolower_l(ch, libc->lt);
 }
 
 static bool
@@ -199,19 +243,23 @@ char_is_cased_libc(char ch, pg_locale_t locale)
 {
 	bool		is_multibyte = pg_database_encoding_max_length() > 1;
 
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	if (is_multibyte && IS_HIGHBIT_SET(ch))
 		return true;
 	else
-		return isalpha_l((unsigned char) ch, locale->info.lt);
+		return isalpha_l((unsigned char) ch, libc->lt);
 }
 
 static pg_wchar
 toupper_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() != PG_UTF8);
 
 	if (wc <= (pg_wchar) UCHAR_MAX)
-		return toupper_l((unsigned char) wc, locale->info.lt);
+		return toupper_l((unsigned char) wc, libc->lt);
 	else
 		return wc;
 }
@@ -219,10 +267,12 @@ toupper_libc_sb(pg_wchar wc, pg_locale_t locale)
 static pg_wchar
 toupper_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	if (sizeof(wchar_t) >= 4 || wc <= (pg_wchar) 0xFFFF)
-		return towupper_l((wint_t) wc, locale->info.lt);
+		return towupper_l((wint_t) wc, libc->lt);
 	else
 		return wc;
 }
@@ -230,10 +280,12 @@ toupper_libc_mb(pg_wchar wc, pg_locale_t locale)
 static pg_wchar
 tolower_libc_sb(pg_wchar wc, pg_locale_t locale)
 {
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() != PG_UTF8);
 
 	if (wc <= (pg_wchar) UCHAR_MAX)
-		return tolower_l((unsigned char) wc, locale->info.lt);
+		return tolower_l((unsigned char) wc, libc->lt);
 	else
 		return wc;
 }
@@ -241,10 +293,12 @@ tolower_libc_sb(pg_wchar wc, pg_locale_t locale)
 static pg_wchar
 tolower_libc_mb(pg_wchar wc, pg_locale_t locale)
 {
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	if (sizeof(wchar_t) >= 4 || wc <= (pg_wchar) 0xFFFF)
-		return towlower_l((wint_t) wc, locale->info.lt);
+		return towlower_l((wint_t) wc, libc->lt);
 	else
 		return wc;
 }
@@ -355,7 +409,7 @@ strlower_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 
 	if (srclen + 1 <= destsize)
 	{
-		locale_t	loc = locale->info.lt;
+		struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
 		char	   *p;
 
 		if (srclen + 1 > destsize)
@@ -376,7 +430,7 @@ strlower_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			if (locale->is_default)
 				*p = pg_tolower((unsigned char) *p);
 			else
-				*p = tolower_l((unsigned char) *p, loc);
+				*p = tolower_l((unsigned char) *p, libc->lt);
 		}
 	}
 
@@ -387,7 +441,8 @@ static size_t
 strlower_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
-	locale_t	loc = locale->info.lt;
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	size_t		result_size;
 	wchar_t    *workspace;
 	char	   *result;
@@ -409,7 +464,7 @@ strlower_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	char2wchar(workspace, srclen + 1, src, srclen, locale);
 
 	for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
-		workspace[curr_char] = towlower_l(workspace[curr_char], loc);
+		workspace[curr_char] = towlower_l(workspace[curr_char], libc->lt);
 
 	/*
 	 * Make result large enough; case change might change number of bytes
@@ -440,7 +495,7 @@ strtitle_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 
 	if (srclen + 1 <= destsize)
 	{
-		locale_t	loc = locale->info.lt;
+		struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
 		int			wasalnum = false;
 		char	   *p;
 
@@ -466,11 +521,11 @@ strtitle_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			else
 			{
 				if (wasalnum)
-					*p = tolower_l((unsigned char) *p, loc);
+					*p = tolower_l((unsigned char) *p, libc->lt);
 				else
-					*p = toupper_l((unsigned char) *p, loc);
+					*p = toupper_l((unsigned char) *p, libc->lt);
 			}
-			wasalnum = isalnum_l((unsigned char) *p, loc);
+			wasalnum = isalnum_l((unsigned char) *p, libc->lt);
 		}
 	}
 
@@ -481,7 +536,8 @@ static size_t
 strtitle_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
-	locale_t	loc = locale->info.lt;
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	int			wasalnum = false;
 	size_t		result_size;
 	wchar_t    *workspace;
@@ -506,10 +562,10 @@ strtitle_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
 	{
 		if (wasalnum)
-			workspace[curr_char] = towlower_l(workspace[curr_char], loc);
+			workspace[curr_char] = towlower_l(workspace[curr_char], libc->lt);
 		else
-			workspace[curr_char] = towupper_l(workspace[curr_char], loc);
-		wasalnum = iswalnum_l(workspace[curr_char], loc);
+			workspace[curr_char] = towupper_l(workspace[curr_char], libc->lt);
+		wasalnum = iswalnum_l(workspace[curr_char], libc->lt);
 	}
 
 	/*
@@ -541,7 +597,7 @@ strupper_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 
 	if (srclen + 1 <= destsize)
 	{
-		locale_t	loc = locale->info.lt;
+		struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
 		char	   *p;
 
 		memcpy(dest, src, srclen);
@@ -559,7 +615,7 @@ strupper_libc_sb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 			if (locale->is_default)
 				*p = pg_toupper((unsigned char) *p);
 			else
-				*p = toupper_l((unsigned char) *p, loc);
+				*p = toupper_l((unsigned char) *p, libc->lt);
 		}
 	}
 
@@ -570,7 +626,8 @@ static size_t
 strupper_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 				 pg_locale_t locale)
 {
-	locale_t	loc = locale->info.lt;
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	size_t		result_size;
 	wchar_t    *workspace;
 	char	   *result;
@@ -592,7 +649,7 @@ strupper_libc_mb(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	char2wchar(workspace, srclen + 1, src, srclen, locale);
 
 	for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
-		workspace[curr_char] = towupper_l(workspace[curr_char], loc);
+		workspace[curr_char] = towupper_l(workspace[curr_char], libc->lt);
 
 	/*
 	 * Make result large enough; case change might change number of bytes
@@ -620,6 +677,7 @@ create_pg_locale_libc(Oid collid, MemoryContext context)
 	const char *collate;
 	const char *ctype;
 	locale_t	loc;
+	struct libc_provider *libc;
 	pg_locale_t result;
 
 	if (collid == DEFAULT_COLLATION_OID)
@@ -658,16 +716,19 @@ create_pg_locale_libc(Oid collid, MemoryContext context)
 		ReleaseSysCache(tp);
 	}
 
-
 	loc = make_libc_collator(collate, ctype);
 
 	result = MemoryContextAllocZero(context, sizeof(struct pg_locale_struct));
+
+	libc = MemoryContextAllocZero(context, sizeof(struct libc_provider));
+	libc->lt = loc;
+	result->provider_data = (void *) libc;
+
 	result->deterministic = true;
 	result->collate_is_c = (strcmp(collate, "C") == 0) ||
 		(strcmp(collate, "POSIX") == 0);
 	result->ctype_is_c = (strcmp(ctype, "C") == 0) ||
 		(strcmp(ctype, "POSIX") == 0);
-	result->info.lt = loc;
 	if (!result->collate_is_c)
 	{
 #ifdef WIN32
@@ -781,6 +842,8 @@ strncoll_libc(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2,
 	const char *arg2n;
 	int			result;
 
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	if (bufsize1 + bufsize2 > TEXTBUFLEN)
 		buf = palloc(bufsize1 + bufsize2);
 
@@ -811,7 +874,7 @@ strncoll_libc(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2,
 		arg2n = buf2;
 	}
 
-	result = strcoll_l(arg1n, arg2n, locale->info.lt);
+	result = strcoll_l(arg1n, arg2n, libc->lt);
 
 	if (buf != sbuf)
 		pfree(buf);
@@ -835,8 +898,10 @@ strnxfrm_libc(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	size_t		bufsize = srclen + 1;
 	size_t		result;
 
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	if (srclen == -1)
-		return strxfrm_l(dest, src, destsize, locale->info.lt);
+		return strxfrm_l(dest, src, destsize, libc->lt);
 
 	if (bufsize > TEXTBUFLEN)
 		buf = palloc(bufsize);
@@ -845,7 +910,7 @@ strnxfrm_libc(char *dest, size_t destsize, const char *src, ssize_t srclen,
 	memcpy(buf, src, srclen);
 	buf[srclen] = '\0';
 
-	result = strxfrm_l(dest, buf, destsize, locale->info.lt);
+	result = strxfrm_l(dest, buf, destsize, libc->lt);
 
 	if (buf != sbuf)
 		pfree(buf);
@@ -943,6 +1008,8 @@ strncoll_libc_win32_utf8(const char *arg1, ssize_t len1, const char *arg2,
 	int			r;
 	int			result;
 
+	struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 	Assert(GetDatabaseEncoding() == PG_UTF8);
 
 	if (len1 == -1)
@@ -987,7 +1054,7 @@ strncoll_libc_win32_utf8(const char *arg1, ssize_t len1, const char *arg2,
 	((LPWSTR) a2p)[r] = 0;
 
 	errno = 0;
-	result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, locale->info.lt);
+	result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, libc->lt);
 	if (result == 2147483647)	/* _NLSCMPERROR; missing from mingw headers */
 		ereport(ERROR,
 				(errmsg("could not compare Unicode strings: %m")));
@@ -1116,8 +1183,10 @@ wchar2char(char *to, const wchar_t *from, size_t tolen, pg_locale_t locale)
 	}
 	else
 	{
+		struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 		/* Use wcstombs_l for nondefault locales */
-		result = wcstombs_l(to, from, tolen, locale->info.lt);
+		result = wcstombs_l(to, from, tolen, libc->lt);
 	}
 
 	return result;
@@ -1176,8 +1245,10 @@ char2wchar(wchar_t *to, size_t tolen, const char *from, size_t fromlen,
 		}
 		else
 		{
+			struct libc_provider *libc = (struct libc_provider *) locale->provider_data;
+
 			/* Use mbstowcs_l for nondefault locales */
-			result = mbstowcs_l(to, str, tolen, locale->info.lt);
+			result = mbstowcs_l(to, str, tolen, libc->lt);
 		}
 
 		pfree(str);
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index f081091d200..ccf10cd617b 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -151,22 +151,7 @@ struct pg_locale_struct
 	const struct collate_methods *collate;	/* NULL if collate_is_c */
 	const struct ctype_methods *ctype;	/* NULL if ctype_is_c */
 
-	union
-	{
-		struct
-		{
-			const char *locale;
-			bool		casemap_full;
-		}			builtin;
-		locale_t	lt;
-#ifdef USE_ICU
-		struct
-		{
-			const char *locale;
-			UCollator  *ucol;
-		}			icu;
-#endif
-	}			info;
+	void	   *provider_data;
 };
 
 extern void init_database_collation(void);
-- 
2.34.1

From e32a88cc236a84cbc80f00c1713f2e851be1d109 Mon Sep 17 00:00:00 2001
From: Jeff Davis <j...@j-davis.com>
Date: Wed, 9 Oct 2024 10:00:58 -0700
Subject: [PATCH v15 4/4] Don't include ICU headers in pg_locale.h.

---
 src/backend/commands/collationcmds.c  | 4 ++++
 src/backend/utils/adt/formatting.c    | 4 ----
 src/backend/utils/adt/pg_locale.c     | 4 ++++
 src/backend/utils/adt/pg_locale_icu.c | 1 +
 src/backend/utils/adt/varlena.c       | 4 ++++
 src/include/utils/pg_locale.h         | 4 ----
 6 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 8acbfbbeda0..a57fe93c387 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -14,6 +14,10 @@
  */
 #include "postgres.h"
 
+#ifdef USE_ICU
+#include <unicode/ucol.h>
+#endif
+
 #include "access/htup_details.h"
 #include "access/table.h"
 #include "access/xact.h"
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 5bd1e01f7e4..b3d5e0436ee 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -70,10 +70,6 @@
 #include <limits.h>
 #include <wctype.h>
 
-#ifdef USE_ICU
-#include <unicode/ustring.h>
-#endif
-
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
 #include "common/int.h"
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index f26ce0e6cc7..894f141dbb1 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -54,6 +54,10 @@
 
 #include <time.h>
 
+#ifdef USE_ICU
+#include <unicode/ucol.h>
+#endif
+
 #include "access/htup_details.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_database.h"
diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index 19c51504f85..2ff7b960abc 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -13,6 +13,7 @@
 
 #ifdef USE_ICU
 #include <unicode/ucnv.h>
+#include <unicode/ucol.h>
 #include <unicode/ustring.h>
 
 /*
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 34796f2e27c..c57262e1888 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -17,6 +17,10 @@
 #include <ctype.h>
 #include <limits.h>
 
+#ifdef USE_ICU
+#include <unicode/uchar.h>
+#endif
+
 #include "access/detoast.h"
 #include "access/toast_compression.h"
 #include "catalog/pg_collation.h"
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index ccf10cd617b..4c941d02d76 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -14,10 +14,6 @@
 
 #include "mb/pg_wchar.h"
 
-#ifdef USE_ICU
-#include <unicode/ucol.h>
-#endif
-
 /* use for libc locale names */
 #define LOCALE_NAME_BUFLEN 128
 
-- 
2.34.1

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