Add pg_strtoupper and pg_strtolower functions

From c5e9d410133f6174ecf2a89ebc6adda588d2359d Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Mon, 2 May 2022 12:35:21 +0000
Subject: [PATCH v1] Add pg_strtoupper and pg_strtolower functions

---
 src/backend/utils/adt/datetime.c          |  8 ++----
 src/backend/utils/misc/tzparser.c         |  5 +---
 src/bin/psql/tab-complete.c               |  9 ++----
 src/include/port.h                        |  2 ++
 src/interfaces/ecpg/pgtypeslib/datetime.c |  3 +-
 src/port/pgstrcasecmp.c                   | 34 +++++++++++++++++++++++
 src/timezone/pgtz.c                       |  7 ++---
 7 files changed, 45 insertions(+), 23 deletions(-)

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 4c12c4d663..94a24c733f 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -1884,13 +1884,11 @@ DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t, const char *abbr, pg_tz *tzp,
 									  int *offset, int *isdst)
 {
 	char		upabbr[TZ_STRLEN_MAX + 1];
-	unsigned char *p;
 	long int	gmtoff;
 
 	/* We need to force the abbrev to upper case */
 	strlcpy(upabbr, abbr, sizeof(upabbr));
-	for (p = (unsigned char *) upabbr; *p; p++)
-		*p = pg_toupper(*p);
+	pg_strtoupper(upabbr);
 
 	/* Look up the abbrev's meaning at this time in this zone */
 	if (pg_interpret_timezone_abbrev(upabbr,
@@ -4929,7 +4927,6 @@ pg_timezone_abbrevs(PG_FUNCTION_ARGS)
 	char		buffer[TOKMAXLEN + 1];
 	int			gmtoffset;
 	bool		is_dst;
-	unsigned char *p;
 	struct pg_itm_in itm_in;
 	Interval   *resInterval;
 
@@ -5018,8 +5015,7 @@ pg_timezone_abbrevs(PG_FUNCTION_ARGS)
 	 * what ParseDateTime() uses.
 	 */
 	strlcpy(buffer, tp->token, sizeof(buffer));
-	for (p = (unsigned char *) buffer; *p; p++)
-		*p = pg_toupper(*p);
+	pg_strtoupper(buffer);
 
 	values[0] = CStringGetTextDatum(buffer);
 
diff --git a/src/backend/utils/misc/tzparser.c b/src/backend/utils/misc/tzparser.c
index a69cb2d268..18b7ca45bc 100644
--- a/src/backend/utils/misc/tzparser.c
+++ b/src/backend/utils/misc/tzparser.c
@@ -50,8 +50,6 @@ static int	ParseTzFile(const char *filename, int depth,
 static bool
 validateTzEntry(tzEntry *tzentry)
 {
-	unsigned char *p;
-
 	/*
 	 * Check restrictions imposed by datetktbl storage format (see datetime.c)
 	 */
@@ -78,8 +76,7 @@ validateTzEntry(tzEntry *tzentry)
 	/*
 	 * Convert abbrev to lowercase (must match datetime.c's conversion)
 	 */
-	for (p = (unsigned char *) tzentry->abbrev; *p; p++)
-		*p = pg_tolower(*p);
+	pg_strtolower(tzentry->abbrev);
 
 	return true;
 }
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 588c0841fe..3beefb7e05 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -5587,8 +5587,7 @@ complete_from_files(const char *text, int state)
 static char *
 pg_strdup_keyword_case(const char *s, const char *ref)
 {
-	char	   *ret,
-			   *p;
+	char	   *ret;
 	unsigned char first = ref[0];
 
 	ret = pg_strdup(s);
@@ -5598,13 +5597,11 @@ pg_strdup_keyword_case(const char *s, const char *ref)
 		  pset.comp_case == PSQL_COMP_CASE_PRESERVE_UPPER) && islower(first)) ||
 		(pset.comp_case == PSQL_COMP_CASE_PRESERVE_LOWER && !isalpha(first)))
 	{
-		for (p = ret; *p; p++)
-			*p = pg_tolower((unsigned char) *p);
+		pg_strtolower(ret);
 	}
 	else
 	{
-		for (p = ret; *p; p++)
-			*p = pg_toupper((unsigned char) *p);
+		pg_strtoupper(ret);
 	}
 
 	return ret;
diff --git a/src/include/port.h b/src/include/port.h
index 3d103a2b31..bbfb24b4d7 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -163,7 +163,9 @@ extern void pg_usleep(long microsec);
 extern int	pg_strcasecmp(const char *s1, const char *s2);
 extern int	pg_strncasecmp(const char *s1, const char *s2, size_t n);
 extern unsigned char pg_toupper(unsigned char ch);
+extern void pg_strtoupper(char *str);
 extern unsigned char pg_tolower(unsigned char ch);
+extern void pg_strtolower(char *str);
 extern unsigned char pg_ascii_toupper(unsigned char ch);
 extern unsigned char pg_ascii_tolower(unsigned char ch);
 
diff --git a/src/interfaces/ecpg/pgtypeslib/datetime.c b/src/interfaces/ecpg/pgtypeslib/datetime.c
index 1b253747fc..2ed91ed681 100644
--- a/src/interfaces/ecpg/pgtypeslib/datetime.c
+++ b/src/interfaces/ecpg/pgtypeslib/datetime.c
@@ -507,8 +507,7 @@ PGTYPESdate_defmt_asc(date * d, const char *fmt, const char *str)
 			return -1;
 
 		/* convert the whole string to lower case */
-		for (i = 0; str_copy[i]; i++)
-			str_copy[i] = (char) pg_tolower((unsigned char) str_copy[i]);
+		pg_strtolower(str_copy);
 	}
 
 	/* look for numerical tokens */
diff --git a/src/port/pgstrcasecmp.c b/src/port/pgstrcasecmp.c
index fc7ee91e8f..11549bdbed 100644
--- a/src/port/pgstrcasecmp.c
+++ b/src/port/pgstrcasecmp.c
@@ -111,6 +111,23 @@ pg_toupper(unsigned char ch)
 	return ch;
 }
 
+/*
+ * Fold a null-terminated string to upper case.
+ */
+void
+pg_strtoupper(char *str)
+{
+	unsigned char *p;
+
+	for (p = (unsigned char *) str; *p; p++)
+	{
+		if (*p >= 'a' && *p <= 'z')
+			*p += 'A' - 'a';
+		else if (IS_HIGHBIT_SET(*p) && islower(*p))
+			*p = toupper(*p);
+	}
+}
+
 /*
  * Fold a character to lower case.
  *
@@ -128,6 +145,23 @@ pg_tolower(unsigned char ch)
 	return ch;
 }
 
+/*
+ * Fold a null-terminated string to upper case.
+ */
+void
+pg_strtolower(char *str)
+{
+	unsigned char *p;
+
+	for (p = (unsigned char *) str; *p; p++)
+	{
+		if (*p >= 'A' && *p <= 'Z')
+			*p += 'a' - 'A';
+		else if (IS_HIGHBIT_SET(*p) && isupper(*p))
+			*p = tolower(*p);
+	}
+}
+
 /*
  * Fold a character to upper case, following C/POSIX locale rules.
  */
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..9820b21509 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -237,7 +237,6 @@ pg_tzset(const char *name)
 	struct state tzstate;
 	char		uppername[TZ_STRLEN_MAX + 1];
 	char		canonname[TZ_STRLEN_MAX + 1];
-	char	   *p;
 
 	if (strlen(name) > TZ_STRLEN_MAX)
 		return NULL;			/* not going to fit */
@@ -252,10 +251,8 @@ pg_tzset(const char *name)
 	 * can get consistently upcased results from tzparse() in case the name is
 	 * a POSIX-style timezone spec.)
 	 */
-	p = uppername;
-	while (*name)
-		*p++ = pg_toupper((unsigned char) *name++);
-	*p = '\0';
+	strlcpy(uppername, name, sizeof(uppername));
+	pg_strtoupper(uppername);
 
 	tzp = (pg_tz_cache *) hash_search(timezone_cache,
 									  uppername,
-- 
2.25.1