fix: correct typos and improve code quality in ivy_guc.c

Fixed typos ("blow"->"below", "charater"->"character", etc.),
corrected grammar ("whether enable"->"whether to enable"),
removed redundant null terminator assignments,
replaced unsafe memcpy with strcpy for null termination safety,
and replaced goto statements with recursive calls.

Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: OreoYang

src/backend/utils/misc/ivy_guc.c

@@ -56,7 +56,7 @@ int			rowid_seq_cache = 20;
 
 #ifdef IVY_GUC_VAR_STRUCT
 
-/* The comments shown as blow define the
+/* The comments shown as below define the
  * value range of guc parameters "database_mode"
  * and "compatible_db".
  */
@@ -72,7 +72,6 @@ static const struct config_enum_entry db_parser_options[] = {
 	{"pg", PG_PARSER, false},
 	{"oracle", ORA_PARSER, false},
 	{NULL, 0, false}
-
 };
 
 
@@ -126,7 +125,7 @@ static struct config_bool Ivy_ConfigureNamesBool[] =
 	},
 	{
 		{"ivorysql.enable_case_switch", PGC_USERSET, CLIENT_CONN_STATEMENT,
-			gettext_noop("whether enable case conversion feature in oracle compatible mode."),
+			gettext_noop("whether to enable case conversion feature in oracle compatible mode."),
 			NULL,
 			GUC_NO_SHOW_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
 		},
@@ -137,7 +136,7 @@ static struct config_bool Ivy_ConfigureNamesBool[] =
 
 	{
 		{"ivorysql.enable_emptystring_to_NULL", PGC_USERSET, COMPAT_ORACLE_OPTIONS,
-			gettext_noop("whether convert empty string to NULL."),
+			gettext_noop("whether to convert empty string to NULL."),
 			NULL
 		},
 		&enable_emptystring_to_NULL,
@@ -233,7 +232,7 @@ static struct config_int Ivy_ConfigureNamesInt[] =
 
 	{
 		{"ivorysql.port", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
-			gettext_noop("Sets the Oracle TCP port the server listens on."),
+			gettext_noop("Sets the Oracle TCP port that the server listens on."),
 			NULL
 		},
 		&OraPortNumber,
@@ -369,7 +368,7 @@ static struct config_real Ivy_ConfigureNamesReal[] =
 {
 #endif
 #ifdef IVY_GUC_REAL_PARAMS
-	/* Add real guc param at here */
+	/* Add real guc param here */
 
 #endif
 #if 0
@@ -420,7 +419,7 @@ static struct config_enum Ivy_ConfigureNamesEnum[] =
 
 	{
 		{"nls_length_semantics", PGC_USERSET, COMPAT_ORACLE_OPTIONS,
-			gettext_noop("Compatible Oracle NLS parameter for charater data type."),
+			gettext_noop("Compatible Oracle NLS parameter for character data type."),
 			gettext_noop("Valid values are CHAR, BYTE."),
 			GUC_IS_NAME | GUC_NOT_IN_SAMPLE
 		},
@@ -477,7 +476,7 @@ check_compatible_mode(int *newval, void **extra, GucSource source)
 				ereport(ERROR,
 						(errcode(ERRCODE_SYSTEM_ERROR),
 						 errmsg("IVORYSQL_ORA library not found!"),
-						 errhint("You must load IVORYSQL_ORA to use oracle parser..")));
+						 errhint("You must load IVORYSQL_ORA to use oracle parser.")));
 		}
 	}
 	return true;
@@ -530,20 +529,17 @@ nls_case_conversion(char **param, char type)
 {
 	char	   *p;
 
-CASE_CONVERSION:
 	if (type == 'u')
 	{
 		for (p = *param; p < *param + strlen(*param); ++p)
 			if (97 <= *p && *p <= 122)
 				*p -= 32;
-		*p = '\0';
 	}
 	else if (type == 'l')
 	{
 		for (p = *param; p < *param + strlen(*param); ++p)
 			if (65 <= *p && *p <= 90)
 				*p += 32;
-		*p = '\0';
 	}
 	else if (type == 'b')
 	{
@@ -562,13 +558,11 @@ nls_case_conversion(char **param, char type)
 
 		if (has_upper && !has_lower)
 		{
-			type = 'l';
-			goto CASE_CONVERSION;
+			nls_case_conversion(param, 'l');
 		}
 		else if (!has_upper && has_lower)
 		{
-			type = 'u';
-			goto CASE_CONVERSION;
+			nls_case_conversion(param, 'u');
 		}
 	}
 }
@@ -597,9 +591,9 @@ nls_territory_check(char **newval, void **extra, GucSource source)
 		&& (IsNormalProcessingMode() || (IsUnderPostmaster && MyProcPort)))
 	{
 		if (pg_strcasecmp(*newval, "CHINA") == 0)
-			memcpy(*newval, "CHINA", 5);
+			strcpy(*newval, "CHINA");
 		else if (pg_strcasecmp(*newval, "AMERICA") == 0)
-			memcpy(*newval, "AMERICA", 7);
+			strcpy(*newval, "AMERICA");
 		else
 			ereport(ERROR, (errmsg("Cannot access NLS data files "
 								   "or invalid environment specified")));