From e39ece0343fef7bf5a689d75bbafff9386e6e3da Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Mon, 12 Jan 2026 08:35:48 +0100 Subject: [PATCH] Make dmetaphone collation-aware The dmetaphone() SQL function internally upper-cases the argument string. It did this using the toupper() function. That way, it has a dependency on the global LC_CTYPE locale setting, which we want to get rid of. The "double metaphone" algorithm specifically supports the "C with cedilla" letter, so just using ASCII case conversion wouldn't work. To fix that, use the passed-in collation and use the str_toupper() function, which has full awareness of collations and collation providers. Note that this does not change the fact that this function only works correctly with single-byte encodings. The change to str_toupper() makes the case conversion multibyte-enabled, but the rest of the function is still not ready. Reviewed-by: Jeff Davis Discussion: https://www.postgresql.org/message-id/108e07a2-0632-4f00-984d-fe0e0d0ec726%40eisentraut.org --- contrib/fuzzystrmatch/dmetaphone.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/contrib/fuzzystrmatch/dmetaphone.c b/contrib/fuzzystrmatch/dmetaphone.c index 227d8b11ddc..062667527c2 100644 --- a/contrib/fuzzystrmatch/dmetaphone.c +++ b/contrib/fuzzystrmatch/dmetaphone.c @@ -99,6 +99,7 @@ The remaining code is authored by Andrew Dunstan and #include "postgres.h" #include "utils/builtins.h" +#include "utils/formatting.h" /* turn off assertions for embedded function */ #define NDEBUG @@ -117,7 +118,7 @@ The remaining code is authored by Andrew Dunstan and #include /* prototype for the main function we got from the perl module */ -static void DoubleMetaphone(char *str, char **codes); +static void DoubleMetaphone(const char *str, Oid collid, char **codes); #ifndef DMETAPHONE_MAIN @@ -142,7 +143,7 @@ dmetaphone(PG_FUNCTION_ARGS) arg = PG_GETARG_TEXT_PP(0); aptr = text_to_cstring(arg); - DoubleMetaphone(aptr, codes); + DoubleMetaphone(aptr, PG_GET_COLLATION(), codes); code = codes[0]; if (!code) code = ""; @@ -171,7 +172,7 @@ dmetaphone_alt(PG_FUNCTION_ARGS) arg = PG_GETARG_TEXT_PP(0); aptr = text_to_cstring(arg); - DoubleMetaphone(aptr, codes); + DoubleMetaphone(aptr, PG_GET_COLLATION(), codes); code = codes[1]; if (!code) code = ""; @@ -278,13 +279,17 @@ IncreaseBuffer(metastring *s, int chars_needed) } -static void -MakeUpper(metastring *s) +static metastring * +MakeUpper(metastring *s, Oid collid) { - char *i; + char *newstr; + metastring *newms; - for (i = s->str; *i; i++) - *i = toupper((unsigned char) *i); + newstr = str_toupper(s->str, s->length, collid); + newms = NewMetaString(newstr); + DestroyMetaString(s); + + return newms; } @@ -392,7 +397,7 @@ MetaphAdd(metastring *s, const char *new_str) static void -DoubleMetaphone(char *str, char **codes) +DoubleMetaphone(const char *str, Oid collid, char **codes) { int length; metastring *original; @@ -414,7 +419,7 @@ DoubleMetaphone(char *str, char **codes) primary->free_string_on_destroy = 0; secondary->free_string_on_destroy = 0; - MakeUpper(original); + original = MakeUpper(original, collid); /* skip these when at start of word */ if (StringAt(original, 0, 2, "GN", "KN", "PN", "WR", "PS", "")) @@ -1430,7 +1435,7 @@ main(int argc, char **argv) if (argc > 1) { - DoubleMetaphone(argv[1], codes); + DoubleMetaphone(argv[1], DEFAULT_COLLATION_OID, codes); printf("%s|%s\n", codes[0], codes[1]); } }