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| author | Jeff Davis <jdavis@postgresql.org> | 2025-01-24 14:56:22 -0800 |
|---|---|---|
| committer | Jeff Davis <jdavis@postgresql.org> | 2025-01-24 14:56:22 -0800 |
| commit | bfc5992069cf00b189af83d96a83ae5ebb65e938 (patch) | |
| tree | 94332f38e12deb4a6dcfdc011c42848069190ec5 /src/backend/utils/adt/pg_locale.c | |
| parent | f15538cd27d4eeb7d665263a3d7b5700362d7eb0 (diff) | |
| download | postgresql-bfc5992069cf00b189af83d96a83ae5ebb65e938.tar.gz postgresql-bfc5992069cf00b189af83d96a83ae5ebb65e938.zip | |
Add SQL function CASEFOLD().
Useful for caseless matching. Similar to LOWER(), but avoids edge-case
problems with using LOWER() for caseless matching.
For collations that support it, CASEFOLD() handles characters with
more than two case variations or multi-character case variations. Some
characters may fold to uppercase. The results of case folding are also
more stable across Unicode versions than LOWER() or UPPER().
Discussion: https://postgr.es/m/a1886ddfcd8f60cb3e905c93009b646b4cfb74c5.camel%40j-davis.com
Reviewed-by: Ian Lawrence Barwick
Diffstat (limited to 'src/backend/utils/adt/pg_locale.c')
| -rw-r--r-- | src/backend/utils/adt/pg_locale.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c index 94444acd2c5..7d92f580a57 100644 --- a/src/backend/utils/adt/pg_locale.c +++ b/src/backend/utils/adt/pg_locale.c @@ -106,6 +106,8 @@ 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); @@ -113,6 +115,8 @@ 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); @@ -1447,6 +1451,26 @@ pg_strupper(char *dst, size_t dstsize, const char *src, ssize_t srclen, return 0; /* keep compiler quiet */ } +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); + else + /* shouldn't happen */ + PGLOCALE_SUPPORT_ERROR(locale->provider); + + return 0; /* keep compiler quiet */ +} + /* * pg_strcoll * |