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mirror of https://github.com/postgres/postgres.git synced 2025-09-05 02:22:28 +03:00

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
This commit is contained in:
Jeff Davis
2025-01-24 14:56:22 -08:00
parent f15538cd27
commit bfc5992069
14 changed files with 278 additions and 3 deletions

View File

@@ -31,6 +31,8 @@ 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);
struct WordBoundaryState
@@ -107,6 +109,14 @@ strupper_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
locale->info.builtin.casemap_full);
}
size_t
strfold_builtin(char *dest, size_t destsize, const char *src, ssize_t srclen,
pg_locale_t locale)
{
return unicode_strfold(dest, destsize, src, srclen,
locale->info.builtin.casemap_full);
}
pg_locale_t
create_pg_locale_builtin(Oid collid, MemoryContext context)
{