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Support C.UTF-8 locale in the new builtin collation provider.

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The builtin C.UTF-8 locale has similar semantics to the libc locale of
the same name. That is, code point sort order (fast, memcmp-based)
combined with Unicode semantics for character operations such as
pattern matching, regular expressions, and
LOWER()/INITCAP()/UPPER(). The character semantics are based on
Unicode simple case mappings.

The builtin provider's C.UTF-8 offers several important advantages
over libc:

 * faster sorting -- benefits from additional optimizations such as
   abbreviated keys and varstrfastcmp_c
 * faster case conversion, e.g. LOWER(), at least compared with some
   libc implementations
 * available on all platforms with identical semantics, and the
   semantics are stable, testable, and documentable within a given
   Postgres major version

Being based on memcmp, the builtin C.UTF-8 locale does not offer
natural language sort order. But it is an improvement for most use
cases that might otherwise use libc's "C.UTF-8" locale, as well as
many use cases that use libc's "C" locale.

Discussion: https://postgr.es/m/ff4c2f2f9c8fc7ca27c1c24ae37ecaeaeaff6b53.camel%40j-davis.com
Reviewed-by: Daniel Vérité, Peter Eisentraut, Jeremy Schneider
This commit is contained in:
Jeff Davis
2024-03-19 15:24:41 -07:00
parent fd0398fcb0
commit f69319f2f1
17 changed files with 494 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/backend/regex/regc_pg_locale.c
View File

@ -16,6 +16,8 @@
*/
#include "catalog/pg_collation.h"
#include "common/unicode_case.h"
#include "common/unicode_category.h"
#include "utils/pg_locale.h"
/*
@ -64,6 +66,7 @@
typedef enum
{
PG_REGEX_LOCALE_C, /* C locale (encoding independent) */
PG_REGEX_BUILTIN, /* built-in Unicode semantics */
PG_REGEX_LOCALE_WIDE, /* Use <wctype.h> functions */
PG_REGEX_LOCALE_1BYTE, /* Use <ctype.h> functions */
PG_REGEX_LOCALE_WIDE_L, /* Use locale_t <wctype.h> functions */
@ -266,7 +269,12 @@ pg_set_regex_collation(Oid collation)
if (GetDatabaseEncoding() == PG_UTF8)
{
if (pg_regex_locale)
pg_regex_strategy = PG_REGEX_LOCALE_WIDE_L;
{
if (pg_regex_locale->provider == COLLPROVIDER_BUILTIN)
pg_regex_strategy = PG_REGEX_BUILTIN;
else
pg_regex_strategy = PG_REGEX_LOCALE_WIDE_L;
}
else
pg_regex_strategy = PG_REGEX_LOCALE_WIDE;
}
@ -290,6 +298,8 @@ pg_wc_isdigit(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISDIGIT));
case PG_REGEX_BUILTIN:
return pg_u_isdigit(c, true);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswdigit((wint_t) c);
@ -322,6 +332,8 @@ pg_wc_isalpha(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISALPHA));
case PG_REGEX_BUILTIN:
return pg_u_isalpha(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswalpha((wint_t) c);
@ -354,6 +366,8 @@ pg_wc_isalnum(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISALNUM));
case PG_REGEX_BUILTIN:
return pg_u_isalnum(c, true);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswalnum((wint_t) c);
@ -395,6 +409,8 @@ pg_wc_isupper(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISUPPER));
case PG_REGEX_BUILTIN:
return pg_u_isupper(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswupper((wint_t) c);
@ -427,6 +443,8 @@ pg_wc_islower(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISLOWER));
case PG_REGEX_BUILTIN:
return pg_u_islower(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswlower((wint_t) c);
@ -459,6 +477,8 @@ pg_wc_isgraph(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISGRAPH));
case PG_REGEX_BUILTIN:
return pg_u_isgraph(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswgraph((wint_t) c);
@ -491,6 +511,8 @@ pg_wc_isprint(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISPRINT));
case PG_REGEX_BUILTIN:
return pg_u_isprint(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswprint((wint_t) c);
@ -523,6 +545,8 @@ pg_wc_ispunct(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISPUNCT));
case PG_REGEX_BUILTIN:
return pg_u_ispunct(c, true);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswpunct((wint_t) c);
@ -555,6 +579,8 @@ pg_wc_isspace(pg_wchar c)
case PG_REGEX_LOCALE_C:
return (c <= (pg_wchar) 127 &&
(pg_char_properties[c] & PG_ISSPACE));
case PG_REGEX_BUILTIN:
return pg_u_isspace(c);
case PG_REGEX_LOCALE_WIDE:
if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
return iswspace((wint_t) c);
@ -588,6 +614,8 @@ pg_wc_toupper(pg_wchar c)
if (c <= (pg_wchar) 127)
return pg_ascii_toupper((unsigned char) c);
return c;
case PG_REGEX_BUILTIN:
return unicode_uppercase_simple(c);
case PG_REGEX_LOCALE_WIDE:
/* force C behavior for ASCII characters, per comments above */
if (c <= (pg_wchar) 127)
@ -628,6 +656,8 @@ pg_wc_tolower(pg_wchar c)
if (c <= (pg_wchar) 127)
return pg_ascii_tolower((unsigned char) c);
return c;
case PG_REGEX_BUILTIN:
return unicode_lowercase_simple(c);
case PG_REGEX_LOCALE_WIDE:
/* force C behavior for ASCII characters, per comments above */
if (c <= (pg_wchar) 127)
@ -792,6 +822,9 @@ pg_ctype_get_cache(pg_wc_probefunc probefunc, int cclasscode)
max_chr = (pg_wchar) MAX_SIMPLE_CHR;
#endif
break;
case PG_REGEX_BUILTIN:
max_chr = (pg_wchar) MAX_SIMPLE_CHR;
break;
case PG_REGEX_LOCALE_WIDE:
case PG_REGEX_LOCALE_WIDE_L:
max_chr = (pg_wchar) MAX_SIMPLE_CHR;
@ -809,6 +842,7 @@ pg_ctype_get_cache(pg_wc_probefunc probefunc, int cclasscode)
max_chr = (pg_wchar) MAX_SIMPLE_CHR;
break;
default:
Assert(false);
max_chr = 0; /* can't get here, but keep compiler quiet */
break;
}