Unicode case mapping tables and functions.

Implements Unicode simple case mapping, in which all code points map
to exactly one other code point unconditionally.

These tables are generated from UnicodeData.txt, which is already
being used by other infrastructure in src/common/unicode. The tables
are checked into the source tree, so they only need to be regenerated
when we update the Unicode version.

In preparation for the builtin collation provider, and possibly useful
for other callers.

Discussion: https://postgr.es/m/ff4c2f2f9c8fc7ca27c1c24ae37ecaeaeaff6b53.camel%40j-davis.com
Reviewed-by: Peter Eisentraut, Daniel Verite, Jeremy Schneider

1 files changed, 27 insertions, 0 deletions

diff --git a/src/include/common/unicode_case.h b/src/include/common/unicode_case.h
new file mode 100644
index 00000000000..ad6f62cc41d
--- /dev/null
+++ b/src/include/common/unicode_case.h
@@ -0,0 +1,27 @@
+/*-------------------------------------------------------------------------
+ *
+ * unicode_case.h
+ *	  Routines for converting character case.
+ *
+ * These definitions can be used by both frontend and backend code.
+ *
+ * Copyright (c) 2017-2023, PostgreSQL Global Development Group
+ *
+ * src/include/common/unicode_case.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef UNICODE_CASE_H
+#define UNICODE_CASE_H
+
+#include "mb/pg_wchar.h"
+
+pg_wchar	unicode_lowercase_simple(pg_wchar ucs);
+pg_wchar	unicode_titlecase_simple(pg_wchar ucs);
+pg_wchar	unicode_uppercase_simple(pg_wchar ucs);
+size_t		unicode_strlower(char *dst, size_t dstsize, const char *src,
+							 size_t srclen);
+size_t		unicode_strupper(char *dst, size_t dstsize, const char *src,
+							 size_t srclen);
+
+#endif							/* UNICODE_CASE_H */