From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001
From: Vladimir Azarov <avm@intermediate-node.net>
Date: Tue, 1 Oct 2024 15:47:05 +0200
Subject: Initial version

---
 src/locale/newlocale.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/locale/newlocale.c

(limited to 'src/locale/newlocale.c')

diff --git a/src/locale/newlocale.c b/src/locale/newlocale.c
new file mode 100644
index 0000000..9ac3cd3
--- /dev/null
+++ b/src/locale/newlocale.c
@@ -0,0 +1,70 @@
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include "locale_impl.h"
+#include "lock.h"
+
+#define malloc __libc_malloc
+#define calloc undef
+#define realloc undef
+#define free undef
+
+static int default_locale_init_done;
+static struct __locale_struct default_locale, default_ctype_locale;
+
+int __loc_is_allocated(locale_t loc)
+{
+	return loc && loc != C_LOCALE && loc != UTF8_LOCALE
+		&& loc != &default_locale && loc != &default_ctype_locale;
+}
+
+static locale_t do_newlocale(int mask, const char *name, locale_t loc)
+{
+	struct __locale_struct tmp;
+
+	for (int i=0; i<LC_ALL; i++) {
+		tmp.cat[i] = (!(mask & (1<<i)) && loc) ? loc->cat[i] :
+			__get_locale(i, (mask & (1<<i)) ? name : "");
+		if (tmp.cat[i] == LOC_MAP_FAILED)
+			return 0;
+	}
+
+	/* For locales with allocated storage, modify in-place. */
+	if (__loc_is_allocated(loc)) {
+		*loc = tmp;
+		return loc;
+	}
+
+	/* Otherwise, first see if we can use one of the builtin locales.
+	 * This makes the common usage case for newlocale, getting a C locale
+	 * with predictable behavior, very fast, and more importantly, fail-safe. */
+	if (!memcmp(&tmp, C_LOCALE, sizeof tmp)) return C_LOCALE;
+	if (!memcmp(&tmp, UTF8_LOCALE, sizeof tmp)) return UTF8_LOCALE;
+
+	/* And provide builtins for the initial default locale, and a
+	 * variant of the C locale honoring the default locale's encoding. */
+	if (!default_locale_init_done) {
+		for (int i=0; i<LC_ALL; i++)
+			default_locale.cat[i] = __get_locale(i, "");
+		default_ctype_locale.cat[LC_CTYPE] = default_locale.cat[LC_CTYPE];
+		default_locale_init_done = 1;
+	}
+	if (!memcmp(&tmp, &default_locale, sizeof tmp)) return &default_locale;
+	if (!memcmp(&tmp, &default_ctype_locale, sizeof tmp))
+		return &default_ctype_locale;
+
+	/* If no builtin locale matched, attempt to allocate and copy. */
+	if ((loc = malloc(sizeof *loc))) *loc = tmp;
+
+	return loc;
+}
+
+locale_t __newlocale(int mask, const char *name, locale_t loc)
+{
+	LOCK(__locale_lock);
+	loc = do_newlocale(mask, name, loc);
+	UNLOCK(__locale_lock);
+	return loc;
+}
+
+weak_alias(__newlocale, newlocale);
-- 
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