1 files changed, 132 insertions, 0 deletions
diff --git a/tests/c32rtomb.c b/tests/c32rtomb.c
new file mode 100644
index 00000000..260bf097
--- /dev/null
+++ b/tests/c32rtomb.c
@@ -0,0 +1,132 @@
+/* Convert 32-bit wide character to multibyte character.
+   Copyright (C) 2020-2024 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2020.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <uchar.h>
+
+#include <errno.h>
+#include <wchar.h>
+
+#include "attribute.h" /* FALLTHROUGH */
+#include "localcharset.h"
+#include "streq.h"
+
+#if GL_CHAR32_T_IS_UNICODE
+# include "lc-charset-unicode.h"
+#endif
+
+size_t
+c32rtomb (char *s, char32_t wc, mbstate_t *ps)
+#undef c32rtomb
+{
+#if HAVE_WORKING_MBRTOC32
+
+# if C32RTOMB_RETVAL_BUG
+  if (s == NULL)
+    /* We know the NUL wide character corresponds to the NUL character.  */
+    return 1;
+# endif
+
+  return c32rtomb (s, wc, ps);
+
+#elif _GL_SMALL_WCHAR_T
+
+  if (s == NULL)
+    return wcrtomb (NULL, 0, ps);
+  else
+    {
+      /* Special-case all encodings that may produce wide character values
+         > WCHAR_MAX.  */
+      const char *encoding = locale_charset ();
+      if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
+        {
+          /* Special-case the UTF-8 encoding.  Assume that the wide-character
+             encoding in a UTF-8 locale is UCS-2 or, equivalently, UTF-16.  */
+          if (wc < 0x80)
+            {
+              s[0] = (unsigned char) wc;
+              return 1;
+            }
+          else
+            {
+              int count;
+
+              if (wc < 0x800)
+                count = 2;
+              else if (wc < 0x10000)
+                {
+                  if (wc < 0xd800 || wc >= 0xe000)
+                    count = 3;
+                  else
+                    {
+                      errno = EILSEQ;
+                      return (size_t)(-1);
+                    }
+                }
+              else if (wc < 0x110000)
+                count = 4;
+              else
+                {
+                  errno = EILSEQ;
+                  return (size_t)(-1);
+                }
+
+              switch (count) /* note: code falls through cases! */
+                {
+                case 4: s[3] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x10000;
+                  FALLTHROUGH;
+                case 3: s[2] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x800;
+                  FALLTHROUGH;
+                case 2: s[1] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0xc0;
+              /*case 1:*/ s[0] = wc;
+                }
+              return count;
+            }
+        }
+      else
+        {
+          if ((wchar_t) wc == wc)
+            return wcrtomb (s, (wchar_t) wc, ps);
+          else
+            {
+              errno = EILSEQ;
+              return (size_t)(-1);
+            }
+        }
+    }
+
+#else
+
+  /* char32_t and wchar_t are equivalent.  */
+# if GL_CHAR32_T_IS_UNICODE && GL_CHAR32_T_VS_WCHAR_T_NEEDS_CONVERSION
+  if (wc != 0)
+    {
+      wc = unicode_to_locale_encoding (wc);
+      if (wc == 0)
+        {
+          errno = EILSEQ;
+          return (size_t)(-1);
+        }
+    }
+# endif
+  return wcrtomb (s, (wchar_t) wc, ps);
+
+#endif
+}