about summary refs log tree commit diff
path: root/wcsmbs/test-mbrtoc8.c
diff options
context:
space:
mode:
Diffstat (limited to 'wcsmbs/test-mbrtoc8.c')
-rw-r--r--wcsmbs/test-mbrtoc8.c539
1 files changed, 539 insertions, 0 deletions
diff --git a/wcsmbs/test-mbrtoc8.c b/wcsmbs/test-mbrtoc8.c
new file mode 100644
index 0000000000..16d73e2d7d
--- /dev/null
+++ b/wcsmbs/test-mbrtoc8.c
@@ -0,0 +1,539 @@
+/* Test mbrtoc8.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <uchar.h>
+#include <wchar.h>
+#include <support/check.h>
+#include <support/support.h>
+
+static int
+test_utf8 (void)
+{
+  xsetlocale (LC_ALL, "de_DE.UTF-8");
+
+  /* No inputs.  */
+  {
+    const char *mbs = "";
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 0, &s), (size_t) -2); /* no input */
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Null character.  */
+  {
+    const char *mbs = "\x00"; /* 0x00 => U+0000 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 0);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0x00);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* First non-null character in the code point range that maps to a single
+     code unit.  */
+  {
+    const char *mbs = "\x01"; /* 0x01 => U+0001 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0x01);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Last character in the code point range that maps to a single code unit.  */
+  {
+    const char *mbs = "\x7F"; /* 0x7F => U+007F */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0x7F);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* First character in the code point range that maps to two code units.  */
+  {
+    const char *mbs = "\xC2\x80"; /* 0xC2 0x80 => U+0080 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 2);
+    mbs += 2;
+    TEST_COMPARE (buf[0], 0xC2);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xC2\x80"; /* 0xC2 0x80 => U+0080 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xC2);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Last character in the code point range that maps to two code units.  */
+  {
+    const char *mbs = "\xDF\xBF"; /* 0xDF 0xBF => U+07FF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 2);
+    mbs += 2;
+    TEST_COMPARE (buf[0], 0xDF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xDF\xBF"; /* 0xDF 0xBF => U+07FF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xDF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* First character in the code point range that maps to three code units.  */
+  {
+    const char *mbs = u8"\xE0\xA0\x80"; /* 0xE0 0xA0 0x80 => U+0800 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xE0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xA0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = u8"\xE0\xA0\x80"; /* 0xE0 0xA0 0x80 => U+0800 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xE0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xA0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Last character in the code point range that maps to three code units
+     before the surrogate code point range.  */
+  {
+    const char *mbs = "\xED\x9F\xBF"; /* 0xED 0x9F 0xBF => U+D7FF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xED);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x9F);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xED\x9F\xBF"; /* 0xED 0x9F 0xBF => U+D7FF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xED);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x9F);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* First character in the code point range that maps to three code units
+     after the surrogate code point range.  */
+  {
+    const char *mbs = "\xEE\x80\x80"; /* 0xEE 0x80 0x80 => U+E000 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xEE);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xEE\x80\x80"; /* 0xEE 0x80 0x80 => U+E000 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xEE);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Not a BOM.  */
+  {
+    const char *mbs = "\xEF\xBB\xBF"; /* 0xEF 0xBB 0xBF => U+FEFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBB);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xEF\xBB\xBF"; /* 0xEF 0xBB 0xBF => U+FEFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBB);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Replacement character.  */
+  {
+    const char *mbs = "\xEF\xBF\xBD"; /* 0xEF 0xBF 0xBD => U+FFFD */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBD);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xEF\xBF\xBD"; /* 0xEF 0xBF 0xBD => U+FFFD */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBD);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Last character in the code point range that maps to three code units.  */
+  {
+    const char *mbs = "\xEF\xBF\xBF"; /* 0xEF 0xBF 0xBF => U+FFFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 3);
+    mbs += 3;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xEF\xBF\xBF"; /* 0xEF 0xBF 0xBF => U+FFFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xEF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* First character in the code point range that maps to four code units.  */
+  {
+    const char *mbs = "\xF0\x90\x80\x80"; /* 0xF0 0x90 0x80 0x80 => U+10000 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 4);
+    mbs += 4;
+    TEST_COMPARE (buf[0], 0xF0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x90);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xF0\x90\x80\x80"; /* 0xF0 0x90 0x80 0x80 => U+10000 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xF0);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x90);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x80);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Last character in the code point range that maps to four code units.  */
+  {
+    const char *mbs = "\xF4\x8F\xBF\xBF"; /* 0xF4 0x8F 0xBF 0xBF => U+10FFFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 4);
+    mbs += 4;
+    TEST_COMPARE (buf[0], 0xF4);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8F);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\xF4\x8F\xBF\xBF"; /* 0xF4 0x8F 0xBF 0xBF => U+10FFFF */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xF4);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8F);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xBF);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  return 0;
+}
+
+static int
+test_big5_hkscs (void)
+{
+  xsetlocale (LC_ALL, "zh_HK.BIG5-HKSCS");
+
+  /* A double byte character that maps to a pair of two byte UTF-8 code unit
+     sequences.  */
+  {
+    const char *mbs = "\x88\x62"; /* 0x88 0x62 => U+00CA U+0304 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 2);
+    mbs += 2;
+    TEST_COMPARE (buf[0], 0xC3);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8A);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xCC);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x84);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\x88\x62"; /* 0x88 0x62 => U+00CA U+0304 */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xC3);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8A);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xCC);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x84);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Another double byte character that maps to a pair of two byte UTF-8 code
+     unit sequences.  */
+  {
+    const char *mbs = "\x88\xA5"; /* 0x88 0xA5 => U+00EA U+030C */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) 2);
+    mbs += 2;
+    TEST_COMPARE (buf[0], 0xC3);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xAA);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xCC);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, strlen (mbs) + 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8C);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  /* Same as last test, but one code unit at a time.  */
+  {
+    const char *mbs = "\x88\xA5"; /* 0x88 0xA5 => U+00EA U+030C */
+    char8_t buf[1] = { 0 };
+    mbstate_t s = { 0 };
+
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -2);
+    mbs += 1;
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) 1);
+    mbs += 1;
+    TEST_COMPARE (buf[0], 0xC3);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xAA);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0xCC);
+    TEST_COMPARE (mbrtoc8 (buf, mbs, 1, &s), (size_t) -3);
+    TEST_COMPARE (buf[0], 0x8C);
+    TEST_VERIFY (mbsinit (&s));
+  }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  test_utf8 ();
+  test_big5_hkscs ();
+  return 0;
+}
+
+#include <support/test-driver.c>