libs/libc/wchar: add fgetwc implementation

Signed-off-by: guoshichao <guoshichao@xiaomi.com>

include/wchar.h

@@ -142,7 +142,8 @@ extern "C"
 wint_t            btowc(int);
 int               fwprintf(FILE *, FAR const wchar_t *, ...);
 int               fwscanf(FILE *, FAR const wchar_t *, ...);
-wint_t            fgetwc(FILE *);
+wint_t            fgetwc(FAR FILE *);
+wint_t            fgetwc_unlocked(FAR FILE *f);
 FAR wchar_t      *fgetws(wchar_t *, int, FILE *);
 wint_t            fputwc(wchar_t, FILE *);
 wint_t            fputwc_unlocked(wchar_t, FAR FILE *);

libs/libc/libc.csv

@@ -64,6 +64,8 @@
 "fgetc","stdio.h","defined(CONFIG_FILE_STREAM)","int","FAR FILE *"
 "fgetpos","stdio.h","defined(CONFIG_FILE_STREAM)","int","FAR FILE *","FAR fpos_t *"
 "fgets","stdio.h","defined(CONFIG_FILE_STREAM)","FAR char *","FAR char *","int","FAR FILE *"
+"fgetwc","wchar.h","defined(CONFIG_FILE_STREAM)","wint_t","FAR FILE *"
+"fgetwc_unlocked","wchar.h","defined(CONFIG_FILE_STREAM)","wint_t","FAR FILE *"
 "fileno","stdio.h","","int","FAR FILE *"
 "flockfile","stdio.h","!defined(CONFIG_FILE_STREAM)","void","FAR FILE *"
 "fnmatch","fnmatch.h","","int","FAR const char *","FAR const char *","int"

libs/libc/stdio/CMakeLists.txt

@@ -105,7 +105,8 @@ if(CONFIG_FILE_STREAM)
     lib_putwc.c
     lib_fputws.c
     lib_fopencookie.c
-    lib_fmemopen.c)
+    lib_fmemopen.c
+    lib_fgetwc.c)
 endif()
 
 target_sources(c PRIVATE ${SRCS})

libs/libc/stdio/Make.defs

@@ -48,7 +48,7 @@ CSRCS += lib_feof.c lib_ferror.c lib_rewind.c lib_clearerr.c
 CSRCS += lib_scanf.c lib_vscanf.c lib_fscanf.c lib_vfscanf.c lib_tmpfile.c
 CSRCS += lib_setbuf.c lib_setvbuf.c lib_libfilelock.c lib_libgetstreams.c
 CSRCS += lib_setbuffer.c lib_fputwc.c lib_putwc.c lib_fputws.c
-CSRCS += lib_fopencookie.c lib_fmemopen.c lib_open_memstream.c
+CSRCS += lib_fopencookie.c lib_fmemopen.c lib_open_memstream.c lib_fgetwc.c
 endif
 
 # Add the stdio directory to the build

libs/libc/stdio/lib_fgetwc.c

@@ -0,0 +1,121 @@
+/****************************************************************************
+ * libs/libc/stdio/lib_fgetwc.c
+ *
+ * Copyright © 2005-2014 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <wchar.h>
+#include <errno.h>
+#include <string.h>
+
+#ifdef CONFIG_FILE_STREAM
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: fgetwc_unlocked
+ *
+ * Description:
+ *   Get wide character from stream without lock the stream
+ *
+ * Input Parameters:
+ *   f - Pointer to a FILE object that identifies an input stream, during
+ *   the read operaiton, the stream will not be locked
+ *
+ * Returned Value:
+ *   Return the character read is returned,
+ *   Return WEOF is the sequence of bytes that read cannot be interpreted as
+ *   a valid wide characted, and sets the errno to EILSEQ
+ *
+ ****************************************************************************/
+
+wint_t fgetwc_unlocked(FAR FILE *f)
+{
+  mbstate_t st;
+  wchar_t wc;
+  int c;
+  char b;
+  size_t l = -2;
+
+  memset(&st, 0, sizeof(mbstate_t));
+
+  /* Convert character byte-by-byte */
+
+  while (l == -2)
+    {
+      b = c = getc_unlocked(f);
+      if (c < 0)
+        {
+          if (!mbsinit(&st))
+            {
+              set_errno(EILSEQ);
+            }
+
+          f->fs_flags |= __FS_FLAG_EOF;
+          return WEOF;
+        }
+
+      l = mbrtowc(&wc, &b, 1, &st);
+      if (l == -1)
+        {
+          f->fs_flags |= __FS_FLAG_EOF;
+          return WEOF;
+        }
+    }
+
+  return wc;
+}
+
+/****************************************************************************
+ * Name: fgetwc
+ *
+ * Description:
+ *   Get wide character from stream
+ *
+ * Input Parameters:
+ *   f - Pointer to a FILE object that identifies an input stream, the stream
+ *   will be locked during the read operation
+ *
+ * Returned Value:
+ *   Return the character read is returned,
+ *   Return WEOF is the sequence of bytes that read cannot be interpreted as
+ *   a valid wide characted, and sets the errno to EILSEQ
+ *
+ ****************************************************************************/
+
+wint_t fgetwc(FAR FILE *f)
+{
+  wint_t c;
+  flockfile(f);
+  c = fgetwc_unlocked(f);
+  funlockfile(f);
+  return c;
+}
+
+#endif /* CONFIG_FILE_STREAM */