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-rw-r--r--wcsmbs/mbsrtowcs.c114
1 files changed, 94 insertions, 20 deletions
diff --git a/wcsmbs/mbsrtowcs.c b/wcsmbs/mbsrtowcs.c
index dc026b7252..712b199271 100644
--- a/wcsmbs/mbsrtowcs.c
+++ b/wcsmbs/mbsrtowcs.c
@@ -1,6 +1,6 @@
 /* Copyright (C) 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
-Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>
+Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
 
 The GNU C Library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Library General Public License as
@@ -17,9 +17,16 @@ License along with the GNU C Library; see the file COPYING.LIB.  If
 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 Boston, MA 02111-1307, USA.  */
 
+#include <errno.h>
 #include <wchar.h>
 
+#ifndef EILSEQ
+#define EILSEQ EINVAL
+#endif
 
+
+/* We don't need the state really because we don't have shift states
+   to maintain between calls to this function.  */
 static mbstate_t internal;
 
 size_t
@@ -29,35 +36,102 @@ mbsrtowcs (dst, src, len, ps)
      size_t len;
      mbstate_t *ps;
 {
-  size_t result = 0;
+  size_t written = 0;
+  const char *run = *src;
 
   if (ps == NULL)
     ps = &internal;
 
-  /*************************************************************\
-  |* This is no complete implementation.  While the multi-byte *|
-  |* character handling is not finished this will do.	       *|
-  \*************************************************************/
+  if (dst == NULL)
+    /* The LEN parameter has to be ignored if we don't actually write
+       anything.  */
+    len = ~0;
 
-  while (len > 0 && **src != '\0')
+  /* Copy all words.  */
+  while (written < len)
     {
-      /* For now there is no possibly illegal MB char sequence.  */
-      if (dst != NULL)
-	dst[result] = (wchar_t) **src;
-      ++result;
-      ++(*src);
-      --len;
-    }
+      wchar_t value;
+      size_t count;
+      unsigned char byte = *run++;
 
-  if (len > 0)
-    {
+      /* We expect a start of a new multibyte character.  */
+      if (byte < 0x80)
+	{
+	  /* One byte sequence.  */
+	  count = 0;
+	  value = byte;
+	}
+      else if ((byte & 0xe0) == 0xc0)
+	{
+	  count = 1;
+	  value = byte & 0x1f;
+	}
+      else if ((byte & 0xf0) == 0xe0)
+	{
+	  /* We expect three bytes.  */
+	  count = 2;
+	  value = byte & 0x0f;
+	}
+      else if ((byte & 0xf8) == 0xf0)
+	{
+	  /* We expect four bytes.  */
+	  count = 3;
+	  value = byte & 0x07;
+	}
+      else if ((byte & 0xfc) == 0xf8)
+	{
+	  /* We expect five bytes.  */
+	  count = 4;
+	  value = byte & 0x03;
+	}
+      else if ((byte & 0xfe) == 0xfc)
+	{
+	  /* We expect six bytes.  */
+	  count = 5;
+	  value = byte & 0x01;
+	}
+      else
+	{
+	  /* This is an illegal encoding.  */
+	  errno = EILSEQ;
+	  return (size_t) -1;
+	}
+
+      /* Read the possible remaining bytes.  */
+      while (count-- > 0)
+	{
+	  byte = *run++;
+
+	  if ((byte & 0xc0) != 0x80)
+	    {
+	      /* This is an illegal encoding.  */
+	      errno = EILSEQ;
+	      return (size_t) -1;
+	    }
+
+	  value <<= 6;
+	  value |= byte & 0x3f;
+	}
+
+      /* Store value is required.  */
       if (dst != NULL)
+	*dst++ = value;
+
+      /* The whole sequence is read.  Check whether end of string is
+	 reached.  */
+      if (value == L'\0')
 	{
-	  dst[result] = L'\0';
-	  *ps = 0;
+	  /* Found the end of the string.  */
+	  *src = NULL;
+	  return written;
 	}
-      *src = NULL;
+
+      /* Increment counter of produced words.  */
+      ++written;
     }
 
-  return result;
+  /* Store address of next byte to process.  */
+  *src = run;
+
+  return written;
 }