(utf8_wctomb): New function.

(print_unicode_char): Pass the Unicode character to iconv in UTF-8
format instead of in UCS-4 with platform dependent endianness.

1 files changed, 112 insertions, 48 deletions

diff --git a/lib/unicodeio.c b/lib/unicodeio.c
index 676126058..148d64ea6 100644
--- a/lib/unicodeio.c
+++ b/lib/unicodeio.c
@@ -28,6 +28,7 @@
 #endif
 
 #include <stdio.h>
+#include <string.h>
 
 #include <errno.h>
 #ifndef errno
@@ -36,12 +37,6 @@ extern int errno;
 
 #if HAVE_ICONV
 # include <iconv.h>
-/* Name of UCS-4 encoding with machine dependent endianness and alignment.  */
-# ifdef _LIBICONV_VERSION
-#  define UCS4_NAME "UCS-4-INTERNAL"
-# else
-#  define UCS4_NAME "INTERNAL"
-# endif
 #endif
 
 #include <error.h>
@@ -55,72 +50,141 @@ extern int errno;
 
 #include "unicodeio.h"
 
-/* Use md5.h for its nice detection of unsigned 32-bit type.  */
-#include "md5.h"
-#undef uint32_t
-#define uint32_t md5_uint32
+/* When we pass a Unicode character to iconv(), we must pass it in a
+   suitable encoding. The standardized Unicode encodings are
+   UTF-8, UCS-2, UCS-4, UTF-16, UTF-16BE, UTF-16LE, UTF-7.
+   UCS-2 supports only characters up to \U0000FFFF.
+   UTF-16 and variants support only characters up to \U0010FFFF.
+   UTF-7 is way too complex and not supported by glibc-2.1.
+   UCS-4 specification leaves doubts about endianness and byte order
+   mark. glibc currently interprets it as big endian without byte order
+   mark, but this is not backed by an RFC.
+   So we use UTF-8. It supports characters up to \U7FFFFFFF and is
+   unambiguously defined.  */
+
+/* Stores the UTF-8 representation of the Unicode character wc in r[0..5].
+   Returns the number of bytes stored, or -1 if wc is out of range.  */
+static int
+utf8_wctomb (unsigned char *r, unsigned int wc)
+{
+  int count;
+
+  if (wc < 0x80)
+    count = 1;
+  else if (wc < 0x800)
+    count = 2;
+  else if (wc < 0x10000)
+    count = 3;
+  else if (wc < 0x200000)
+    count = 4;
+  else if (wc < 0x4000000)
+    count = 5;
+  else if (wc <= 0x7fffffff)
+    count = 6;
+  else
+    return -1;
+
+  switch (count)
+    {
+      /* Note: code falls through cases! */
+      case 6: r[5] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x4000000;
+      case 5: r[4] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x200000;
+      case 4: r[3] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x10000;
+      case 3: r[2] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x800;
+      case 2: r[1] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0xc0;
+      case 1: r[0] = wc;
+    }
+
+  return count;
+}
+
+/* Luckily, the encoding's name is platform independent.  */
+#define UTF8_NAME "UTF-8"
 
 /* Outputs the Unicode character CODE to the output stream STREAM.
    Assumes that the locale doesn't change between two calls.  */
 void
 print_unicode_char (FILE *stream, unsigned int code)
 {
-#if HAVE_ICONV
   static int initialized;
-  static iconv_t ucs4_to_local;
+  static int is_utf8;
+#if HAVE_ICONV
+  static iconv_t utf8_to_local;
+#endif
 
-  uint32_t in;
-  char outbuf[25];
-  const char *inptr;
-  size_t inbytesleft;
-  char *outptr;
-  size_t outbytesleft;
-  size_t res;
+  char inbuf[6];
+  int count;
 
   if (!initialized)
     {
       extern const char *locale_charset (void);
       const char *charset = locale_charset ();
 
-      ucs4_to_local = (charset != NULL
-		       ? iconv_open (charset, UCS4_NAME)
-		       : (iconv_t)(-1));
-      if (ucs4_to_local == (iconv_t)(-1))
+      is_utf8 = (charset != NULL && !strcmp (charset, UTF8_NAME));
+#if HAVE_ICONV
+      if (!is_utf8)
 	{
-	  /* For an unknown encoding, assume ASCII.  */
-	  ucs4_to_local = iconv_open ("ASCII", UCS4_NAME);
-	  if (ucs4_to_local == (iconv_t)(-1))
-	    error (1, 0, _("cannot output U+%04X: iconv function not usable"),
-		   code);
+	  utf8_to_local = (charset != NULL
+			   ? iconv_open (charset, UTF8_NAME)
+			   : (iconv_t)(-1));
+	  if (utf8_to_local == (iconv_t)(-1))
+	    {
+	      /* For an unknown encoding, assume ASCII.  */
+	      utf8_to_local = iconv_open ("ASCII", UTF8_NAME);
+	      if (utf8_to_local == (iconv_t)(-1))
+		error (1, 0,
+		       _("cannot output U+%04X: iconv function not usable"),
+		       code);
+	    }
 	}
+#endif
       initialized = 1;
     }
 
-  in = code;
-  inptr = (char *) &in;
-  inbytesleft = sizeof (in);
-  outptr = outbuf;
-  outbytesleft = sizeof (outbuf);
-
-  /* Convert the character.  */
-  res = iconv (ucs4_to_local, &inptr, &inbytesleft, &outptr, &outbytesleft);
-  if (inbytesleft > 0 || res == (size_t)(-1))
-    error (1, res == (size_t)(-1) ? errno : 0,
-	   _("cannot convert U+%04X to local character set"), code);
+  /* Convert the character to UTF-8.  */
+  count = utf8_wctomb ((unsigned char *) inbuf, code);
+  if (count < 0)
+    error (1, 0, _("U+%04X: character out of range"), code);
 
-  /* Avoid glibc-2.1 bug.  */
+  if (is_utf8)
+    {
+      fwrite (inbuf, 1, count, stream);
+    }
+  else
+    {
+#if HAVE_ICONV
+      char outbuf[25];
+      const char *inptr;
+      size_t inbytesleft;
+      char *outptr;
+      size_t outbytesleft;
+      size_t res;
+
+      inptr = inbuf;
+      inbytesleft = count;
+      outptr = outbuf;
+      outbytesleft = sizeof (outbuf);
+
+      /* Convert the character from UTF-8 to the locale's charset.  */
+      res = iconv (utf8_to_local, &inptr, &inbytesleft, &outptr, &outbytesleft);
+      if (inbytesleft > 0 || res == (size_t)(-1))
+	error (1, res == (size_t)(-1) ? errno : 0,
+	       _("cannot convert U+%04X to local character set"), code);
+
+      /* Avoid glibc-2.1 bug.  */
 # if defined _LIBICONV_VERSION || !(__GLIBC__ - 0 == 2 && __GLIBC_MINOR__ - 0 <= 1)
 
-  /* Get back to the initial shift state.  */
-  res = iconv (ucs4_to_local, NULL, NULL, &outptr, &outbytesleft);
-  if (res == (size_t)(-1))
-    error (1, errno, _("cannot convert U+%04X to local character set"), code);
-
+      /* Get back to the initial shift state.  */
+      res = iconv (utf8_to_local, NULL, NULL, &outptr, &outbytesleft);
+      if (res == (size_t)(-1))
+	error (1, errno, _("cannot convert U+%04X to local character set"),
+	       code);
 # endif
 
-  fwrite (outbuf, 1, outptr - outbuf, stream);
-
+      fwrite (outbuf, 1, outptr - outbuf, stream);
 #else
-  error (1, 0, _("cannot output U+%04X: iconv function not available"), code);
+      error (1, 0, _("cannot output U+%04X: iconv function not available"),
+	     code);
 #endif
+    }
 }