Fortran: Implement read_x for UTF-8 encoded files.

	PR fortran/99210

libgfortran/ChangeLog:

	* io/read.c (read_x): If UTF-8 encoding is enabled, use
	read_utf8 to move one character over in the read buffer.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr99210.f90: New test.

1 files changed, 17 insertions, 0 deletions

diff --git a/libgfortran/io/read.c b/libgfortran/io/read.c
index 0ffcf76fd38..e2d2f8be806 100644
--- a/libgfortran/io/read.c
+++ b/libgfortran/io/read.c
@@ -1307,6 +1307,23 @@ read_x (st_parameter_dt *dtp, size_t n)
     
   if (n == 0)
     return;
+    
+  if (dtp->u.p.current_unit->flags.encoding == ENCODING_UTF8)
+    {
+      gfc_char4_t c;
+      size_t nbytes, j;
+    
+      /* Proceed with decoding one character at a time.  */
+      for (j = 0; j < n; j++)
+	{
+	  c = read_utf8 (dtp, &nbytes);
+    
+	  /* Check for a short read and if so, break out.  */
+	  if (nbytes == 0 || c == (gfc_char4_t)0)
+	    break;
+	}
+      return;
+    }
 
   length = n;