From: Jim Meyering <jim@meyering.net>
Date: Sat, 14 Jun 1997 17:31:40 +0000 (+0000)
Subject: (cut_fields): Detect when the input is empty and handle
X-Git-Tag: SH-UTILS-1_16a~31
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2f1768f67675dc38f54b20c0122ec1f2944a994d;p=thirdparty%2Fcoreutils.git

(cut_fields): Detect when the input is empty and handle
that special case.  Before `cut -f1 </dev/null' would improperly
output a single newline.  Reported by Phil Richards.
---

diff --git a/src/cut.c b/src/cut.c
index 549a0e342e..a9cd23154c 100644
--- a/src/cut.c
+++ b/src/cut.c
@@ -526,10 +526,16 @@ cut_fields (FILE *stream)
   unsigned int field_idx;
   int found_any_selected_field;
   int buffer_first_field;
+  int empty_input;
 
   found_any_selected_field = 0;
   field_idx = 1;
 
+  c = getc (stream);
+  empty_input = (c == EOF);
+  if (c != EOF)
+    ungetc (c, stream);
+
   /* To support the semantics of the -s flag, we may have to buffer
      all of the first field to determine whether it is `delimited.'
      But that is unnecessary if all non-delimited lines must be printed
@@ -577,22 +583,25 @@ cut_fields (FILE *stream)
 	  ++field_idx;
 	}
 
-      if (print_kth (field_idx))
+      if (c != EOF)
 	{
-	  if (found_any_selected_field)
-	    putchar (delim);
-	  found_any_selected_field = 1;
-
-	  while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
+	  if (print_kth (field_idx))
 	    {
-	      putchar (c);
+	      if (found_any_selected_field)
+		putchar (delim);
+	      found_any_selected_field = 1;
+
+	      while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
+		{
+		  putchar (c);
+		}
 	    }
-	}
-      else
-	{
-	  while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
+	  else
 	    {
-	      /* Empty.  */
+	      while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
+		{
+		  /* Empty.  */
+		}
 	    }
 	}
 
@@ -611,7 +620,7 @@ cut_fields (FILE *stream)
       else if (c == '\n' || c == EOF)
 	{
 	  if (found_any_selected_field
-	      || !(suppress_non_delimited && field_idx == 1))
+	      || (!empty_input && !(suppress_non_delimited && field_idx == 1)))
 	    putchar ('\n');
 	  if (c == EOF)
 	    break;