patch: do not emit trailing blanks in context header

[Jim Meyering]

Hi Paul,

Here's a little patch to avoid emitting trailing white space
in context headers:

2006-09-04  Jim Meyering  <address@hidden>

        * src/context.c (print_context_function): Do not print
        trailing white space in a context header.

Index: src/context.c
===================================================================
RCS file: /sources/diffutils/diffutils/src/context.c,v
retrieving revision 1.18
diff -u -r1.18 context.c
--- src/context.c       7 May 2006 08:16:19 -0000       1.18
+++ src/context.c       4 Sep 2006 08:59:07 -0000
@@ -137,6 +137,9 @@
   putc (' ', out);
   for (i = 0; i < 40 && function[i] != '\n'; i++)
     continue;
+  /* Trim any trailing white space.  */
+  while (0 < i && isspace ((unsigned char) function[i - 1]))
+    --i;
   fwrite (function, sizeof (char), i, out);
 }
 

This doesn't really matter, of course, but when the only trailing blanks
in a diff are those in context headers, it's a little annoying.

You can demonstrate/test with these commands:

    (printf '%-40s\n' f; printf '1\n') > 1
    (printf '%-40s\n' f; printf '2\n') > 2
    diff -u0 -p 1 2 | cat -A
    diff.old -u0 -p 1 2 | cat -A

Here's the output I get:

    --- 1^I2006-09-04 11:08:12.610304116 +0200$
    +++ 2^I2006-09-04 11:08:12.621301533 +0200$
    @@ -2 +2 @@ f$
    -1$
    +2$
    --- 1^I2006-09-04 11:08:12.610304116 +0200$
    +++ 2^I2006-09-04 11:08:12.621301533 +0200$
    @@ -2 +2 @@ f                                       $
    -1$
    +2$