Fix uniq to conform to POSIX, which requires that "uniq -d -u"

must output nothing.  Problem reported by Josh Hyman.

(enum output_mode, mode): Remove, replacing with:
(output_unique, output_first_repeated, output_later_repeated):
New vars.  All uses of "mode" changed to use these variables,
which are not mutually exclusive as "mode" was.
(writeline): New arg "match", used to control whether to
obey output_first_repeated or output_later_repeated.
All callers changed.
(check_file, main): Adjust to above changes.

diff --git a/src/uniq.c b/src/uniq.c
index dd3aa1d..f0c3997 100644 (file)
--- a/src/uniq.c
+++ b/src/uniq.c
@@ -74,16 +74,12 @@ enum countmode
    times they occurred in the input. */
 static enum countmode countmode;
 
-enum output_mode
-{
-  output_repeated,             /* -d Only lines that are repeated. */
-  output_all_repeated,         /* -D All lines that are repeated. */
-  output_unique,               /* -u Only lines that are not repeated. */
-  output_all                   /* Default.  Print first copy of each line. */
-};
-
-/* Which lines to output. */
-static enum output_mode mode;
+/* Which lines to output: unique lines, the first of a group of
+   repeated lines, and the second and subsequented of a group of
+   repeated lines.  */
+static bool output_unique;
+static bool output_first_repeated;
+static bool output_later_repeated;
 
 /* If nonzero, ignore case when comparing.  */
 static int ignore_case;
@@ -240,15 +236,17 @@ different (char *old, char *new, size_t oldlen, size_t newlen)
 
 /* Output the line in linebuffer LINE to stream STREAM
    provided that the switches say it should be output.
+   MATCH is true if the line matches the previous line.
    If requested, print the number of times it occurred, as well;
    LINECOUNT + 1 is the number of times that the line occurred. */
 
 static void
-writeline (const struct linebuffer *line, FILE *stream, int linecount)
+writeline (struct linebuffer const *line, FILE *stream,
+          bool match, int linecount)
 {
-  if ((mode == output_unique && linecount != 0)
-      || (mode == output_repeated && linecount == 0)
-      || (mode == output_all_repeated && linecount == 0))
+  if (! (linecount == 0 ? output_unique
+        : !match ? output_first_repeated
+        : output_later_repeated))
     return;
 
   if (countmode == count_occurrences)
@@ -295,7 +293,7 @@ check_file (const char *infile, const char *outfile)
      this optimization lets uniq output each different line right away,
      without waiting to see if the next one is different.  */
 
-  if (mode == output_all && countmode == count_none)
+  if (output_unique && output_first_repeated && countmode == count_none)
     {
       char *prevfield IF_LINT (= NULL);
       size_t prevlen IF_LINT (= 0);
@@ -334,7 +332,7 @@ check_file (const char *infile, const char *outfile)
 
       while (!feof (istream))
        {
-         int match;
+         bool match;
          char *thisfield;
          size_t thislen;
          if (readline (thisline, istream) == 0)
@@ -346,7 +344,7 @@ check_file (const char *infile, const char *outfile)
          if (match)
            ++match_count;
 
-          if (mode == output_all_repeated && delimit_groups != DM_NONE)
+          if (delimit_groups != DM_NONE)
            {
              if (!match)
                {
@@ -362,9 +360,9 @@ check_file (const char *infile, const char *outfile)
                }
            }
 
-         if (!match || mode == output_all_repeated)
+         if (!match || output_later_repeated)
            {
-             writeline (prevline, ostream, match_count);
+             writeline (prevline, ostream, match, match_count);
              SWAP_LINES (prevline, thisline);
              prevfield = thisfield;
              prevlen = thislen;
@@ -373,7 +371,7 @@ check_file (const char *infile, const char *outfile)
            }
        }
 
-      writeline (prevline, ostream, match_count);
+      writeline (prevline, ostream, false, match_count);
     }
 
  closefiles:
@@ -410,7 +408,8 @@ main (int argc, char **argv)
   skip_chars = 0;
   skip_fields = 0;
   check_chars = SIZE_MAX;
-  mode = output_all;
+  output_unique = output_first_repeated = true;
+  output_later_repeated = false;
   countmode = count_none;
   delimit_groups = DM_NONE;
 
@@ -480,11 +479,12 @@ main (int argc, char **argv)
          break;
 
        case 'd':
-         mode = output_repeated;
+         output_unique = false;
          break;
 
        case 'D':
-         mode = output_all_repeated;
+         output_unique = false;
+         output_later_repeated = true;
          if (optarg == NULL)
            delimit_groups = DM_NONE;
          else
@@ -508,7 +508,7 @@ main (int argc, char **argv)
          break;
 
        case 'u':
-         mode = output_unique;
+         output_first_repeated = false;
          break;
 
        case 'w':
@@ -532,7 +532,7 @@ main (int argc, char **argv)
       usage (EXIT_FAILURE);
     }
 
-  if (countmode == count_occurrences && mode == output_all_repeated)
+  if (countmode == count_occurrences && output_later_repeated)
     {
       error (0, 0,
           _("printing all duplicated lines and repeat counts is meaningless"));