grep: short-circuit -v to bail out on first match

A small optimization. There is no need to try matching the current
input line against any further patterns if a match was already
found and -v is specified.

function                                             old     new   delta
grep_file                                           1463    1440     -23

Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Niko Vähäsarja <niko@tuxera.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/findutils/grep.c b/findutils/grep.c
index 9d9da422c..2cbe7ea91 100644
--- a/findutils/grep.c
+++ b/findutils/grep.c
@@ -443,15 +443,23 @@ static int grep_file(FILE *file)
                                         }
                                 }
                         }
-                        /* If it's non-inverted search, we can stop
-                         * at first match */
-                        if (found && !invert_search)
-                                goto do_found;
+                        /* If it's a non-inverted search, we can stop
+                         * at first match and report it.
+                         * If it's an inverted search, we can move on
+                         * to the next line of input, ignoring the
+                         * rest of the patterns.
+                         */
+                        if (found) {
+                                //if (invert_search)
+                                //      goto do_not_found;
+                                //goto do_found;
+                                break; // this accomplishes both
+                        }
                         pattern_ptr = pattern_ptr->link;
                 } /* while (pattern_ptr) */
 
                 if (found ^ invert_search) {
- do_found:
+ //do_found:
                         /* keep track of matches */
                         nmatches++;
 
@@ -552,6 +560,7 @@ static int grep_file(FILE *file)
                 }
 #if ENABLE_FEATURE_GREP_CONTEXT
                 else { /* no match */
+ //do_not_found:
                         /* if we need to print some context lines after the last match, do so */
                         if (print_n_lines_after) {
                                 print_line(line, strlen(line), linenum, '-');