Add -s (simulate) and -v (verbose) flags to ftsort

The -s flag prevents ftsort from writing back results to disk.  The -v
(verbose) flag enables more detailed output.  These flags are useful
when debugging traces and filtering.

1 files changed, 24 insertions, 6 deletions

diff --git a/src/ftsort.c b/src/ftsort.c
index 5ddb48f..03e2686 100644
--- a/src/ftsort.c
+++ b/src/ftsort.c
@@ -1,5 +1,5 @@
 /*    ft2sort -- Sort Feather-Trace events in a binary file by sequence number.
- *    Copyright (C) 2011  B. Brandenburg.
+ *    Copyright (C) 2011,2012  B. Brandenburg.
  *
  *    This program is free software; you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
@@ -35,6 +35,7 @@ static unsigned int holes      = 0;
 static unsigned int reordered  = 0;
 
 #define LOOK_AHEAD 1000
+static int want_verbose = 0;
 
 /* wall-clock time in seconds */
 double wctime(void)
@@ -133,8 +134,10 @@ static void restore_byte_order(struct timestamp* start, struct timestamp* end)
 #define USAGE                                                   \
         "Usage: ftsort [-e] <logfile> \n"                       \
         "   -e: endianess swap      -- restores byte order \n"  \
+        "   -s: simulate            -- don't overwrite file\n"  \
+        "   -v: verbose             -- be chatty\n"             \
         "\n"                                                    \
-        "WARNING: Changes are permanent.\n"
+        "WARNING: Changes are permanent, unless -s is specified.\n"
 
 static void die(char* msg)
 {
@@ -145,7 +148,7 @@ static void die(char* msg)
         exit(1);
 }
 
-#define OPTS "e"
+#define OPTS "esv"
 
 int main(int argc, char** argv)
 {
@@ -153,6 +156,7 @@ int main(int argc, char** argv)
         size_t size, count;
         struct timestamp *ts, *end;
         int swap_byte_order = 0;
+        int simulate = 0;
         int opt;
         double start, stop;
 
@@ -161,6 +165,12 @@ int main(int argc, char** argv)
                 case 'e':
                         swap_byte_order = 1;
                         break;
+                case 's':
+                        simulate = 1;
+                        break;
+                case 'v':
+                        want_verbose = 1;
+                        break;
                 default:
                         die("Unknown option.");
                         break;
@@ -172,8 +182,13 @@ int main(int argc, char** argv)
 
         start = wctime();
 
-        if (map_file_rw(argv[optind], &mapped, &size))
-                die("could not map file");
+        if (simulate) {
+                if (map_file(argv[optind], &mapped, &size))
+                        die("could not RO map file");
+        } else {
+                if (map_file_rw(argv[optind], &mapped, &size))
+                        die("could not RW map file");
+        }
 
         ts    = (struct timestamp*) mapped;
         count = size / sizeof(struct timestamp);
@@ -185,7 +200,10 @@ int main(int argc, char** argv)
         reorder(ts, end);
 
         /* write back */
-        msync(ts, size, MS_SYNC | MS_INVALIDATE);
+        if (simulate)
+                fprintf(stderr, "Note: not writing back results.\n");
+        else
+                msync(ts, size, MS_SYNC | MS_INVALIDATE);
 
         stop = wctime();