[hackers] [sbase] tr: add dflag, error with usage() on invalid flag combination || Hiltjo Posthuma

[git]

commit ff474a8cbc9514424c9d18013febfb8faca001c7
Author: Hiltjo Posthuma <hil...@codemadness.org>
Date:   Wed Apr 9 14:12:34 2014 +0200

    tr: add dflag, error with usage() on invalid flag combination
    
    Signed-off-by: Hiltjo Posthuma <hil...@codemadness.org>

diff --git a/tr.c b/tr.c
index 0ac0c86..aad2245 100644
--- a/tr.c
+++ b/tr.c
@@ -12,7 +12,7 @@
 static void
 usage(void)
 {
-       eprintf("usage: %s set1 [set2]
", argv0);
+       eprintf("usage: %s [-d] set1 [set2]
", argv0);
 }
 
 static void
@@ -117,6 +117,7 @@ main(int argc, char *argv[])
        char *buf = NULL;
        size_t size = 0;
        void (*mapfunc)(const wchar_t*, char*);
+       int dflag = 0;
 
        setlocale(LC_ALL, "");
 
@@ -126,6 +127,9 @@ main(int argc, char *argv[])
                eprintf("mmap:");
 
        ARGBEGIN {
+       case 'd':
+               dflag = 1;
+               break;
        default:
                usage();
        } ARGEND;
@@ -133,12 +137,16 @@ main(int argc, char *argv[])
        if(argc == 0)
                usage();
 
-       if(argc >= 2) {
-               parsemapping(argv[0], argv[1], mappings);
-               mapfunc = maptoset;
-       } else {
+       if(dflag) {
+               if(argc >= 2)
+                       usage();
                parsemapping(argv[0], NULL, mappings);
                mapfunc = maptonull;
+       } else {
+               if(argc != 2)
+                       usage();
+               parsemapping(argv[0], argv[1], mappings);
+               mapfunc = maptoset;
        }
 
        while(afgets(&buf, &size, stdin))