renumbas: add *useless* -b option (just for shiggles).

1 files changed, 16 insertions, 3 deletions

diff --git a/renumbas.c b/renumbas.c
index 62a4f07..6f4f51e 100644
--- a/renumbas.c
+++ b/renumbas.c
@@ -13,6 +13,7 @@ unsigned short startlineno = 10;
 unsigned short increment   = 10;
 unsigned short limit       = 0;
 unsigned short newno;
+int backwards = 0;
 
 void print_help(void) {
    printf("Usage: %s [-v] [-s start-lineno] [-i increment] [-f first-lineno] <inputfile> <outputfile>\n", self);
@@ -20,6 +21,7 @@ void print_help(void) {
    printf("  -s <num>: Starting line number (default: 10).\n");
    printf("  -i <num>: Increment (default: 10).\n");
    printf("  -f <num>: Don't renumber lines less than <num> (default: 0).\n");
+	printf("        -b: Number backwards (creates invalid program).\n");
 }
 
 unsigned short getlineno(char opt, const char *arg) {
@@ -46,9 +48,10 @@ unsigned short getlineno(char opt, const char *arg) {
 void parse_args(int argc, char **argv) {
 	int opt;
 
-	while( (opt = getopt(argc, argv, "vs:i:f:")) != -1) {
+	while( (opt = getopt(argc, argv, "vbs:i:f:")) != -1) {
 		switch(opt) {
-			case 'v': verbose = 1; break;
+			case 'v': verbose   = 1; break;
+			case 'b': backwards = 1; break;
 			case 's': startlineno = getlineno(opt, optarg); break;
 			case 'i': increment   = getlineno(opt, optarg); break;
 			case 'f': limit       = getlineno(opt, optarg); break;
@@ -86,7 +89,17 @@ CALLBACK(renumber_line) {
 	for(i = 0; i < refcounts[lineno]; i++)
 		memmove(program + linerefs[lineno][i].pos, fpnewno, 6);
 	setword(pos, newno);
-	newno += increment;
+
+	if(backwards) {
+		if(newno < increment) {
+			fprintf(stderr, "%s: Fatal: New line number %d would be <0.\n", self, newno);
+			exit(1);
+		} else {
+			newno -= increment;
+		}
+	} else {
+		newno += increment;
+	}
 }
 
 void check_refs(void) {