unprotbas: exit status 2 for unprotected program; add -c (check only).

3 files changed, 78 insertions, 29 deletions

diff --git a/unprotbas.1 b/unprotbas.1
index 3b8b832..0036a30 100644
--- a/unprotbas.1
+++ b/unprotbas.1
@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "UNPROTBAS" 1 "2024-05-18" "0.2.1" "Urchlay's Atari 8-bit Tools"
+.TH "UNPROTBAS" 1 "2024-05-19" "0.2.1" "Urchlay's Atari 8-bit Tools"
 .SH NAME
 unprotbas \- Unprotect LIST-protected Atari 8-bit BASIC programs
 .SH SYNOPSIS
@@ -51,7 +51,7 @@ the terminal).
 .INDENT 0.0
 .TP
 .B \fB\-v\fP
-Verbose operation.
+Verbose operation. TODO: it\(aqs always verbose right now...
 .TP
 .B \fB\-f\fP
 Force the variable name table to be rebuilt, even if it looks OK.
@@ -63,10 +63,24 @@ needed).
 .B \fB\-g\fP
 Remove any "garbage" data from the end of the file. By default,
 it\(aqs left as\-is, in case it\(aqs actually data used by the program.
+.TP
+.B \fB\-c\fP
+Check only. Does a dry run. Loads the program, unprotects it in
+memory, but doesn\(aqt write the result anywhere. In this mode, there
+is no \fBoutput\-file\fP\&.
 .UNINDENT
 .SH EXIT STATUS
-.sp
-Exit status is zero for success, non\-zero for failure.
+.INDENT 0.0
+.TP
+.B 0
+\fBinput\-file\fP was protected, unprotection was successful.
+.TP
+.B 1
+I/O error, or \fBinput\-file\fP isn\(aqt a valid BASIC program.
+.TP
+.B 2
+\fBinput\-file\fP is already an unprotected BASIC program.
+.UNINDENT
 .SH DETAILS
 .sp
 In the Atari BASIC world, it\(aqs possible to create a SAVEd (tokenized)
@@ -123,10 +137,13 @@ named A through Z, A1 through A9, B1 through B9, etc, etc. It\(aqll
 require human intelligence to figure out what each variable is for,
 since the names are meaningless.
 .sp
-The \fBoutput\-file\fP may be larger than the \fBinput\-file\fP was, since
-some types of variable\-name scrambling shrink the variable name
-table to the minimum size (one byte per name); the rebuilt table
-will be larger.
+The \fBoutput\-file\fP may not be the exact size that the
+\fBinput\-file\fP was. Some types of variable\-name scrambling shrink
+the variable name table to the minimum size (one byte per name), so
+the rebuilt table will be larger. Other types of scrambling leave
+the variable name table at its original size, but \fBunprotbas\fP
+generates only one\- and two\-character variable names, so the rebuilt
+table might be smaller.
 .TP
 .B Bad next\-line pointer
 Generally, this is done with line number 32768. Yes, this line
diff --git a/unprotbas.c b/unprotbas.c
index 8dc6844..845c75b 100644
--- a/unprotbas.c
+++ b/unprotbas.c
@@ -42,6 +42,8 @@ char *self;
 int keepvars = 0;
 int forcevars = 0;
 int keepgarbage = 1;
+int checkonly = 0;
+int was_protected = 0;
 int verbose = 0;
 
 /* file handles */
@@ -57,6 +59,7 @@ void die(const char *msg) {
 int readfile(void) {
 	int got = fread(data, 1, 65535, input_file);
 	fprintf(stderr, "read %d bytes\n", got);
+	fclose(input_file);
 	return got;
 }
 
@@ -369,6 +372,7 @@ void print_help(void) {
 	fprintf(stderr, "-f: force variable name table rebuild\n");
 	fprintf(stderr, "-n: do not rebuild variable name table, even if it's invalid\n");
 	fprintf(stderr, "-g: remove trailing garbage, if present\n");
+	fprintf(stderr, "-c: check only; no output file\n");
 	fprintf(stderr, "Use - as a filename to read from stdin and/or write to stdout\n");
 }
 
@@ -432,6 +436,7 @@ void parse_args(int argc, char **argv) {
 				case 'f': forcevars++; break;
 				case 'n': keepvars++; break;
 				case 'g': keepgarbage = 0; break;
+				case 'c': checkonly = 1; break;
 				case 0:
 							 if(!input_file)
 								 open_input(NULL);
@@ -445,7 +450,7 @@ void parse_args(int argc, char **argv) {
 		} else {
 			if(!input_file)
 				open_input(*argv);
-			else if(!output_file)
+			else if(!checkonly && !output_file)
 				open_output(*argv);
 			else
 				invalid_args(*argv);
@@ -453,7 +458,7 @@ void parse_args(int argc, char **argv) {
 	}
 
 	if(!input_file) die("no input file given (use - for stdin)");
-	if(!output_file) die("no output file given (use - for stdout)");
+	if(!checkonly && !output_file) die("no output file given (use - for stdout)");
 	if(keepvars && forcevars) die("-f and -n are mutually exclusive");
 }
 
@@ -465,26 +470,38 @@ int main(int argc, char **argv) {
 
 	if(lomem) die("This doesn't look like an Atari BASIC program (no $0000 signature)");
 
-	/*
-	fprintf(stderr, "data at STMTAB (we hope):\n");
-	for(int i=codestart; i<filelen; i++) {
-		fprintf(stderr, "%02x ", data[i]);
-	}
-	fprintf(stderr, "\n");
-	*/
-
 	if(!keepvars) {
-		if(fixvars())
+		if(fixvars()) {
+			was_protected = 1;
 			fprintf(stderr, "Variable names replaced\n");
-		else
+		} else {
 			fprintf(stderr, "Variable names were already OK\n");
+		}
 	}
 
-	if(fixcode())
+	if(fixcode()) {
 		fprintf(stderr, "Fixed invalid offset in code\n");
-	else
+		was_protected = 1;
+	} else {
 		fprintf(stderr, "No invalid offsets\n");
+	}
+
+	if(was_protected)
+		fprintf(stderr, "Program was protected.\n");
+	else
+		fprintf(stderr, "Program was not protected.\n");
+
+	if(checkonly) {
+		fprintf(stderr, "Check-only mode; no output written.\n");
+		if(was_protected)
+			return 0;
+		else
+			return 2;
+	}
+
+	int got = fwrite(data, 1, filelen, output_file);
+	fclose(output_file);
+	fprintf(stderr, "wrote %d bytes\n", got);
 
-	fwrite(data, filelen, 1, output_file);
 	return 0;
 }
diff --git a/unprotbas.rst b/unprotbas.rst
index 557d27d..b3a9926 100644
--- a/unprotbas.rst
+++ b/unprotbas.rst
@@ -33,7 +33,7 @@ OPTIONS
 =======
 
 **-v**
-  Verbose operation.
+  Verbose operation. TODO: it's always verbose right now...
 
 **-f**
   Force the variable name table to be rebuilt, even if it looks OK.
@@ -46,10 +46,22 @@ OPTIONS
   Remove any "garbage" data from the end of the file. By default,
   it's left as-is, in case it's actually data used by the program.
 
+**-c**
+  Check only. Does a dry run. Loads the program, unprotects it in
+  memory, but doesn't write the result anywhere. In this mode, there
+  is no **output-file**.
+
 EXIT STATUS
 ===========
 
-Exit status is zero for success, non-zero for failure.
+0
+  **input-file** was protected, unprotection was successful.
+
+1
+  I/O error, or **input-file** isn't a valid BASIC program.
+
+2
+  **input-file** is already an unprotected BASIC program.
 
 DETAILS
 =======
@@ -99,10 +111,13 @@ Variable name table scrambling
   require human intelligence to figure out what each variable is for,
   since the names are meaningless.
 
-  The **output-file** may be larger than the **input-file** was, since
-  some types of variable-name scrambling shrink the variable name
-  table to the minimum size (one byte per name); the rebuilt table
-  will be larger.
+  The **output-file** may not be the exact size that the
+  **input-file** was. Some types of variable-name scrambling shrink
+  the variable name table to the minimum size (one byte per name), so
+  the rebuilt table will be larger. Other types of scrambling leave
+  the variable name table at its original size, but **unprotbas**
+  generates only one- and two-character variable names, so the rebuilt
+  table might be smaller.
 
 Bad next-line pointer
   Generally, this is done with line number 32768. Yes, this line