Add -f (fix EOF junk) option to unalf.

7 files changed, 35 insertions, 7 deletions

diff --git a/TODO.txt b/TODO.txt
index fa913d8..12c3fbf 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,5 +1,3 @@
-- unalf -f option (fix, by removing the junk at EOF if found)
-
 - rename project. calling it "unalf" when it contains both alf and
   unalf is confusing. think of a good name first.
 
diff --git a/src/io.c b/src/io.c
index 4e20505..53bc0dd 100644
--- a/src/io.c
+++ b/src/io.c
@@ -14,8 +14,16 @@ static void die_not_alf(void) {
 	exit(1);
 }
 
-static void eof_junk(void) {
-	fprintf(stderr, "%s: junk at EOF (ignoring)\n", self);
+/* truncating the file by name could be a race condition, but I don't
+   think it's going to be a real-world problem for anyone. */
+static void eof_junk(long pos) {
+	fprintf(stderr, "%s: junk at EOF (%s)\n", self, opts.fixjunk ? "removing" : "ignoring");
+	if(opts.fixjunk) {
+		if(truncate(in_filename, pos) < 0) {
+			fprintf(stderr, "%s: could not remove junk: ", self);
+			perror(in_filename);
+		}
+	}
 }
 
 static void check_hdr_size(const char *name, unsigned long size) {
@@ -49,6 +57,9 @@ static void sanity_check_header(void) {
 int read_alf_header(void) {
 	u8 h1, h2;
 	int bytes;
+	long read_pos;
+
+	read_pos = ftell(in_file);
 
 	bytes = fread(mem + alf_header, 1, 29, in_file);
 
@@ -59,7 +70,7 @@ int read_alf_header(void) {
 			die_not_alf();
 	} else if(bytes < 29) {
 		if(headers_read) {
-			eof_junk();
+			eof_junk(read_pos);
 			return 0;
 		} else {
 			die_not_alf();
@@ -79,7 +90,7 @@ int read_alf_header(void) {
 	}
 
 	if(headers_read)
-		eof_junk();
+		eof_junk(read_pos);
 	else
 		die_not_alf();
 
diff --git a/src/opts.c b/src/opts.c
index 58a13c2..416163c 100644
--- a/src/opts.c
+++ b/src/opts.c
@@ -1,6 +1,6 @@
 #include "unalf.h"
 
-#define OPTIONS "aeklLopqtvVd:x:"
+#define OPTIONS "aefklLopqtvVd:x:"
 
 /* uncomment to test exclude/include glob lists */
 // #define DEBUG_GLOBS
@@ -37,6 +37,7 @@ void parse_opts(int argc, char * const *argv) {
 			case 'a': opts.txtconv++; break;
 			case 'e': opts.listonly = opts.testonly = 0; break;
 			case 'k': opts.keepdot++; break;
+			case 'f': opts.fixjunk++; opts.testonly = 1; opts.listonly = 0; opts.quiet = 1; break;
 			case 'l': opts.listonly++; opts.testonly = 0; break;
 			case 'L': opts.lowercase++; break;
 			case 'o': opts.overwrite++; break;
diff --git a/src/unalf.1 b/src/unalf.1
index 396a5f6..36b7802 100644
--- a/src/unalf.1
+++ b/src/unalf.1
@@ -102,6 +102,15 @@ default action.
 .
 .INDENT 0.0
 .TP
+.B  \-f
+Fix (remove) junk at EOF. This option truncates the \fIalf\-file\fP\&.
+It is the only \fBunalf\fP option that writes to the input file. No
+backup is made.
+.UNINDENT
+.\" fix (remove) junk at EOF.
+.
+.INDENT 0.0
+.TP
 .B  \-h\fP,\fB  \-\-help
 Show built\-in help message.
 .UNINDENT
diff --git a/src/unalf.h b/src/unalf.h
index 1cb71bf..743282d 100644
--- a/src/unalf.h
+++ b/src/unalf.h
@@ -82,6 +82,7 @@ typedef struct {
 	int extract_to_stdout;
 	int quiet;
 	int verbose_list;
+	int fixjunk;
 } opts_t;
 
 #define MAX_EXCLUDES 256
diff --git a/src/unalf.rst b/src/unalf.rst
index 24774e6..c6ad52c 100644
--- a/src/unalf.rst
+++ b/src/unalf.rst
@@ -82,6 +82,13 @@ OPTIONS
 
 .. extract files (redundant; this is the default action).
 
+-f
+  Fix (remove) junk at EOF. This option truncates the *alf-file*.
+  It is the only **unalf** option that writes to the input file. No
+  backup is made.
+
+.. fix (remove) junk at EOF.
+
 -h, --help
    Show built-in help message.
 
diff --git a/src/usage.c b/src/usage.c
index 9808f35..f25e707 100644
--- a/src/usage.c
+++ b/src/usage.c
@@ -2,6 +2,7 @@ const char *usage_msg[] = {
 	"  -a: convert EOLs and tabs in text files.",
 	"  -d output-dir: set output directory (created if needed).",
 	"  -e: extract files (redundant; this is the default action).",
+	"  -f: fix (remove) junk at EOF.",
 	"  -h, --help: show this help message.",
 	"  -k: keep trailing periods (dots) in filenames.",
 	"  -l: list files in archive (filenames only).",