From 080e54f17ecb4a255332466725c1ce944f39f5c1 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Wed, 26 Nov 2025 04:14:30 -0500
Subject: alf: Store correct date/time.

---
 src/Makefile |  7 +++++--
 src/alf.c    | 48 +++++++++++++++++++++++++++++++++++-------------
 src/unalf.h  |  5 +----
 3 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index d09d8dc..0106dc7 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -41,7 +41,7 @@ CFLAGS=-DVERSION='"$(VERSION)"' -Wall -I../f65 $(COPT)
 
 UNALF_OBJS=unalf.o io.o listalf.o extract.o f65.o glob.o opts.o usage.o self.o asmcode.o
 ALFSUM_OBJS=alfsum.o self.o
-ALF_OBJS=alf.o
+ALF_OBJS=alf.o self.o
 
 .PHONY: all clean install crosswin windows windows-upload realclean
 
@@ -53,9 +53,12 @@ all: unalf unalf.1 alfsum alfsum.1 alf alf.1
 unalf: $(UNALF_OBJS)
 	$(CC) $(LDFLAGS) -o $@ $(UNALF_OBJS)
 
-alfsum: alfsum.o self.o
+alfsum: $(ALFSUM_OBJS)
 	$(CC) $(LDFLAGS) -o $@ $(ALFSUM_OBJS)
 
+alf: $(ALF_OBJS)
+	$(CC) $(LDFLAGS) -o $@ $(ALF_OBJS)
+
 usage.o: usage.c
 
 f65.o: ../f65/f65.c ../f65/f65.h
diff --git a/src/alf.c b/src/alf.c
index 0dd8d88..63b1d05 100644
--- a/src/alf.c
+++ b/src/alf.c
@@ -1,17 +1,13 @@
-/* eventual options:
-	-a append
-	-o overwrite (instead of backup~)
-	-v verbose
- */
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
 #include <unistd.h>
 #include <limits.h>
+#include <sys/stat.h>
+#include <time.h>
 
-#define self "unalf"
+#include "self.h"
 
 #ifndef u8
 #define u8 unsigned char
@@ -35,6 +31,8 @@ int input_len, output_len, out_bitpos;
 int opt_append = 0;
 int opt_overwrite = 0;
 
+struct stat in_file_stat;
+
 typedef struct s_token {
 	u8 *start;
 	u16 length;
@@ -127,6 +125,22 @@ void atarify_filename(char *result) {
 		*p = toupper(*p);
 }
 
+/* see Arcinfo for the gory details. */
+unsigned long get_msdos_date_time(void) {
+	time_t t = in_file_stat.st_mtim.tv_sec;
+	struct tm *tm;
+	int msdos_year;
+	u16 ms_date, ms_time;
+
+	tm = gmtime(&t);
+
+	msdos_year = tm->tm_year + 1900 - 1980;
+
+	ms_date = tm->tm_mday | (tm->tm_mon << 5) | (msdos_year << 9);
+	ms_time = (tm->tm_min << 5) | (tm->tm_hour << 11);
+	return ms_date | (ms_time << 16);
+}
+
 void create_header(void) {
 	char hdr_filename[13];
 
@@ -137,7 +151,7 @@ void create_header(void) {
 	strncat((char *)&output_buf[2], hdr_filename, 13);
 	output_buf[14] = 0x00;
 	store_quad(15, 0); /* compressed size, fill in later */
-	store_quad(19, 0); /* date/time (TODO: real timestamp) */
+	store_quad(19, get_msdos_date_time());
 	store_cksum();
 	store_quad(25, input_len);
 	output_len = 29;
@@ -243,6 +257,7 @@ void crunch_file(const char *filename) {
 	/* read in entire input, couldn't do it this way on the Atari */
 	input_len = fread(input_buf, 1, MAX_INPUT_SIZE - 1, in_file);
 	output_len = 0;
+	fstat(fileno(in_file), &in_file_stat); /* for timestamp */
 	fclose(in_file);
 
 	memset(output_buf, 0, sizeof(output_buf));
@@ -262,15 +277,22 @@ void make_backup(void) {
 	rename(out_filename, bak);
 }
 
+void usage(void) {
+	puts("alf (ALF compressor) v" VERSION " by B. Watson, WTFPL.");
+	printf("Usage: %s [-a|-o] archive.alf file [file ...]\n", self);
+	puts("Options:");
+	puts("  -a: append to archive");
+	puts("  -o: overwrite archive (don't make backup with ~)");
+	exit(0);
+}
+
 int main(int argc, char **argv) {
 	int opt;
 
+	set_self(argv[0]);
+
 	if(argc < 2 || !strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")) {
-		fprintf(stderr, "Usage: %s [-a|-o] archive.alf file [file ...]\n", self);
-		fprintf(stderr, "Options:\n");
-		fprintf(stderr, "  -a: append to archive\n");
-		fprintf(stderr, "  -o: overwrite archive (don't make backup with ~)\n");
-		exit(1);
+		usage();
 	}
 
 	while((opt = getopt(argc, argv, "ao")) != -1) {
diff --git a/src/unalf.h b/src/unalf.h
index cab319f..1cb71bf 100644
--- a/src/unalf.h
+++ b/src/unalf.h
@@ -6,6 +6,7 @@
 #include <ctype.h>
 #include <sys/stat.h>
 #include <f65.h>
+#include "self.h"
 
 #ifndef VERSION
 #define VERSION "???"
@@ -64,10 +65,6 @@ void fix_filename(void);
 /* opts.c */
 void parse_opts(int argc, char * const *argv);
 
-/* self.c */
-extern char *self;
-void set_self(char *argv0);
-
 /* unalf.c */
 extern char *self;
 extern FILE *out_file;
-- 
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