Clean up JED file generation

In order to track versioning of individual JED files better,
add a better time stamp to each of them:
- If a JED files is checked into git already and no changes
  to the file occured, use the timestamp of the last change
  to this file. (Default)
- If a JED files is checked into git already and changes to
  the file occured, use the timestamp of the file's last
  modification.
- If a JED files is NOT checked into git already, also use
  the timestamp of the file's last modification.

In addition, recalculate the file checksum (not the same as
the data checksum) after this change, just in case.

Makefile

@@ -8,12 +8,17 @@ OPT  = 1
 
 all: $(JED)
 
-clean:
-	rm -f $(JED)
-
-jedec/%.jed: source/%.pld Makefile
+jedec/%.jed: source/%.pld Makefile util/jedcrc
 	$(CUPL) -jm$(OPT) $(LIBCUPL) $<
 	mv $(<:source/u%.pld=source/U%.jed) $(<:source/%.pld=jedec/%.jed)
+	util/fixup_jed.sh $< $(<:source/%.pld=jedec/%.jed)
 
 jedec/u305.jed : OPT=3 # U305 says: COMPILE -M3
 
+util/jedcrc : util/jedcrc.c
+
+clean:
+	rm -f util/jedcrc
+distclean: clean
+	rm -f $(JED)
+

util/date.sh

@@ -0,0 +1,46 @@
+#
+# Script to find "best" time stamp of a file
+# - If file is checked into git and unchanged, use git check-in date
+# - If file is checked into git and changed, use file modification date
+# - If file is not checked into git, use file modification date
+#
+
+change_date() {
+case $(uname) in
+NetBSD|OpenBSD|DragonFly|FreeBSD|Darwin)
+        eval $(stat -s $1)
+	echo $st_mtime
+        ;;
+*)
+        stat -c %Y $1
+esac
+}
+
+FILE=$1
+
+if [ "$(git rev-parse --is-inside-work-tree 2>/dev/null)" = "true" ]; then
+
+    if ! git diff --quiet $FILE; then
+        TIMESOURCE="file date"
+        DATE=$(change_date "$FILE")
+    else
+
+        TIMESOURCE=git
+        DATE=$(LANG= git log --no-show-signature -1 --format="format:%ct" $FILE 2>/dev/null || \
+        	LANG= git log -1 --format="format:%ct" $FILE)
+    fi
+else
+        TIMESOURCE="file date"
+        DATE=$(change_date $FILE)
+fi
+
+# echo $TIMESOURCE
+
+case $(uname) in
+NetBSD|OpenBSD|DragonFly|FreeBSD|Darwin)
+        LANG= date -r $DATE +"%a %b %d %T %Y"
+        ;;
+*)
+        LANG= date +"%a %b %d %T %Y" -d @$DATE
+esac
+

util/fixup_jed.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+PLD=$1
+JED=$2
+
+DATE=$( util/date.sh $PLD )
+perl -pi -e "s/^Created.*/Created         $DATE
/" $JED
+
+CHECKSUM=$( LANG= util/jedcrc $JED| sed "s/Checksum: //" |tr -d "\r")
+perl -pi -e "s/\\003..../\\003$CHECKSUM/" $JED
+
+echo "Fixed up $JED ($DATE, CHK=$CHECKSUM)"

util/jedcrc.c

@@ -0,0 +1,66 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define STX 0x02
+#define ETX 0x03
+
+int main(int argc, char** argv) {
+  FILE* src = NULL;
+  uint16_t sum = 0;
+  int c;
+  bool start = false;
+  bool end = false;
+
+  if (argc != 2) {
+    fprintf(
+        stderr,
+        "usage: %s PATH\n\n"
+        "Calculate the checksum of the data in a JEDEC .jed file.\n"
+        "If PATH is -, read from stdin instead.\n",
+        argv[0]);
+    return 1;
+  }
+
+  if (strlen(argv[1]) == 1 && argv[1][0] == '-') {
+    src = stdin;
+  } else {
+    src = fopen(argv[1], "rb");
+    if (!src) {
+      perror(argv[1]);
+      return 1;
+    }
+  }
+
+  while (!((c = fgetc(src)) & ~0x7F)) {
+    if (!start && c == STX) {
+      start = true;
+    }
+
+    if (start && !end) {
+      sum += (uint16_t)c;
+    }
+
+    if (!end && c == ETX) {
+      end = true;
+      break;
+    }
+  }
+
+  if (src != stdin) {
+    fclose(src);
+  }
+
+  if (start && end) {
+    printf("Checksum: %04hX\n", sum);
+  } else if (!start) {
+    fprintf(stderr, "No STX byte found\n");
+    return 1;
+  } else if (!end) {
+    fprintf(stderr, "No ETX byte found\n");
+    return 1;
+  }
+
+  return 0;
+}