From d70164ccbb3846e2fbf5e73cb3b636b0c7aa0b8e Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sat, 27 Apr 2024 15:44:40 -0400
Subject: xexcat: implement -f2.

---
 xexcat.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 62 insertions(+), 16 deletions(-)

diff --git a/xexcat.c b/xexcat.c
index c4234bd..46f418e 100644
--- a/xexcat.c
+++ b/xexcat.c
@@ -29,28 +29,74 @@ char *usage =
 	"  -a              Force run address to load address of 1st segment.\n"
 	"  -f 1|2          Input is DASM -f1 or -f2 format, not xex.\n";
 
-int read_seg(xex_segment *seg, FILE *f, int type) {
+static int readaddr(FILE *f) {
 	int i, j;
 
+	if( (i = fgetc(f)) < 0 )
+		return -1;
+	if( (j = fgetc(f)) < 0 )
+		return -1;
+
+	return i | (j << 8);
+}
+
+/* byte 0 = LSB of load address, byte 1 = MSB, rest = data. */
+int read_f1(xex_segment *seg, FILE *f) {
+	int i, addr, c;
+
+	addr = readaddr(f);
+	if(addr < 0)
+		return 0;
+
+	seg->start_addr = addr;
+	for(i = 0; (i < 65536) && ((c = fgetc(f)) >= 0); i++) {
+		seg->object[i] = c;
+		seg->len++;
+	}
+
+	/* guard against the file being >64K length */
+	fseek(f, 0, SEEK_END);
+
+	seg->end_addr = seg->start_addr + seg->len - 1;
+	seg->has_ff_header = 1;
+
+	return (i != 0);
+}
+
+/* -f2 is segmented, each segment starts with a 4-byte header:
+	0/1 are LSB/MSB of start address, 2/3 are LSB/MSB of length. */
+int read_f2(xex_segment *seg, FILE *f) {
+	int i, addr, c;
+
+	addr = readaddr(f);
+	if(addr < 0)
+		return 0;
+
+	seg->start_addr = addr;
+
+	addr = readaddr(f);
+	if(addr < 0)
+		return 0;
+	seg->len = addr;
+
+	for(i = 0; (i < seg->len) && ((c = fgetc(f)) >= 0); i++) {
+		if(c < 0) return 0;
+		seg->object[i] = c;
+	}
+
+	seg->end_addr = seg->start_addr + seg->len - 1;
+	seg->has_ff_header = 1;
+	xex_print_seg_info(seg);
+	return 1;
+}
+
+int read_seg(xex_segment *seg, FILE *f, int type) {
 	switch(type) {
-		/* byte 0 = LSB of load address, byte 1 = MSB, rest = data. */
 		case 1:
-			if( (i = fgetc(f)) < 0 )
-				return 0;
-			if( (j = fgetc(f)) < 0 )
-				return 0;
-			seg->start_addr = i | (j << 8);
-			for(i = 0; (i < 65536) && ((j = fgetc(f)) >= 0); i++) {
-				seg->object[i] = j;
-				seg->len++;
-			}
-			seg->end_addr = seg->start_addr + seg->len - 1;
-			seg->has_ff_header = 1;
-			xex_print_seg_info(seg);
-			return (i != 0);
+			return read_f1(seg, f);
 
 		case 2:
-			return 0;
+			return read_f2(seg, f);
 
 		case 0:
 		default:
-- 
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