From 4d9236336cdd59b4dc7d933e50ef51a62eff3b72 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Sat, 4 Dec 2021 06:31:24 +0100
Subject: [PATCH] jpeginfo: parse TIFF UNDEFINED values

---
 tools/jpeginfo.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/jpeginfo.c b/tools/jpeginfo.c
index ea2218f..e4e9a67 100644
--- a/tools/jpeginfo.c
+++ b/tools/jpeginfo.c
@@ -601,6 +601,20 @@ parse_exif_ascii(struct tiffer_entry *entry)
 	return a;
 }
 
+static jv
+parse_exif_undefined(struct tiffer_entry *entry)
+{
+	const char *alphabet = "0123456789abcdef";
+	char *buf = calloc(1, 2 * entry->remaining_count + 1);
+	for (uint32_t i = 0; i < entry->remaining_count; i++) {
+		buf[2 * i + 0] = alphabet[entry->p[i] >> 4];
+		buf[2 * i + 1] = alphabet[entry->p[i] & 0xF];
+	}
+	jv s = jv_string(buf);
+	free(buf);
+	return s;
+}
+
 static jv
 parse_exif_entry(jv o, struct tiffer *T, struct tiffer_entry *entry)
 {
@@ -613,11 +627,13 @@ parse_exif_entry(jv o, struct tiffer *T, struct tiffer_entry *entry)
 		value = parse_exif_subifds(T, entry);
 	} else if (entry->type == ASCII) {
 		value = parse_exif_ascii(entry);
+	} else if (entry->type == UNDEFINED) {
+		value = parse_exif_undefined(entry);
 	} else if ((numeric = tiffer_real(T, entry, &real))) {
 		value = jv_number(real);
 	}
 
-	// TODO(p): Decode UNDEFINED as a hex dump, and iterate over all values.
+	// TODO(p): Iterate over all numeric values.
 	for (const struct tiff_entry *p = tiff_entries; p->name; p++) {
 		if (p->tag != entry->tag)
 			continue;