Fix 32-bit build warnings

2 files changed, 11 insertions, 5 deletions

diff --git a/fiv-io.c b/fiv-io.c
index c434773..5c18daf 100644
--- a/fiv-io.c
+++ b/fiv-io.c
@@ -1263,7 +1263,7 @@ parse_mpf_index_ifd(struct tiffer *T)
 
 static bool
 parse_mpf(
-	GPtrArray *individuals, const uint8_t *mpf, size_t len, const uint8_t *end)
+	GPtrArray *individuals, const uint8_t *mpf, size_t len, size_t total_len)
 {
 	struct tiffer T;
 	if (!tiffer_init(&T, mpf, len) || !tiffer_next_ifd(&T))
@@ -1274,7 +1274,7 @@ parse_mpf(
 	uint32_t *offsets = parse_mpf_index_ifd(&T);
 	if (offsets) {
 		for (const uint32_t *o = offsets; *o; o++)
-			if (*o <= end - mpf)
+			if (*o <= total_len)
 				g_ptr_array_add(individuals, (gpointer) mpf + *o);
 		free(offsets);
 	}
@@ -1378,7 +1378,7 @@ parse_jpeg_metadata(const char *data, size_t len, struct jpeg_metadata *meta)
 		if (meta->mpf && marker == APP2 && p - payload >= 8 &&
 			!memcmp(payload, "MPF\0", 4) && !meta->mpf->len) {
 			payload += 4;
-			parse_mpf(meta->mpf, payload, p - payload, end);
+			parse_mpf(meta->mpf, payload, p - payload, end - payload);
 		}
 
 		// TODO(p): Extract the main XMP segment.
diff --git a/tiffer.h b/tiffer.h
index b4e582e..870ad26 100644
--- a/tiffer.h
+++ b/tiffer.h
@@ -156,12 +156,18 @@ tiffer_next_ifd(struct tiffer *self)
 	return tiffer_u16(self, &self->remaining_fields);
 }
 
+static size_t
+tiffer_length(const struct tiffer *self)
+{
+	return self->begin > self->end ? 0 : self->end - self->begin;
+}
+
 /// Initialize a derived TIFF reader for a subIFD at the given location.
 static bool
 tiffer_subifd(
 	const struct tiffer *self, uint32_t offset, struct tiffer *subreader)
 {
-	if (self->begin > self->end || self->end - self->begin < offset)
+	if (tiffer_length(self) < offset)
 		return false;
 
 	*subreader = *self;
@@ -332,7 +338,7 @@ tiffer_next_entry(struct tiffer *self, struct tiffer_entry *entry)
 	if (values_size <= sizeof offset) {
 		entry->p = self->p;
 		self->p += sizeof offset;
-	} else if (tiffer_u32(self, &offset) && self->end - self->begin >= offset) {
+	} else if (tiffer_u32(self, &offset) && tiffer_length(self) >= offset) {
 		entry->p = self->begin + offset;
 	} else {
 		return false;