From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 23 Aug 2021 14:18:17 +0000 (+0200)
Subject: mp4: Simplify parse_sub_atoms().
X-Git-Tag: v0.7.1~7^2~32
X-Git-Url: http://git.tuebingen.mpg.de/?a=commitdiff_plain;h=eb369edec255c992294a77b83f981e46c5de7906;p=paraslash.git

mp4: Simplify parse_sub_atoms().

This converts the while loop into a for loop and replaces the
counted_size variable by "dest" to clarify the loop structure. We
also move the two 8-bit variables into the loop as they are only used
there and skip their pointless initializations.
---

diff --git a/mp4.c b/mp4.c
index e2512db1..d030d62d 100644
--- a/mp4.c
+++ b/mp4.c
@@ -712,18 +712,16 @@ static bool need_atom(uint8_t atom_type, bool meta_only)
 static int parse_sub_atoms(struct mp4 *f, uint64_t total_size, bool meta_only)
 {
 	int ret;
-	uint64_t size;
-	uint8_t atom_type = 0;
-	uint64_t counted_size = 0;
-	uint8_t header_size = 0;
+	uint64_t dest, size, end = get_position(f) + total_size;
 
-	while (counted_size < total_size) {
+	for (dest = get_position(f); dest < end; set_position(f, dest)) {
+		uint8_t header_size, atom_type;
 		ret = atom_read_header(f, &atom_type, &header_size, &size);
 		if (ret <= 0)
 			return ret;
 		if (size == 0)
 			return -1;
-		counted_size += size;
+		dest = get_position(f) + size - header_size;
 		if (atom_type == ATOM_TRAK) {
 			if (f->total_tracks >= MAX_TRACKS)
 				return -1;
@@ -734,10 +732,8 @@ static int parse_sub_atoms(struct mp4 *f, uint64_t total_size, bool meta_only)
 			f->udta_offset = get_position(f) - header_size;
 			f->udta_size = size;
 		}
-		if (!need_atom(atom_type, meta_only)) {
-			set_position(f, get_position(f) + size - header_size);
+		if (!need_atom(atom_type, meta_only))
 			continue;
-		}
 		if (atom_type < SUBATOMIC) /* atom contains subatoms */
 			ret = parse_sub_atoms(f, size - header_size, meta_only);
 		else