From 44dd8a6ecf8514c576b3b1c9e009105b5d5bafa9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Torbjo=CC=88rn=20Einarsson?= <torbjorn@einarssons.se>
Date: Wed, 25 Jan 2023 22:43:23 +0100
Subject: [PATCH] version 0.33.2 - restore parsing behavior for non-complete
 mdat

---
 Versions.md    |  1 +
 mp4/box.go     |  2 +-
 mp4/boxsr.go   | 10 ++++++++--
 mp4/mdat.go    |  5 ++++-
 mp4/version.go |  4 ++--
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/Versions.md b/Versions.md
index 578f83a3..a4f729ef 100644
--- a/Versions.md
+++ b/Versions.md
@@ -2,6 +2,7 @@
 
 | Version | Highlights |
 | ------  | ---------- |
+| 0.33.2 | Reset parsing of non-complete mdat box to previous behavior |
 | 0.33.1 | Fix parsing of HEVC SPS scaling list data present flag |
 | 0.33.0 | Support QuickTime meta box. New possibility to disable parsing of specific boxes |
 | 0.32.0 | Repo moved to github.com/Eyevinn/mp4ff |
diff --git a/mp4/box.go b/mp4/box.go
index fdb58dd5..a33322f5 100644
--- a/mp4/box.go
+++ b/mp4/box.go
@@ -362,7 +362,7 @@ func makebuf(b Box) []byte {
 	return make([]byte, b.Size()-boxHeaderSize)
 }
 
-// readBoxBody - read box body and check length
+// readBoxBody reads complete box body. Returns error if not possible
 func readBoxBody(r io.Reader, h BoxHeader) ([]byte, error) {
 	bodyLen := h.Size - uint64(h.Hdrlen)
 	if bodyLen == 0 {
diff --git a/mp4/boxsr.go b/mp4/boxsr.go
index 49c2f6f4..e9b0ec34 100644
--- a/mp4/boxsr.go
+++ b/mp4/boxsr.go
@@ -138,8 +138,14 @@ func DecodeBoxSR(startPos uint64, sr bits.SliceReader) (Box, error) {
 	if err != nil {
 		return nil, err
 	}
-	if h.Size > uint64(sr.NrRemainingBytes())+uint64(h.Hdrlen) {
-		return nil, fmt.Errorf("decode box %q, size %d too big", h.Name, h.Size)
+
+	maxSize := uint64(sr.NrRemainingBytes()) + uint64(h.Hdrlen)
+	// In the following, we do not block mdat to allow for the case
+	// that the first kiloBytes of a file are fetched and parsed to
+	// get the init part of a file. In the future, a new decode option that
+	// stops before the mdat starts is a better alternative.
+	if h.Size > maxSize && h.Name != "mdat" {
+		return nil, fmt.Errorf("decode box %q, size %d too big (max %d)", h.Name, h.Size, maxSize)
 	}
 
 	d, ok := decodersSR[h.Name]
diff --git a/mp4/mdat.go b/mp4/mdat.go
index eb803458..8907ff8c 100644
--- a/mp4/mdat.go
+++ b/mp4/mdat.go
@@ -32,7 +32,10 @@ func DecodeMdat(hdr BoxHeader, startPos uint64, r io.Reader) (Box, error) {
 	return &MdatBox{startPos, data, nil, 0, largeSize}, nil
 }
 
-// DecodeMdatSR - box-specific decode
+// DecodeMdatSR decodes an mdat box
+//
+// Currently no content and no error is returned if not full length available.
+// If not enough content, an accumulated error is stored in sr, though
 func DecodeMdatSR(hdr BoxHeader, startPos uint64, sr bits.SliceReader) (Box, error) {
 	largeSize := hdr.Hdrlen > boxHeaderSize
 	return &MdatBox{startPos, sr.ReadBytes(hdr.payloadLen()), nil, 0, largeSize}, nil
diff --git a/mp4/version.go b/mp4/version.go
index a6ef1e5d..64346b1a 100644
--- a/mp4/version.go
+++ b/mp4/version.go
@@ -7,8 +7,8 @@ import (
 )
 
 var (
-	commitVersion string = "v0.33.1"    // May be updated using build flags
-	commitDate    string = "1674662982" // commitDate in Epoch seconds (may be overridden using build flags)
+	commitVersion string = "v0.33.2"    // May be updated using build flags
+	commitDate    string = "1674682900" // commitDate in Epoch seconds (may be overridden using build flags)
 )
 
 // GetVersion - get version and also commitHash and commitDate if inserted via Makefile