[PATCH 0/1] MR11730: windowscodecs: Pass pcbRead to IStream::Read() in jpeg_decoder_get_metadata_blocks().

[Shaun Ren (＠shaunren)]

Some non-conforming IStream implementations, including SharpDX, do not
handle a NULL pcbRead for Read() [^1]. This causes the game "Surviving
Deponia Playtest" to display a black main menu.

[^1]: https://github.com/sharpdx/SharpDX/blob/ab36f12303e24aa60fe804866617716b6ded...

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11730

[PATCH 1/1] windowscodecs: Pass pcbRead to IStream::Read() in jpeg_decoder_get_metadata_blocks().

[Shaun Ren]

From: Shaun Ren <[e-mail]>

Some non-conforming IStream implementations, including SharpDX, do not
handle a NULL pcbRead for Read(). This causes the game "Surviving
Deponia Playtest" to display a black main menu.
---
 dlls/windowscodecs/libjpeg.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/windowscodecs/libjpeg.c b/dlls/windowscodecs/libjpeg.c
index 40119084e68..5282ae7066c 100644
--- a/dlls/windowscodecs/libjpeg.c
+++ b/dlls/windowscodecs/libjpeg.c
@@ -338,6 +338,7 @@ static HRESULT CDECL jpeg_decoder_get_metadata_blocks(struct decoder* iface, UIN
     struct decoder_block block;
     USHORT marker, length;
     ULONGLONG offset;
+    ULONG bytesread;
     BYTE header[4];
     bool add_block;
     HRESULT hr;
@@ -357,7 +358,7 @@ static HRESULT CDECL jpeg_decoder_get_metadata_blocks(struct decoder* iface, UIN
     memset(&results, 0, sizeof(results));
     for (;;)
     {
-        if (stream_read(This->stream, header, 4, NULL) != S_OK)
+        if (stream_read(This->stream, header, 4, &bytesread) != S_OK || bytesread != 4)
             break;
         offset += 4;
 
@@ -368,7 +369,7 @@ static HRESULT CDECL jpeg_decoder_get_metadata_blocks(struct decoder* iface, UIN
         if (marker == APP1)
         {
             /* APP1 marker might appear multiple times, it's reused for different metadata blocks. */
-            if (stream_read(This->stream, header, 4, NULL) != S_OK)
+            if (stream_read(This->stream, header, 4, &bytesread) != S_OK || bytesread != 4)
                 break;
             stream_seek(This->stream, -4, STREAM_SEEK_CUR, NULL);
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/11730

[Nikolay Sivov (＠nsivov)]

It was added with 2a167eb4ea844a090ca0247cf233633f697e3a85, in !7653. Looks like every other call to stream_read() is already correct in that regard. We could potentially have a test for this, using some stream wrapper, so that it doesn't regress later. Not sure how valuable it is.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11730#note_149597

[PATCH 0/1] MR11730: windowscodecs: Pass pcbRead to IStream::Read() in jpeg_decoder_get_metadata_blocks(). - approved

[Esme Povirk (＠madewokherd)]

This merge request was approved by Esme Povirk.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11730

[Esme Povirk (＠madewokherd)]

On Mon Aug 24 16:59:01 2026 +0000, Nikolay Sivov wrote:
> It was added with 2a167eb4ea844a090ca0247cf233633f697e3a85, in !7653.
> Looks like every other call to stream_read() is already correct in that
> regard. We could potentially have a test for this, using some stream
> wrapper, so that it doesn't regress later. Not sure how valuable it is.
We might consider having the stream_read wrapper handle this implicitly, so if NULL is passed in it would:
* Handle passing a non-NULL argument for pcbRead.
* If fewer bytes are read than requested, return a failing hr.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11730#note_149707

[PATCH 0/1] MR11730: windowscodecs: Pass pcbRead to IStream::Read() in jpeg_decoder_get_metadata_blocks(). - approved

[Esme Povirk (＠madewokherd)]

This merge request was approved by Esme Povirk.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11730