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Binary Xml format broken on big-endian machines #74494
Description
The binary format used by XmlDictionaryReader and XmlDictionaryWriter is supposed to be always little-endian.
However, the current code does not implement this correctly when running on big-endian systems. These pre-existing problems were recently exposed by additional and updated test cases added here:
#73332 (XmlDictionaryReader)
#71478 (XmlDictionaryWriter)
See #73332 (comment) for more details.
Activity
StephenMolloy commentedon Aug 24, 2022
@uweigand - I think the fix for this should be pretty straightforward as we do account for endian-ness for most types. The problem is that I don't have any big-endian hardware to test with. We would welcome a PR if you want to create one and verify it on your s390x.
And as @jkotas said in the original comment thread that spurred this issue - serialized representation ("on the wire" if you will) should always be little-endian for DataContractSerializer.
uweigand commentedon Aug 25, 2022
@StephenMolloy OK, I'll work on coming up with a PR to fix this, hopefully within the next few days. Thanks!
KalleOlaviNiemitalo commentedon Aug 25, 2022
The format is documented in [MC-NBFX]: .NET Binary Format: XML Data Structure, where §2.1 Common Definitions indeed specifies little-endian byte order.
Fix XmlBinaryReader/XmlBinaryWriter on big-endian systems (#74599)