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CSHARP-5614: Fix deserialization of primitive arrays on Big Endian systems #1683

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Merged
merged 3 commits into from
Jun 12, 2025
+23 −20
Merged

CSHARP-5614: Fix deserialization of primitive arrays on Big Endian systems #1683

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89a8e71
fix(bson): correct deserialization of primitive arrays using BinaryPr…
medhatiwari May 6, 2025
9180338
CSHARP-5614: Fix deserialization of primitive arrays on Big Endian sy…
medhatiwari Jun 11, 2025
31d88d5
CSHARP-5614: added BinaryPrimitivesCompat.ReadDoubleLittleEndian for …
medhatiwari Jun 11, 2025
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43 changes: 23 additions & 20 deletions src/MongoDB.Bson/Serialization/Serializers/PrimitivesArrayReader.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using System;
using System.Buffers.Binary;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using MongoDB.Bson.IO;
Expand Down Expand Up @@ -73,7 +74,8 @@ private static T[] ReadBsonArray<T>(
using var buffer = ThreadStaticBuffer.RentBuffer(array.Length);

var bytes = buffer.Bytes;
array.GetBytes(0, bytes, 0, array.Length);
array.GetBytes(0, bytes, 0, array.Length);
var span = bytes.AsSpan();

var result = new List<T>();

Expand All @@ -82,10 +84,10 @@ private static T[] ReadBsonArray<T>(

while (index < maxIndex)
{
ValidateBsonType(bsonDataType);
ValidateBsonType(bsonDataType, span);

// Skip name
while (bytes[index] != 0) { index++; };
while (span[index] != 0) { index++; }
index++; // Skip string terminating 0

T value = default;
Expand All @@ -95,85 +97,86 @@ private static T[] ReadBsonArray<T>(
{
case ConversionType.DoubleToSingle:
{
var v = (float)BitConverter.ToDouble(bytes, index);
var v = (float)BinaryPrimitivesCompat.ReadDoubleLittleEndian(span.Slice(index));

value = Unsafe.As<float, T>(ref v);
break;
}
case ConversionType.DoubleToDouble:
{
var v = BitConverter.ToDouble(bytes, index);
var v = BinaryPrimitivesCompat.ReadDoubleLittleEndian(span.Slice(index));

value = Unsafe.As<double, T>(ref v);
break;
}
case ConversionType.Decimal128ToDecimal128:
{
var lowBits = (ulong)BitConverter.ToInt64(bytes, index);
var highBits = (ulong)BitConverter.ToInt64(bytes, index + 8);
var lowBits = BinaryPrimitives.ReadUInt64LittleEndian(span.Slice(index));
var highBits = BinaryPrimitives.ReadUInt64LittleEndian(span.Slice(index + 8));
var v = Decimal128.ToDecimal(Decimal128.FromIEEEBits(highBits, lowBits));

value = Unsafe.As<decimal, T>(ref v);
break;
}
case ConversionType.BoolToBool:
{
var v = bytes[index] != 0;
var v = span[index] != 0;

value = Unsafe.As<bool, T>(ref v);
break;
}
case ConversionType.Int32ToInt8:
{
var v = (sbyte)BitConverter.ToInt32(bytes, index);
var v = (sbyte)BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<sbyte, T>(ref v);

break;
}
case ConversionType.Int32ToUInt8:
{
var v = (byte)BitConverter.ToInt32(bytes, index);
var v = (byte)BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<byte, T>(ref v);
break;
}
case ConversionType.Int32ToInt16:
{
var v = (short)BitConverter.ToInt32(bytes, index);
var v = (short)BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<short, T>(ref v);
break;
}
case ConversionType.Int32ToUInt16:
{
var v = (ushort)BitConverter.ToInt32(bytes, index);
var v = (ushort)BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<ushort, T>(ref v);
break;
}
case ConversionType.Int32ToChar:
{
var v = BitConverter.ToChar(bytes, index);
var v = (char)(ushort)BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<char, T>(ref v);
break;
}
case ConversionType.Int32ToInt32:
{
var v = BitConverter.ToInt32(bytes, index);
var v = BinaryPrimitives.ReadInt32LittleEndian(span.Slice(index));
value = Unsafe.As<int, T>(ref v);
break;
}
case ConversionType.Int32ToUInt32:
{
var v = BitConverter.ToUInt32(bytes, index);
var v = BinaryPrimitives.ReadUInt32LittleEndian(span.Slice(index));
value = Unsafe.As<uint, T>(ref v);
break;
}
case ConversionType.Int64ToInt64:
{
var v = BitConverter.ToInt64(bytes, index);
var v = BinaryPrimitives.ReadInt64LittleEndian(span.Slice(index));
value = Unsafe.As<long, T>(ref v);
break;
}
case ConversionType.Int64ToUInt64:
{
var v = BitConverter.ToUInt64(bytes, index);
var v = BinaryPrimitives.ReadUInt64LittleEndian(span.Slice(index));
value = Unsafe.As<ulong, T>(ref v);
break;
}
Expand All @@ -186,13 +189,13 @@ private static T[] ReadBsonArray<T>(
index += bsonDataSize;
}

ValidateBsonType(BsonType.EndOfDocument);
ValidateBsonType(BsonType.EndOfDocument, span);

return result.ToArray();

void ValidateBsonType(BsonType bsonType)
void ValidateBsonType(BsonType bsonType, Span<byte> span)
{
if ((BsonType)bytes[index] != bsonType)
if ((BsonType)span[index] != bsonType)
{
throw new InvalidOperationException();
}
Expand Down