# ReadPackedFixedStringDelta(NativeArray<byte>, NativeArray<byte>, in StreamCompressionModel)

> Read and copy data into the given NativeArray of bytes, an error will be logged if not enough bytes are available in the array.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Collections](/engine/6000.7/script-reference/unity/collections.md)
* **Assembly:** UnityEngine.ManagedKernelModule

## ReadPackedFixedStringDelta(NativeArray\<byte>, NativeArray\<byte>, StreamCompressionModel)

```csharp
public ushort ReadPackedFixedStringDelta(NativeArray<byte> data, NativeArray<byte> baseData, in StreamCompressionModel model)
```

### Parameters

**** (\[NativeArray\<byte>]\(/engine/6000.7/script-reference/unity/collections/nativearray1)): Array for the current fixed string.**** (\[NativeArray\<byte>]\(/engine/6000.7/script-reference/unity/collections/nativearray1)): Array containing the previous value, used to compute the diff.**** (\[StreamCompressionModel]\(/engine/6000.7/script-reference/unity/collections/streamcompressionmodel)): [StreamCompressionModel](/engine/6000.7/script-reference/unity/collections/streamcompressionmodel.md) model for writing value in a packed manner.

### Returns

| Type                                                           | Description                                                     |
| -------------------------------------------------------------- | --------------------------------------------------------------- |
| [ushort](https://learn.microsoft.com/dotnet/api/system.uint16) | Length of data read into byte array, or zero if error occurred. |