BigfootDev/flatbuffers
1
0
Fork 1
mirror of https://github.com/google/flatbuffers.git synced 2026-06-25 12:08:39 +00:00
Code Issues Packages Projects Releases Wiki Activity

Correct span and non-span versions of ToArray() and ToArrayPadded() methods (#8734)

Browse Source 
* Correction of bug inside ToArray<T> methods

Avoid allocating too large buffers (len is expressed in bytes, not in Ts).
Added validation to ensure len is a multiple of SizeOf<T>() before converting to array.

* Update ByteBuffer.cs

* Refactor ToArray and ToArrayPadded methods

I understand from failed test that pos, len, padLeft and padRight are expressed in Ts

* Refactor ToArray and ToArrayPadded methods

* Final correction
All functions parameters expressed in bytes for homogeneity
Tests run:
  - UNSAFE_BYTEBUFFER=true/ENABLE_SPAN_T=true: passed
  - UNSAFE_BYTEBUFFER=true/ENABLE_SPAN_T=false: passed
  - UNSAFE_BYTEBUFFER=false/ENABLE_SPAN_T=false: passed
  - UNSAFE_BYTEBUFFER=false/ENABLE_SPAN_T=true: configuration forbidden by compilation
Correction of FlatBuffers.Test.csproj to allow UNSAFE_BYTEBUFFER/ENABLE_SPAN_T tests
Correction of FlatBuffersExampleTests.cs: I think the test was not run because it could not pass (to be reviewed carefully)
This commit is contained in:
vsmcea
2025-10-25 20:58:05 +02:00
committed by GitHub
parent 27325e002a
commit 95053e6a47
4 changed files with 69 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
net/FlatBuffers/ByteBuffer.cs
View File

@@ -38,13 +38,13 @@
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
#if ENABLE_SPAN_T && UNSAFE_BYTEBUFFER
using System.Buffers.Binary;
#else
using System.IO;
#endif
#if ENABLE_SPAN_T && !UNSAFE_BYTEBUFFER
@@ -245,34 +245,36 @@ namespace Google.FlatBuffers
#endif
// Get a portion of the buffer casted into an array of type T, given
// the buffer position and length.
// the buffer position (in bytes) and length (in bytes).
public T[] ToArray<T>(int posInBytes, int lenInBytes)
where T : struct
{
AssertOffsetAndLength(posInBytes, lenInBytes);
#if ENABLE_SPAN_T && UNSAFE_BYTEBUFFER
public T[] ToArray<T>(int pos, int len)
where T : struct
{
AssertOffsetAndLength(pos, len);
return MemoryMarshal.Cast<byte, T>(_buffer.ReadOnlySpan.Slice(pos)).Slice(0, len).ToArray();
}
return MemoryMarshal.Cast<byte, T>(_buffer.ReadOnlySpan.Slice(posInBytes, lenInBytes)).ToArray();
#else
public T[] ToArray<T>(int pos, int len)
where T : struct
{
AssertOffsetAndLength(pos, len);
T[] arr = new T[len];
Buffer.BlockCopy(_buffer.Buffer, pos, arr, 0, ArraySize(arr));
return arr;
}
var lenInTs = ConvertBytesToTs<T>(lenInBytes);
var arrayOfTs = new T[lenInTs];
Buffer.BlockCopy(_buffer.Buffer, posInBytes, arrayOfTs, 0, lenInBytes);
return arrayOfTs;
#endif
}
public T[] ToArrayPadded<T>(int pos, int len, int padLeft, int padRight)
public T[] ToArrayPadded<T>(int posInBytes, int lenInBytes, int padLeftInBytes, int padRightInBytes)
where T : struct
{
AssertOffsetAndLength(pos, len);
int totalBytes = padLeft + len + padRight;
byte[] raw = _buffer.Buffer;
T[] arr = new T[totalBytes];
Buffer.BlockCopy(raw, pos, arr, padLeft, len);
return arr;
AssertOffsetAndLength(posInBytes, lenInBytes);
var padLeftInTs = ConvertBytesToTs<T>(padLeftInBytes);
var lenInTs = ConvertBytesToTs<T>(lenInBytes);
var padRightInTs = ConvertBytesToTs<T>(padRightInBytes);
var sizeInTs = padLeftInTs + lenInTs + padRightInTs;
var arrayOfTs = new T[sizeInTs];
#if ENABLE_SPAN_T && UNSAFE_BYTEBUFFER
MemoryMarshal.Cast<byte, T>(_buffer.ReadOnlySpan.Slice(posInBytes, lenInBytes)).CopyTo(arrayOfTs.AsSpan().Slice(padLeftInTs));
#else
Buffer.BlockCopy(_buffer.Buffer, posInBytes, arrayOfTs, padLeftInBytes, lenInBytes);
#endif
return arrayOfTs;
}
public byte[] ToSizedArrayPadded(int padLeft, int padRight)
@@ -455,9 +457,31 @@ namespace Google.FlatBuffers
#endif
}
public static int ConvertTsToBytes<T>(int valueInTs)
where T : struct
{
var sizeOfT = SizeOf<T>();
var valueInBytes = valueInTs * sizeOfT;
return valueInBytes;
}
public static int ConvertBytesToTs<T>(int valueInBytes)
where T : struct
{
var sizeOfT = SizeOf<T>();
var valueInTs = valueInBytes / sizeOfT;
#if !BYTEBUFFER_NO_BOUNDS_CHECK
if (valueInTs * sizeOfT != valueInBytes)
{
throw new ArgumentException($"{valueInBytes} must be a multiple of SizeOf<{typeof(T).Name}>()={sizeOfT}");
}
#endif
return valueInTs;
}
#if ENABLE_SPAN_T && UNSAFE_BYTEBUFFER
public void PutSbyte(int offset, sbyte value)
public void PutSbyte(int offset, sbyte value)
{
AssertOffsetAndLength(offset, sizeof(sbyte));
_buffer.Span[offset] = (byte)value;