ValueStringBuilder
struct ValueStringBuilder
using System.Buffers;
using System.Reflection;
using System.Runtime.CompilerServices;
namespace System.Text
{
[CompilerFeatureRequired("RefStructs")]
[DefaultMember("Item")]
internal ref struct ValueStringBuilder
{
private char[] _arrayToReturnToPool;
private Span<char> _chars;
private int _pos;
public int Length => _pos;
public ValueStringBuilder(Span<char> initialBuffer)
{
_arrayToReturnToPool = null;
_chars = initialBuffer;
_pos = 0;
}
public override string ToString()
{
string result = _chars.Slice(0, _pos).ToString();
Dispose();
return result;
}
public ReadOnlySpan<char> AsSpan(int start, int length)
{
return _chars.Slice(start, length);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Append(char c)
{
int pos = _pos;
Span<char> chars = _chars;
if ((uint)pos < (uint)chars.Length) {
chars[pos] = c;
_pos = pos + 1;
} else
GrowAndAppend(c);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Append(string s)
{
if (s != null) {
int pos = _pos;
if (s.Length == 1 && (uint)pos < (uint)_chars.Length) {
_chars[pos] = s[0];
_pos = pos + 1;
} else
AppendSlow(s);
}
}
private void AppendSlow(string s)
{
int pos = _pos;
if (pos > _chars.Length - s.Length)
Grow(s.Length);
s.CopyTo(_chars.Slice(pos));
_pos += s.Length;
}
public void Append([ScopedRef] ReadOnlySpan<char> value)
{
if (_pos > _chars.Length - value.Length)
Grow(value.Length);
value.CopyTo(_chars.Slice(_pos));
_pos += value.Length;
}
[MethodImpl(MethodImplOptions.NoInlining)]
private void GrowAndAppend(char c)
{
Grow(1);
Append(c);
}
[MethodImpl(MethodImplOptions.NoInlining)]
private void Grow(int additionalCapacityBeyondPos)
{
int minimumLength = (int)Math.Max((uint)(_pos + additionalCapacityBeyondPos), Math.Min((uint)(_chars.Length * 2), 2147483591));
char[] array = ArrayPool<char>.Shared.Rent(minimumLength);
_chars.Slice(0, _pos).CopyTo(array);
char[] arrayToReturnToPool = _arrayToReturnToPool;
_chars = (_arrayToReturnToPool = array);
if (arrayToReturnToPool != null)
ArrayPool<char>.Shared.Return(arrayToReturnToPool, false);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void Dispose()
{
char[] arrayToReturnToPool = _arrayToReturnToPool;
this = default(System.Text.ValueStringBuilder);
if (arrayToReturnToPool != null)
ArrayPool<char>.Shared.Return(arrayToReturnToPool, false);
}
}
}