using System.Runtime.CompilerServices; namespace System.Text.Json { internal struct BitStack { private const int AllocationFreeMaxDepth = 64; private const int DefaultInitialArraySize = 2; private int[] _array; private ulong _allocationFreeContainer; private int _currentDepth; public int CurrentDepth => _currentDepth; [MethodImpl(MethodImplOptions.AggressiveInlining)] public void PushTrue() { if (_currentDepth < 64) _allocationFreeContainer = ((_allocationFreeContainer << 1) | 1); else PushToArray(true); _currentDepth++; } [MethodImpl(MethodImplOptions.AggressiveInlining)] public void PushFalse() { if (_currentDepth < 64) _allocationFreeContainer <<= 1; else PushToArray(false); _currentDepth++; } [MethodImpl(MethodImplOptions.NoInlining)] private void PushToArray(bool value) { if (_array == null) _array = new int[2]; int remainder; int num = Div32Rem(_currentDepth - 64, out remainder); if (num >= _array.Length) DoubleArray(num); int num2 = _array[num]; num2 = ((!value) ? (num2 & ~(1 << remainder)) : (num2 | (1 << remainder))); _array[num] = num2; } [MethodImpl(MethodImplOptions.AggressiveInlining)] public bool Pop() { _currentDepth--; if (_currentDepth >= 64) { if (_currentDepth != 64) return PopFromArray(); return (_allocationFreeContainer & 1) != 0; } _allocationFreeContainer >>= 1; return (_allocationFreeContainer & 1) != 0; } [MethodImpl(MethodImplOptions.NoInlining)] private bool PopFromArray() { int remainder; int num = Div32Rem(_currentDepth - 64 - 1, out remainder); return (_array[num] & (1 << remainder)) != 0; } private void DoubleArray(int minSize) { int newSize = Math.Max(minSize + 1, _array.Length * 2); Array.Resize(ref _array, newSize); } public void SetFirstBit() { _currentDepth++; _allocationFreeContainer = 1; } public void ResetFirstBit() { _currentDepth++; _allocationFreeContainer = 0; } [MethodImpl(MethodImplOptions.AggressiveInlining)] private static int Div32Rem(int number, out int remainder) { uint result = (uint)number / 32; remainder = (number & 31); return (int)result; } } }