File size: 4,041 Bytes
18a519f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 | using System;
namespace UnityEngine.InputSystem.Utilities
{
// this parser uses Span<T> so it's only available from later unity versions
#if UNITY_2021_2_OR_NEWER
internal struct PredictiveParser
{
public void ExpectSingleChar(ReadOnlySpan<char> str, char c)
{
if (str[m_Position] != c)
throw new InvalidOperationException($"Expected a '{c}' character at position {m_Position} in : {str.ToString()}");
++m_Position;
}
public int ExpectInt(ReadOnlySpan<char> str)
{
int pos = m_Position;
int sign = 1;
if (str[pos] == '-')
{
sign = -1;
++pos;
}
int value = 0;
for (;;)
{
var n = str[pos];
if (n >= '0' && n <= '9')
{
value *= 10;
value += n - '0';
++pos;
}
else
break;
}
if (m_Position == pos)
throw new InvalidOperationException($"Expected an int at position {m_Position} in {str.ToString()}");
m_Position = pos;
return value * sign;
}
public ReadOnlySpan<char> ExpectString(ReadOnlySpan<char> str)
{
var startPos = m_Position;
if (str[startPos] != '\"')
throw new InvalidOperationException($"Expected a '\"' character at position {m_Position} in {str.ToString()}");
++m_Position;
for (;;)
{
var c = str[m_Position];
c |= ' ';
if (c >= 'a' && c <= 'z')
{
++m_Position;
continue;
}
break;
}
// if the first non-alpha character is not a quote, throw
if (str[m_Position] != '\"')
throw new InvalidOperationException($"Expected a closing '\"' character at position {m_Position} in string: {str.ToString()}");
if (m_Position - startPos == 1)
return ReadOnlySpan<char>.Empty;
var output = str.Slice(startPos + 1, m_Position - startPos - 1);
++m_Position;
return output;
}
public bool AcceptSingleChar(ReadOnlySpan<char> str, char c)
{
if (str[m_Position] != c)
return false;
m_Position++;
return true;
}
public bool AcceptString(ReadOnlySpan<char> input, out ReadOnlySpan<char> output)
{
output = default;
var startPos = m_Position;
var endPos = startPos;
if (input[endPos] != '\"')
return false;
++endPos;
for (;;)
{
var c = input[endPos];
c |= ' ';
if (c >= 'a' && c <= 'z')
{
++endPos;
continue;
}
break;
}
// if the first non-alpha character is not a quote, throw
if (input[endPos] != '\"')
return false;
// empty string?
if (m_Position - startPos == 1)
output = ReadOnlySpan<char>.Empty;
else
output = input.Slice(startPos + 1, endPos - startPos - 1);
m_Position = endPos + 1;
return true;
}
public void AcceptInt(ReadOnlySpan<char> str)
{
// skip negative sign
if (str[m_Position] == '-')
++m_Position;
for (;;)
{
var n = str[m_Position];
if (n >= '0' && n <= '9')
++m_Position;
else
break;
}
}
private int m_Position;
}
#endif
}
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