public static bool TryParseInt32(ReadOnlySpan<byte> text, out int value, out int bytesConsumed)
{
int textLength = text.Length;
if (textLength < 1) goto FalseExit;
int sign = 1;
int index = default;
int num = text[index];
if (num == '-')
{
sign = -1;
index++;
if (index >= textLength) goto FalseExit;
num = text[index];
}
else if (num == '+')
{
index++;
if (index >= textLength) goto FalseExit;
num = text[index];
}
int answer = default;
if (IsDigit(num))
{
if (num == '0')
{
do
{
index++;
if (index >= textLength) goto Done;
num = text[index];
} while (num == '0');
if (!IsDigit(num)) goto Done;
}
int len = textLength - index;
if (len < Int32OverflowLength)
{
switch (len)
{
case 9:
answer = (num - '0');
index = textLength - 8;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 8;
case 8:
answer = answer * 10 + (num - '0');
index = textLength - 7;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 7;
case 7:
answer = answer * 10 + (num - '0');
index = textLength - 6;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 6;
case 6:
answer = answer * 10 + (num - '0');
index = textLength - 5;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 5;
case 5:
answer = answer * 10 + (num - '0');
index = textLength - 4;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 4;
case 4:
answer = answer * 10 + (num - '0');
index = textLength - 3;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 3;
case 3:
answer = answer * 10 + (num - '0');
index = textLength - 2;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 2;
case 2:
answer = answer * 10 + (num - '0');
index = textLength - 1;
num = text[index];
if (!IsDigit(num))
{
goto Done;
}
goto case 1;
case 1:
answer = answer * 10 + (num - '0');
index = textLength;
goto Done;
}
}
else if (len == Int32OverflowLength)
{
switch (Int32OverflowLength)
{
case 10:
answer = (num - '0');
num = text[textLength - 9];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 9;
goto Done;
}
goto case 9;
case 9:
answer = answer * 10 + (num - '0');
num = text[textLength - 8];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 8;
goto Done;
}
goto case 8;
case 8:
answer = answer * 10 + (num - '0');
num = text[textLength - 7];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 7;
goto Done;
}
goto case 7;
case 7:
answer = answer * 10 + (num - '0');
num = text[textLength - 6];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 6;
goto Done;
}
goto case 6;
case 6:
answer = answer * 10 + (num - '0');
num = text[textLength - 5];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 5;
goto Done;
}
goto case 5;
case 5:
answer = answer * 10 + (num - '0');
num = text[textLength - 4];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 4;
goto Done;
}
goto case 4;
case 4:
answer = answer * 10 + (num - '0');
num = text[textLength - 3];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 3;
goto Done;
}
goto case 3;
case 3:
answer = answer * 10 + (num - '0');
num = text[textLength - 2];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 2;
goto Done;
}
goto case 2;
case 2:
answer = answer * 10 + (num - '0');
num = text[textLength - 1];
if (!IsDigit(num))
{
index = index + Int32OverflowLength - 1;
goto Done;
}
goto case 1;
case 1:
num -= '0';
if (WillOverFlow(answer, num, sign)) goto FalseExit;
answer = answer * 10 + num;
index = index + Int32OverflowLength;
goto Done;
}
}
else
{
index += Int32OverflowLength;
switch (Int32OverflowLength)
{
case 10:
answer = (num - '0');
num = text[index - 9];
if (!IsDigit(num))
{
index -= 9;
goto Done;
}
goto case 9;
case 9:
answer = answer * 10 + (num - '0');
num = text[index - 8];
if (!IsDigit(num))
{
index -= 8;
goto Done;
}
goto case 8;
case 8:
answer = answer * 10 + (num - '0');
num = text[index - 7];
if (!IsDigit(num))
{
index -= 7;
goto Done;
}
goto case 7;
case 7:
answer = answer * 10 + (num - '0');
num = text[index - 6];
if (!IsDigit(num))
{
index -= 6;
goto Done;
}
goto case 6;
case 6:
answer = answer * 10 + (num - '0');
num = text[index - 5];
if (!IsDigit(num))
{
index -= 5;
goto Done;
}
goto case 5;
case 5:
answer = answer * 10 + (num - '0');
num = text[index - 4];
if (!IsDigit(num))
{
index -= 4;
goto Done;
}
goto case 4;
case 4:
answer = answer * 10 + (num - '0');
num = text[index - 3];
if (!IsDigit(num))
{
index -= 3;
goto Done;
}
goto case 3;
case 3:
answer = answer * 10 + (num - '0');
num = text[index - 2];
if (!IsDigit(num))
{
index -= 2;
goto Done;
}
goto case 2;
case 2:
answer = answer * 10 + (num - '0');
num = text[index - 1];
if (!IsDigit(num))
{
index -= 1;
goto Done;
}
goto case 1;
case 1:
num -= '0';
if (WillOverFlow(answer, num, sign) || IsDigit(text[index])) goto FalseExit;
answer = answer * 10 + num;
goto Done;
}
}
goto Done;
}
FalseExit:
bytesConsumed = default;
value = default;
return false;
Done:
bytesConsumed = index;
value = answer * sign;
return true;
}
