/// <summary>
/// Converts a string to a number (used in type coercion).
/// </summary>
/// <returns> The result of parsing the string as a number. </returns>
internal static double CoerceToNumber(string input)
{
var reader = new System.IO.StringReader(input);
// Skip whitespace and line terminators.
while (IsWhiteSpaceOrLineTerminator(reader.Peek()))
{
reader.Read();
}
// Empty strings return 0.
int firstChar = reader.Read();
if (firstChar == -1)
{
return(0.0);
}
// The number can start with a plus or minus sign.
bool negative = false;
switch (firstChar)
{
case '-':
negative = true;
firstChar = reader.Read();
break;
case '+':
firstChar = reader.Read();
break;
}
// Infinity or -Infinity are also valid.
if (firstChar == 'I')
{
var restOfString1 = reader.ReadToEnd();
if (restOfString1 == null)
{
throw new InvalidOperationException("Reader returned null.");
}
if (restOfString1.StartsWith("nfinity", StringComparison.Ordinal))
{
// Check the end of the string for junk.
for (int i = 7; i < restOfString1.Length; i++)
{
if (IsWhiteSpaceOrLineTerminator(restOfString1[i]) == false)
{
return(double.NaN);
}
}
return(negative ? double.NegativeInfinity : double.PositiveInfinity);
}
}
// Return NaN if the first digit is not a number or a period.
if ((firstChar < '0' || firstChar > '9') && firstChar != '.')
{
return(double.NaN);
}
// Parse the number.
NumberParser.ParseCoreStatus status;
double result = NumberParser.ParseCore(reader, (char)firstChar, out status, true, false);
// Handle various error cases.
switch (status)
{
case ParseCoreStatus.NoDigits:
case ParseCoreStatus.NoExponent:
return(double.NaN);
}
// Check the end of the string for junk.
var nfinityString = reader.ReadToEnd();
if (nfinityString == null)
{
throw new InvalidOperationException("Reader returned null.");
}
if (nfinityString.Any(t => IsWhiteSpaceOrLineTerminator(t) == false))
{
return(double.NaN);
}
return(negative ? -result : result);
}
/// <summary>
/// Converts any JavaScript value to a primitive number value.
/// </summary>
/// <param name="value"> The value to convert. </param>
/// <returns> A primitive number value. </returns>
public static double ToNumber(object value)
{
if (value is double)
{
return((double)value);
}
if (value is SByte)
{
return((SByte)value);
}
if (value is Int16)
{
return((Int16)value);
}
if (value is Int32)
{
return((Int32)value);
}
if (value is Int64)
{
return((Int64)value);
}
if (value is Byte)
{
return((Byte)value);
}
if (value is UInt16)
{
return((UInt16)value);
}
if (value is UInt32)
{
return((UInt32)value);
}
if (value is UInt64)
{
return((UInt64)value);
}
if (value == null || value == Undefined.Value)
{
return(double.NaN);
}
if (value == Null.Value)
{
return(+0);
}
if (value is bool)
{
return((bool)value ? 1 : 0);
}
if (value is string)
{
return(NumberParser.CoerceToNumber((string)value));
}
if (value is ConcatenatedString)
{
return(NumberParser.CoerceToNumber(value.ToString()));
}
if (value is ObjectInstance)
{
return(ToNumber(ToPrimitive(value, PrimitiveTypeHint.Number)));
}
throw new ArgumentException(string.Format("Cannot convert object of type '{0}' to a number.", value.GetType()), "value");
}
