private string EncodeCore(string input, int idxOfFirstCharWhichRequiresEncoding)
{
Debug.Assert(idxOfFirstCharWhichRequiresEncoding >= 0);
Debug.Assert(idxOfFirstCharWhichRequiresEncoding < input.Length);
int numCharsWhichMayRequireEncoding = input.Length - idxOfFirstCharWhichRequiresEncoding;
int sbCapacity = checked (idxOfFirstCharWhichRequiresEncoding + EncoderCommon.GetCapacityOfOutputStringBuilder(numCharsWhichMayRequireEncoding, _maxOutputCharsPerInputChar));
Debug.Assert(sbCapacity >= input.Length);
// Allocate the StringBuilder with the first (known to not require encoding) part of the input string,
// then begin encoding from the last (potentially requiring encoding) part of the input string.
StringBuilder builder = new StringBuilder(input, 0, idxOfFirstCharWhichRequiresEncoding, sbCapacity);
Writer writer = new Writer(builder);
fixed(char *pInput = input)
{
EncodeCore(ref writer, &pInput[idxOfFirstCharWhichRequiresEncoding], (uint)numCharsWhichMayRequireEncoding);
}
return(builder.ToString());
}
[InlineData(512, Int32.MaxValue, 16 * 1024)] // make sure we can handle numeric overflow
public void GetCapacityOfOutputStringBuilder(int numCharsToEncode, int worstCaseOutputCharsPerInputChar, int expectedResult)
{
Assert.Equal(expectedResult, EncoderCommon.GetCapacityOfOutputStringBuilder(numCharsToEncode, worstCaseOutputCharsPerInputChar));
}