private static unsafe void GetIndexOfFirstInvalidUtf8Sequence_Test_Core(byte[] input, int expectedRetVal, int expectedRuneCount, int expectedSurrogatePairCount)
{
// Arrange
using BoundedMemory <byte> boundedMemory = BoundedMemory.AllocateFromExistingData(input);
boundedMemory.MakeReadonly();
// Act
int actualRetVal;
int actualSurrogatePairCount;
int actualRuneCount;
fixed(byte *pInputBuffer = &MemoryMarshal.GetReference(boundedMemory.Span))
{
byte *pFirstInvalidByte = Utf8Utility.GetPointerToFirstInvalidByte(pInputBuffer, input.Length, out int utf16CodeUnitCountAdjustment, out int scalarCountAdjustment);
long ptrDiff = pFirstInvalidByte - pInputBuffer;
Assert.True((ulong)ptrDiff <= (uint)input.Length, "ptrDiff was outside expected range.");
Assert.True(utf16CodeUnitCountAdjustment <= 0, "UTF-16 code unit count adjustment must be 0 or negative.");
Assert.True(scalarCountAdjustment <= 0, "Scalar count adjustment must be 0 or negative.");
actualRetVal = (ptrDiff == input.Length) ? -1 : (int)ptrDiff;
// The last two 'out' parameters are:
// a) The number to be added to the "bytes processed" return value to come up with the total UTF-16 code unit count, and
// b) The number to be added to the "total UTF-16 code unit count" value to come up with the total scalar count.
int totalUtf16CodeUnitCount = (int)ptrDiff + utf16CodeUnitCountAdjustment;
actualRuneCount = totalUtf16CodeUnitCount + scalarCountAdjustment;
// Surrogate pair count is number of UTF-16 code units less the number of scalars.
actualSurrogatePairCount = totalUtf16CodeUnitCount - actualRuneCount;
}
// Assert
Assert.Equal(expectedRetVal, actualRetVal);
Assert.Equal(expectedRuneCount, actualRuneCount);
Assert.Equal(expectedSurrogatePairCount, actualSurrogatePairCount);
}
