public virtual void TestCharSequenceCharAt()
{
CharsRef c = new CharsRef("abc");
Assert.AreEqual('b', c.CharAt(1));
try
{
c.CharAt(-1);
Assert.Fail();
}
catch (System.IndexOutOfRangeException expected)
{
// expected exception
}
try
{
c.CharAt(3);
Assert.Fail();
}
catch (System.IndexOutOfRangeException expected)
{
// expected exception
}
}
/// <summary>
/// Encode characters from a char[] source, starting at
/// offset for length chars. After encoding, result.offset will always be 0.
/// </summary>
// TODO: broken if incoming result.offset != 0
public static void UTF16toUTF8(CharsRef source, int offset, int length, BytesRef result)
{
int upto = 0;
int i = offset;
int end = offset + length;
var @out = result.Bytes;
// Pre-allocate for worst case 4-for-1
int maxLen = length * 4;
if (@out.Length < maxLen)
{
@out = result.Bytes = new byte[maxLen];
}
result.Offset = 0;
while (i < end)
{
int code = (int)source.CharAt(i++);
if (code < 0x80)
{
@out[upto++] = (byte)code;
}
else if (code < 0x800)
{
@out[upto++] = (byte)(0xC0 | (code >> 6));
@out[upto++] = (byte)(0x80 | (code & 0x3F));
}
else if (code < 0xD800 || code > 0xDFFF)
{
@out[upto++] = (byte)(0xE0 | (code >> 12));
@out[upto++] = (byte)(0x80 | ((code >> 6) & 0x3F));
@out[upto++] = (byte)(0x80 | (code & 0x3F));
}
else
{
// surrogate pair
// confirm valid high surrogate
if (code < 0xDC00 && i < end)
{
var utf32 = (int)source.CharAt(i);
// confirm valid low surrogate and write pair
if (utf32 >= 0xDC00 && utf32 <= 0xDFFF)
{
utf32 = (code << 10) + utf32 + SURROGATE_OFFSET;
i++;
@out[upto++] = (byte)(0xF0 | (utf32 >> 18));
@out[upto++] = (byte)(0x80 | ((utf32 >> 12) & 0x3F));
@out[upto++] = (byte)(0x80 | ((utf32 >> 6) & 0x3F));
@out[upto++] = (byte)(0x80 | (utf32 & 0x3F));
continue;
}
}
// replace unpaired surrogate or out-of-order low surrogate
// with substitution character
@out[upto++] = unchecked ((byte)0xEF);
@out[upto++] = unchecked ((byte)0xBF);
@out[upto++] = unchecked ((byte)0xBD);
}
}
//assert matches(source, offset, length, out, upto);
result.Length = upto;
}
