public static std_core._sslice SliceExtend(std_core._sslice slice, BigInteger bcount)
{
int count = IntToInt32(bcount);
if (count == 0)
{
return(slice);
}
int i = slice.start + slice.len;
if (count > 0)
{
while (i < slice.str.Length && count > 0)
{
count--;
i += (Char.IsHighSurrogate(slice.str[i]) && i < slice.str.Length - 1 ? 2 : 1);
}
}
else
{
while (i > slice.start && i > 0 && count < 0)
{
count++;
i -= (Char.IsLowSurrogate(slice.str[i - 1]) && i > slice.start + 1 ? 2 : 1);
}
}
return(new std_core._sslice(slice.str, slice.start, (i > slice.start ? i - slice.start : 0)));
}
public static string SliceToString(std_core._sslice slice)
{
if (slice.start == 0 && slice.len == slice.str.Length)
{
return(slice.str);
}
return(slice.str.Substring(slice.start, slice.len));
}
public static BigInteger SliceCount(std_core._sslice slice)
{
int n = 0;
for (int i = slice.start; i < slice.start + slice.len; i++)
{
n++;
if (Char.IsHighSurrogate(slice.str[i]))
{
i += 1;
}
}
return(new BigInteger(n));
}
public static std_core._sslice SliceAdvance(std_core._sslice slice, BigInteger bcount)
{
int count = IntToInt32(bcount);
if (count == 0)
{
return(slice);
}
int i = slice.start;
int end = slice.start + slice.len;
int sliceCount = IntToInt32(SliceCount(slice));
int extra = 0;
if (count > 0)
{
while (i < slice.str.Length && extra < count)
{
extra++;
i += (Char.IsHighSurrogate(slice.str[i]) && i < slice.str.Length - 1 ? 2 : 1);
}
if (end > i && sliceCount > extra)
{
return(SliceExtend(new std_core._sslice(slice.str, i, end - i), extra));
}
}
else
{
while (i > 0 && extra < -count)
{
extra++;
i -= (Char.IsLowSurrogate(slice.str[i - 1]) && i > 1 ? 2 : 1);
}
if (sliceCount > extra)
{
return(SliceExtend(new std_core._sslice(slice.str, i, slice.start - i), sliceCount - extra));
}
}
return(SliceExtend(new std_core._sslice(slice.str, i, 0), sliceCount));
}
public static std_core._maybe <std_core._Tuple2_ <int, std_core._sslice> > SliceNext(std_core._sslice slice)
{
if (slice.len <= 0)
{
return(std_core._maybe <std_core._Tuple2_ <int, std_core._sslice> > .Nothing_);
}
char c = slice.str[slice.start];
int n = 1;
if (Char.IsHighSurrogate(c) && slice.len > 1)
{
char lo = slice.str[slice.start + 1];
if (Char.IsLowSurrogate(lo))
{
c = (char)Char.ConvertToUtf32(slice.str, slice.start);
n = 2;
}
}
return(new std_core._maybe <std_core._Tuple2_ <int, std_core._sslice> >(
new std_core._Tuple2_ <int, std_core._sslice>(
(int)c, new std_core._sslice(slice.str, slice.start + n, slice.len - n))));
}
