public int Compare(UnmanagedStringArray.UnmanagedString string1, UnmanagedStringArray.UnmanagedString string2)
{
Debug.Assert(string1.IsNull == false);
Debug.Assert(string2.IsNull == false);
var string1State = new AlphanumericStringComparisonState(string1);
var string2State = new AlphanumericStringComparisonState(string2);
// Walk through two the strings with two markers.
while (string1State.CurPositionInString < string1State.StringLength &&
string2State.CurPositionInString < string2State.StringLength)
{
string1State.ScanNextAlphabeticOrNumericSequence();
string2State.ScanNextAlphabeticOrNumericSequence();
var result = string1State.CompareWithAnotherState(string2State);
if (result != 0)
{
return(result);
}
}
if (string1State.CurPositionInString < string1State.StringLength)
{
return(1);
}
if (string2State.CurPositionInString < string2State.StringLength)
{
return(-1);
}
return(0);
}
public int CompareWithAnotherState(AlphanumericStringComparisonState other)
{
var string1State = this;
var string2State = other;
// if both seqeunces are numbers, compare between them
if (string1State.CurSequenceIsNumber && string2State.CurSequenceIsNumber)
{
// if effective numbers are not of the same length, it means that we can tell which is greatedr (in an order of magnitude, actually)
if (string1State.NumberLength != string2State.NumberLength)
{
return(string1State.NumberLength.CompareTo(string2State.NumberLength));
}
// else, it means they should be compared by string, again, we compare only the effective numbers
return(System.Globalization.CultureInfo.InvariantCulture.CompareInfo.Compare(
string1State.OriginalString, string1State.CurPositionInString - string1State.NumberLength, string1State.NumberLength,
string2State.OriginalString, string2State.CurPositionInString - string2State.NumberLength, string1State.NumberLength));
}
// if one of the sequences is a number and the other is not, the number is always smaller
if (string1State.CurSequenceIsNumber != string2State.CurSequenceIsNumber)
{
if (string1State.CurSequenceIsNumber)
{
return(-1);
}
return(1);
}
return(System.Globalization.CultureInfo.InvariantCulture.CompareInfo.Compare(
string1State.OriginalString, string1State.CurSequenceStartPosition, string1State.CurPositionInString - string1State.CurSequenceStartPosition,
string2State.OriginalString, string2State.CurSequenceStartPosition, string2State.CurPositionInString - string2State.CurSequenceStartPosition));
}
public unsafe int Compare(string string1, string string2)
{
if (string1 == null)
{
return(0);
}
if (string2 == null)
{
return(0);
}
var string1State = new AlphanumericStringComparisonState(string1);
var string2State = new AlphanumericStringComparisonState(string2);
// Walk through two the strings with two markers.
while (string1State.CurPositionInString < string1State.StringLength &&
string2State.CurPositionInString < string2State.StringLength)
{
string1State.ScanNextAlphabeticOrNumericSequence();
string2State.ScanNextAlphabeticOrNumericSequence();
var result = string1State.CompareWithAnotherState(string2State);
if (result != 0)
{
return(result);
}
}
if (string1State.CurPositionInString < string1State.StringLength)
{
return(1);
}
if (string2State.CurPositionInString < string2State.StringLength)
{
return(-1);
}
return(0);
}
public int CompareWithAnotherState(AlphanumericStringComparisonState other)
{
var string1State = this;
var string2State = other;
// if both sequences are numbers, compare between them
if (string1State.CurSequenceIsNumber && string2State.CurSequenceIsNumber)
{
// if effective numbers are not of the same length, it means that we can tell which is greater (in an order of magnitude, actually)
if (string1State.NumberLength != string2State.NumberLength)
{
return(string1State.NumberLength.CompareTo(string2State.NumberLength));
}
// else, it means they should be compared by string, again, we compare only the effective numbers
// One digit is always one byte, so no need to care about chars vs bytes
return(string1State.OriginalString.StringAsBytes.Slice(string1State.StringBufferOffset - string1State.NumberLength, string1State.NumberLength)
.SequenceCompareTo(string2State.OriginalString.StringAsBytes.Slice(string2State.StringBufferOffset - string2State.NumberLength,
string2State.NumberLength)));
}
// if one of the sequences is a number and the other is not, the number is always smaller
if (string1State.CurSequenceIsNumber != string2State.CurSequenceIsNumber)
{
if (string1State.CurSequenceIsNumber)
{
return(-1);
}
return(1);
}
// should be case insensitive
char ch1 = default;
char ch2 = default;
var offset1 = string1State.CurSequenceStartPosition;
var offset2 = string2State.CurSequenceStartPosition;
var length1 = string1State.StringBufferOffset - string1State.CurSequenceStartPosition;
var length2 = string2State.StringBufferOffset - string2State.CurSequenceStartPosition;
while (length1 > 0 && length2 > 0)
{
var read1 = ReadOneChar(string1State.OriginalString.StringAsBytes, offset1, ref ch1);
var read2 = ReadOneChar(string2State.OriginalString.StringAsBytes, offset2, ref ch2);
length1 -= read1;
length2 -= read2;
var result = char.ToLowerInvariant(ch1) - char.ToLowerInvariant(ch2);
if (result == 0)
{
offset1 += read1;
offset2 += read2;
continue;
}
return(result);
}
return(length1 - length2);
}
