System.Convert.ConvertToBase64Array C# (CSharp) Method

        private static unsafe int ConvertToBase64Array(char* outChars, byte* inData, int offset, int length, bool insertLineBreaks) {
            int lengthmod3 = length%3;
            int calcLength = offset + (length - lengthmod3);
            int j=0;
            int charcount = 0;
            //Convert three bytes at a time to base64 notation.  This will consume 4 chars.
            int i;

            // get a pointer to the base64Table to avoid unnecessary range checking
            fixed(char* base64 = base64Table) {
                for (i=offset; i<calcLength; i+=3)
                {
                    if (insertLineBreaks) {
                        if (charcount == 76) {
                            outChars[j++] = '\r';
                            outChars[j++] = '\n';
                            charcount = 0;
                        }
                        charcount += 4;
                    }
                    outChars[j] = base64[(inData[i]&0xfc)>>2];
                    outChars[j+1] = base64[((inData[i]&0x03)<<4) | ((inData[i+1]&0xf0)>>4)];
                    outChars[j+2] = base64[((inData[i+1]&0x0f)<<2) | ((inData[i+2]&0xc0)>>6)];
                    outChars[j+3] = base64[(inData[i+2]&0x3f)];
                    j += 4;
                }

                //Where we left off before
                i =  calcLength;

                if (insertLineBreaks && (lengthmod3 !=0) && (charcount == 76)) {
                    outChars[j++] = '\r';
                    outChars[j++] = '\n';
                }
                    
                switch(lengthmod3)
                {
                case 2: //One character padding needed
                    outChars[j] = base64[(inData[i]&0xfc)>>2];
                    outChars[j+1] = base64[((inData[i]&0x03)<<4)|((inData[i+1]&0xf0)>>4)];
                    outChars[j+2] = base64[(inData[i+1]&0x0f)<<2];
                    outChars[j+3] = base64[64]; //Pad
                    j+=4;
                    break;
                case 1: // Two character padding needed
                    outChars[j] = base64[(inData[i]&0xfc)>>2];
                    outChars[j+1] = base64[(inData[i]&0x03)<<4];
                    outChars[j+2] = base64[64]; //Pad
                    outChars[j+3] = base64[64]; //Pad
                    j+=4;
                    break;
                }
            }
            
            return j;
        }