System.NumberFormatter.CustomInfo.Format C# (CSharp) Method

			public string Format (string format, int offset, int length, NumberFormatInfo nfi, bool positive, StringBuilder sb_int, StringBuilder sb_dec, StringBuilder sb_exp)
			{
				StringBuilder sb = new StringBuilder ();
				char literal = '\0';
				bool integerArea = true;
				bool decimalArea = false;
				int intSharpCounter = 0;
				int sb_int_index = 0;
				int sb_dec_index = 0;

				int[] groups = nfi.RawNumberGroupSizes;
				string groupSeparator = nfi.NumberGroupSeparator;
				int intLen = 0, total = 0, groupIndex = 0, counter = 0, groupSize = 0;
				if (UseGroup && groups.Length > 0) {
					intLen = sb_int.Length;
					for (int i = 0; i < groups.Length; i++) {
						total += groups [i];
						if (total <= intLen)
							groupIndex = i;
					}
					groupSize = groups [groupIndex];
					int fraction = intLen > total ? intLen - total : 0;
					if (groupSize == 0) {
						while (groupIndex >= 0 && groups [groupIndex] == 0)
							groupIndex--;

						groupSize = fraction > 0 ? fraction : groups [groupIndex];
					}
					if (fraction == 0)
						counter = groupSize;
					else {
						groupIndex += fraction / groupSize;
						counter = fraction % groupSize;
						if (counter == 0)
							counter = groupSize;
						else
							groupIndex++;
					}
				}
				else
					UseGroup = false;

				for (int i = offset; i - offset < length; i++) {
					char c = format [i];

					if (c == literal && c != '\0') {
						literal = '\0';
						continue;
					}
					if (literal != '\0') {
						sb.Append (c);
						continue;
					}

					switch (c) {
					case '\\':
						i++;
						if (i - offset < length)
							sb.Append (format [i]);
						continue;
					case '\'':
					case '\"':
						if (c == '\"' || c == '\'')
							literal = c;
						continue;
					case '#':
						goto case '0';
					case '0':
						if (integerArea) {
							intSharpCounter++;
							if (IntegerDigits - intSharpCounter < sb_int.Length + sb_int_index || c == '0')
								while (IntegerDigits - intSharpCounter + sb_int_index < sb_int.Length) {
									sb.Append (sb_int [sb_int_index++]);
									if (UseGroup && --intLen > 0 && --counter == 0) {
										sb.Append (groupSeparator);
										if (--groupIndex < groups.Length && groupIndex >= 0)
											groupSize = groups [groupIndex];
										counter = groupSize;
									}
								}
							break;
						}
						else if (decimalArea) {
							if (sb_dec_index < sb_dec.Length)
								sb.Append (sb_dec [sb_dec_index++]);
							break;
						}

						sb.Append (c);
						break;
					case 'e':
					case 'E':
						if (sb_exp == null || !UseExponent) {
							sb.Append (c);
							break;
						}

						bool flag1 = true;
						bool flag2 = false;

						int q;
						for (q = i + 1; q - offset < length; q++) {
							if (format [q] == '0') {
								flag2 = true;
								continue;
							}
							if (q == i + 1 && (format [q] == '+' || format [q] == '-'))
								continue;
							if (!flag2)
								flag1 = false;
							break;
						}

						if (flag1) {
							i = q - 1;
							integerArea = (DecimalPointPos < 0);
							decimalArea = !integerArea;

							sb.Append (c);
							sb.Append (sb_exp);
							sb_exp = null;
						}
						else
							sb.Append (c);

						break;
					case '.':
						if (DecimalPointPos == i) {
							if (DecimalDigits > 0) {
								while (sb_int_index < sb_int.Length)
									sb.Append (sb_int [sb_int_index++]);
							}
							if (sb_dec.Length > 0)
								sb.Append (nfi.NumberDecimalSeparator);
						}
						integerArea = false;
						decimalArea = true;
						break;
					case ',':
						break;
					case '%':
						sb.Append (nfi.PercentSymbol);
						break;
					case '\u2030':
						sb.Append (nfi.PerMilleSymbol);
						break;
					default:
						sb.Append (c);
						break;
					}
				}

				if (!positive)
					sb.Insert (0, nfi.NegativeSign);

				return sb.ToString ();
			}
		}