using System; using System.Collections.Generic; using System.IO; using System.IO.Pipelines; using System.Linq; using System.Text; namespace BencodeNET { internal static class UtilityExtensions { public static bool IsDigit(this char c) { return c >= '0' && c <= '9'; } public static MemoryStream AsStream(this string str, Encoding encoding) { return new MemoryStream(encoding.GetBytes(str)); } public static TValue GetValueOrDefault(this IDictionary dictionary, TKey key) { return dictionary.TryGetValue(key, out var value) ? value : default; } public static IEnumerable Flatten(this IEnumerable> source) { return source.SelectMany(x => x); } public static int DigitCount(this int value) => DigitCount((long) value); public static int DigitCount(this long value) { var sign = value < 0 ? 1 : 0; if (value == long.MinValue) return 20; value = Math.Abs(value); if (value < 10) return sign + 1; if (value < 100) return sign + 2; if (value < 1000) return sign + 3; if (value < 10000) return sign + 4; if (value < 100000) return sign + 5; if (value < 1000000) return sign + 6; if (value < 10000000) return sign + 7; if (value < 100000000) return sign + 8; if (value < 1000000000) return sign + 9; if (value < 10000000000) return sign + 10; if (value < 100000000000) return sign + 11; if (value < 1000000000000) return sign + 12; if (value < 10000000000000) return sign + 13; if (value < 100000000000000) return sign + 14; if (value < 1000000000000000) return sign + 15; if (value < 10000000000000000) return sign + 16; if (value < 100000000000000000) return sign + 17; if (value < 1000000000000000000) return sign + 18; return sign + 19; } public static bool TrySetLength(this Stream stream, long length) { if (!stream.CanWrite || !stream.CanSeek) return false; try { if (stream.Length >= length) return false; stream.SetLength(length); return true; } catch { return false; } } public static void Write(this Stream stream, int number) { Span buffer = stackalloc byte[11]; var bytesRead = Encoding.ASCII.GetBytes(number.ToString().AsSpan(), buffer); stream.Write(buffer.Slice(0, bytesRead)); } public static void Write(this Stream stream, long number) { Span buffer = stackalloc byte[20]; var bytesRead = Encoding.ASCII.GetBytes(number.ToString().AsSpan(), buffer); stream.Write(buffer.Slice(0, bytesRead)); } public static void Write(this Stream stream, char c) { stream.WriteByte((byte) c); } public static void WriteChar(this PipeWriter writer, char c) { writer.GetSpan(1)[0] = (byte) c; writer.Advance(1); } public static void WriteCharAt(this Span bytes, char c, int index) { bytes[index] = (byte) c; } public static string AsString(this ReadOnlySpan chars) { return new string(chars); } public static string AsString(this Span chars) { return new string(chars); } public static string AsString(this Memory chars) { return new string(chars.Span); } } }