Created
March 28, 2021 22:16
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| using System; | |
| using System.Collections.Generic; | |
| using System.Linq; | |
| class Program | |
| { | |
| public static void Main() | |
| { | |
| var encoded = LEB128.EncodeSignedLeb128FromInt32(624485); | |
| var str = string.Concat(encoded.Select(entry => entry.ToString("X"))); | |
| Console.WriteLine(str); | |
| var result = LEB128.DecodeSignedLeb128(encoded); | |
| Console.WriteLine(result); | |
| } | |
| } | |
| class LEB128 | |
| { | |
| public static byte[] EncodeSignedLeb128FromInt32(long value) | |
| { | |
| var result = new List<byte>(); | |
| while (true) { | |
| var b = value & 0x7f; | |
| value >>= 7; | |
| if ((value == 0 && (b & 0x40) == 0) || (value == -1 && (b & 0x40) != 0)) | |
| { | |
| result.Add((byte)b); | |
| return result.ToArray(); | |
| } | |
| result.Add((byte)(b | 0x80)); | |
| } | |
| } | |
| public static long DecodeSignedLeb128(byte[] input) | |
| { | |
| var result = 0; | |
| var shift = 0; | |
| foreach (var b in input) | |
| { | |
| result |= (b & 0x7f) << shift; | |
| shift += 7; | |
| if ((0x80 & b) == 0) | |
| { | |
| if (shift < 32 && (b & 0x40) != 0) | |
| { | |
| return result | (~0 << shift); | |
| } | |
| break; | |
| } | |
| } | |
| return result; | |
| } | |
| } |
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Description
Encode and decode LEB128 (according to what Wikipedia says) in C#.
Try it online.
Output