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83 lines
2.8 KiB
C#
83 lines
2.8 KiB
C#
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
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// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
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using System;
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using System.Collections.Generic;
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using System.IO;
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using osu.Game.Storyboards;
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namespace osu.Game.Beatmaps.Formats
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{
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public abstract class Decoder
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{
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private static readonly Dictionary<string, Func<string, Decoder>> decoders = new Dictionary<string, Func<string, Decoder>>();
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static Decoder()
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{
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LegacyDecoder.Register();
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JsonBeatmapDecoder.Register();
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}
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/// <summary>
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/// Retrieves a <see cref="Decoder"/> to parse a <see cref="Beatmap"/>.
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/// </summary>
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/// <param name="stream">A stream pointing to the <see cref="Beatmap"/>.</param>
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public static Decoder GetDecoder(StreamReader stream)
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{
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if (stream == null)
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throw new ArgumentNullException(nameof(stream));
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string line;
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do
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{ line = stream.ReadLine()?.Trim(); }
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while (line != null && line.Length == 0);
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if (line == null || !decoders.ContainsKey(line))
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throw new IOException(@"Unknown file format");
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return decoders[line](line);
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}
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/// <summary>
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/// Registers an instantiation function for a <see cref="Decoder"/>.
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/// </summary>
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/// <param name="magic">A string in the file which triggers this decoder to be used.</param>
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/// <param name="constructor">A function which constructs the <see cref="Decoder"/> given <paramref name="magic"/>.</param>
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protected static void AddDecoder(string magic, Func<string, Decoder> constructor)
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{
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decoders[magic] = constructor;
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}
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/// <summary>
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/// Retrieves a <see cref="Decoder"/> to parse a <see cref="Storyboard"/>
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/// </summary>
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public abstract Decoder GetStoryboardDecoder();
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public virtual Beatmap DecodeBeatmap(StreamReader stream)
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{
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var beatmap = new Beatmap
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{
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BeatmapInfo = new BeatmapInfo
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{
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Metadata = new BeatmapMetadata(),
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BaseDifficulty = new BeatmapDifficulty(),
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},
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};
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ParseBeatmap(stream, beatmap);
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return beatmap;
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}
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protected abstract void ParseBeatmap(StreamReader stream, Beatmap beatmap);
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public virtual Storyboard DecodeStoryboard(StreamReader stream)
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{
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var storyboard = new Storyboard();
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ParseStoryboard(stream, storyboard);
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return storyboard;
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}
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protected abstract void ParseStoryboard(StreamReader stream, Storyboard storyboard);
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}
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}
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