| | | 1 | | using System; |
| | | 2 | | using System.Globalization; |
| | | 3 | | using System.Text.RegularExpressions; |
| | | 4 | | |
| | | 5 | | namespace MusicTheory.Theory.Time; |
| | | 6 | | |
| | | 7 | | /// <summary> |
| | | 8 | | /// Duration の簡易文字列表現パーサ/フォーマッタ。 |
| | | 9 | | /// サポート: |
| | | 10 | | /// - 基本値の略号: W(whole), H(half), Q(quarter), E(eighth), S(sixteenth), T(thirty-second), X(sixty-fourth), O(128th), D/B(d |
| | | 11 | | /// - 分数表記: "1/4", "3/8" など（Whole=1 を基準） |
| | | 12 | | /// - 付点: 終端の '.' を 1〜3 個（例: "Q.", "1/8.."） |
| | | 13 | | /// - 連符: 末尾に "(a:b)" または "*a:b" を付与（例: "E(3:2)", "1/8*5:4"） |
| | | 14 | | /// 未対応/不正な表記は TryParse=false を返し、Parse は ArgumentException を投げます。 |
| | | 15 | | /// </summary> |
| | | 16 | | public static class DurationNotation |
| | | 17 | | { |
| | | 18 | | public static bool TryParse(string text, out Duration duration) |
| | | 19 | | { |
| | 8 | 20 | | duration = default; |
| | 8 | 21 | | if (string.IsNullOrWhiteSpace(text)) return false; |
| | 8 | 22 | | var s = text.Trim(); |
| | | 23 | | |
| | | 24 | | // 1) 連符抽出: (a:b) or *a:b （末尾にあるとみなす） |
| | 8 | 25 | | Tuplet? tuplet = null; |
| | 8 | 26 | | var mParen = Regex.Match(s, "\\((\\d+)\\s*:\\s*(\\d+)\\)\\s*$"); |
| | 8 | 27 | | var mStar = !mParen.Success ? Regex.Match(s, "\\*(\\d+)\\s*:\\s*(\\d+)\\s*$") : Match.Empty; |
| | 8 | 28 | | if (mParen.Success || mStar.Success) |
| | | 29 | | { |
| | 3 | 30 | | var m = mParen.Success ? mParen : mStar; |
| | 3 | 31 | | if (!int.TryParse(m.Groups[1].Value, NumberStyles.None, CultureInfo.InvariantCulture, out var a)) return fal |
| | 3 | 32 | | if (!int.TryParse(m.Groups[2].Value, NumberStyles.None, CultureInfo.InvariantCulture, out var b)) return fal |
| | 3 | 33 | | if (a <= 0 || b <= 0) return false; |
| | 3 | 34 | | tuplet = new Tuplet(a, b); |
| | 3 | 35 | | s = s.Substring(0, (mParen.Success ? mParen.Index : mStar.Index)).TrimEnd(); |
| | | 36 | | } |
| | | 37 | | |
| | | 38 | | // 2) 付点抽出: 末尾 '.' を数える（最大3） |
| | 8 | 39 | | int dots = 0; |
| | 25 | 40 | | for (int i = s.Length - 1; i >= 0 && s[i] == '.'; i--) dots++; |
| | 8 | 41 | | if (dots > Duration.MaxDots) return false; |
| | 10 | 42 | | if (dots > 0) s = s.Substring(0, s.Length - dots).TrimEnd(); |
| | | 43 | | |
| | | 44 | | // 3) 本体: 略号 もしくは 分数 n/d |
| | | 45 | | RationalFactor fraction; |
| | 8 | 46 | | if (TryParseAbbrev(s, out var baseValue)) |
| | | 47 | | { |
| | 6 | 48 | | var (n, d) = baseValue.GetFraction(); |
| | 6 | 49 | | fraction = new RationalFactor(n, d); |
| | | 50 | | } |
| | 2 | 51 | | else if (TryParseFraction(s, out var num, out var den)) |
| | | 52 | | { |
| | 2 | 53 | | fraction = new RationalFactor(num, den); |
| | | 54 | | } |
| | | 55 | | else |
| | | 56 | | { |
| | 0 | 57 | | return false; |
| | | 58 | | } |
| | | 59 | | |
| | | 60 | | // 4) 付点適用 |
| | 8 | 61 | | if (dots > 0) |
| | | 62 | | { |
| | 2 | 63 | | int pow = 1 << dots; // 2^dots |
| | 2 | 64 | | int numMul = 2 * pow - 1; |
| | 2 | 65 | | fraction = fraction * new RationalFactor(numMul, pow); |
| | | 66 | | } |
| | | 67 | | |
| | | 68 | | // 5) 連符適用 |
| | 8 | 69 | | if (tuplet.HasValue) |
| | | 70 | | { |
| | 3 | 71 | | fraction = fraction * tuplet.Value.FactorRational; // normal/actual |
| | | 72 | | } |
| | | 73 | | |
| | 8 | 74 | | duration = new Duration(fraction); |
| | 8 | 75 | | return true; |
| | | 76 | | } |
| | | 77 | | |
| | | 78 | | public static Duration Parse(string text) |
| | 0 | 79 | | => TryParse(text, out var d) ? d : throw new ArgumentException($"Invalid duration notation: '{text}'"); |
| | | 80 | | |
| | | 81 | | /// <summary> |
| | | 82 | | /// Duration を簡易記法へフォーマット。分解に成功すれば略号+付点(+連符)を返し、失敗時は既約分数で返す。 |
| | | 83 | | /// 例: Quarter+dots1 → "Q." / Eighth triplet → "E(3:2)" / 既知以外 → "num/den" |
| | | 84 | | /// </summary> |
| | | 85 | | public static string ToNotation(Duration duration, bool extendedTuplets = false) |
| | | 86 | | { |
| | 3 | 87 | | if (duration.TryDecomposeFull(out var baseValue, out var dots, out var tuplet, extendedTuplets)) |
| | | 88 | | { |
| | 3 | 89 | | string core = AbbrevFor(baseValue); |
| | 3 | 90 | | core += new string('.', dots); |
| | 3 | 91 | | if (tuplet.HasValue) |
| | | 92 | | { |
| | 2 | 93 | | var t = tuplet.Value; |
| | 2 | 94 | | if (extendedTuplets) |
| | | 95 | | { |
| | 1 | 96 | | core += $"*{t.ActualCount}:{t.NormalCount}"; |
| | | 97 | | } |
| | | 98 | | else |
| | | 99 | | { |
| | 1 | 100 | | core += $"({t.ActualCount}:{t.NormalCount})"; |
| | | 101 | | } |
| | | 102 | | } |
| | 3 | 103 | | return core; |
| | | 104 | | } |
| | | 105 | | // fallback: fraction |
| | 0 | 106 | | var f = duration.WholeFraction; |
| | 0 | 107 | | return $"{f.Numerator}/{f.Denominator}"; |
| | | 108 | | } |
| | | 109 | | |
| | | 110 | | private static bool TryParseAbbrev(string s, out BaseNoteValue value) |
| | | 111 | | { |
| | 8 | 112 | | value = default; |
| | 8 | 113 | | if (string.IsNullOrEmpty(s)) return false; |
| | 8 | 114 | | switch (s.Trim().ToUpperInvariant()) |
| | | 115 | | { |
| | 0 | 116 | | case "D": case "B": value = BaseNoteValue.DoubleWhole; return true; // Breve/Double |
| | 0 | 117 | | case "W": value = BaseNoteValue.Whole; return true; |
| | 0 | 118 | | case "H": value = BaseNoteValue.Half; return true; |
| | 4 | 119 | | case "Q": value = BaseNoteValue.Quarter; return true; |
| | 8 | 120 | | case "E": value = BaseNoteValue.Eighth; return true; |
| | 0 | 121 | | case "S": value = BaseNoteValue.Sixteenth; return true; |
| | 0 | 122 | | case "T": value = BaseNoteValue.ThirtySecond; return true; |
| | 0 | 123 | | case "X": value = BaseNoteValue.SixtyFourth; return true; |
| | 0 | 124 | | case "O": value = BaseNoteValue.OneHundredTwentyEighth; return true; |
| | 2 | 125 | | default: return false; |
| | | 126 | | } |
| | | 127 | | } |
| | | 128 | | |
| | | 129 | | private static bool TryParseFraction(string s, out int num, out int den) |
| | | 130 | | { |
| | 2 | 131 | | num = den = 0; |
| | 2 | 132 | | var parts = s.Split('/', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries); |
| | 2 | 133 | | if (parts.Length != 2) return false; |
| | 2 | 134 | | if (!int.TryParse(parts[0], NumberStyles.Integer, CultureInfo.InvariantCulture, out num)) return false; |
| | 2 | 135 | | if (!int.TryParse(parts[1], NumberStyles.Integer, CultureInfo.InvariantCulture, out den)) return false; |
| | 2 | 136 | | if (den == 0) return false; |
| | 2 | 137 | | return true; |
| | | 138 | | } |
| | | 139 | | |
| | | 140 | | private static string AbbrevFor(BaseNoteValue v) |
| | 3 | 141 | | => v switch |
| | 3 | 142 | | { |
| | 0 | 143 | | BaseNoteValue.DoubleWhole => "D", |
| | 0 | 144 | | BaseNoteValue.Whole => "W", |
| | 0 | 145 | | BaseNoteValue.Half => "H", |
| | 0 | 146 | | BaseNoteValue.Quarter => "Q", |
| | 3 | 147 | | BaseNoteValue.Eighth => "E", |
| | 0 | 148 | | BaseNoteValue.Sixteenth => "S", |
| | 0 | 149 | | BaseNoteValue.ThirtySecond => "T", |
| | 0 | 150 | | BaseNoteValue.SixtyFourth => "X", |
| | 0 | 151 | | BaseNoteValue.OneHundredTwentyEighth => "O", |
| | 0 | 152 | | _ => "?" |
| | 3 | 153 | | }; |
| | | 154 | | } |