67 lines
2.3 KiB
C#
67 lines
2.3 KiB
C#
using System.Linq;
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using System.Runtime.CompilerServices;
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namespace Benchmark
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{
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public readonly struct Identity
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{
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public Identity(string prefix, int index, int revision)
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{
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Prefix = prefix;
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Index = index;
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Revision = revision;
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}
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public string Prefix { get; }
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public int Index { get; }
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public int Revision { get; }
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public static bool TryParse(string value, out Identity identity)
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{
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identity = default;
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var position = value.Length;
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if (!TryGetNumber(value, null, ref position, out var revision)) return false;
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if (value[position] != '-') return false;
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if (!TryGetNumber(value, 7, ref position, out var index)) return false;
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if (!TryGetPrefix(value, ref position, out var prefix)) return false;
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identity = new Identity(prefix, index, revision);
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return true;
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}
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private static bool TryGetPrefix(in string identity, ref int lastPosition, out string prefix)
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{
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prefix = identity.Remove(lastPosition + 1);
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if (prefix.Length < 3) return false;
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return !prefix.Any(character => character < 'A' || character > 'Z');
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}
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private static bool TryGetNumber(in string identity, int? exactLength, ref int currentPosition, out int revision)
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{
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revision = 0;
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var start = currentPosition;
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for (currentPosition = start - 1; currentPosition >= 0; currentPosition--)
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{
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var current = identity[currentPosition];
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if(current == '0') continue;
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if (current < '1' || current > '9') break;
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revision += (current - '0') * IntegerPow(10, start - currentPosition - 1);
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}
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if (exactLength != null && start - (currentPosition + 1) != exactLength) return false;
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return revision != default;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static int IntegerPow(int x, int y)
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{
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if (y == 0) return 1;
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var result = x;
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for (var i = 1; i < y; i++)
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{
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result *= x;
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}
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return result;
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}
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}
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} |