Initial commit

2026-05-07 03:23:56 +00:00
commit 5e8575f42a
42 changed files with 2330 additions and 0 deletions
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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using GameOfLife.Entities;
+
+namespace GameOfLife.IO
+{
+    // https://conwaylife.com/wiki/Apgcode
+    public class ApgcodeDecoder
+    {
+        private static readonly Regex PrefixRegex = new Regex(@"(?<header>.+(?=_))?_?(?<code>.+)");
+        private static readonly Regex ExpansionRegex = new Regex(@"y(\w+)");
+        public Pattern Pattern { get; }
+        public PatternMetadata Metadata { get; }
+
+        public ApgcodeDecoder(string apgcode, string name = null)
+        {
+            var match = PrefixRegex.Match(apgcode);
+            if (!match.Success)
+                throw new ArgumentException("Invalid apgcode");
+            var header = match.Groups["header"].Value;
+            var code = match.Groups["code"].Value;
+            if (!string.IsNullOrEmpty(header))
+                Metadata = new ApgcodePatternMetaData(header,name);
+
+            var expanded = ExpandAbbreviations(code);
+            Pattern = DecodeCells(expanded).ToPattern();
+        }
+
+        private IEnumerable<Cell> DecodeCells(string expanded)
+        {
+            var rowNum = 0;
+            foreach (var strip in expanded.Split('z'))
+            {
+                var colBits = strip.Select(ConvertToUint).ToArray();
+                for (var i = 0; i < 5; i++)
+                {
+                    var colNum = 0;
+                    foreach (var colBit in colBits)
+                    {
+                        if ((colBit >> i & 0b_1) == 1)
+                            yield return new Cell(colNum, rowNum);
+                        colNum++;
+                    }
+
+                    rowNum++;
+                }
+            }
+        }
+
+        public static string ExpandAbbreviations(string apgcode)
+        {
+            apgcode = apgcode.Replace("w", "00");
+            apgcode = apgcode.Replace("x", "000");
+            apgcode = ExpansionRegex.Replace(apgcode, m =>
+                new string('0', 4 + Convert.ToInt32(ConvertToUint(m.Groups[1].Value[0]))));
+            return apgcode;
+        }
+
+        public static uint ConvertToUint(char c)
+        {
+            if (c >= '0' && c <= '9')
+                return (uint)(c - '0');
+            if (c >= 'a' && c <= 'z')
+                return (uint)(c - 'a' + 10);
+            throw new Exception("Cannot convert char " + c.ToString());
+        }
+    }
+}