feat(analysis): add sprite scanner

src/Chip8.Analysis/SpriteCandidate.cs

@@ -0,0 +1,76 @@
+using System.Globalization;
+using System.Text;
+
+namespace Chip8.Analysis;
+
+public sealed class SpriteCandidate
+{
+    public SpriteCandidate(ushort address, int rows, int bytesPerRow, byte[] bytes, ushort loadAddress, ushort drawAddress)
+    {
+        this.address = address;
+        this.rows = rows;
+        this.bytesPerRow = bytesPerRow;
+        this.bytes = bytes;
+        this.loadAddress = loadAddress;
+        this.drawAddress = drawAddress;
+    }
+
+    public ushort address { get; }
+    public int rows { get; }
+    public int bytesPerRow { get; }
+    public byte[] bytes { get; }
+    public ushort loadAddress { get; }
+    public ushort drawAddress { get; }
+
+    public int widthPixels => bytesPerRow * 8;
+
+    public int setPixelCount
+    {
+        get
+        {
+            int count = 0;
+            foreach (byte value in bytes)
+            {
+                int bits = value;
+                while (bits != 0)
+                {
+                    count += bits & 1;
+                    bits >>= 1;
+                }
+            }
+            return count;
+        }
+    }
+
+    public bool isBlank => setPixelCount == 0;
+
+    public bool pixel(int row, int column)
+    {
+        int byteIndex = row * bytesPerRow + column / 8;
+        if (byteIndex >= bytes.Length)
+        {
+            return false;
+        }
+        int bit = 7 - column % 8;
+        return (bytes[byteIndex] & (1 << bit)) != 0;
+    }
+
+    public string renderAscii(char on = '#', char off = '.')
+    {
+        var builder = new StringBuilder();
+        for (int row = 0; row < rows; row++)
+        {
+            for (int column = 0; column < widthPixels; column++)
+            {
+                builder.Append(pixel(row, column) ? on : off);
+            }
+            builder.Append('\n');
+        }
+        return builder.ToString();
+    }
+
+    public override string ToString() =>
+        "sprite@0x" + address.ToString("X4", CultureInfo.InvariantCulture)
+        + " " + widthPixels + "x" + rows
+        + " (" + setPixelCount + " px, drawn at 0x" + drawAddress.ToString("X4", CultureInfo.InvariantCulture) + ")";
+}