using System; using static System.Buffers.Binary.BinaryPrimitives; namespace PKHeX.Core; /// /// Unpacks data from legality binary inputs. /// public static class LearnsetReader { private static readonly Learnset EMPTY = new(Array.Empty(), Array.Empty()); /// /// Loads a learnset using the 8-bit-per-move storage structure used by Generation 1 & 2 games. /// /// Raw ROM data containing the contiguous moves /// Highest species ID for the input game. public static Learnset[] GetArray(ReadOnlySpan input, int maxSpecies) { int offset = 0; var result = new Learnset[maxSpecies + 1]; for (int i = 0; i < result.Length; i++) result[i] = ReadLearnset8(input, ref offset); return result; } /// /// Loads a learnset by reading 16-bit move,level pairs. /// /// Entry data public static Learnset[] GetArray(BinLinkerAccessor entries) { var result = new Learnset[entries.Length]; for (int i = 0; i < result.Length; i++) result[i] = ReadLearnset16(entries[i]); return result; } /// /// Reads a Level up move pool definition from a contiguous chunk of GB era ROM data. /// /// Moves and Levels are 8-bit private static Learnset ReadLearnset8(ReadOnlySpan data, ref int offset) { int end = offset; // scan for count if (data[end] == 0) { ++offset; return EMPTY; } do { end += 2; } while (data[end] != 0); var count = (end - offset) / 2; var moves = new ushort[count]; var levels = new byte[count]; for (int i = 0; i < moves.Length; i++) { levels[i] = data[offset++]; moves[i] = data[offset++]; } ++offset; return new Learnset(moves, levels); } /// /// Reads a Level up move pool definition from a single move pool definition. /// /// Count of moves, followed by Moves and Levels which are 16-bit private static Learnset ReadLearnset16(ReadOnlySpan data) { if (data.Length == 0) return EMPTY; var count = (data.Length / 4) - 1; var moves = new ushort[count]; var levels = new byte[count]; for (int i = 0; i < count; i++) { var move = data.Slice(i * 4, 4); levels[i] = move[2]; moves[i] = ReadUInt16LittleEndian(move); } return new Learnset(moves, levels); } }