begin implementing klotski logic

CMakeLists.txt

@@ -12,6 +12,7 @@ add_executable(masssprings
     src/main.cpp
     src/renderer.cpp
     src/mass_springs.cpp
+    src/klotski.cpp
 )
 
 target_include_directories(masssprings PUBLIC ${RAYLIB_CPP_INCLUDE_DIR})

include/klotski.hpp

@@ -0,0 +1,237 @@
+#ifndef __KLOTSKI_HPP_
+#define __KLOTSKI_HPP_
+
+#include <array>
+#include <cstddef>
+#include <format>
+#include <iostream>
+#include <string>
+#include <vector>
+
+// #define DBG_PRINT
+
+enum Direction {
+  NOR = 1 << 0,
+  EAS = 1 << 1,
+  SOU = 1 << 2,
+  WES = 1 << 3,
+};
+
+// A block is represented as a 2-digit string "wh", where w is the block width
+// and h the block height.
+// The target block (to remove from the board) is represented as a 2-letter
+// string "xy", where x is the block width and y the block height and
+// width/height are represented by [abcdefghi] (~= [123456789]).
+class Block {
+public:
+  int x;
+  int y;
+  int width;
+  int height;
+  bool target;
+
+public:
+  Block(int x, int y, int width, int height, bool target)
+      : x(x), y(y), width(width), height(height), target(target) {
+    if (x < 0 || x + width >= 10 || y < 0 || y + height >= 10) {
+      std::cerr << "Block must fit on a 9x9 board!" << std::endl;
+      exit(1);
+    }
+
+#ifdef DBG_PRINT
+    std::cout << ToString() << std::endl;
+#endif
+  }
+
+  Block(int x, int y, std::string block) : x(x), y(y) {
+    if (block == "..") {
+      this->x = 0;
+      this->y = 0;
+      width = 0;
+      height = 0;
+      target = false;
+      return;
+    }
+
+    const std::array<char, 9> chars{'a', 'b', 'c', 'd', 'e',
+                                    'f', 'g', 'h', 'i'};
+
+    target = false;
+    for (const char c : chars) {
+      if (block.contains(c)) {
+        target = true;
+        break;
+      }
+    }
+
+    if (target) {
+      width = static_cast<int>(block.at(0)) - static_cast<int>('a') + 1;
+      height = static_cast<int>(block.at(1)) - static_cast<int>('a') + 1;
+    } else {
+      width = std::stoi(block.substr(0, 1));
+      height = std::stoi(block.substr(1, 1));
+    }
+
+    if (x < 0 || x + width >= 10 || y < 0 || y + height >= 10) {
+      std::cerr << "Block must fit on a 9x9 board!" << std::endl;
+      exit(1);
+    }
+    if (block.length() != 2) {
+      std::cerr << "Block representation must have length [2]!" << std::endl;
+      exit(1);
+    }
+
+#ifdef DBG_PRINT
+    std::cout << "At: (" << x << ", " << y << "), Size: (" << width << ", "
+              << height << "), Target: " << target << std::endl;
+#endif
+  }
+
+  Block(const Block &copy)
+      : x(copy.x), y(copy.y), width(copy.width), height(copy.height),
+        target(copy.target) {}
+
+  Block &operator=(const Block &copy) = delete;
+
+  Block(Block &&move)
+      : x(move.x), y(move.y), width(move.width), height(move.height),
+        target(move.target) {}
+
+  Block &operator=(Block &&move) = delete;
+
+  bool operator==(const Block &other) {
+    return x == other.x && y == other.y && width && other.width &&
+           target == other.target;
+  }
+
+  bool operator!=(const Block &other) { return !(*this == other); }
+
+  ~Block() {}
+
+public:
+  auto Hash() -> int;
+
+  static auto Invalid() -> Block const;
+
+  auto IsValid() -> bool;
+
+  auto ToString() -> std::string;
+
+  auto Covers(int xx, int yy) -> bool;
+
+  auto Collides(const Block &other) -> bool;
+};
+
+// A state is represented by a string "WxH:blocks", where W is the board width,
+// H is the board height and blocks is an enumeration of each of the board's
+// cells, with each cell being a 2-letter or 2-digit block representation (a 3x3
+// board would have a string representation with length 4 + 3*3 * 2).
+// The board's cells are enumerated from top-left to bottom-right with each
+// block's pivot being its top-left corner.
+class State {
+public:
+  int width;
+  int height;
+  std::string state;
+
+  // https://en.cppreference.com/w/cpp/iterator/input_iterator.html
+  class BlockIterator {
+  public:
+    using difference_type = std::ptrdiff_t;
+    using value_type = Block;
+
+  private:
+    const State &state;
+    int current_pos;
+
+  public:
+    BlockIterator(const State &state) : state(state), current_pos(0) {}
+
+    BlockIterator(const State &state, int current_pos)
+        : state(state), current_pos(current_pos) {}
+
+    Block operator*() const {
+      return Block(current_pos % state.width, current_pos / state.width,
+                   state.state.substr(current_pos * 2 + 4, 2));
+    }
+
+    BlockIterator &operator++() {
+      do {
+        current_pos++;
+      } while (state.state.substr(current_pos * 2 + 4, 2) == "..");
+      return *this;
+    }
+
+    bool operator==(const BlockIterator &other) {
+      return state == other.state && current_pos == other.current_pos;
+    }
+
+    bool operator!=(const BlockIterator &other) { return !(*this == other); }
+  };
+
+public:
+  State(int width, int height)
+      : width(width), height(height),
+        state(std::format("{}x{}:{}", width, height,
+                          std::string(width * height * 2, '.'))) {
+    if (width <= 0 || width >= 10 || height <= 0 || height >= 10) {
+      std::cerr << "State width/height must be in [1, 9]!" << std::endl;
+      exit(1);
+    }
+
+#ifdef DBG_PRINT
+    std::cout << "State(" << width << ", " << height << "): \"" << state << "\""
+              << std::endl;
+#endif
+  }
+
+  State(std::string state)
+      : width(std::stoi(state.substr(0, 1))),
+        height(std::stoi(state.substr(2, 1))), state(state) {
+    if (width <= 0 || width >= 10 || height <= 0 || height >= 10) {
+      std::cerr << "State width/height must be in [1, 9]!" << std::endl;
+      exit(1);
+    }
+    if (state.length() != width * height * 2 + 4) {
+      std::cerr
+          << "State representation must have length [width * height * 2 + 4]!"
+          << std::endl;
+      exit(1);
+    }
+  }
+
+  State(const State &copy)
+      : width(copy.width), height(copy.height), state(copy.state) {}
+
+  State &operator=(const State &copy) = delete;
+
+  State(State &&move)
+      : width(move.width), height(move.height), state(std::move(move.state)) {}
+
+  State &operator=(State &&move) = delete;
+
+  bool operator==(const State &other) const { return state == other.state; }
+
+  bool operator!=(const State &other) const { return !(*this == other); }
+
+  BlockIterator begin() { return BlockIterator(*this); }
+
+  BlockIterator end() { return BlockIterator(*this, width * height); }
+
+  ~State() {}
+
+public:
+  auto Hash() -> int;
+
+  auto AddBlock(Block block) -> bool;
+
+  auto GetBlock(int x, int y) -> Block;
+
+  auto RemoveBlock(int x, int y) -> bool;
+
+  auto MoveBlockAt(int x, int y, Direction dir) -> bool;
+
+  auto GetNextStates() -> std::vector<State>;
+};
+
+#endif

src/klotski.cpp

@@ -0,0 +1,130 @@
+#include "klotski.hpp"
+
+auto Block::Hash() -> int {
+  std::string s = std::format("{},{},{},{}", x, y, width, height);
+  return std::hash<std::string>{}(s);
+}
+
+auto Block::Invalid() -> Block const {
+  Block block = Block(0, 0, 1, 1, false);
+  block.width = 0;
+  block.height = 0;
+  return block;
+}
+
+auto Block::IsValid() -> bool { return width != 0 && height != 0; }
+
+auto Block::ToString() -> std::string {
+  if (target) {
+    return std::format("{}{}",
+                       static_cast<char>(width + static_cast<int>('a') - 1),
+                       static_cast<char>(height + static_cast<int>('a') - 1));
+  } else {
+    return std::format("{}{}", width, height);
+  }
+}
+
+auto Block::Covers(int xx, int yy) -> bool {
+  return xx >= x && xx < x + width && yy >= y && yy < y + height;
+}
+
+auto Block::Collides(const Block &other) -> bool {
+  return x < other.x + other.width && x + width > other.x &&
+         y < other.y + other.height && y + height > other.y;
+}
+
+auto State::Hash() -> int { return std::hash<std::string>{}(state); }
+
+auto State::AddBlock(Block block) -> bool {
+  if (block.x + block.width > width || block.y + block.height > height) {
+    return false;
+  }
+
+  for (Block b : *this) {
+    if (b.Collides(block)) {
+      return false;
+    }
+  }
+
+  int index = 4 + (width * block.y + block.x) * 2;
+  state.replace(index, 2, block.ToString());
+
+  return true;
+}
+
+auto State::GetBlock(int x, int y) -> Block {
+  if (x >= width || y >= height) {
+    return Block::Invalid();
+  }
+
+  for (Block b : *this) {
+    if (b.Covers(x, y)) {
+      return b;
+    }
+  }
+
+  return Block::Invalid();
+}
+
+auto State::RemoveBlock(int x, int y) -> bool {
+  Block b = GetBlock(x, y);
+  if (!b.IsValid()) {
+    return false;
+  }
+
+  int index = 4 + (width * b.y + b.x) * 2;
+  state.replace(index, 2, "..");
+
+  return true;
+}
+
+auto State::MoveBlockAt(int x, int y, Direction dir) -> bool {
+  Block block = GetBlock(x, y);
+  if (!block.IsValid()) {
+    return false;
+  }
+
+  // Get target block
+  int target_x = block.x;
+  int target_y = block.y;
+  switch (dir) {
+  case Direction::NOR:
+    if (target_y < 1) {
+      return false;
+    }
+    target_y--;
+    break;
+  case Direction::EAS:
+    if (target_x + block.width >= width) {
+      return false;
+    }
+    target_x++;
+    break;
+  case Direction::SOU:
+    if (target_y + block.height >= height) {
+      return false;
+    }
+    target_y++;
+    break;
+  case Direction::WES:
+    if (target_x < 1) {
+      return false;
+    }
+    target_x--;
+    break;
+  }
+  Block target =
+      Block(target_x, target_y, block.width, block.height, block.target);
+
+  // Check collisions
+  for (Block b : *this) {
+    if (b != block && b.Collides(target)) {
+      return false;
+    }
+  }
+
+  RemoveBlock(x, y);
+  AddBlock(target);
+
+  return true;
+}