1 files changed, 83 insertions, 0 deletions

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+// Godot save decoder algorithm by Chris Souvey.
+
+#include "godot_variant.h"
+
+#include <algorithm>
+#include <charconv>
+#include <cstddef>
+#include <fstream>
+#include <string>
+#include <tuple>
+#include <variant>
+#include <vector>
+
+namespace {
+
+uint16_t ReadUint16(std::basic_istream<char>& stream) {
+  uint16_t result;
+  stream.read(reinterpret_cast<char*>(&result), 2);
+  return result;
+}
+
+uint32_t ReadUint32(std::basic_istream<char>& stream) {
+  uint32_t result;
+  stream.read(reinterpret_cast<char*>(&result), 4);
+  return result;
+}
+
+GodotVariant ParseVariant(std::basic_istream<char>& stream) {
+  uint16_t type = ReadUint16(stream);
+  stream.ignore(2);
+
+  switch (type) {
+    case 1: {
+      // bool
+      bool boolval = (ReadUint32(stream) == 1);
+      return {boolval};
+    }
+    case 15: {
+      // nodepath
+      uint32_t name_length = ReadUint32(stream) & 0x7fffffff;
+      uint32_t subname_length = ReadUint32(stream) & 0x7fffffff;
+      uint32_t flags = ReadUint32(stream);
+
+      std::vector<std::string> result;
+      for (size_t i = 0; i < name_length + subname_length; i++) {
+        uint32_t char_length = ReadUint32(stream);
+        uint32_t padded_length = (char_length % 4 == 0)
+                                     ? char_length
+                                     : (char_length + 4 - (char_length % 4));
+        std::vector<char> next_bytes(padded_length);
+        stream.read(next_bytes.data(), padded_length);
+        std::string next_piece;
+        std::copy(next_bytes.begin(),
+                  std::next(next_bytes.begin(), char_length),
+                  std::back_inserter(next_piece));
+        result.push_back(next_piece);
+      }
+
+      return {result};
+    }
+    case 19: {
+      // array
+      uint32_t length = ReadUint32(stream) & 0x7fffffff;
+      std::vector<GodotVariant> result;
+      for (size_t i = 0; i < length; i++) {
+        result.push_back(ParseVariant(stream));
+      }
+      return {result};
+    }
+    default: {
+      // eh
+      return {std::monostate{}};
+    }
+  }
+}
+
+}  // namespace
+
+GodotVariant ParseGodotFile(std::string filename) {
+  std::ifstream file_stream(filename, std::ios_base::binary);
+  file_stream.ignore(4);
+  return ParseVariant(file_stream);
+}