write battle/challenge records structures

src/PSOEncryption.cc

@@ -885,3 +885,44 @@ void decrypt_trivial_gci_data(void* data, size_t size, uint8_t basis) {
     bytes[z] ^= key;
   }
 }
+
+template <typename StringT, bool IsEncrypt>
+StringT crypt_challenge_rank_text(const void* src, size_t size) {
+  if (size == 0) {
+    return StringT();
+  }
+
+  StringT ret;
+  StringReader r(src, size);
+  typename StringT::value_type prev = 0;
+  while (!r.eof()) {
+    typename StringT::value_type ch = r.get<typename StringT::value_type>();
+    if (ch == 0) {
+      break;
+    }
+    if (ret.empty()) {
+      ret.push_back(ch ^ 0x7F);
+    } else {
+      ret.push_back(IsEncrypt ? ((ch - prev) ^ 0x7F) : ((ch ^ 0x7F) + ret.back()));
+    }
+    prev = ch;
+  }
+
+  return ret;
+}
+
+string encrypt_challenge_rank_text(const uint8_t* src, size_t size) {
+  return crypt_challenge_rank_text<string, true>(src, size);
+}
+
+string decrypt_challenge_rank_text(const uint8_t* src, size_t size) {
+  return crypt_challenge_rank_text<string, false>(src, size);
+}
+
+u16string encrypt_challenge_rank_text(const char16_t* src, size_t size) {
+  return crypt_challenge_rank_text<u16string, true>(src, size);
+}
+
+u16string decrypt_challenge_rank_text(const char16_t* src, size_t size) {
+  return crypt_challenge_rank_text<u16string, false>(src, size);
+}