decrypt Ep3 player config at load time

src/Episode3/DataIndexes.cc

@@ -1177,6 +1177,19 @@ void PlayerConfig::encrypt(uint8_t basis) {
   this->basis = basis;
 }
 
+bool PlayerConfig::card_count_checksums_correct() const {
+  for (size_t z = 0; z < this->card_count_checksums.size(); z++) {
+    uint16_t checksum_value = 0;
+    for (size_t w = 0; w < 20; w++) {
+      checksum_value += reinterpret_cast<const uint8_t*>(&this->card_counts)[z * 50 + w];
+    }
+    if (this->card_count_checksums[z] != checksum_value) {
+      return false;
+    }
+  }
+  return true;
+}
+
 PlayerConfigNTE::PlayerConfigNTE(const PlayerConfig& config)
     : rank_text(config.rank_text),
       unknown_a1(config.unknown_a1),

src/Episode3/DataIndexes.hh

@@ -865,7 +865,8 @@ struct PlayerConfig {
   /* 0138:---- */ PlayerRecordsBattleBE unused_offline_records;
   /* 0150:---- */ parray<uint8_t, 4> unknown_a4;
   // The PlayerDataSegment structure begins here. In newserv, we combine this
-  // structure into PlayerConfig since the two are always used together.
+  // structure into PlayerConfig since the two are always used together on the
+  // server side.
   /* 0154:0000 */ uint8_t is_encrypted;
   /* 0155:0001 */ uint8_t basis;
   /* 0156:0002 */ parray<uint8_t, 2> unused;
@@ -938,6 +939,8 @@ struct PlayerConfig {
 
   void decrypt();
   void encrypt(uint8_t basis);
+
+  bool card_count_checksums_correct() const;
 } __packed_ws__(PlayerConfig, 0x2350);
 
 struct PlayerConfigNTE {