Support reading and writing the trainers' money from the save file.

It was implemented to be used for the Pokéshop idea for PokeMe64

examples/checkSave/main.cpp

@@ -55,12 +55,18 @@ int main(int argc, char** argv)
     {
         Gen1GameReader gameReader(romReader, saveManager, gen1Type);
         printf("%s", (gameReader.isMainChecksumValid()) ? "Game save valid!\n" : "Game save NOT valid!\n");
+        printf("OT: %u\n", gameReader.getTrainerID());
+        printf("Name: %s\n", gameReader.getTrainerName());
+        printf("Money: %u\n", gameReader.getTrainerMoney());
     }
     else if (gen2Type != Gen2GameType::INVALID)
     {
         Gen2GameReader gameReader(romReader, saveManager, gen2Type);
         printf("%s", (gameReader.isMainChecksumValid()) ? "Main save valid!\n" : "Main save NOT valid!\n");
         printf("%s", (gameReader.isBackupChecksumValid()) ? "Backup save valid!\n" : "Backup save NOT valid!\n");
+        printf("OT: %u\n", gameReader.getTrainerID());
+        printf("Name: %s\n", gameReader.getTrainerName());
+        printf("Money: %u\n", gameReader.getTrainerMoney());
     }
 
     free(romBuffer);

include/gen1/Gen1GameReader.h

@@ -86,6 +86,17 @@ public:
      */
     uint16_t getTrainerID() const;
 
+    /**
+     * @brief This function retrieves the amount of pokédollars the trainer currently has
+     */
+    uint32_t getTrainerMoney() const;
+
+    /**
+     * @brief Sets the amount of pokédollars the trainer currently has
+     * NOTE: the value is capped to 16777215 as this is the maximum value that can be represented by 3 bytes
+     */
+    void setTrainerMoney(uint32_t amount);
+
     /**
      * Retrieves the current map the player is in.
      */

include/gen1/Gen1Localization.h

@@ -76,6 +76,7 @@ typedef struct Gen1LocalizationRomOffsets
 typedef struct Gen1LocalizationSRAMOffsets
 {
     uint32_t trainerID;
+    uint32_t trainerMoney;
     uint32_t currentMap;
     uint32_t dexSeen;
     uint32_t dexOwned;

include/gen2/Gen2GameReader.h

@@ -131,6 +131,18 @@ public:
      */
     const char *getTrainerName() const;
 
+    /**
+     * @brief This function retrieves the amount of pokédollars the trainer currently has
+     */
+    uint32_t getTrainerMoney() const;
+
+    /**
+     * @brief Sets the amount of pokédollars the trainer currently has
+     * NOTE: the value is capped to 16777215 as this is the maximum value that can be represented by 3 bytes
+     */
+    void setTrainerMoney(uint32_t amount);
+
+
     /**
      * @brief Get the rival name from the save file
      * Note: the resulting const char* does not need to be free'd.

include/gen2/Gen2Localization.h

@@ -69,6 +69,7 @@ typedef struct Gen2LocalizationSRAMOffsets
     uint32_t currentBox;
     uint32_t dexSeen;
     uint32_t dexOwned;
+    uint32_t trainerMoney;
     uint32_t party;
     uint32_t eventFlags;
     uint32_t mainChecksum;

src/gen1/Gen1GameReader.cpp

@@ -10,7 +10,7 @@
 /**
  * @brief This function calculates the main data checksum
  */
-uint8_t calculateMainDataChecksum(ISaveManager& saveManager, Gen1LocalizationLanguage localization)
+static uint8_t calculateMainDataChecksum(ISaveManager& saveManager, Gen1LocalizationLanguage localization)
 {
     Gen1Checksum checksum;
     const uint32_t checksummedDataStart = 0x2598;
@@ -30,7 +30,7 @@ uint8_t calculateMainDataChecksum(ISaveManager& saveManager, Gen1LocalizationLan
     return checksum.get();
 }
 
-uint8_t calculateWholeBoxBankChecksum(ISaveManager& saveManager, uint8_t bankIndex)
+static uint8_t calculateWholeBoxBankChecksum(ISaveManager& saveManager, uint8_t bankIndex)
 {
     Gen1Checksum checksum;
     const uint16_t checksummedDataStart = 0x0;
@@ -49,6 +49,50 @@ uint8_t calculateWholeBoxBankChecksum(ISaveManager& saveManager, uint8_t bankInd
     return checksum.get();
 }
 
+/**
+ * @brief This function decodes a binary coded decimal number stored in big endian format.
+ * (see: https://en.wikipedia.org/wiki/Binary-coded_decimal)
+ * It assumes 4 bits per digit and all digits are decimal (0-9)
+ * 
+ * @param bcdData the buffer containing the Binary coded decimal data
+ * @param numDigits number of digits in the buffer
+ */
+static uint32_t decodeBigEndianBinaryCodedDecimalNumber(const uint8_t *bcdData, uint8_t numDigits)
+{
+    uint32_t result = 0;
+    // The + 1 is because the division always rounds down.
+    // but we want to make sure that if there's an odd number of digits, we still process the last one
+    for(uint8_t i=0; i < (numDigits + 1) / 2; ++i)
+    {
+        const uint8_t upperNibble = (bcdData[i] >> 4);
+        const uint8_t lowerNibble = (bcdData[i] & 0xF);
+        result = (result * 100) + (upperNibble * 10) + lowerNibble;
+    }
+    return result;
+}
+
+/**
+ * @brief This function encodes a binary coded decimal number in big endian format.
+ * (see: https://en.wikipedia.org/wiki/Binary-coded_decimal)
+ * The output will use 4 bits per digit and all digits are decimal (0-9)
+ * 
+ * @param bcdData a buffer with sufficient size to hold the binary encoded decimal data
+ * @param numDigits number of digits to encode
+ */
+static void encodeBigEndianBinaryCodedDecimalNumber(uint32_t value, uint8_t *outBcdData, uint8_t numDigits)
+{
+    // since we're doing big endian, but we're extracting the digits from least significant to most significant,
+    // we need to fill the output buffer backwards
+    for(int8_t i = numDigits - 1; i >= 0; i -= 2)
+    {
+        const uint8_t lowerNibble = value % 10;
+        value /= 10;
+        const uint8_t upperNibble = value % 10;
+        value /= 10;
+        outBcdData[i] = (upperNibble << 4) | lowerNibble;
+    }
+}
+
 Gen1GameReader::Gen1GameReader(IRomReader &romReader, ISaveManager &saveManager, Gen1GameType gameType, Gen1LocalizationLanguage language)
     : romReader_(romReader)
     , saveManager_(saveManager)
@@ -347,6 +391,30 @@ uint16_t Gen1GameReader::getTrainerID() const
     return result;
 }
 
+uint32_t Gen1GameReader::getTrainerMoney() const
+{
+    const uint32_t savOffset = gen1_getSRAMOffsets(localization_).trainerMoney;
+    saveManager_.seek(savOffset);
+
+    uint8_t encodedAmount[3];
+    saveManager_.read(encodedAmount, 3);
+
+    // for gen 1, money is stored as a big-endian BCD number (source: https://bulbapedia.bulbagarden.net/wiki/Save_data_structure_(Generation_I)#Main_Data)
+    return decodeBigEndianBinaryCodedDecimalNumber(encodedAmount, 6);
+}
+
+void Gen1GameReader::setTrainerMoney(uint32_t amount)
+{
+    const uint32_t savOffset = gen1_getSRAMOffsets(localization_).trainerMoney;
+    saveManager_.seek(savOffset);
+
+    // for gen 1, money is stored as a big-endian BCD number (source: https://bulbapedia.bulbagarden.net/wiki/Save_data_structure_(Generation_I)#Main_Data)
+    uint8_t encodedAmount[3];
+    encodeBigEndianBinaryCodedDecimalNumber(amount, encodedAmount, 6);
+
+    saveManager_.write(encodedAmount, 3);
+}
+
 Gen1Maps Gen1GameReader::getCurrentMap() const
 {
     uint8_t result;

src/gen1/Gen1Localization.cpp

@@ -151,6 +151,7 @@ static const Gen1LocalizationRomOffsets g1_localizationROMOffsetsY[] = {
 
 static const Gen1LocalizationSRAMOffsets g1_sRAMOffsetsInternational = {
     .trainerID = 0x2605,
+    .trainerMoney = 0x25F3,
     .currentMap = 0x260A,
     .dexSeen = 0x25B6,
     .dexOwned = 0x25A3,
@@ -162,6 +163,7 @@ static const Gen1LocalizationSRAMOffsets g1_sRAMOffsetsInternational = {
 
 static const Gen1LocalizationSRAMOffsets g1_sRAMOffsetsJapan = {
     .trainerID = 0x25FB,
+    .trainerMoney = 0x25EE,
     .currentMap = 0x2600,
     .dexSeen = 0x25B1,
     .dexOwned = 0x259E,

src/gen2/Gen2GameReader.cpp

@@ -642,6 +642,24 @@ const char *Gen2GameReader::getTrainerName() const
     return result;
 }
 
+uint32_t Gen2GameReader::getTrainerMoney() const
+{
+    uint32_t result = 0;
+    const uint32_t savOffset = gen2_getSRAMOffsets(gameType_, localization_).trainerMoney;
+
+    saveManager_.seek(savOffset);
+    saveManager_.readUint24(result, Endianness::BIG);
+    return result;
+}
+
+void Gen2GameReader::setTrainerMoney(uint32_t amount)
+{
+    const uint32_t savOffset = gen2_getSRAMOffsets(gameType_, localization_).trainerMoney;
+
+    saveManager_.seek(savOffset);
+    saveManager_.writeUint24(amount, Endianness::BIG);
+}
+
 const char *Gen2GameReader::getRivalName() const
 {
     static char result[20];

src/gen2/Gen2Localization.cpp

@@ -222,6 +222,7 @@ static const Gen2LocalizationSRAMOffsets g2_dummySRAMOffsets = {
     .currentBox = 0,
     .dexSeen = 0,
     .dexOwned = 0,
+    .trainerMoney = 0,
     .party = 0,
     .eventFlags = 0,
     .mainChecksum = 0,
@@ -243,6 +244,7 @@ static const Gen2LocalizationSRAMOffsets g2_internationalSRAMOffsetsGS = {
     .currentBox = 0x2D6C,
     .dexSeen = 0x2A6C,
     .dexOwned = 0x2A4C,
+    .trainerMoney = 0x23DB,
     .party = 0x288A,
     .eventFlags = 0x261F,
     .mainChecksum = 0x2D69,
@@ -264,6 +266,7 @@ static const Gen2LocalizationSRAMOffsets g2_internationalSRAMOffsetsC = {
     .currentBox = 0x2D10,
     .dexSeen = 0x2A47,
     .dexOwned = 0x2A27,
+    .trainerMoney = 0x23DC,
     .party = 0x2865,
     .eventFlags = 0x2600,
     .mainChecksum = 0x2D0D,
@@ -297,6 +300,7 @@ static const Gen2LocalizationSRAMOffsets g2_localizationSRAMOffsetsGS[] = {
         .currentBox = 0x2DAE,
         .dexSeen = 0x2AAE,
         .dexOwned = 0x2A8E,
+        .trainerMoney = 0x23D3,
         .party = 0x28CC,
         .eventFlags = 0x25F7,
         .mainChecksum = 0x2DAB,
@@ -318,6 +322,7 @@ static const Gen2LocalizationSRAMOffsets g2_localizationSRAMOffsetsGS[] = {
         .currentBox = 0x2D10,
         .dexSeen = 0x29EE,
         .dexOwned = 0x29CE,
+        .trainerMoney = 0x23BC,
         .party = 0x283E,
         .eventFlags = 0x2600,
         .mainChecksum = 0x2D0D,
@@ -354,6 +359,7 @@ static const Gen2LocalizationSRAMOffsets g2_localizationSRAMOffsetsC[] = {
         .currentBox = 0x2D10,
         .dexSeen = 0x29CA,
         .dexOwned = 0x29AA,
+        .trainerMoney = 0x23BE,
         .party = 0x281A,
         .eventFlags = 0x25E2,
         .mainChecksum = 0x2D0D,