path: root/src/save.c

#include "save.h"
#include "gba/eeprom.h"
#include "sound.h"
#include "menu.h"
#include "main.h"
#include "fileselect.h"

typedef struct SaveFileStatus {
    u16 checksum1;
    u16 checksum2;
    u32 status;
} SaveFileStatus;

typedef struct {
    u16 size;
    u16 checksum1;
    u16 checksum2;
    u16 address1;
    u16 address2;
} SaveFileEEPROMAddresses;

static SaveResult HandleSaveInit(u32);
static SaveResult HandleSaveInProgress(u32);
static SaveResult HandleSaveDone(u32);

const SaveFileEEPROMAddresses* GetSaveFileEEPROMAddresses(u32);
u32 DataDoubleReadWithStatus(u32, void* data);
u32 DataDoubleWriteWithStatus(u32, const void* data);
u32 VerifyChecksum(SaveFileStatus* fileStatus, u16* data, u32 size);
u16 CalculateChecksum(u16* data, u32);
u32 WriteSaveFile(u32 index, SaveFile* saveFile);
void SetFileStatusInit(u32 index);

u32 ReadSaveFileStatus(u32 address, SaveFileStatus* fileStatus);
u32 ParseSaveFileStatus(const SaveFileStatus* fileStatus);
u32 WriteSaveFileStatus(u32 address, const SaveFileStatus* fileStatus);

u32 DataRead(u32 address, void* data, u32 size);
u32 DataWrite(u32 address, const void* data, u32 size);
u32 DataCompare(u32 address, const void* data, u32 size);

const char gUnk_0811E470[4] = "LINK";

#if defined(DEMO_USA) || defined(DEMO_JP)
const u8 demoUnknown0 = 0x0;
#ifdef DEMO_USA
const u8 demoUnknown1[] = {
    // demo_timer for the three save files
    0x0f, 0x0a, 0x0a, // gUnk_02000010.field_0x7 == 0
    0x0f, 0x0f, 0x0f, // gUnk_02000010.field_0x7 == 1
    0x08, 0x05, 0x05, // gUnk_02000010.field_0x7 == 2
    0x00, 0x00
};
#else
const u8 demoUnknown1[] = { 0 };
#endif
#else
const u8 padding[2] = { 0, 0 };
#endif

static SaveResult (*const sSaveHandlers[])(u32) = { HandleSaveInit, HandleSaveInProgress, HandleSaveDone };

#if defined(DEMO_USA) || defined(DEMO_JP)

#ifdef DEMO_USA
asm("demoPointer1: .incbin \"demo/save1.bin\"");
asm("demoPointer2: .incbin \"demo/save2.bin\"");
asm("demoPointer3: .incbin \"demo/save3.bin\"");

extern const u8 demoPointer1[];
extern const u8 demoPointer2[];
extern const u8 demoPointer3[];

const u8* const demoPointers[] = { demoPointer1, demoPointer2, demoPointer3 };
#endif
#else

#if defined(JP) || defined(EU)
static const char sSignatureLong[32] = "AGBZELDA:THE MINISH CAP:ZELDA 3";
#else
static const char sSignatureLong[32] = "AGBZELDA:THE MINISH CAP:ZELDA 5";
#endif

// Save file is untouched
static const SaveFileStatus sSaveDescInit = { 0xffff, 0xffff, 'TINI' };
// Save file is deleted
static const SaveFileStatus sSaveDescDeleted = { 0xffff, 0xffff, 'FleD' };

const char sDummyData[8] = "DAMEDAME";
const SaveFileEEPROMAddresses gSaveFileEEPROMAddresses[] = { //
    // Save 0
    { 0x500, 0x30, 0x1030, 0x80, 0x1080 },
    // Save 1
    { 0x500, 0x40, 0x1040, 0x580, 0x1580 },
    // Save 2
    { 0x500, 0x50, 0x1050, 0xa80, 0x1a80 },
    // 3: Save Header
    { 0x10, 0x20, 0x1020, 0x70, 0x1070 },
    // 4: Signature (sSignatureLong)
    { 0x20, 0, 0, 0, 0x1000 },
    // 5: ? sub_0807CF3C, sub_0807CF1C, InitSaveData
    { 0x20, 0x60, 0x1060, 0xf80, 0x1f80 },
    // 6: ? unused?
    { 0x8, 0xfa0, 0x1fa0, 0xfa0, 0x1fa0 }
};
#endif

void sub_0807CD9C(void) {
    UpdateGlobalProgress();
}

SaveResult HandleSave(u32 action) {
    return sSaveHandlers[gMenu.storyPanelIndex](action);
}

SaveResult HandleSaveInit(u32 action) {
    gSoundPlayingInfo.volumeMasterTarget -= 8;
    if (gSoundPlayingInfo.volumeMaster <= 0) {
        gMenu.field_0xa = 8;
        gMenu.storyPanelIndex = SAVE_IN_PROGRESS;
    }
    return SAVE_BUSY;
}

SaveResult HandleSaveInProgress(u32 action) {
    u32 temp;

    if (gMenu.field_0xa == 0) {
        InitDMA();
        switch (action) {
            case 0:
                temp = WriteSaveFile(gSaveHeader->saveFileId, &gSave);
                break;
            case 1:
                SetFileStatusDeleted(gSaveHeader->saveFileId);
                temp = 1;
                break;
            case 2:
                temp = WriteSaveHeader(gSaveHeader);
                break;
        }
        gMenu.field_0xa = temp;
        gMenu.storyPanelIndex = SAVE_DONE;
        InitVBlankDMA();
    } else {
        gMenu.field_0xa--;
    }
    return SAVE_BUSY;
}

SaveResult HandleSaveDone(u32 action) {
    SaveResult result;

    result = SAVE_BUSY;
    gSoundPlayingInfo.volumeMasterTarget += 8;
    if (gSoundPlayingInfo.volumeMasterUnk <= gSoundPlayingInfo.volumeMasterTarget) {
        gSoundPlayingInfo.volumeMasterTarget = gSoundPlayingInfo.volumeMasterUnk;
        sub_08050384();
        gMenu.storyPanelIndex = SAVE_INIT;
        if (gMenu.field_0xa == 1) {
            result = SAVE_OK;
        } else {
            result = SAVE_ERROR;
        }
    }
    return result;
}

u32 InitSaveData(void) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    CpuSet(NULL, &gSave, 0x4b4);
    return 1;
#else
    const SaveFileEEPROMAddresses* eepromAddresses;
    u32 error;

    EEPROMConfigure(0x40);
    eepromAddresses = GetSaveFileEEPROMAddresses(4);
    error = 0;
    if (DataCompare(eepromAddresses->address1, sSignatureLong, eepromAddresses->size) == 0) {
        error++;
    }
    if (DataCompare(eepromAddresses->address2, sSignatureLong, eepromAddresses->size) == 0) {
        error += 2;
    }
    if (error != 0) {
        if (error == 3) {
            SetFileStatusInit(5);
            SetFileStatusInit(3);
            SetFileStatusInit(2);
            SetFileStatusInit(1);
            SetFileStatusInit(0);
        }
        DataWrite(eepromAddresses->address2, sSignatureLong, eepromAddresses->size);
        DataWrite(eepromAddresses->address1, sSignatureLong, eepromAddresses->size);
    }
    return 1;
#endif
}

u32 WriteSaveFile(u32 index, SaveFile* saveFile) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 1;
#else
    return DataDoubleWriteWithStatus(index, saveFile);
#endif
}

u32 WriteSaveHeader(SaveHeader* saveHeader) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 1;
#else
    return DataDoubleWriteWithStatus(3, saveHeader);
#endif
}

u32 sub_0807CF1C(u8* arg0) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 1;
#else
    return DataDoubleWriteWithStatus(5, arg0);
#endif
}

s32 ReadSaveFile(u32 index, SaveFile* saveFile) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 1;
#else
    return DataDoubleReadWithStatus(index, saveFile);
#endif
}

u32 ReadSaveHeader(SaveHeader* saveHeader) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 0;
#else
    return DataDoubleReadWithStatus(3, saveHeader);
#endif
}

u32 sub_0807CF3C(u8* arg0) {
#if defined(DEMO_USA) || defined(DEMO_JP)
    return 0;
#else
    return DataDoubleReadWithStatus(5, arg0);
#endif
}

void SetFileStatusDeleted(u32 index) {
#if !(defined(DEMO_USA) || defined(DEMO_JP))
    const SaveFileEEPROMAddresses* eepromAddresses;

    eepromAddresses = GetSaveFileEEPROMAddresses(index);
    WriteSaveFileStatus(eepromAddresses->checksum2, &sSaveDescDeleted);
    WriteSaveFileStatus(eepromAddresses->checksum1, &sSaveDescDeleted);
#endif
}

#if !(defined(DEMO_USA) || defined(DEMO_JP))
void SetFileStatusInit(u32 index) {
    const SaveFileEEPROMAddresses* eepromAddresses;
    const SaveFileStatus* fileStatus;

    eepromAddresses = GetSaveFileEEPROMAddresses(index);
    fileStatus = &sSaveDescInit;
    WriteSaveFileStatus(eepromAddresses->checksum2, fileStatus);
    WriteSaveFileStatus(eepromAddresses->checksum1, fileStatus);
}

u32 DataDoubleWriteWithStatus(u32 index, const void* data) {
    SaveFileStatus fileStatus;

    u32 ret;
    const SaveFileEEPROMAddresses* eepromAddresses;
    bool32 write1success, write2success;
    u16 checksum;

    eepromAddresses = GetSaveFileEEPROMAddresses(index);

    fileStatus.status = 'MCZ3';
    checksum = CalculateChecksum((u16*)&fileStatus.status, 4);
    checksum += CalculateChecksum((u16*)data, eepromAddresses->size);
    fileStatus.checksum1 = checksum;
    fileStatus.checksum2 = -(u32)checksum;
    write1success = DataWrite(eepromAddresses->address1, data, eepromAddresses->size);
    if (write1success) {
        write1success = WriteSaveFileStatus(eepromAddresses->checksum1, &fileStatus);
    }
    write2success = DataWrite(eepromAddresses->address2, data, eepromAddresses->size);
    if (write2success) {
        write2success = WriteSaveFileStatus(eepromAddresses->checksum2, &fileStatus);
    }

    ret = 0;
    if (write1success || write2success) {
        ret = 1;
    }
    return ret;
}

u32 DataDoubleReadWithStatus(u32 index, void* data) {
    vu32 set_0;
    SaveFileStatus fileStatus;

    const SaveFileEEPROMAddresses* eepromAddresses;
    u32 read1status;
    u32 read2status;
    u32 ret;
    u32 temp;

    eepromAddresses = GetSaveFileEEPROMAddresses(index);
    read1status = ReadSaveFileStatus(eepromAddresses->checksum1, &fileStatus);
    if (read1status == 2) {
        if ((DataRead(eepromAddresses->address1, data, eepromAddresses->size) == 0) ||
            (VerifyChecksum(&fileStatus, (u16*)data, eepromAddresses->size) == 0)) {
            // read 1 failed
            read1status = 0;
        } else {
            return 1;
        }
    }
    read2status = ReadSaveFileStatus(eepromAddresses->checksum2, &fileStatus);
    if (read2status == 2) {
        if ((DataRead(eepromAddresses->address2, data, eepromAddresses->size) != 0) &&
            (VerifyChecksum(&fileStatus, (u16*)data, (u32)eepromAddresses->size) != 0)) {
            return 1;
        }
        // read 2 failed
        read2status = 0;
    }
    set_0 = 0;
    CpuSet((u16*)&set_0, data, eepromAddresses->size >> 2 | CPU_SET_SRC_FIXED | CPU_SET_32BIT);
    temp = read1status | read2status;
    ret = 0;
    if (temp == 0) {
        ret = -1; // both reads failed
    }
    return ret;
}

u32 VerifyChecksum(SaveFileStatus* fileStatus, u16* data, u32 size) {
    u32 temp;
    u16 checksum;

    checksum = CalculateChecksum((u16*)&fileStatus->status, 4);
    checksum += CalculateChecksum(data, size);

    if ((fileStatus->checksum1 != checksum) ||
        (temp = fileStatus->checksum1 << 0x10, fileStatus->checksum2 != (-temp >> 0x10)) ||
        (fileStatus->status != 'MCZ3')) {
        return 0;
    } else
        return 1;
}

u32 ReadSaveFileStatus(u32 address, SaveFileStatus* fileStatus) {
    u32 ret;

    if (!DataRead(address, fileStatus, 8)) {
        ret = 0;
    } else {
        ret = ParseSaveFileStatus(fileStatus);
    }
    if (!ret && DataRead(address + 8, fileStatus, 8)) {
        ret = ParseSaveFileStatus(fileStatus);
    }
    return ret;
}

/**
 * 2 for valid existing file
 * 1 for valid empty file
 * 0 for bad file
 * @param fileStatus
 * @return
 */
u32 ParseSaveFileStatus(const SaveFileStatus* fileStatus) {
    u32 ret;
    switch (fileStatus->status) {
        case 'MCZ3':
            if (fileStatus->checksum1 + fileStatus->checksum2 == 0x10000) {
                ret = 2;
            } else {
                ret = 0;
            }
            break;
        case 'FleD':
        case 'TINI':
            ret = 0;
            if ((fileStatus->checksum1 & fileStatus->checksum2) == 0xffff) {
                ret = 1;
            }
            break;
        default:
            ret = 0;
            break;
    }
    return ret;
}

bool32 WriteSaveFileStatus(u32 address, const struct SaveFileStatus* fileStatus) {
    bool32 success;

    success = DataWrite(address, fileStatus, 8);
    if (!success) {
        success = DataWrite(address + 8, fileStatus, 8);
    }
    return success;
}

u16 CalculateChecksum(u16* data, u32 size) {
    u32 checksum;

    checksum = 0;
    while (size != 0) {
        checksum += (*data ^ size);
        data++;
        size = size - 2;
    }
    return checksum;
}

const SaveFileEEPROMAddresses* GetSaveFileEEPROMAddresses(u32 index) {
    return &gSaveFileEEPROMAddresses[index];
}

/**
 * read arbitrary data from EEPROM
 * @param address EEPROM address
 * @param data buffer to read into
 * @param size size in bytes to read
 * @return TRUE on success
 */
bool32 DataRead(u32 address, void* data, u32 size) {
    size /= 8;
    address /= 8;
    while (size-- > 0) {
        if (EEPROMRead(address, data))
            return FALSE;
        address++;
        data += 8;
    }
    return TRUE;
}

/**
 * write arbitrary data to EEPROM
 * @param address EEPROM address
 * @param data buffer to write from
 * @param size size in bytes to write
 * @return TRUE on success
 */
bool32 DataWrite(u32 address, const void* data, u32 size) {
    size /= 8;
    address /= 8;
    while (size-- > 0) {
        if (EEPROMWrite0_8k_Check(address, data)) {
            EEPROMWrite0_8k_Check(address, (const u16*)sDummyData);
            return FALSE;
        }
        address++;
        data += 8;
    }
    return TRUE;
}

/**
 * compare arbitrary data with EEPROM
 * @param address EEPROM address
 * @param data buffer to compare to
 * @param size size in bytes to compare
 * @return TRUE on success
 */
bool32 DataCompare(u32 address, const void* data, u32 size) {
    size /= 8;
    address /= 8;
    while (size-- > 0) {
        if (EEPROMCompare(address, data))
            return FALSE;
        address++;
        data += 8;
    }
    return TRUE;
}
#endif