1 files changed, 88 insertions, 24 deletions

diff --git a/src/DSi_NAND.cpp b/src/DSi_NAND.cpp
index 4366ce6..912fee4 100644
--- a/src/DSi_NAND.cpp
+++ b/src/DSi_NAND.cpp
@@ -1,5 +1,5 @@
 /*
-    Copyright 2016-2021 Arisotura
+    Copyright 2016-2022 melonDS team
 
     This file is part of melonDS.
 
@@ -49,8 +49,48 @@ UINT FF_ReadNAND(BYTE* buf, LBA_t sector, UINT num);
 UINT FF_WriteNAND(BYTE* buf, LBA_t sector, UINT num);
 
 
-bool Init(FILE* nandfile, u8* es_keyY)
+bool Init(u8* es_keyY)
 {
+    CurFile = nullptr;
+
+    std::string nandpath = Platform::GetConfigString(Platform::DSi_NANDPath);
+    std::string instnand = nandpath + Platform::InstanceFileSuffix();
+
+    FILE* nandfile = Platform::OpenLocalFile(instnand, "r+b");
+    if ((!nandfile) && (Platform::InstanceID() > 0))
+    {
+        FILE* orig = Platform::OpenLocalFile(nandpath, "rb");
+        if (!orig)
+        {
+            printf("Failed to open DSi NAND\n");
+            return false;
+        }
+
+        fseek(orig, 0, SEEK_END);
+        long len = ftell(orig);
+        fseek(orig, 0, SEEK_SET);
+
+        nandfile = Platform::OpenLocalFile(instnand, "w+b");
+        if (nandfile)
+        {
+            u8* tmpbuf = new u8[0x10000];
+            for (long i = 0; i < len; i+=0x10000)
+            {
+                long blklen = 0x10000;
+                if ((i+blklen) > len) blklen = len-i;
+
+                fread(tmpbuf, blklen, 1, orig);
+                fwrite(tmpbuf, blklen, 1, nandfile);
+            }
+            delete[] tmpbuf;
+        }
+
+        fclose(orig);
+        fclose(nandfile);
+
+        nandfile = Platform::OpenLocalFile(instnand, "r+b");
+    }
+
     if (!nandfile)
         return false;
 
@@ -138,10 +178,17 @@ void DeInit()
     f_unmount("0:");
     ff_disk_close();
 
+    if (CurFile) fclose(CurFile);
     CurFile = nullptr;
 }
 
 
+FILE* GetFile()
+{
+    return CurFile;
+}
+
+
 void GetIDs(u8* emmc_cid, u64& consoleid)
 {
     memcpy(emmc_cid, eMMC_CID, 16);
@@ -919,29 +966,44 @@ bool CreateSaveFile(const char* path, u32 len)
     u32 clustersize, maxfiles, totsec16, fatsz16;
 
     // CHECKME!
-    // code inspired from https://github.com/JeffRuLz/TMFH/blob/master/arm9/src/sav.c
-    if (len < 573440)
-    {
-        clustersize = 512;
-        maxfiles = 16;
-    }
-    else if (len < 5472256)
+    // code inspired from https://github.com/Epicpkmn11/NTM/blob/master/arm9/src/sav.c
+    const u16 sectorsize = 0x200;
+
+    // fit maximum sectors for the size
+    const u16 maxsectors = len / sectorsize;
+    u16 tracksize = 1;
+    u16 headcount = 1;
+    u16 totsec16next = 0;
+    while (totsec16next <= maxsectors)
     {
-        clustersize = 2048;
-        maxfiles = 256;
+        totsec16next = tracksize * (headcount + 1) * (headcount + 1);
+        if (totsec16next <= maxsectors)
+        {
+            headcount++;
+            totsec16 = totsec16next;
+
+            tracksize++;
+            totsec16next = tracksize * headcount * headcount;
+            if (totsec16next <= maxsectors)
+            {
+                totsec16 = totsec16next;
+            }
+        }
     }
-    else
+    totsec16next = (tracksize + 1) * headcount * headcount;
+    if (totsec16next <= maxsectors)
     {
-        clustersize = 4096;
-        maxfiles = 256;
+        tracksize++;
+        totsec16 = totsec16next;
     }
 
-    if (len <= 0x4000)        fatsz16 = 1;
-    else if (len <= 0x200000) fatsz16 = 3;
-    else                      fatsz16 = 6;
+    maxfiles = len < 0x8C000 ? 0x20 : 0x200;
+    clustersize = (totsec16 > (8 << 10)) ? 8 : (totsec16 > (1 << 10) ? 4 : 1);
 
-    if (len == 0x4000) totsec16 = 27;
-    else               totsec16 = len >> 9;
+    #define ALIGN(v, a) (((v) % (a)) ? ((v) + (a) - ((v) % (a))) : (v))
+    u16 totalclusters = ALIGN(totsec16, clustersize) / clustersize;
+    u32 fatbytes = (ALIGN(totalclusters, 2) / 2) * 3; // 2 sectors -> 3 byte
+    fatsz16 = ALIGN(fatbytes, sectorsize) / sectorsize;
 
     FF_FIL file;
     FRESULT res;
@@ -960,17 +1022,19 @@ bool CreateSaveFile(const char* path, u32 len)
     // create FAT header
     data[0x000] = 0xE9;
     memcpy(&data[0x003], "MSWIN4.1", 8);
-    *(u16*)&data[0x00B] = 512; // bytes per sector
-    data[0x00D] = clustersize >> 9;
+    *(u16*)&data[0x00B] = sectorsize; // bytes per sector
+    data[0x00D] = clustersize;
     *(u16*)&data[0x00E] = 1; // reserved sectors
     data[0x010] = 2; // num FATs
-    *(u16*)&data[0x011] = maxfiles << 1;
+    *(u16*)&data[0x011] = maxfiles;
     *(u16*)&data[0x013] = totsec16;
     data[0x015] = 0xF8;
     *(u16*)&data[0x016] = fatsz16;
-    data[0x024] = 0x07;
+    *(u16*)&data[0x018] = tracksize;
+    *(u16*)&data[0x01A] = headcount;
+    data[0x024] = 0x05;
     data[0x026] = 0x29;
-    *(u32*)&data[0x027] = 305419896;
+    *(u32*)&data[0x027] = 0x12345678;
     memcpy(&data[0x02B], "VOLUMELABEL", 11);
     memcpy(&data[0x036], "FAT12   ", 8);
     *(u16*)&data[0x1FE] = 0xAA55;