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/*
Copyright 2016-2019 StapleButter
This file is part of melonDS.
melonDS is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option)
any later version.
melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with melonDS. If not, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include "Savestate.h"
#include "melon_fopen.h"
/*
Savestate format
header:
00 - magic MELN
04 - version major
06 - version minor
08 - length
0C - game serial
10 - ARM9 binary checksum
14 - ARM7 binary checksum
18 - reserved
1C - reserved
section header:
00 - section magic
04 - section length
08 - reserved
0C - reserved
Implementation details
version difference:
* different major means savestate file is incompatible
* different minor means adjustments may have to be made
*/
Savestate::Savestate(char* filename, bool save)
{
char* magic = "MELN";
Error = false;
if (save)
{
Saving = true;
file = melon_fopen(filename, "wb");
if (!file)
{
printf("savestate: file %s doesn't exist\n", filename);
Error = true;
return;
}
VersionMajor = SAVESTATE_MAJOR;
VersionMinor = SAVESTATE_MINOR;
fwrite(magic, 4, 1, file);
fwrite(&VersionMajor, 2, 1, file);
fwrite(&VersionMinor, 2, 1, file);
fseek(file, 8, SEEK_CUR); // length to be fixed later
}
else
{
Saving = false;
file = melon_fopen(filename, "rb");
if (!file)
{
printf("savestate: file %s doesn't exist\n", filename);
Error = true;
return;
}
u32 len;
fseek(file, 0, SEEK_END);
len = (u32)ftell(file);
fseek(file, 0, SEEK_SET);
u32 buf = 0;
fread(&buf, 4, 1, file);
if (buf != ((u32*)magic)[0])
{
printf("savestate: invalid magic %08X\n", buf);
Error = true;
return;
}
VersionMajor = 0;
VersionMinor = 0;
fread(&VersionMajor, 2, 1, file);
if (VersionMajor != SAVESTATE_MAJOR)
{
printf("savestate: bad version major %d, expecting %d\n", VersionMajor, SAVESTATE_MAJOR);
Error = true;
return;
}
fread(&VersionMinor, 2, 1, file);
// TODO: handle it???
buf = 0;
fread(&buf, 4, 1, file);
if (buf != len)
{
printf("savestate: bad length %d\n", buf);
Error = true;
return;
}
fseek(file, 4, SEEK_CUR);
}
CurSection = -1;
}
Savestate::~Savestate()
{
if (Error) return;
if (Saving)
{
if (CurSection != -1)
{
u32 pos = (u32)ftell(file);
fseek(file, CurSection+4, SEEK_SET);
u32 len = pos - CurSection;
fwrite(&len, 4, 1, file);
fseek(file, pos, SEEK_SET);
}
fseek(file, 0, SEEK_END);
u32 len = (u32)ftell(file);
fseek(file, 8, SEEK_SET);
fwrite(&len, 4, 1, file);
}
if (file) fclose(file);
}
void Savestate::Section(char* magic)
{
if (Error) return;
if (Saving)
{
if (CurSection != -1)
{
u32 pos = (u32)ftell(file);
fseek(file, CurSection+4, SEEK_SET);
u32 len = pos - CurSection;
fwrite(&len, 4, 1, file);
fseek(file, pos, SEEK_SET);
}
CurSection = (u32)ftell(file);
fwrite(magic, 4, 1, file);
fseek(file, 12, SEEK_CUR);
}
else
{
fseek(file, 0x10, SEEK_SET);
for (;;)
{
u32 buf = 0;
fread(&buf, 4, 1, file);
if (buf != ((u32*)magic)[0])
{
if (buf == 0)
{
printf("savestate: section %s not found. blarg\n", magic);
return;
}
buf = 0;
fread(&buf, 4, 1, file);
fseek(file, buf-8, SEEK_CUR);
continue;
}
fseek(file, 12, SEEK_CUR);
break;
}
}
}
void Savestate::Var8(u8* var)
{
if (Error) return;
if (Saving)
{
fwrite(var, 1, 1, file);
}
else
{
fread(var, 1, 1, file);
}
}
void Savestate::Var16(u16* var)
{
if (Error) return;
if (Saving)
{
fwrite(var, 2, 1, file);
}
else
{
fread(var, 2, 1, file);
}
}
void Savestate::Var32(u32* var)
{
if (Error) return;
if (Saving)
{
fwrite(var, 4, 1, file);
}
else
{
fread(var, 4, 1, file);
}
}
void Savestate::Var64(u64* var)
{
if (Error) return;
if (Saving)
{
fwrite(var, 8, 1, file);
}
else
{
fread(var, 8, 1, file);
}
}
void Savestate::VarArray(void* data, u32 len)
{
if (Error) return;
if (Saving)
{
fwrite(data, len, 1, file);
}
else
{
fread(data, len, 1, file);
}
}
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