nestopia/source/core/NstPatcherIps.cpp
2012-09-02 13:13:55 -04:00

364 lines
7.2 KiB
C++

////////////////////////////////////////////////////////////////////////////////////////
//
// Nestopia - NES/Famicom emulator written in C++
//
// Copyright (C) 2003-2008 Martin Freij
//
// This file is part of Nestopia.
//
// Nestopia 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 2 of the License, or
// (at your option) any later version.
//
// Nestopia 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 Nestopia; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
////////////////////////////////////////////////////////////////////////////////////////
#include <new>
#include <cstring>
#include <iosfwd>
#include "NstStream.hpp"
#include "NstPatcherIps.hpp"
namespace Nes
{
namespace Core
{
Ips::~Ips()
{
Destroy();
}
bool Ips::IsIps(std::istream& stream)
{
try
{
byte data[5];
Stream::In(&stream).Peek( data, 5 );
return
(
data[0] == Ascii<'P'>::V &&
data[1] == Ascii<'A'>::V &&
data[2] == Ascii<'T'>::V &&
data[3] == Ascii<'C'>::V &&
data[4] == Ascii<'H'>::V
);
}
catch (...)
{
return false;
}
}
Result Ips::Load(std::istream& stdStream)
{
Destroy();
if (!IsIps(stdStream))
return RESULT_ERR_INVALID_FILE;
try
{
Stream::In stream( &stdStream );
stream.Seek( 5 );
while (!stream.Eof())
{
byte data[4];
stream.Read( data, 3 );
if
(
data[0] == Ascii<'E'>::V &&
data[1] == Ascii<'O'>::V &&
data[2] == Ascii<'F'>::V
)
break;
blocks.push_back(Block());
Block& block = blocks.back();
block.data = NULL;
block.offset = dword(data[0]) << 16 | uint(data[1]) << 8 | data[2];
stream.Read( data, 2 );
block.length = uint(data[0]) << 8 | data[1];
if (block.length)
{
block.fill = NO_FILL;
block.data = new byte [block.length];
stream.Read( block.data, block.length );
}
else
{
stream.Read( data, 2 );
block.length = uint(data[0]) << 8 | data[1];
if (block.length)
block.fill = stream.Read8();
else
throw RESULT_ERR_CORRUPT_FILE;
}
}
}
catch (Result result)
{
Destroy();
return result;
}
catch (const std::bad_alloc&)
{
Destroy();
return RESULT_ERR_OUT_OF_MEMORY;
}
catch (...)
{
Destroy();
return RESULT_ERR_GENERIC;
}
return RESULT_OK;
}
Result Ips::Save(std::ostream& stdStream) const
{
try
{
Stream::Out stream( &stdStream );
byte data[8];
data[0] = Ascii<'P'>::V;
data[1] = Ascii<'A'>::V;
data[2] = Ascii<'T'>::V;
data[3] = Ascii<'C'>::V;
data[4] = Ascii<'H'>::V;
stream.Write( data, 5 );
for (Blocks::const_iterator it(blocks.begin()), end(blocks.end()); it != end; ++it)
{
data[0] = it->offset >> 16 & 0xFF;
data[1] = it->offset >> 8 & 0xFF;
data[2] = it->offset >> 0 & 0xFF;
stream.Write( data, 3 );
if (it->fill != NO_FILL)
{
data[0] = 0;
data[1] = 0;
stream.Write( data, 2 );
}
data[0] = it->length >> 8 & 0xFF;
data[1] = it->length >> 0 & 0xFF;
stream.Write( data, 2 );
if (it->fill == NO_FILL)
stream.Write( it->data, it->length );
else
stream.Write8( it->fill );
}
data[0] = Ascii<'E'>::V;
data[1] = Ascii<'O'>::V;
data[2] = Ascii<'F'>::V;
stream.Write( data, 3 );
}
catch (Result result)
{
return result;
}
catch (const std::bad_alloc&)
{
return RESULT_ERR_OUT_OF_MEMORY;
}
catch (...)
{
return RESULT_ERR_GENERIC;
}
return RESULT_OK;
}
Result Ips::Test(std::istream&) const
{
return RESULT_OK;
}
Result Ips::Test(const byte*,dword) const
{
return RESULT_OK;
}
bool Ips::Patch(const byte* const src,byte* const dst,const dword length,const dword offset) const
{
NST_ASSERT( !length || (src && dst) );
bool patched = false;
if (length)
{
if (src != dst)
std::memcpy( dst, src, length );
for (Blocks::const_iterator it(blocks.begin()), end(blocks.end()); it != end; ++it)
{
NST_ASSERT( it->length );
if (it->offset < offset)
continue;
if (it->offset >= offset + length)
break;
const dword pos = it->offset - offset;
const dword part = NST_MIN(it->length,length-pos);
if (it->fill == NO_FILL)
std::memcpy( dst + pos, it->data, part );
else
std::memset( dst + pos, it->fill, part );
patched = true;
}
}
return patched;
}
Result Ips::Create(const byte* const src,const byte* const dst,const dword length)
{
NST_ASSERT( !length || (src && dst) );
Destroy();
try
{
for (dword i=0; i < length; )
{
dword j = i++;
if (src[j] == dst[j])
continue;
for (dword k=0; i < length; ++i)
{
if (src[i] != dst[i])
{
k = 0;
}
else if (k++ == MIN_EQUAL)
{
i -= MIN_EQUAL;
break;
}
}
do
{
if (j == AsciiId<'F','O','E'>::V)
--j;
blocks.push_back(Block());
Block& block = blocks.back();
block.data = NULL;
block.offset = j;
uint c = dst[j];
dword k = j;
const dword stop = NST_MIN(j + MAX_BLOCK,i);
while (++k != stop && c == dst[k]);
if (k - j >= MIN_BEG_RUN)
{
block.fill = c;
block.length = k - j;
}
else
{
dword l = k;
if (k + 1 < stop)
{
c = dst[k];
for (l=k++; k < stop; ++k)
{
if (c != dst[k])
{
c = dst[k];
l = k;
}
else if (k - l == MIN_MID_RUN)
{
k = l;
break;
}
}
}
if (k == stop && k - l >= MIN_END_RUN)
k = l;
if (k == AsciiId<'F','O','E'>::V)
++k;
block.fill = NO_FILL;
block.length = k - j;
block.data = new byte [block.length];
std::memcpy( block.data, dst + j, block.length );
}
j = k;
}
while (j != i);
}
}
catch (Result result)
{
Destroy();
return result;
}
catch (const std::bad_alloc&)
{
Destroy();
return RESULT_ERR_OUT_OF_MEMORY;
}
catch (...)
{
Destroy();
return RESULT_ERR_GENERIC;
}
return RESULT_OK;
}
void Ips::Destroy()
{
for (Blocks::iterator it(blocks.begin()), end(blocks.end()); it != end; ++it)
delete [] it->data;
blocks.clear();
}
}
}