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file_sys: Implement function to apply IPS patches
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88
src/core/file_sys/ips_layer.cpp
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88
src/core/file_sys/ips_layer.cpp
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@ -0,0 +1,88 @@
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// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#include "common/assert.h"
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#include "common/swap.h"
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#include "core/file_sys/ips_layer.h"
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#include "core/file_sys/vfs_vector.h"
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namespace FileSys {
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enum class IPSFileType {
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IPS,
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IPS32,
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Error,
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};
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static IPSFileType IdentifyMagic(const std::vector<u8>& magic) {
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if (magic.size() != 5)
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return IPSFileType::Error;
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if (magic == std::vector<u8>{'P', 'A', 'T', 'C', 'H'})
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return IPSFileType::IPS;
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if (magic == std::vector<u8>{'I', 'P', 'S', '3', '2'})
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return IPSFileType::IPS32;
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return IPSFileType::Error;
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}
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VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips) {
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if (in == nullptr || ips == nullptr)
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return nullptr;
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const auto type = IdentifyMagic(ips->ReadBytes(0x5));
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if (type == IPSFileType::Error)
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return nullptr;
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auto in_data = in->ReadAllBytes();
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std::vector<u8> temp(type == IPSFileType::IPS ? 3 : 4);
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u64 offset = 5; // After header
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while (ips->Read(temp.data(), temp.size(), offset) == temp.size()) {
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offset += temp.size();
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if (type == IPSFileType::IPS32 && temp == std::vector<u8>{'E', 'E', 'O', 'F'} ||
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type == IPSFileType::IPS && temp == std::vector<u8>{'E', 'O', 'F'}) {
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break;
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}
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u32 real_offset{};
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if (type == IPSFileType::IPS32)
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real_offset = (temp[0] << 24) | (temp[1] << 16) | (temp[2] << 8) | temp[3];
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else
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real_offset = (temp[0] << 16) | (temp[1] << 8) | temp[2];
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u16 data_size{};
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if (ips->ReadObject(&data_size, offset) != sizeof(u16))
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return nullptr;
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data_size = Common::swap16(data_size);
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offset += sizeof(u16);
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if (data_size == 0) { // RLE
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u16 rle_size{};
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if (ips->ReadObject(&rle_size, offset) != sizeof(u16))
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return nullptr;
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rle_size = Common::swap16(data_size);
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offset += sizeof(u16);
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const auto data = ips->ReadByte(offset++);
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if (data == boost::none)
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return nullptr;
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if (real_offset + rle_size > in_data.size())
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rle_size = in_data.size() - real_offset;
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std::memset(in_data.data() + real_offset, data.get(), rle_size);
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} else { // Standard Patch
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auto read = data_size;
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if (real_offset + read > in_data.size())
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read = in_data.size() - real_offset;
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if (ips->Read(in_data.data() + real_offset, read, offset) != data_size)
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return nullptr;
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offset += data_size;
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}
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}
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if (temp != std::vector<u8>{'E', 'E', 'O', 'F'} && temp != std::vector<u8>{'E', 'O', 'F'})
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return nullptr;
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return std::make_shared<VectorVfsFile>(in_data, in->GetName(), in->GetContainingDirectory());
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}
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} // namespace FileSys
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15
src/core/file_sys/ips_layer.h
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15
src/core/file_sys/ips_layer.h
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@ -0,0 +1,15 @@
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// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <memory>
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#include "core/file_sys/vfs.h"
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namespace FileSys {
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VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips);
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} // namespace FileSys
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