use 2mb pages

Signed-off-by: Caio Oliveira <caiooliveirafarias0@gmail.com>

src/common/fs/file.cpp

@@ -7,18 +7,25 @@
 #include <vector>
 
 #include "common/assert.h"
+#include "common/bit_util.h"
 #include "common/fs/file.h"
 #include "common/fs/fs.h"
+#include "common/fs/fs_types.h"
 #ifdef __ANDROID__
 #include "common/fs/fs_android.h"
 #endif
 #include "common/logging.h"
+#include "common/literals.h"
 
 #ifdef _WIN32
 #include <io.h>
 #include <share.h>
+#include <windows.h>
 #else
 #include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #endif
 
 #ifdef _MSC_VER
@@ -36,13 +43,13 @@ namespace {
 #ifdef _WIN32
 
 /**
- * Converts the file access mode and file type enums to a file access mode wide string.
- *
- * @param mode File access mode
- * @param type File type
- *
- * @returns A pointer to a wide string representing the file access mode.
- */
+* Converts the file access mode and file type enums to a file access mode wide string.
+*
+* @param mode File access mode
+* @param type File type
+*
+* @returns A pointer to a wide string representing the file access mode.
+*/
 [[nodiscard]] constexpr const wchar_t* AccessModeToWStr(FileAccessMode mode, FileType type) {
     switch (type) {
     case FileType::BinaryFile:
@@ -79,12 +86,12 @@ namespace {
 }
 
 /**
- * Converts the file-share access flag enum to a Windows defined file-share access flag.
- *
- * @param flag File-share access flag
- *
- * @returns Windows defined file-share access flag.
- */
+* Converts the file-share access flag enum to a Windows defined file-share access flag.
+*
+* @param flag File-share access flag
+*
+* @returns Windows defined file-share access flag.
+*/
 [[nodiscard]] constexpr int ToWindowsFileShareFlag(FileShareFlag flag) {
     switch (flag) {
     case FileShareFlag::ShareNone:
@@ -102,13 +109,13 @@ namespace {
 #else
 
 /**
- * Converts the file access mode and file type enums to a file access mode string.
- *
- * @param mode File access mode
- * @param type File type
- *
- * @returns A pointer to a string representing the file access mode.
- */
+* Converts the file access mode and file type enums to a file access mode string.
+*
+* @param mode File access mode
+* @param type File type
+*
+* @returns A pointer to a string representing the file access mode.
+*/
 [[nodiscard]] constexpr const char* AccessModeToStr(FileAccessMode mode, FileType type) {
     switch (type) {
     case FileType::BinaryFile:
@@ -147,12 +154,12 @@ namespace {
 #endif
 
 /**
- * Converts the seek origin enum to a seek origin integer.
- *
- * @param origin Seek origin
- *
- * @returns Seek origin integer.
- */
+* Converts the seek origin enum to a seek origin integer.
+*
+* @param origin Seek origin
+*
+* @returns Seek origin integer.
+*/
 [[nodiscard]] constexpr int ToSeekOrigin(SeekOrigin origin) {
     switch (origin) {
     case SeekOrigin::SetOrigin:
@@ -178,7 +185,7 @@ std::string ReadStringFromFile(const std::filesystem::path& path, FileType type)
 }
 
 size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
-                         std::string_view string) {
+                        std::string_view string) {
     if (Exists(path) && !IsFile(path)) {
         return 0;
     }
@@ -189,7 +196,7 @@ size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
 }
 
 size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
-                          std::string_view string) {
+                        std::string_view string) {
     if (Exists(path) && !IsFile(path)) {
         return 0;
     }
@@ -244,69 +251,189 @@ FileType IOFile::GetType() const {
     return file_type;
 }
 
+#if defined(__unix__)
+static int PlatformMapReadOnly(IOFile& io, const char* path) {
+    io.mmap_fd = open(path, O_RDONLY);
+    if (io.mmap_fd > 0) {
+        struct stat st;
+        fstat(io.mmap_fd, &st);
+        io.mmap_size = st.st_size;
+
+        int map_flags = MAP_PRIVATE;
+#ifdef MAP_PREFAULT_READ
+        // Prefaults reads so the final resulting pagetable from this big stupid mmap()
+        // isn't comically lazily loaded, we just coalesce everything in-place for our
+        // lovely mmap flags; if we didn't prefault the reads the page table will be
+        // constructed in-place (i.e on a read-by-read basis) causing lovely soft-faults
+        // which would nuke any performance gains.
+        //
+        // This of course incurs a cost in the initial mmap(2) call, but that is fine.
+        map_flags |= MAP_PREFAULT_READ;
+#endif
+#ifdef MAP_NOSYNC
+        // This causes physical media to not be synched to our file/memory
+        // This means that if the read-only file is written to, we won't see changes
+        // or we may see changes which are just funnily scattered, in any case
+        // this presumes the files won't be changed during execution
+        //
+        // Do not ever use this on write files (if we ever support that); this will create
+        // a fun amount of fragmentation on the disk.
+        map_flags |= MAP_NOSYNC;
+#endif
+#if defined(NDEBUG) && defined(MAP_NOCORE)
+        map_flags |= MAP_NOCORE;
+#endif
+#ifdef MAP_HUGE_2MB
+        map_flags |= MAP_HUGE_2MB; //2mb pages
+#elif defined(MAP_ALIGNED)
+        // File must be big enough that it's worth to super align. We can't just super-align every
+        // file otherwise we will run out of alignments for actually important files :)
+        // System doesn't guarantee a super alignment, but if it's available it will delete
+        // about 3 layers(?) of the TLB tree for each read/write.
+        // Again the cost of faults may make this negligible gains, but hey, we gotta work
+        // what we gotta work with.
+        map_flags |= MAP_ALIGNED(21); //2^21 = 2mb use 2MB pages
+#endif
+        io.mmap_base = (u8*)mmap(nullptr, io.mmap_size, PROT_READ, map_flags, io.mmap_fd, 0);
+        if (io.mmap_base == MAP_FAILED) {
+            close(io.mmap_fd);
+            io.mmap_fd = -1;
+        } else {
+            using namespace Common::Literals;
+            // For small files it is acceptable to use a full readahead
+            // See https://github.com/torvalds/linux/blob/e80d033851b3bc94c3d254ac66660ddd0a49d72c/include/linux/pagemap.h#L1392
+            if (u64(st.st_size) >= 256_MiB) {
+                posix_madvise(io.mmap_base, io.mmap_size, POSIX_MADV_RANDOM);
+            } else {
+                posix_madvise(io.mmap_base, io.mmap_size, POSIX_MADV_SEQUENTIAL);
+            }
+        }
+    }
+    return io.mmap_fd;
+}
+static void PlatformUnmap(IOFile& io) {
+    if (io.mmap_fd != -1) {
+        munmap(io.mmap_base, io.mmap_size);
+        close(io.mmap_fd);
+        io.mmap_fd = -1;
+    }
+}
+#elif defined(__APPLE__)
+// NO IMPLEMENTATION YET
+#else
+static int PlatformMapReadOnly(IOFile& io, const wchar_t* path) {
+    io.file_handle = CreateFileW(path, GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, nullptr);
+    if (HANDLE(io.file_handle) != INVALID_HANDLE_VALUE) {
+        io.mapping_handle = CreateFileMappingW(HANDLE(io.file_handle), nullptr, PAGE_READONLY, 0, 0, nullptr);
+        if (io.mapping_handle) {
+            io.mmap_base = (u8*)MapViewOfFile(HANDLE(io.mapping_handle), FILE_MAP_READ, 0, 0, 0);
+            if (io.mmap_base) {
+                _LARGE_INTEGER pvalue;
+                GetFileSizeEx(io.file_handle, &pvalue);
+                io.mmap_size = uint32_t(pvalue.QuadPart);
+            } else {
+                CloseHandle(io.mapping_handle);
+                CloseHandle(io.file_handle);
+                return -1;
+            }
+        } else {
+            CloseHandle(io.file_handle);
+            return -1;
+        }
+    }
+    return 0;
+}
+static void PlatformUnmap(IOFile& io) {
+    if(io.mapping_handle) {
+        if(io.mmap_base)
+            UnmapViewOfFile(HANDLE(io.mmap_base));
+        CloseHandle(HANDLE(io.mapping_handle));
+    }
+    if(io.file_handle != INVALID_HANDLE_VALUE)
+        CloseHandle(HANDLE(io.file_handle));
+}
+#endif
+
 void IOFile::Open(const fs::path& path, FileAccessMode mode, FileType type, FileShareFlag flag) {
     Close();
-
     file_path = path;
     file_access_mode = mode;
     file_type = type;
-
     errno = 0;
-
 #ifdef _WIN32
-    if (flag != FileShareFlag::ShareNone) {
-        file = _wfsopen(path.c_str(), AccessModeToWStr(mode, type), ToWindowsFileShareFlag(flag));
-    } else {
-        _wfopen_s(&file, path.c_str(), AccessModeToWStr(mode, type));
+    // TODO: this probably can use better logic but oh well I'm not a windowser
+    file_handle = nullptr;
+    if (type == FileType::BinaryFile && mode == FileAccessMode::Read) {
+        if (PlatformMapReadOnly(*this, path.c_str()) == -1) {
+            LOG_ERROR(Common_Filesystem, "Error mmap'ing file"); //: {}", path.c_str());
+        }
+    }
+    if (file_handle == nullptr) {
+        if (flag != FileShareFlag::ShareNone) {
+            file = _wfsopen(path.c_str(), AccessModeToWStr(mode, type), ToWindowsFileShareFlag(flag));
+        } else {
+            _wfopen_s(&file, path.c_str(), AccessModeToWStr(mode, type));
+        }
     }
 #elif __ANDROID__
     if (Android::IsContentUri(path)) {
         ASSERT_MSG(mode == FileAccessMode::Read, "Content URI file access is for read-only!");
-        const auto fd = Android::OpenContentUri(path, Android::OpenMode::Read);
-        if (fd != -1) {
-            file = fdopen(fd, "r");
-            const auto error_num = errno;
-            if (error_num != 0 && file == nullptr) {
-                LOG_ERROR(Common_Filesystem, "Error opening file: {}, error: {}", path.c_str(),
-                          strerror(error_num));
+        if (PlatformMapReadOnly(*this, path.c_str()) == -1) {
+            LOG_ERROR(Common_Filesystem, "Error mmap'ing file: {}", path.c_str());
+            int const fd = Android::OpenContentUri(path, Android::OpenMode::Read);
+            if (fd != -1) {
+                file = fdopen(fd, "r");
+                if (errno != 0 && file == nullptr)
+                    LOG_ERROR(Common_Filesystem, "Error opening file: {}, error: {}", path.c_str(), strerror(errno));
+            } else {
+                LOG_ERROR(Common_Filesystem, "Error opening file: {}", path.c_str());
             }
-        } else {
-            LOG_ERROR(Common_Filesystem, "Error opening file: {}", path.c_str());
         }
     } else {
         file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
     }
+#elif defined(__HAIKU__) || defined(__managarm__) || defined(__OPENORBIS__) || defined(__APPLE__)
+    file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
+#elif defined(__unix__)
+    if (type == FileType::BinaryFile && mode == FileAccessMode::Read) {
+        if (PlatformMapReadOnly(*this, path.c_str()) == -1) {
+            LOG_ERROR(Common_Filesystem, "Error mmap'ing file: {}", path.c_str());
+        }
+    }
+    if (mmap_fd == -1) {
+        file = std::fopen(path.c_str(), AccessModeToStr(mode, type)); // mmap(2) failed or simply we can't use it
+    }
 #else
+    // Some other fancy OS (ahem fucking Darwin/Mac OSX)
     file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
 #endif
-
     if (!IsOpen()) {
         const auto ec = std::error_code{errno, std::generic_category()};
         LOG_ERROR(Common_Filesystem, "Failed to open the file at path={}, ec_message={}",
-                  PathToUTF8String(file_path), ec.message());
+            PathToUTF8String(file_path), ec.message());
     }
 }
 
 void IOFile::Close() {
-    if (!IsOpen()) {
-        return;
+#if defined(__APPLE__)
+    // NO IMPLEMENTATION YET
+#else
+    PlatformUnmap(*this);
+#endif
+    if (file) {
+        errno = 0;
+        const auto close_result = std::fclose(file) == 0;
+        if (!close_result) {
+            const auto ec = std::error_code{errno, std::generic_category()};
+            LOG_ERROR(Common_Filesystem, "Failed to close the file at path={}, ec_message={}",
+                PathToUTF8String(file_path), ec.message());
+        }
+        file = nullptr;
     }
-
-    errno = 0;
-
-    const auto close_result = std::fclose(file) == 0;
-
-    if (!close_result) {
-        const auto ec = std::error_code{errno, std::generic_category()};
-        LOG_ERROR(Common_Filesystem, "Failed to close the file at path={}, ec_message={}",
-                  PathToUTF8String(file_path), ec.message());
-    }
-
-    file = nullptr;
 }
 
 bool IOFile::IsOpen() const {
-    return file != nullptr;
+    return file != nullptr || IsMappedFile();
 }
 
 std::string IOFile::ReadString(size_t length) const {
@@ -323,137 +450,132 @@ size_t IOFile::WriteString(std::span<const char> string) const {
 }
 
 bool IOFile::Flush() const {
-    if (!IsOpen()) {
-        return false;
+    ASSERT(!IsMappedFile());
+    if (file) {
+        errno = 0;
+        auto const flush_result = std::fflush(file) == 0;
+        if (!flush_result) {
+            const auto ec = std::error_code{errno, std::generic_category()};
+            LOG_ERROR(Common_Filesystem, "Failed to flush the file at path={}, ec_message={}",
+                PathToUTF8String(file_path), ec.message());
+        }
+        return flush_result;
     }
-
-    errno = 0;
-
-#ifdef _WIN32
-    const auto flush_result = std::fflush(file) == 0;
-#else
-    const auto flush_result = std::fflush(file) == 0;
-#endif
-
-    if (!flush_result) {
-        const auto ec = std::error_code{errno, std::generic_category()};
-        LOG_ERROR(Common_Filesystem, "Failed to flush the file at path={}, ec_message={}",
-                  PathToUTF8String(file_path), ec.message());
-    }
-
-    return flush_result;
+    return false;
 }
 
 bool IOFile::Commit() const {
-    if (!IsOpen()) {
-        return false;
-    }
-
-    errno = 0;
-
+    ASSERT(!IsMappedFile());
+    if (file) {
+        errno = 0;
 #ifdef _WIN32
-    const auto commit_result = std::fflush(file) == 0 && _commit(fileno(file)) == 0;
+        const auto commit_result = std::fflush(file) == 0 && _commit(fileno(file)) == 0;
 #else
-    const auto commit_result = std::fflush(file) == 0 && fsync(fileno(file)) == 0;
+        const auto commit_result = std::fflush(file) == 0 && fsync(fileno(file)) == 0;
 #endif
-
-    if (!commit_result) {
-        const auto ec = std::error_code{errno, std::generic_category()};
-        LOG_ERROR(Common_Filesystem, "Failed to commit the file at path={}, ec_message={}",
-                  PathToUTF8String(file_path), ec.message());
+        if (!commit_result) {
+            const auto ec = std::error_code{errno, std::generic_category()};
+            LOG_ERROR(Common_Filesystem, "Failed to commit the file at path={}, ec_message={}",
+                PathToUTF8String(file_path), ec.message());
+        }
+        return commit_result;
     }
-
-    return commit_result;
+    return false;
 }
 
 bool IOFile::SetSize(u64 size) const {
-    if (!IsOpen()) {
-        return false;
-    }
-
-    errno = 0;
-
+    ASSERT(!IsMappedFile());
+    if (file) {
+        errno = 0;
 #ifdef _WIN32
-    const auto set_size_result = _chsize_s(fileno(file), static_cast<s64>(size)) == 0;
+        const auto set_size_result = _chsize_s(fileno(file), s64(size)) == 0;
 #else
-    const auto set_size_result = ftruncate(fileno(file), static_cast<s64>(size)) == 0;
+        const auto set_size_result = ftruncate(fileno(file), s64(size)) == 0;
 #endif
-
-    if (!set_size_result) {
-        const auto ec = std::error_code{errno, std::generic_category()};
-        LOG_ERROR(Common_Filesystem, "Failed to resize the file at path={}, size={}, ec_message={}",
-                  PathToUTF8String(file_path), size, ec.message());
+        if (!set_size_result) {
+            const auto ec = std::error_code{errno, std::generic_category()};
+            LOG_ERROR(Common_Filesystem, "Failed to resize the file at path={}, size={}, ec_message={}",
+                PathToUTF8String(file_path), size, ec.message());
+        }
+        return set_size_result;
     }
-
-    return set_size_result;
+    return false;
 }
 
 u64 IOFile::GetSize() const {
-    if (!IsOpen()) {
-        return 0;
-    }
+    if (IsMappedFile())
+        return mmap_size;
+    if (file) {
+        // Flush any unwritten buffered data into the file prior to retrieving the file mmap_size.
+        std::fflush(file);
+#if __ANDROID__
+        u64 file_size = 0;
+        if (Android::IsContentUri(file_path)) {
+            file_size = Android::GetSize(file_path);
+        } else {
+            std::error_code ec;
 
-    // Flush any unwritten buffered data into the file prior to retrieving the file size.
-    std::fflush(file);
+            file_size = fs::file_size(file_path, ec);
 
-#ifdef __ANDROID__
-    u64 file_size = 0;
-    if (Android::IsContentUri(file_path)) {
-        file_size = Android::GetSize(file_path);
-    } else {
+            if (ec) {
+                LOG_ERROR(Common_Filesystem, "Failed to retrieve the file mmap_size of path={}, ec_message={}",
+                    PathToUTF8String(file_path), ec.message());
+                return 0;
+            }
+        }
+#else
         std::error_code ec;
-
-        file_size = fs::file_size(file_path, ec);
-
+        auto const file_size = fs::file_size(file_path, ec);
         if (ec) {
-            LOG_ERROR(Common_Filesystem,
-                      "Failed to retrieve the file size of path={}, ec_message={}",
-                      PathToUTF8String(file_path), ec.message());
+            LOG_ERROR(Common_Filesystem, "Failed to retrieve the file mmap_size of path={}, ec_message={}",
+                PathToUTF8String(file_path), ec.message());
             return 0;
         }
-    }
-#else
-    std::error_code ec;
-
-    const auto file_size = fs::file_size(file_path, ec);
-
-    if (ec) {
-        LOG_ERROR(Common_Filesystem, "Failed to retrieve the file size of path={}, ec_message={}",
-                  PathToUTF8String(file_path), ec.message());
-        return 0;
-    }
 #endif
-
-    return file_size;
+        return file_size;
+    }
+    return 0;
 }
 
 bool IOFile::Seek(s64 offset, SeekOrigin origin) const {
-    if (!IsOpen()) {
-        return false;
+    if (IsMappedFile()) {
+        // fuck you to whoever made this method const
+        switch (origin) {
+        case SeekOrigin::SetOrigin:
+            mmap_offset = s64(offset);
+            break;
+        case SeekOrigin::CurrentPosition:
+            mmap_offset += s64(offset);
+            break;
+        case SeekOrigin::End:
+            mmap_offset = s64(mmap_size) + s64(offset);
+            break;
+        }
+        return true;
     }
-
-    errno = 0;
-
-    const auto seek_result = fseeko(file, offset, ToSeekOrigin(origin)) == 0;
-
-    if (!seek_result) {
-        const auto ec = std::error_code{errno, std::generic_category()};
-        LOG_ERROR(Common_Filesystem,
-                  "Failed to seek the file at path={}, offset={}, origin={}, ec_message={}",
-                  PathToUTF8String(file_path), offset, origin, ec.message());
+    if (file) {
+        errno = 0;
+        const auto seek_result = fseeko(file, offset, ToSeekOrigin(origin)) == 0;
+        if (!seek_result) {
+            const auto ec = std::error_code{errno, std::generic_category()};
+            LOG_ERROR(Common_Filesystem, "Failed to seek the file at path={}, offset={}, origin={}, ec_message={}",
+                PathToUTF8String(file_path), offset, origin, ec.message());
+        }
+        return seek_result;
     }
-
-    return seek_result;
+    return false;
 }
 
 s64 IOFile::Tell() const {
-    if (!IsOpen()) {
-        return 0;
+    if (IsMappedFile()) {
+        errno = 0;
+        return s64(mmap_offset);
     }
-
-    errno = 0;
-
-    return ftello(file);
+    if (file) {
+        errno = 0;
+        return ftello(file);
+    }
+    return 0;
 }
 
 } // namespace Common::FS

src/common/fs/file.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <cstdio>
+#include <cstring>
 #include <filesystem>
 #include <span>
 #include <type_traits>
@@ -24,12 +25,12 @@ enum class SeekOrigin {
 };
 
 /**
- * Opens a file stream at path with the specified open mode.
- *
- * @param file_stream Reference to file stream
- * @param path Filesystem path
- * @param open_mode File stream open mode
- */
+* Opens a file stream at path with the specified open mode.
+*
+* @param file_stream Reference to file stream
+* @param path Filesystem path
+* @param open_mode File stream open mode
+*/
 template <typename FileStream>
 void OpenFileStream(FileStream& file_stream, const std::filesystem::path& path,
                     std::ios_base::openmode open_mode) {
@@ -48,14 +49,14 @@ void OpenFileStream(FileStream& file_stream, const Path& path, std::ios_base::op
 #endif
 
 /**
- * Reads an entire file at path and returns a string of the contents read from the file.
- * If the filesystem object at path is not a regular file, this function returns an empty string.
- *
- * @param path Filesystem path
- * @param type File type
- *
- * @returns A string of the contents read from the file.
- */
+* Reads an entire file at path and returns a string of the contents read from the file.
+* If the filesystem object at path is not a regular file, this function returns an empty string.
+*
+* @param path Filesystem path
+* @param type File type
+*
+* @returns A string of the contents read from the file.
+*/
 [[nodiscard]] std::string ReadStringFromFile(const std::filesystem::path& path, FileType type);
 
 #ifdef _WIN32
@@ -70,18 +71,18 @@ template <typename Path>
 #endif
 
 /**
- * Writes a string to a file at path and returns the number of characters successfully written.
- * If a file already exists at path, its contents will be erased.
- * If a file does not exist at path, it creates and opens a new empty file for writing.
- * If the filesystem object at path exists and is not a regular file, this function returns 0.
- *
- * @param path Filesystem path
- * @param type File type
- *
- * @returns Number of characters successfully written.
- */
+* Writes a string to a file at path and returns the number of characters successfully written.
+* If a file already exists at path, its contents will be erased.
+* If a file does not exist at path, it creates and opens a new empty file for writing.
+* If the filesystem object at path exists and is not a regular file, this function returns 0.
+*
+* @param path Filesystem path
+* @param type File type
+*
+* @returns Number of characters successfully written.
+*/
 [[nodiscard]] size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
-                                       std::string_view string);
+                                    std::string_view string);
 
 #ifdef _WIN32
 template <typename Path>
@@ -95,15 +96,15 @@ template <typename Path>
 #endif
 
 /**
- * Appends a string to a file at path and returns the number of characters successfully written.
- * If a file does not exist at path, it creates and opens a new empty file for appending.
- * If the filesystem object at path exists and is not a regular file, this function returns 0.
- *
- * @param path Filesystem path
- * @param type File type
- *
- * @returns Number of characters successfully written.
- */
+* Appends a string to a file at path and returns the number of characters successfully written.
+* If a file does not exist at path, it creates and opens a new empty file for appending.
+* If the filesystem object at path exists and is not a regular file, this function returns 0.
+*
+* @param path Filesystem path
+* @param type File type
+*
+* @returns Number of characters successfully written.
+*/
 [[nodiscard]] size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
                                         std::string_view string);
 
@@ -131,14 +132,14 @@ public:
                     FileShareFlag flag = FileShareFlag::ShareReadOnly);
 
     /**
-     * An IOFile is a lightweight wrapper on C Library file operations.
-     * Automatically closes an open file on the destruction of an IOFile object.
-     *
-     * @param path Filesystem path
-     * @param mode File access mode
-     * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
-     * @param flag (Windows only) File-share access flag, default is ShareReadOnly
-     */
+    * An IOFile is a lightweight wrapper on C Library file operations.
+    * Automatically closes an open file on the destruction of an IOFile object.
+    *
+    * @param path Filesystem path
+    * @param mode File access mode
+    * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
+    * @param flag (Windows only) File-share access flag, default is ShareReadOnly
+    */
     explicit IOFile(const std::filesystem::path& path, FileAccessMode mode,
                     FileType type = FileType::BinaryFile,
                     FileShareFlag flag = FileShareFlag::ShareReadOnly);
@@ -152,84 +153,70 @@ public:
     IOFile& operator=(IOFile&& other) noexcept;
 
     /**
-     * Gets the path of the file.
-     *
-     * @returns The path of the file.
-     */
+    * Gets the path of the file.
+    *
+    * @returns The path of the file.
+    */
     [[nodiscard]] std::filesystem::path GetPath() const;
 
     /**
-     * Gets the access mode of the file.
-     *
-     * @returns The access mode of the file.
-     */
+    * Gets the access mode of the file.
+    *
+    * @returns The access mode of the file.
+    */
     [[nodiscard]] FileAccessMode GetAccessMode() const;
 
     /**
-     * Gets the type of the file.
-     *
-     * @returns The type of the file.
-     */
+    * Gets the type of the file.
+    *
+    * @returns The type of the file.
+    */
     [[nodiscard]] FileType GetType() const;
 
     /**
-     * Opens a file at path with the specified file access mode.
-     * This function behaves differently depending on the FileAccessMode.
-     * These behaviors are documented in each enum value of FileAccessMode.
-     *
-     * @param path Filesystem path
-     * @param mode File access mode
-     * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
-     * @param flag (Windows only) File-share access flag, default is ShareReadOnly
-     */
+    * Opens a file at path with the specified file access mode.
+    * This function behaves differently depending on the FileAccessMode.
+    * These behaviors are documented in each enum value of FileAccessMode.
+    *
+    * @param path Filesystem path
+    * @param mode File access mode
+    * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
+    * @param flag (Windows only) File-share access flag, default is ShareReadOnly
+    */
     void Open(const std::filesystem::path& path, FileAccessMode mode,
-              FileType type = FileType::BinaryFile,
-              FileShareFlag flag = FileShareFlag::ShareReadOnly);
-
-// #ifdef _WIN32
-//     template <typename Path>
-//     void Open(const Path& path, FileAccessMode mode, FileType type = FileType::BinaryFile,
-//               FileShareFlag flag = FileShareFlag::ShareReadOnly) {
-//         using ValueType = typename Path::value_type;
-//         if constexpr (IsChar<ValueType>) {
-//             Open(ToU8String(path), mode, type, flag);
-//         } else {
-//             Open(std::filesystem::path{path}, mode, type, flag);
-//         }
-//     }
-// #endif
+            FileType type = FileType::BinaryFile,
+            FileShareFlag flag = FileShareFlag::ShareReadOnly);
 
     /// Closes the file if it is opened.
     void Close();
 
     /**
-     * Checks whether the file is open.
-     * Use this to check whether the calls to Open() or Close() succeeded.
-     *
-     * @returns True if the file is open, false otherwise.
-     */
+    * Checks whether the file is open.
+    * Use this to check whether the calls to Open() or Close() succeeded.
+    *
+    * @returns True if the file is open, false otherwise.
+    */
     [[nodiscard]] bool IsOpen() const;
 
     /**
-     * Helper function which deduces the value type of a contiguous STL container used in ReadSpan.
-     * If T is not a contiguous container as defined by the concept IsContiguousContainer, this
-     * calls ReadObject and T must be a trivially copyable object.
-     *
-     * See ReadSpan for more details if T is a contiguous container.
-     * See ReadObject for more details if T is a trivially copyable object.
-     *
-     * @tparam T Contiguous container or trivially copyable object
-     *
-     * @param data Container of T::value_type data or reference to object
-     *
-     * @returns Count of T::value_type data or objects successfully read.
-     */
+    * Helper function which deduces the value type of a contiguous STL container used in ReadSpan.
+    * If T is not a contiguous container as defined by the concept IsContiguousContainer, this
+    * calls ReadObject and T must be a trivially copyable object.
+    *
+    * See ReadSpan for more details if T is a contiguous container.
+    * See ReadObject for more details if T is a trivially copyable object.
+    *
+    * @tparam T Contiguous container or trivially copyable object
+    *
+    * @param data Container of T::value_type data or reference to object
+    *
+    * @returns Count of T::value_type data or objects successfully read.
+    */
     template <typename T>
     [[nodiscard]] size_t Read(T& data) const {
         if constexpr (IsContiguousContainer<T>) {
             using ContiguousType = typename T::value_type;
-            static_assert(std::is_trivially_copyable_v<ContiguousType>,
-                          "Data type must be trivially copyable.");
+            static_assert(std::is_trivially_copyable_v<ContiguousType>, "Data type must be trivially copyable.");
             return ReadSpan<ContiguousType>(data);
         } else {
             return ReadObject(data) ? 1 : 0;
@@ -237,25 +224,24 @@ public:
     }
 
     /**
-     * Helper function which deduces the value type of a contiguous STL container used in WriteSpan.
-     * If T is not a contiguous STL container as defined by the concept IsContiguousContainer, this
-     * calls WriteObject and T must be a trivially copyable object.
-     *
-     * See WriteSpan for more details if T is a contiguous container.
-     * See WriteObject for more details if T is a trivially copyable object.
-     *
-     * @tparam T Contiguous container or trivially copyable object
-     *
-     * @param data Container of T::value_type data or const reference to object
-     *
-     * @returns Count of T::value_type data or objects successfully written.
-     */
+    * Helper function which deduces the value type of a contiguous STL container used in WriteSpan.
+    * If T is not a contiguous STL container as defined by the concept IsContiguousContainer, this
+    * calls WriteObject and T must be a trivially copyable object.
+    *
+    * See WriteSpan for more details if T is a contiguous container.
+    * See WriteObject for more details if T is a trivially copyable object.
+    *
+    * @tparam T Contiguous container or trivially copyable object
+    *
+    * @param data Container of T::value_type data or const reference to object
+    *
+    * @returns Count of T::value_type data or objects successfully written.
+    */
     template <typename T>
     [[nodiscard]] size_t Write(const T& data) const {
         if constexpr (IsContiguousContainer<T>) {
             using ContiguousType = typename T::value_type;
-            static_assert(std::is_trivially_copyable_v<ContiguousType>,
-                          "Data type must be trivially copyable.");
+            static_assert(std::is_trivially_copyable_v<ContiguousType>, "Data type must be trivially copyable.");
             return WriteSpan<ContiguousType>(data);
         } else {
             static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
@@ -264,197 +250,219 @@ public:
     }
 
     /**
-     * Reads a span of T data from a file sequentially.
-     * This function reads from the current position of the file pointer and
-     * advances it by the (count of T * sizeof(T)) bytes successfully read.
-     *
-     * Failures occur when:
-     * - The file is not open
-     * - The opened file lacks read permissions
-     * - Attempting to read beyond the end-of-file
-     *
-     * @tparam T Data type
-     *
-     * @param data Span of T data
-     *
-     * @returns Count of T data successfully read.
-     */
+    * Reads a span of T data from a file sequentially.
+    * This function reads from the current position of the file pointer and
+    * advances it by the (count of T * sizeof(T)) bytes successfully read.
+    *
+    * Failures occur when:
+    * - The file is not open
+    * - The opened file lacks read permissions
+    * - Attempting to read beyond the end-of-file
+    *
+    * @tparam T Data type
+    *
+    * @param data Span of T data
+    *
+    * @returns Count of T data successfully read.
+    */
     template <typename T>
         requires std::is_trivially_copyable_v<T>
     [[nodiscard]] size_t ReadSpan(std::span<T> data) const {
-        if (!IsOpen()) {
-            return 0;
+        if (IsMappedFile()) {
+            std::memcpy(data.data(), mmap_base + mmap_offset, sizeof(T) * data.size());
+            return data.size();
         }
-        return std::fread(data.data(), sizeof(T), data.size(), file);
+        return IsOpen() ? std::fread(data.data(), sizeof(T), data.size(), file) : 0;
     }
 
     /**
-     * Writes a span of T data to a file sequentially.
-     * This function writes from the current position of the file pointer and
-     * advances it by the (count of T * sizeof(T)) bytes successfully written.
-     *
-     * Failures occur when:
-     * - The file is not open
-     * - The opened file lacks write permissions
-     *
-     * @tparam T Data type
-     *
-     * @param data Span of T data
-     *
-     * @returns Count of T data successfully written.
-     */
+    * Writes a span of T data to a file sequentially.
+    * This function writes from the current position of the file pointer and
+    * advances it by the (count of T * sizeof(T)) bytes successfully written.
+    *
+    * Failures occur when:
+    * - The file is not open
+    * - The opened file lacks write permissions
+    *
+    * @tparam T Data type
+    *
+    * @param data Span of T data
+    *
+    * @returns Count of T data successfully written.
+    */
     template <typename T>
     [[nodiscard]] size_t WriteSpan(std::span<const T> data) const {
         static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
-
-        if (!IsOpen()) {
-            return 0;
+        if (IsMappedFile()) {
+            std::memcpy(mmap_base + mmap_offset, data.data(), sizeof(T) * data.size());
+            return data.size();
         }
-
-        return std::fwrite(data.data(), sizeof(T), data.size(), file);
+        return IsOpen() ? std::fwrite(data.data(), sizeof(T), data.size(), file) : 0;
     }
 
     /**
-     * Reads a T object from a file sequentially.
-     * This function reads from the current position of the file pointer and
-     * advances it by the sizeof(T) bytes successfully read.
-     *
-     * Failures occur when:
-     * - The file is not open
-     * - The opened file lacks read permissions
-     * - Attempting to read beyond the end-of-file
-     *
-     * @tparam T Data type
-     *
-     * @param object Reference to object
-     *
-     * @returns True if the object is successfully read from the file, false otherwise.
-     */
+    * Reads a T object from a file sequentially.
+    * This function reads from the current position of the file pointer and
+    * advances it by the sizeof(T) bytes successfully read.
+    *
+    * Failures occur when:
+    * - The file is not open
+    * - The opened file lacks read permissions
+    * - Attempting to read beyond the end-of-file
+    *
+    * @tparam T Data type
+    *
+    * @param object Reference to object
+    *
+    * @returns True if the object is successfully read from the file, false otherwise.
+    */
     template <typename T>
     [[nodiscard]] bool ReadObject(T& object) const {
         static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
         static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
-
-        if (!IsOpen()) {
-            return false;
+        if (IsMappedFile()) {
+            std::memcpy(&object, mmap_base + mmap_offset, sizeof(T));
+#ifdef _WIN32
+            return bool(sizeof(T));
+#else
+            return sizeof(T);
+#endif
         }
-
-        return std::fread(&object, sizeof(T), 1, file) == 1;
+        return IsOpen() ? std::fread(&object, sizeof(T), 1, file) == 1 : false;
     }
 
     /**
-     * Writes a T object to a file sequentially.
-     * This function writes from the current position of the file pointer and
-     * advances it by the sizeof(T) bytes successfully written.
-     *
-     * Failures occur when:
-     * - The file is not open
-     * - The opened file lacks write permissions
-     *
-     * @tparam T Data type
-     *
-     * @param object Const reference to object
-     *
-     * @returns True if the object is successfully written to the file, false otherwise.
-     */
+    * Writes a T object to a file sequentially.
+    * This function writes from the current position of the file pointer and
+    * advances it by the sizeof(T) bytes successfully written.
+    *
+    * Failures occur when:
+    * - The file is not open
+    * - The opened file lacks write permissions
+    *
+    * @tparam T Data type
+    *
+    * @param object Const reference to object
+    *
+    * @returns True if the object is successfully written to the file, false otherwise.
+    */
     template <typename T>
     [[nodiscard]] bool WriteObject(const T& object) const {
         static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
         static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
-
-        if (!IsOpen()) {
-            return false;
+        if (IsMappedFile()) {
+            std::memcpy(mmap_base + mmap_offset, &object, sizeof(T));
+#ifdef _WIN32
+            return sizeof(T) != 0;
+#else
+            return sizeof(T);
+#endif
         }
-
-        return std::fwrite(&object, sizeof(T), 1, file) == 1;
+        return IsOpen() ? std::fwrite(&object, sizeof(T), 1, file) == 1 : false;
     }
 
     /**
-     * Specialized function to read a string of a given length from a file sequentially.
-     * This function writes from the current position of the file pointer and
-     * advances it by the number of characters successfully read.
-     * The size of the returned string may not match length if not all bytes are successfully read.
-     *
-     * @param length Length of the string
-     *
-     * @returns A string read from the file.
-     */
+    * Specialized function to read a string of a given length from a file sequentially.
+    * This function writes from the current position of the file pointer and
+    * advances it by the number of characters successfully read.
+    * The size of the returned string may not match length if not all bytes are successfully read.
+    *
+    * @param length Length of the string
+    *
+    * @returns A string read from the file.
+    */
     [[nodiscard]] std::string ReadString(size_t length) const;
 
     /**
-     * Specialized function to write a string to a file sequentially.
-     * This function writes from the current position of the file pointer and
-     * advances it by the number of characters successfully written.
-     *
-     * @param string Span of const char backed std::string or std::string_view
-     *
-     * @returns Number of characters successfully written.
-     */
+    * Specialized function to write a string to a file sequentially.
+    * This function writes from the current position of the file pointer and
+    * advances it by the number of characters successfully written.
+    *
+    * @param string Span of const char backed std::string or std::string_view
+    *
+    * @returns Number of characters successfully written.
+    */
     [[nodiscard]] size_t WriteString(std::span<const char> string) const;
 
     /**
-     * Attempts to flush any unwritten buffered data into the file.
-     *
-     * @returns True if the flush was successful, false otherwise.
-     */
+    * Attempts to flush any unwritten buffered data into the file.
+    *
+    * @returns True if the flush was successful, false otherwise.
+    */
     bool Flush() const;
 
     /**
-     * Attempts to commit the file into the disk.
-     * Note that this is an expensive operation as this forces the operating system to write
-     * the contents of the file associated with the file descriptor into the disk.
-     *
-     * @returns True if the commit was successful, false otherwise.
-     */
+    * Attempts to commit the file into the disk.
+    * Note that this is an expensive operation as this forces the operating system to write
+    * the contents of the file associated with the file descriptor into the disk.
+    *
+    * @returns True if the commit was successful, false otherwise.
+    */
     bool Commit() const;
 
     /**
-     * Resizes the file to a given size.
-     * If the file is resized to a smaller size, the remainder of the file is discarded.
-     * If the file is resized to a larger size, the new area appears as if zero-filled.
-     *
-     * Failures occur when:
-     * - The file is not open
-     *
-     * @param size File size in bytes
-     *
-     * @returns True if the file resize succeeded, false otherwise.
-     */
+    * Resizes the file to a given size.
+    * If the file is resized to a smaller size, the remainder of the file is discarded.
+    * If the file is resized to a larger size, the new area appears as if zero-filled.
+    *
+    * Failures occur when:
+    * - The file is not open
+    *
+    * @param size File size in bytes
+    *
+    * @returns True if the file resize succeeded, false otherwise.
+    */
     [[nodiscard]] bool SetSize(u64 size) const;
 
     /**
-     * Gets the size of the file.
-     *
-     * Failures occur when:
-     * - The file is not open
-     *
-     * @returns The file size in bytes of the file. Returns 0 on failure.
-     */
+    * Gets the size of the file.
+    *
+    * Failures occur when:
+    * - The file is not open
+    *
+    * @returns The file size in bytes of the file. Returns 0 on failure.
+    */
     [[nodiscard]] u64 GetSize() const;
 
     /**
-     * Moves the current position of the file pointer with the specified offset and seek origin.
-     *
-     * @param offset Offset from seek origin
-     * @param origin Seek origin
-     *
-     * @returns True if the file pointer has moved to the specified offset, false otherwise.
-     */
+    * Moves the current position of the file pointer with the specified offset and seek origin.
+    *
+    * @param offset Offset from seek origin
+    * @param origin Seek origin
+    *
+    * @returns True if the file pointer has moved to the specified offset, false otherwise.
+    */
     [[nodiscard]] bool Seek(s64 offset, SeekOrigin origin = SeekOrigin::SetOrigin) const;
 
     /**
-     * Gets the current position of the file pointer.
-     *
-     * @returns The current position of the file pointer.
-     */
+    * Gets the current position of the file pointer.
+    *
+    * @returns The current position of the file pointer.
+    */
     [[nodiscard]] s64 Tell() const;
 
-private:
+#ifdef _WIN32
+    inline bool IsMappedFile() const noexcept { return mapping_handle != nullptr; }
+#else // POSIX
+    inline bool IsMappedFile() const noexcept { return mmap_fd != -1; }
+#endif
+
     std::filesystem::path file_path;
     FileAccessMode file_access_mode{};
     FileType file_type{};
-
     std::FILE* file = nullptr;
+    // Any decent system should have mmap() for files
+    // Systems with artifical mmap() limitations should simply change the logic within file.cpp
+    // and reduce the threshold for which the mmap() is set to
+#ifdef _WIN32
+    void *mapping_handle = nullptr;
+    void *file_handle = nullptr;
+#else // POSIX
+    int mmap_fd = -1;
+#endif
+    u8* mmap_base = nullptr;
+    size_t mmap_size = 0;
+    mutable s64 mmap_offset = 0; // fuck you
 };
 
 } // namespace Common::FS

src/core/file_sys/ips_layer.cpp

@@ -3,12 +3,10 @@
 
 #include <algorithm>
 #include <cstring>
+#include <map>
 #include <sstream>
 #include <string>
 #include <utility>
-#include <span>
-#include <cctype>
-#include <ankerl/unordered_dense.h>
 
 #include "common/hex_util.h"
 #include "common/logging.h"
@@ -24,30 +22,61 @@ enum class IPSFileType {
     Error,
 };
 
-static IPSFileType IdentifyMagic(std::span<const u8> magic) {
-    if (magic.size() >= 5) {
-        if (std::memcmp(magic.data(), "PATCH", 5) == 0)
-            return IPSFileType::IPS;
-        if (std::memcmp(magic.data(), "IPS32", 5) == 0)
-            return IPSFileType::IPS32;
+constexpr std::array<std::pair<const char*, const char*>, 11> ESCAPE_CHARACTER_MAP{{
+    {"\\a", "\a"},
+    {"\\b", "\b"},
+    {"\\f", "\f"},
+    {"\\n", "\n"},
+    {"\\r", "\r"},
+    {"\\t", "\t"},
+    {"\\v", "\v"},
+    {"\\\\", "\\"},
+    {"\\\'", "\'"},
+    {"\\\"", "\""},
+    {"\\\?", "\?"},
+}};
+
+static IPSFileType IdentifyMagic(const std::vector<u8>& magic) {
+    if (magic.size() != 5) {
+        return IPSFileType::Error;
     }
+
+    static constexpr std::array<u8, 5> patch_magic{{'P', 'A', 'T', 'C', 'H'}};
+    if (std::equal(magic.begin(), magic.end(), patch_magic.begin())) {
+        return IPSFileType::IPS;
+    }
+
+    static constexpr std::array<u8, 5> ips32_magic{{'I', 'P', 'S', '3', '2'}};
+    if (std::equal(magic.begin(), magic.end(), ips32_magic.begin())) {
+        return IPSFileType::IPS32;
+    }
+
     return IPSFileType::Error;
 }
 
-static bool IsEOF(IPSFileType type, std::span<const u8> magic) {
-    return (type == IPSFileType::IPS && magic.size() > 3 && std::memcmp(magic.data(), "EOF", 3) == 0)
-        || (type == IPSFileType::IPS32 && magic.size() > 4 && std::memcmp(magic.data(), "EEOF", 4) == 0);
+static bool IsEOF(IPSFileType type, const std::vector<u8>& data) {
+    static constexpr std::array<u8, 3> eof{{'E', 'O', 'F'}};
+    if (type == IPSFileType::IPS && std::equal(data.begin(), data.end(), eof.begin())) {
+        return true;
+    }
+
+    static constexpr std::array<u8, 4> eeof{{'E', 'E', 'O', 'F'}};
+    return type == IPSFileType::IPS32 && std::equal(data.begin(), data.end(), eeof.begin());
 }
 
 VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips) {
     if (in == nullptr || ips == nullptr)
         return nullptr;
 
-    auto in_data = in->ReadAllBytes();
-    auto const type = IdentifyMagic(in_data);
+    const auto type = IdentifyMagic(ips->ReadBytes(0x5));
     if (type == IPSFileType::Error)
         return nullptr;
 
+    auto in_data = in->ReadAllBytes();
+    if (in_data.size() == 0) {
+        return nullptr;
+    }
+
     std::vector<u8> temp(type == IPSFileType::IPS ? 3 : 4);
     u64 offset = 5; // After header
     while (ips->Read(temp.data(), temp.size(), offset) == temp.size()) {
@@ -56,9 +85,12 @@ VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips) {
             break;
         }
 
-        u32 real_offset = (type == IPSFileType::IPS32)
-            ? ((temp[0] << 24) | (temp[1] << 16) | (temp[2] << 8) | temp[3])
-            : ((temp[0] << 16) | (temp[1] << 8) | temp[2]);
+        u32 real_offset{};
+        if (type == IPSFileType::IPS32)
+            real_offset = (temp[0] << 24) | (temp[1] << 16) | (temp[2] << 8) | temp[3];
+        else
+            real_offset = (temp[0] << 16) | (temp[1] << 8) | temp[2];
+
         if (real_offset > in_data.size()) {
             return nullptr;
         }
@@ -81,35 +113,34 @@ VirtualFile PatchIPS(const VirtualFile& in, const VirtualFile& ips) {
                 return nullptr;
 
             if (real_offset + rle_size > in_data.size())
-                rle_size = u16(in_data.size() - real_offset);
+                rle_size = static_cast<u16>(in_data.size() - real_offset);
             std::memset(in_data.data() + real_offset, *data, rle_size);
         } else { // Standard Patch
             auto read = data_size;
             if (real_offset + read > in_data.size())
-                read = u16(in_data.size() - real_offset);
+                read = static_cast<u16>(in_data.size() - real_offset);
             if (ips->Read(in_data.data() + real_offset, read, offset) != data_size)
                 return nullptr;
             offset += data_size;
         }
     }
-    if (IsEOF(type, temp)) {
-        return std::make_shared<VectorVfsFile>(std::move(in_data), in->GetName(), in->GetContainingDirectory());
+
+    if (!IsEOF(type, temp)) {
+        return nullptr;
     }
-    return nullptr;
+
+    return std::make_shared<VectorVfsFile>(std::move(in_data), in->GetName(),
+                                           in->GetContainingDirectory());
 }
 
-
-struct IPSwitchRecord {
-    std::array<uint8_t, 256 - sizeof(size_t)> data;
-    size_t count;
-};
 struct IPSwitchCompiler::IPSwitchPatch {
-    ankerl::unordered_dense::map<u32, IPSwitchRecord> records;
+    std::string name;
     bool enabled;
+    std::map<u32, std::vector<u8>> records;
 };
 
 IPSwitchCompiler::IPSwitchCompiler(VirtualFile patch_text_) : patch_text(std::move(patch_text_)) {
-    Parse(patch_text->ReadAllBytes());
+    Parse();
 }
 
 IPSwitchCompiler::~IPSwitchCompiler() = default;
@@ -118,159 +149,201 @@ std::array<u8, 32> IPSwitchCompiler::GetBuildID() const {
     return nso_build_id;
 }
 
-static IPSwitchRecord EscapeStringSequences(std::string_view sv) {
-    IPSwitchRecord r{};
-    for (auto it = sv.cbegin(); it != sv.cend(); ) {
-        if (*it == '\\' && it + 1 < sv.cend()) {
-            switch (it[1]) {
-            case 'n': r.data[r.count] = '\n'; break;
-            case 't': r.data[r.count] = '\t'; break;
-            case 'b': r.data[r.count] = '\b'; break;
-            case 'r': r.data[r.count] = '\r'; break;
-            case 'e': r.data[r.count] = '\e'; break;
-            case 'v': r.data[r.count] = '\v'; break;
-            case '?': r.data[r.count] = '\?'; break;
-            default: r.data[r.count] = it[1]; break;
-            }
-            ++r.count;
-            it += 2;
-        } else {
-            ++r.count;
-            ++it;
+bool IPSwitchCompiler::IsValid() const {
+    return valid;
+}
+
+static bool StartsWith(std::string_view base, std::string_view check) {
+    return base.size() >= check.size() && base.substr(0, check.size()) == check;
+}
+
+static std::string EscapeStringSequences(std::string in) {
+    for (const auto& seq : ESCAPE_CHARACTER_MAP) {
+        for (auto index = in.find(seq.first); index != std::string::npos;
+             index = in.find(seq.first, index)) {
+            in.replace(index, std::strlen(seq.first), seq.second);
+            index += std::strlen(seq.second);
         }
     }
-    return r;
+
+    return in;
 }
 
-[[nodiscard]] static inline std::array<u8, 32> ReadNSOBuildId(std::string_view const s) {
-    std::array<u8, 32> r{};
-    for (std::size_t i = 0; i < s.size(); ++i)
-        r[i / 2] |= u8(u8(Common::ToHexNibble(s[i])) << u8((i % 2) * 4));
-    return r;
+void IPSwitchCompiler::ParseFlag(const std::string& line) {
+    if (StartsWith(line, "@flag offset_shift ")) {
+        // Offset Shift Flag
+        offset_shift = std::strtoll(line.substr(19).c_str(), nullptr, 0);
+    } else if (StartsWith(line, "@little-endian")) {
+        // Set values to read as little endian
+        is_little_endian = true;
+    } else if (StartsWith(line, "@big-endian")) {
+        // Set values to read as big endian
+        is_little_endian = false;
+    } else if (StartsWith(line, "@flag print_values")) {
+        // Force printing of applied values
+        print_values = true;
+    }
 }
 
-void IPSwitchCompiler::Parse(std::span<u8 const> bytes) {
-    LOG_INFO(Loader, "IPSwitchCompiler: '{}'", patch_text->GetName());
-    bool is_little_endian = false;
-    s64 offset_shift = 0;
-    //bool print_values = false;
+void IPSwitchCompiler::Parse() {
+    const auto bytes = patch_text->ReadAllBytes();
+    std::stringstream s;
+    s.write(reinterpret_cast<const char*>(bytes.data()), bytes.size());
 
-    auto const parse_line = [&](std::string_view const line) {
-        // Keep in mind lines have trimmed spaces (at the end & start)!
-        LOG_INFO(Loader, "<{}>", line);
-        if (line.starts_with("@stop")) {
-            return false; // Force stop
-        } else if (line.starts_with("@nsobid-")) { // NSO Build ID Specifier
-            nso_build_id = ReadNSOBuildId(line.substr(8));
-        } else if (line.starts_with("@enabled")) {
-            patches.push_back({{}, true}); //enabled patch
-        } else if (line.starts_with("@disabled")) {
-            patches.push_back({{}, false}); //disabled patch
-        } else if (line.starts_with("@flag offset_shift ")) {
-            offset_shift = std::strtoll(line.data() + 19, nullptr, 0);  // Offset Shift Flag
-        } else if (line.starts_with("@little-endian")) {
-            is_little_endian = true;  // Set values to read as little endian
-        } else if (line.starts_with("@big-endian")) {
-            is_little_endian = false;  // Set values to read as big endian
-        } else if (line.starts_with("@flag print_values")) {
-            //print_values = true; // Force printing of applied values
-        } else if (line.starts_with("@")) {
-            LOG_WARNING(Loader, "Unknown flag {}", line);
-        } else {
-            size_t offset = size_t(std::strtoul(line.data(), nullptr, 16));
-            offset += size_t(offset_shift);
-            if (auto const first_quote = line.find_first_of("\"\'"); first_quote != std::string::npos) {
-                // string replacement
-                char quote = line[first_quote];
-                auto const start = line.cbegin() + first_quote + 1;
-                auto end = start;
-                for (; end < line.cend() && *end != quote; )
-                    end += (*end == '\\') ? 2 : 1;
-                if (start <= line.cend() && end <= line.cend()) {
-                    LOG_INFO(Loader, "[S] value @ {:#08X} ", offset);
-                    patches.back().records.insert_or_assign(u32(offset), EscapeStringSequences({start, end}));
-                } else {
-                    LOG_WARNING(Loader, "invalid string");
-                }
-            } else if (auto const first_space = line.find_last_of(" /\t\r\n"); first_space != std::string::npos) {
-                IPSwitchRecord r{}; // hex replacement
-                auto const start = line.cbegin() + first_space + 1;
-                auto const end = line.cend();
-                if (start <= line.cend() && end <= line.cend()) {
-                    auto const hs = Common::HexStringToVector({start, end}, is_little_endian);
-                    std::memcpy(r.data.data(), hs.data(), hs.size());
-                    r.count = hs.size();
-                    LOG_INFO(Loader, "[H] value @ {:#08X}", offset);
-                    patches.back().records.insert_or_assign(u32(offset), std::move(r));
-                } else {
-                    LOG_WARNING(Loader, "invalid line");
-                }
-            } else {
-                LOG_WARNING(Loader, "unhandled line!");
-            }
-        }
-        return true; //continue
-    };
+    std::vector<std::string> lines;
+    std::string stream_line;
+    while (std::getline(s, stream_line)) {
+        // Remove a trailing \r
+        if (!stream_line.empty() && stream_line.back() == '\r')
+            stream_line.pop_back();
+        lines.push_back(std::move(stream_line));
+    }
 
-    for (auto it = bytes.begin(); it < bytes.end(); ) {
-        auto const start = it;
-        auto end = start;
-        for (; end < bytes.end() && *end != '\n' && *end != '\r'; ++end)
-            ;
-        it = end + 1; //prepare for next line
-        std::string_view const sline{
-            reinterpret_cast<const char*>(bytes.data() + std::distance(bytes.begin(), start)),
-            size_t(std::distance(start, end))
-        };
-        if (sline.size() > 0) {
-            auto p = sline.cbegin();
-            // skip space off line
-            for (; p < sline.cend() && std::isspace(*p); ++p)
-                ;
-            // now make a nominal preprocessed line: remove comments
-            char quote = '\0';
-            auto const sline_start = p;
-            for (; p < sline.cend(); ) {
-                if ((!quote && p + 1 < sline.cend() && p[0] == '/' && p[1] == '/')
-                || (!quote && p[0] == '#')) {
-                    break;
-                } else if (p[0] == '\"' || p[0] == '\'') {
-                    quote = (p[0] == quote) ? '\0' : p[0];
-                    ++p;
-                } else if (p + 1 < sline.cend() && p[0] == '\\') {
-                    p += 2;
-                } else {
-                    ++p;
-                }
-            }
-            // now we have the preprocessed string ;)
-            std::string_view pp_str(sline_start, p);
-            if (pp_str.size() > 0 && !parse_line(pp_str)) {
+    for (std::size_t i = 0; i < lines.size(); ++i) {
+        auto line = lines[i];
+
+        // Remove midline comments
+        std::size_t comment_index = std::string::npos;
+        bool within_string = false;
+        for (std::size_t k = 0; k < line.size(); ++k) {
+            if (line[k] == '\"' && (k > 0 && line[k - 1] != '\\')) {
+                within_string = !within_string;
+            } else if (line[k] == '\\' && (k < line.size() - 1 && line[k + 1] == '\\')) {
+                comment_index = k;
                 break;
             }
         }
+
+        if (!StartsWith(line, "//") && comment_index != std::string::npos) {
+            last_comment = line.substr(comment_index + 2);
+            line = line.substr(0, comment_index);
+        }
+
+        if (StartsWith(line, "@stop")) {
+            // Force stop
+            break;
+        } else if (StartsWith(line, "@nsobid-")) {
+            // NSO Build ID Specifier
+            const auto raw_build_id = fmt::format("{:0<64}", line.substr(8));
+            nso_build_id = Common::HexStringToArray<0x20>(raw_build_id);
+        } else if (StartsWith(line, "#")) {
+            // Mandatory Comment
+            LOG_INFO(Loader, "[IPSwitchCompiler ('{}')] Forced output comment: {}",
+                     patch_text->GetName(), line.substr(1));
+        } else if (StartsWith(line, "//")) {
+            // Normal Comment
+            last_comment = line.substr(2);
+            if (last_comment.find_first_not_of(' ') == std::string::npos)
+                continue;
+            if (last_comment.find_first_not_of(' ') != 0)
+                last_comment = last_comment.substr(last_comment.find_first_not_of(' '));
+        } else if (StartsWith(line, "@enabled") || StartsWith(line, "@disabled")) {
+            // Start of patch
+            const auto enabled = StartsWith(line, "@enabled");
+            if (i == 0)
+                return;
+            LOG_INFO(Loader, "[IPSwitchCompiler ('{}')] Parsing patch '{}' ({})",
+                     patch_text->GetName(), last_comment, line.substr(1));
+
+            IPSwitchPatch patch{last_comment, enabled, {}};
+
+            // Read rest of patch
+            while (true) {
+                if (i + 1 >= lines.size()) {
+                    break;
+                }
+
+                const auto& patch_line = lines[++i];
+
+                // Patch line may contain comments
+                if (StartsWith(patch_line, "//") || StartsWith(patch_line, "#")) {
+                    continue;
+                }
+
+                // Start of new patch
+                if (StartsWith(patch_line, "@enabled") || StartsWith(patch_line, "@disabled")) {
+                    --i;
+                    break;
+                }
+
+                // Check for a flag
+                if (StartsWith(patch_line, "@")) {
+                    ParseFlag(patch_line);
+                    continue;
+                }
+
+                // 11 - 8 hex digit offset + space + minimum two digit overwrite val
+                if (patch_line.length() < 11)
+                    break;
+                auto offset = std::strtoul(patch_line.substr(0, 8).c_str(), nullptr, 16);
+                offset += static_cast<unsigned long>(offset_shift);
+
+                std::vector<u8> replace;
+                // 9 - first char of replacement val
+                if (patch_line[9] == '\"') {
+                    // string replacement
+                    auto end_index = patch_line.find('\"', 10);
+                    if (end_index == std::string::npos || end_index < 10)
+                        return;
+                    while (patch_line[end_index - 1] == '\\') {
+                        end_index = patch_line.find('\"', end_index + 1);
+                        if (end_index == std::string::npos || end_index < 10)
+                            return;
+                    }
+
+                    auto value = patch_line.substr(10, end_index - 10);
+                    value = EscapeStringSequences(value);
+                    replace.reserve(value.size());
+                    std::copy(value.begin(), value.end(), std::back_inserter(replace));
+                } else {
+                    // hex replacement
+                    const auto value =
+                        patch_line.substr(9, patch_line.find_first_of(" /\r\n", 9) - 9);
+                    replace = Common::HexStringToVector(value, is_little_endian);
+                }
+
+                if (print_values) {
+                    LOG_INFO(Loader,
+                             "[IPSwitchCompiler ('{}')]     - Patching value at offset {:#08x} "
+                             "with byte string '{}'",
+                             patch_text->GetName(), offset, Common::HexToString(replace));
+                }
+
+                patch.records.insert_or_assign(static_cast<u32>(offset), std::move(replace));
+            }
+
+            patches.push_back(std::move(patch));
+        } else if (StartsWith(line, "@")) {
+            ParseFlag(line);
+        }
     }
+
+    valid = true;
 }
 
 VirtualFile IPSwitchCompiler::Apply(const VirtualFile& in) const {
-    if (in == nullptr)
+    if (in == nullptr || !valid)
         return nullptr;
 
     auto in_data = in->ReadAllBytes();
 
     for (const auto& patch : patches) {
-        if (patch.enabled) {
-            for (const auto& record : patch.records) {
-                if (record.first < in_data.size()) {
-                    auto replace_size = record.second.count;
-                    if (record.first + replace_size > in_data.size())
-                        replace_size = in_data.size() - record.first;
-                    std::memcpy(in_data.data() + record.first, record.second.data.data(), replace_size);
-                }
-            }
+        if (!patch.enabled)
+            continue;
+
+        for (const auto& record : patch.records) {
+            if (record.first >= in_data.size())
+                continue;
+            auto replace_size = record.second.size();
+            if (record.first + replace_size > in_data.size())
+                replace_size = in_data.size() - record.first;
+            for (std::size_t i = 0; i < replace_size; ++i)
+                in_data[i + record.first] = record.second[i];
         }
     }
-    return std::make_shared<VectorVfsFile>(std::move(in_data), in->GetName(), in->GetContainingDirectory());
+
+    return std::make_shared<VectorVfsFile>(std::move(in_data), in->GetName(),
+                                           in->GetContainingDirectory());
 }
 
 } // namespace FileSys

src/core/file_sys/ips_layer.h

@@ -1,14 +1,11 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
 // SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
 
 #include <array>
+#include <memory>
 #include <vector>
-#include <span>
 
 #include "common/common_types.h"
 #include "core/file_sys/vfs/vfs.h"
@@ -23,17 +20,24 @@ public:
     ~IPSwitchCompiler();
 
     std::array<u8, 0x20> GetBuildID() const;
+    bool IsValid() const;
     VirtualFile Apply(const VirtualFile& in) const;
 
 private:
     struct IPSwitchPatch;
 
     void ParseFlag(const std::string& flag);
-    void Parse(std::span<u8 const> bytes);
+    void Parse();
+
+    bool valid = false;
 
     VirtualFile patch_text;
     std::vector<IPSwitchPatch> patches;
     std::array<u8, 0x20> nso_build_id{};
+    bool is_little_endian = false;
+    s64 offset_shift = 0;
+    bool print_values = false;
+    std::string last_comment = "";
 };
 
 } // namespace FileSys

src/core/file_sys/patch_manager.cpp

@@ -345,7 +345,8 @@ VirtualDir PatchManager::PatchExeFS(VirtualDir exefs) const {
     return exefs;
 }
 
-std::vector<VirtualFile> PatchManager::CollectPatches(const std::vector<VirtualDir>& patch_dirs, const std::string& build_id) const {
+std::vector<VirtualFile> PatchManager::CollectPatches(const std::vector<VirtualDir>& patch_dirs,
+                                                      const std::string& build_id) const {
     const auto& disabled = Settings::values.disabled_addons[title_id];
     const auto nso_build_id = fmt::format("{:0<64}", build_id);
 
@@ -360,11 +361,16 @@ std::vector<VirtualFile> PatchManager::CollectPatches(const std::vector<VirtualD
             for (const auto& file : exefs_dir->GetFiles()) {
                 if (file->GetExtension() == "ips") {
                     auto name = file->GetName();
-                    const auto this_build_id = fmt::format("{:0<64}", name.substr(0, name.find('.')));
+
+                    const auto this_build_id =
+                        fmt::format("{:0<64}", name.substr(0, name.find('.')));
                     if (nso_build_id == this_build_id)
                         out.push_back(file);
                 } else if (file->GetExtension() == "pchtxt") {
                     IPSwitchCompiler compiler{file};
+                    if (!compiler.IsValid())
+                        continue;
+
                     const auto this_build_id = Common::HexToString(compiler.GetBuildID());
                     if (nso_build_id == this_build_id)
                         out.push_back(file);
@@ -372,6 +378,7 @@ std::vector<VirtualFile> PatchManager::CollectPatches(const std::vector<VirtualD
             }
         }
     }
+
     return out;
 }
 

src/core/hle/service/nim/nim.cpp

@@ -5,33 +5,136 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <chrono>
-#include <ctime>
+#include <mutex>
+#include <string>
+#include <vector>
+
 #include "core/core.h"
 #include "core/hle/kernel/k_event.h"
+#include "core/hle/service/cmif_serialization.h"
+#include "core/hle/service/cmif_types.h"
 #include "core/hle/service/ipc_helpers.h"
 #include "core/hle/service/kernel_helpers.h"
 #include "core/hle/service/nim/nim.h"
+#include "core/hle/service/os/event.h"
 #include "core/hle/service/server_manager.h"
 #include "core/hle/service/service.h"
 
 namespace Service::NIM {
-
 class IShopServiceAsync final : public ServiceFramework<IShopServiceAsync> {
 public:
     explicit IShopServiceAsync(Core::System& system_)
-        : ServiceFramework{system_, "IShopServiceAsync"} {
+        : ServiceFramework{system_, "IShopServiceAsync"},
+          service_context{system_, "IShopServiceAsync"} {
         // clang-format off
         static const FunctionInfo functions[] = {
-            {0, nullptr, "Cancel"},
-            {1, nullptr, "GetSize"},
-            {2, nullptr, "Read"},
-            {3, nullptr, "GetErrorCode"},
-            {4, nullptr, "Request"},
-            {5, nullptr, "Prepare"},
+            {0, D<&IShopServiceAsync::Cancel>, "Cancel"},
+            {1, D<&IShopServiceAsync::GetSize>, "GetSize"},
+            {2, D<&IShopServiceAsync::Read>, "Read"},
+            {3, D<&IShopServiceAsync::GetErrorCode>, "GetErrorCode"},
+            {4, D<&IShopServiceAsync::Request>, "Request"},
+            {5, D<&IShopServiceAsync::Prepare>, "Prepare"},
         };
         // clang-format on
 
         RegisterHandlers(functions);
+
+        completion_event = service_context.CreateEvent("IShopServiceAsync:Completion");
+    }
+
+    ~IShopServiceAsync() override {
+        CancelImpl();
+        service_context.CloseEvent(completion_event);
+    }
+
+    Kernel::KReadableEvent* GetEvent() const {
+        return &completion_event->GetReadableEvent();
+    }
+
+private:
+    KernelHelpers::ServiceContext service_context;
+    Kernel::KEvent* completion_event;
+
+    std::jthread worker;
+    std::atomic<u32> error_code{0};
+
+    std::mutex data_mutex;
+    std::vector<u8> download_data;
+
+    void CancelImpl() {
+        worker.request_stop();
+        if (worker.joinable()) {
+            worker.join();
+        }
+    }
+
+    Result Cancel() {
+        LOG_DEBUG(Service_NIM, "called");
+        CancelImpl();
+        R_SUCCEED();
+    }
+
+    Result GetSize(Out<u64> out_size) {
+        LOG_DEBUG(Service_NIM, "called");
+        std::scoped_lock lock{data_mutex};
+        *out_size = download_data.size();
+        R_SUCCEED();
+    }
+
+    Result Read(Out<u64> out_size, u64 offset, OutBuffer<BufferAttr_HipcAutoSelect> out_buffer) {
+        std::scoped_lock lock{data_mutex};
+
+        u64 actual_read = 0;
+        if (offset < download_data.size()) {
+            actual_read = std::min<u64>(out_buffer.size(), download_data.size() - offset);
+            std::memcpy(out_buffer.data(), download_data.data() + offset, actual_read);
+        }
+
+        *out_size = actual_read;
+        R_SUCCEED();
+    }
+
+    Result GetErrorCode(Out<u32> out_error_code) {
+        LOG_DEBUG(Service_NIM, "called");
+        *out_error_code = error_code.load();
+        R_SUCCEED();
+    }
+
+    Result Request() {
+        LOG_DEBUG(Service_NIM, "(STUBBED) called");
+        CancelImpl();
+
+        error_code.store(0);
+        completion_event->Clear(system.Kernel());
+
+        {
+            std::scoped_lock lock{data_mutex};
+            download_data.clear();
+        }
+
+        worker = std::jthread([this](const std::stop_token& stop_token) {
+            if (stop_token.stop_requested()) {
+                error_code.store(1);
+            } else {
+                std::scoped_lock lock{data_mutex};
+                // Dummy JSON response, else it fails...
+                const std::string dummy_response = "{}";
+                download_data.assign(dummy_response.begin(), dummy_response.end());
+                error_code.store(0);
+            }
+            completion_event->Signal(system.Kernel());
+        });
+
+        R_SUCCEED();
+    }
+
+    Result Prepare(InArray<char, BufferAttr_HipcMapAlias> in_path, InArray<char, BufferAttr_HipcMapAlias> in_post) {
+        LOG_DEBUG(Service_NIM, "called");
+        if (!in_path.empty()) {
+            std::string url(in_path.data(), in_path.size());
+            LOG_INFO(Service_NIM, "Preparing request for URL: {}", url);
+        }
+        R_SUCCEED();
     }
 };
 
@@ -49,11 +152,13 @@ public:
     }
 
 private:
-    void CreateAsyncInterface(HLERequestContext& ctx) {
-        LOG_WARNING(Service_NIM, "(STUBBED) called");
-        IPC::ResponseBuilder rb{ctx, 2, 0, 1};
+    void CreateAsyncInterface(HLERequestContext& ctx) {LOG_DEBUG(Service_NIM, "called");
+        auto async_interface = std::make_shared<IShopServiceAsync>(system);
+
+        IPC::ResponseBuilder rb{ctx, 2, 1, 1};
         rb.Push(ResultSuccess);
-        rb.PushIpcInterface<IShopServiceAsync>(ctx, system);
+        rb.PushCopyObjects(ctx, async_interface->GetEvent());
+        rb.PushIpcInterface<IShopServiceAsync>(ctx, std::move(async_interface));
     }
 };
 

src/qt_common/util/mod.cpp

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 #include <filesystem>
-#include <system_error>
 #include <JlCompress.h>
 #include "frontend_common/mod_manager.h"
 #include "mod.h"
@@ -125,8 +124,8 @@ const QString ExtractMod(const QString& path) {
     fs::remove_all(tmp, ec);
     if (!fs::create_directories(tmp, ec)) {
         QtCommon::Frontend::Critical(tr("Mod Extract Failed"),
-                                    tr("Failed to create temporary directory %1")
-                                        .arg(QString::fromStdString(tmp.string())));
+                                     tr("Failed to create temporary directory %1")
+                                         .arg(QString::fromStdString(tmp.string())));
         return QString();
     }