3 files changed, 214 insertions, 0 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 9877b83fe..c1a645460 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -12,6 +12,8 @@ add_library(core STATIC
     file_sys/errors.h
     file_sys/filesystem.cpp
     file_sys/filesystem.h
+    file_sys/partition_filesystem.cpp
+    file_sys/partition_filesystem.h
     file_sys/path_parser.cpp
     file_sys/path_parser.h
     file_sys/program_metadata.cpp
diff --git a/src/core/file_sys/partition_filesystem.cpp b/src/core/file_sys/partition_filesystem.cpp
new file mode 100644
index 000000000..4a58a9291
--- /dev/null
+++ b/src/core/file_sys/partition_filesystem.cpp
@@ -0,0 +1,125 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cinttypes>
+#include <utility>
+#include "common/file_util.h"
+#include "common/logging/log.h"
+#include "core/file_sys/partition_filesystem.h"
+#include "core/loader/loader.h"
+
+namespace FileSys {
+
+Loader::ResultStatus PartitionFilesystem::Load(const std::string& file_path, size_t offset) {
+    FileUtil::IOFile file(file_path, "rb");
+    if (!file.IsOpen())
+        return Loader::ResultStatus::Error;
+
+    // At least be as large as the header
+    if (file.GetSize() < sizeof(Header))
+        return Loader::ResultStatus::Error;
+
+    // For cartridges, HFSs can get very large, so we need to calculate the size up to
+    // the actual content itself instead of just blindly reading in the entire file.
+    Header pfs_header;
+    if (!file.ReadBytes(&pfs_header, sizeof(Header)))
+        return Loader::ResultStatus::Error;
+
+    bool is_hfs = (memcmp(pfs_header.magic.data(), "HFS", 3) == 0);
+    size_t entry_size = is_hfs ? sizeof(HFSEntry) : sizeof(PFSEntry);
+    size_t metadata_size =
+        sizeof(Header) + (pfs_header.num_entries * entry_size) + pfs_header.strtab_size;
+
+    // Actually read in now...
+    file.Seek(offset, SEEK_SET);
+    std::vector<u8> file_data(metadata_size);
+
+    if (!file.ReadBytes(file_data.data(), metadata_size))
+        return Loader::ResultStatus::Error;
+
+    Loader::ResultStatus result = Load(file_data);
+    if (result != Loader::ResultStatus::Success)
+        LOG_ERROR(Service_FS, "Failed to load PFS from file %s!", file_path.c_str());
+
+    return result;
+}
+
+Loader::ResultStatus PartitionFilesystem::Load(const std::vector<u8>& file_data, size_t offset) {
+    size_t total_size = file_data.size() - offset;
+    if (total_size < sizeof(Header))
+        return Loader::ResultStatus::Error;
+
+    memcpy(&pfs_header, &file_data[offset], sizeof(Header));
+    is_hfs = (memcmp(pfs_header.magic.data(), "HFS", 3) == 0);
+
+    size_t entries_offset = offset + sizeof(Header);
+    size_t entry_size = is_hfs ? sizeof(HFSEntry) : sizeof(PFSEntry);
+    size_t strtab_offset = entries_offset + (pfs_header.num_entries * entry_size);
+    for (u16 i = 0; i < pfs_header.num_entries; i++) {
+        FileEntry entry;
+
+        memcpy(&entry.fs_entry, &file_data[entries_offset + (i * entry_size)], sizeof(FSEntry));
+        entry.name = std::string(reinterpret_cast<const char*>(
+            &file_data[strtab_offset + entry.fs_entry.strtab_offset]));
+        pfs_entries.push_back(std::move(entry));
+    }
+
+    content_offset = strtab_offset + pfs_header.strtab_size;
+
+    return Loader::ResultStatus::Success;
+}
+
+u32 PartitionFilesystem::GetNumEntries() const {
+    return pfs_header.num_entries;
+}
+
+u64 PartitionFilesystem::GetEntryOffset(int index) const {
+    if (index > GetNumEntries())
+        return 0;
+
+    return content_offset + pfs_entries[index].fs_entry.offset;
+}
+
+u64 PartitionFilesystem::GetEntrySize(int index) const {
+    if (index > GetNumEntries())
+        return 0;
+
+    return pfs_entries[index].fs_entry.size;
+}
+
+std::string PartitionFilesystem::GetEntryName(int index) const {
+    if (index > GetNumEntries())
+        return "";
+
+    return pfs_entries[index].name;
+}
+
+u64 PartitionFilesystem::GetFileOffset(const std::string& name) const {
+    for (u32 i = 0; i < pfs_header.num_entries; i++) {
+        if (pfs_entries[i].name == name)
+            return content_offset + pfs_entries[i].fs_entry.offset;
+    }
+
+    return 0;
+}
+
+u64 PartitionFilesystem::GetFileSize(const std::string& name) const {
+    for (u32 i = 0; i < pfs_header.num_entries; i++) {
+        if (pfs_entries[i].name == name)
+            return pfs_entries[i].fs_entry.size;
+    }
+
+    return 0;
+}
+
+void PartitionFilesystem::Print() const {
+    NGLOG_DEBUG(Service_FS, "Magic:                  {:.4}", pfs_header.magic.data());
+    NGLOG_DEBUG(Service_FS, "Files:                  {}", pfs_header.num_entries);
+    for (u32 i = 0; i < pfs_header.num_entries; i++) {
+        NGLOG_DEBUG(Service_FS, " > File {}:              {} (0x{:X} bytes, at 0x{:X})", i,
+                    pfs_entries[i].name.c_str(), pfs_entries[i].fs_entry.size,
+                    GetFileOffset(pfs_entries[i].name));
+    }
+}
+} // namespace FileSys
diff --git a/src/core/file_sys/partition_filesystem.h b/src/core/file_sys/partition_filesystem.h
new file mode 100644
index 000000000..573c90057
--- /dev/null
+++ b/src/core/file_sys/partition_filesystem.h
@@ -0,0 +1,87 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <string>
+#include <vector>
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+#include "common/swap.h"
+
+namespace Loader {
+enum class ResultStatus;
+}
+
+namespace FileSys {
+
+/**
+ * Helper which implements an interface to parse PFS/HFS filesystems.
+ * Data can either be loaded from a file path or data with an offset into it.
+ */
+class PartitionFilesystem {
+public:
+    Loader::ResultStatus Load(const std::string& file_path, size_t offset = 0);
+    Loader::ResultStatus Load(const std::vector<u8>& file_data, size_t offset = 0);
+
+    u32 GetNumEntries() const;
+    u64 GetEntryOffset(int index) const;
+    u64 GetEntrySize(int index) const;
+    std::string GetEntryName(int index) const;
+    u64 GetFileOffset(const std::string& name) const;
+    u64 GetFileSize(const std::string& name) const;
+
+    void Print() const;
+
+private:
+    struct Header {
+        std::array<char, 4> magic;
+        u32_le num_entries;
+        u32_le strtab_size;
+        INSERT_PADDING_BYTES(0x4);
+    };
+
+    static_assert(sizeof(Header) == 0x10, "PFS/HFS header structure size is wrong");
+
+#pragma pack(push, 1)
+    struct FSEntry {
+        u64_le offset;
+        u64_le size;
+        u32_le strtab_offset;
+    };
+
+    static_assert(sizeof(FSEntry) == 0x14, "FS entry structure size is wrong");
+
+    struct PFSEntry {
+        FSEntry fs_entry;
+        INSERT_PADDING_BYTES(0x4);
+    };
+
+    static_assert(sizeof(PFSEntry) == 0x18, "PFS entry structure size is wrong");
+
+    struct HFSEntry {
+        FSEntry fs_entry;
+        u32_le hash_region_size;
+        INSERT_PADDING_BYTES(0x8);
+        std::array<char, 0x20> hash;
+    };
+
+    static_assert(sizeof(HFSEntry) == 0x40, "HFS entry structure size is wrong");
+
+#pragma pack(pop)
+
+    struct FileEntry {
+        FSEntry fs_entry;
+        std::string name;
+    };
+
+    Header pfs_header;
+    bool is_hfs;
+    size_t content_offset;
+
+    std::vector<FileEntry> pfs_entries;
+};
+
+} // namespace FileSys