file_sys: Port Atmosphere-NX fs_mitm implementation

src/core/file_sys/fsmitm_romfsbuild.hpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2018 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Adapted by DarkLordZach for use/interaction with yuzu
+ *
+ * Modifications Copyright 2018 yuzu emulator team
+ * Licensed under GPLv2 or any later version
+ * Refer to the license.txt file included.
+ */
+
+#pragma once
+#include <map>
+#include <boost/detail/container_fwd.hpp>
+#include "common/common_types.h"
+#include "vfs.h"
+
+namespace FileSys {
+
+/* Used as comparator for std::map<char *, RomFSBuild*Context> */
+struct build_ctx_cmp {
+    bool operator()(const char* a, const char* b) const {
+        return strcmp(a, b) < 0;
+    }
+};
+
+struct RomFSDirectoryEntry;
+struct RomFSFileEntry;
+struct RomFSBuildDirectoryContext;
+struct RomFSBuildFileContext;
+
+class RomFSBuildContext {
+private:
+    VirtualDir base;
+    RomFSBuildDirectoryContext* root;
+    std::map<char*, RomFSBuildDirectoryContext*, build_ctx_cmp> directories;
+    std::map<char*, RomFSBuildFileContext*, build_ctx_cmp> files;
+    u64 num_dirs = 0;
+    u64 num_files = 0;
+    u64 dir_table_size = 0;
+    u64 file_table_size = 0;
+    u64 dir_hash_table_size = 0;
+    u64 file_hash_table_size = 0;
+    u64 file_partition_size = 0;
+
+    void VisitDirectory(VirtualDir filesys, RomFSBuildDirectoryContext* parent);
+
+    bool AddDirectory(RomFSBuildDirectoryContext* parent_dir_ctx,
+                      RomFSBuildDirectoryContext* dir_ctx,
+                      RomFSBuildDirectoryContext** out_dir_ctx);
+    bool AddFile(RomFSBuildDirectoryContext* parent_dir_ctx, RomFSBuildFileContext* file_ctx);
+
+public:
+    explicit RomFSBuildContext(VirtualDir base);
+
+    /* This finalizes the context. */
+    std::map<u64, VirtualFile> Build();
+};
+
+static inline RomFSDirectoryEntry* romfs_get_direntry(void* directories, uint32_t offset) {
+    return (RomFSDirectoryEntry*)((uintptr_t)directories + offset);
+}
+
+static inline RomFSFileEntry* romfs_get_fentry(void* files, uint32_t offset) {
+    return (RomFSFileEntry*)((uintptr_t)files + offset);
+}
+
+static inline uint32_t romfs_calc_path_hash(uint32_t parent, const unsigned char* path,
+                                            uint32_t start, size_t path_len) {
+    uint32_t hash = parent ^ 123456789;
+    for (uint32_t i = 0; i < path_len; i++) {
+        hash = (hash >> 5) | (hash << 27);
+        hash ^= path[start + i];
+    }
+
+    return hash;
+}
+
+static inline uint32_t romfs_get_hash_table_count(uint32_t num_entries) {
+    if (num_entries < 3) {
+        return 3;
+    } else if (num_entries < 19) {
+        return num_entries | 1;
+    }
+    uint32_t count = num_entries;
+    while (count % 2 == 0 || count % 3 == 0 || count % 5 == 0 || count % 7 == 0 ||
+           count % 11 == 0 || count % 13 == 0 || count % 17 == 0) {
+        count++;
+    }
+    return count;
+}
+
+} // namespace FileSys