Finish abstract Vfs classes

src/core/file_sys/vfs.cpp

@@ -2,6 +2,62 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <numeric>
 #include "core/file_sys/vfs.h"
 
-namespace FileSys {}
+namespace FileSys {
+
+VfsFile::operator bool() {
+    return IsGood();
+}
+
+boost::optional<u8> VfsFile::ReadByte(u64 offset) {
+    auto vec = ReadBytes(offset, 1);
+    if (vec.empty())
+        return boost::none;
+    return vec[0];
+}
+
+std::vector<u8> VfsFile::ReadAllBytes() {
+    return ReadBytes(0, GetSize());
+}
+
+u64 VfsFile::ReplaceBytes(const std::vector<u8>& data) {
+    if (!Resize(data.size()))
+        return 0;
+    return WriteBytes(data, 0);
+}
+
+boost::optional<VfsFile> VfsDirectory::GetFile(const std::string& name) {
+    auto files = GetFiles();
+    auto iter = std::find_if(files.begin(), files.end(),
+                             [&name](auto file1) { return name == file1.GetName(); });
+    return iter == files.end() ? boost::none : boost::make_optional(*iter);
+}
+
+boost::optional<VfsDirectory> VfsDirectory::GetSubdirectory(const std::string& name) {
+    auto subs = GetSubdirectories();
+    auto iter = std::find_if(subs.begin(), subs.end(),
+                             [&name](auto file1) { return name == file1.GetName(); });
+    return iter == subs.end() ? boost::none : boost::make_optional(*iter);
+}
+
+u64 VfsDirectory::GetSize() {
+    auto files = GetFiles();
+    auto file_total = std::accumulate(files.begin(), files.end(), 0);
+
+    auto sub_dir = GetSubdirectories();
+    auto subdir_total = std::accumulate(sub_dir.begin(), sub_dir.end(), 0);
+
+    return file_total + subdir_total;
+}
+
+bool VfsDirectory::Copy(const std::string& src, const std::string& dest) {
+    auto f1 = CreateFile(src), f2 = CreateFile(dest);
+    if (f1 == boost::none || f2 == boost::none)
+        return false;
+
+    return f2->ReplaceBytes(f1->ReadAllBytes()) == f1->GetSize();
+}
+
+} // namespace FileSys