[VFS] Add support for loading ZArchive files

src/xenia/vfs/devices/disc_zarchive_file.cc

@@ -0,0 +1,46 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2013 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/vfs/devices/disc_zarchive_file.h"
+
+#include <algorithm>
+
+#include "xenia/vfs/devices/disc_zarchive_entry.h"
+
+#include "third_party/zarchive/include/zarchive/zarchivereader.h"
+
+namespace xe {
+namespace vfs {
+
+DiscZarchiveFile::DiscZarchiveFile(uint32_t file_access,
+                                   DiscZarchiveEntry* entry)
+    : File(file_access, entry), entry_(entry) {}
+
+DiscZarchiveFile::~DiscZarchiveFile() = default;
+
+void DiscZarchiveFile::Destroy() { delete this; }
+
+X_STATUS DiscZarchiveFile::ReadSync(void* buffer, size_t buffer_length,
+                                    size_t byte_offset,
+                                    size_t* out_bytes_read) {
+  if (byte_offset >= entry_->size()) {
+    return X_STATUS_END_OF_FILE;
+  }
+  ZArchiveReader* reader = static_cast<ZArchiveReader*>(entry_->opaque_);
+  uint64_t bytes_read =
+      reader->ReadFromFile(entry_->handle_, byte_offset, buffer_length, buffer);
+  size_t real_offset = entry_->data_offset() + byte_offset;
+  size_t real_length =
+      std::min(buffer_length, entry_->data_size() - byte_offset);
+  *out_bytes_read = real_length;
+  return X_STATUS_SUCCESS;
+}
+
+}  // namespace vfs
+}  // namespace xe