Common/FileSystem: Add helpers for ByteStream

src/common/file_system.cpp

@@ -496,6 +496,39 @@ bool WriteFileToString(const char* filename, const std::string_view& sv)
   return true;
 }
 
+std::string ReadStreamToString(ByteStream* stream, bool seek_to_start /* = true */)
+{
+  u64 pos = stream->GetPosition();
+  u64 size = stream->GetSize();
+  if (pos > 0 && seek_to_start)
+  {
+    if (!stream->SeekAbsolute(0))
+      return {};
+
+    pos = 0;
+  }
+
+  Assert(size >= pos);
+  size -= pos;
+  if (size == 0 || size > std::numeric_limits<u32>::max())
+    return {};
+
+  std::string ret;
+  ret.resize(static_cast<size_t>(size));
+  if (!stream->Read2(ret.data(), static_cast<u32>(size)))
+    return {};
+
+  return ret;
+}
+
+bool WriteStreamToString(const std::string_view& sv, ByteStream* stream)
+{
+  if (sv.size() > std::numeric_limits<u32>::max())
+    return false;
+
+  return stream->Write2(sv.data(), static_cast<u32>(sv.size()));
+}
+
 void BuildOSPath(char* Destination, u32 cbDestination, const char* Path)
 {
   u32 i;

src/common/file_system.h

@@ -175,6 +175,9 @@ std::optional<std::string> ReadFileToString(const char* filename);
 bool WriteBinaryFile(const char* filename, const void* data, size_t data_length);
 bool WriteFileToString(const char* filename, const std::string_view& sv);
 
+std::string ReadStreamToString(ByteStream* stream, bool seek_to_start = true);
+bool WriteStreamToString(const std::string_view& sv, ByteStream* stream);
+
 // creates a directory in the local filesystem
 // if the directory already exists, the return value will be true.
 // if Recursive is specified, all parent directories will be created