COMMON: Add a class SafeSubReadStream

SafeSubReadStream is basically a SeekableSubReadStream that
re-seek()s the parent stream before each read(). That way, more than
one SafeSubReadStream of the same parent stream can be used safely
at the same time, at the cost of increasing IO.

1 files changed, 7 insertions, 0 deletions

diff --git a/common/stream.cpp b/common/stream.cpp
index e870e68b2d..a785ac5164 100644
--- a/common/stream.cpp
+++ b/common/stream.cpp
@@ -242,6 +242,13 @@ bool SeekableSubReadStream::seek(int32 offset, int whence) {
 	return ret;
 }
 
+uint32 SafeSubReadStream::read(void *dataPtr, uint32 dataSize) {
+	// Make sure the parent stream is at the right position
+	seek(0, SEEK_CUR);
+
+	return SeekableSubReadStream::read(dataPtr, dataSize);
+}
+
 
 #pragma mark -