1 files changed, 34 insertions, 1 deletions

diff --git a/src/stream.h b/src/stream.h
index a80586b..ba070d3 100644
--- a/src/stream.h
+++ b/src/stream.h
@@ -31,12 +31,45 @@ namespace Bu
                 virtual void setPos( long pos ) = 0;
                 virtual void setPosEnd( long pos ) = 0;
                 virtual bool isEOS() = 0;
+                virtual bool isOpen() = 0;
 
                 virtual void flush() = 0;
 
+                /**
+                 * In non-blocking streams this indicates if a read operation will
+                 * return data at the moment or not.  In blocking streams this should
+                 * return the same value as isEOS().
+                 */
                 virtual bool canRead() = 0;
+
+                /**
+                 * In non-blocking streams this indicates if a write operation will
+                 * succeed or fail.  In some cases writing is not allowed (e.g. 
+                 * internal buffers are full) temporarilly.  In blocking streams this
+                 * should return the same value as isWritable.
+                 */
                 virtual bool canWrite() = 0;
-                virtual bool canSeek() = 0;
+
+                /**
+                 * Indicates if the stream is capable of read operations.  This does not
+                 * indicate if such operations will return useful data, see canRead for
+                 * that.
+                 */
+                virtual bool isReadable() = 0;
+
+                /**
+                 * Indicates if the stream is capable of write operations.  This does
+                 * not indicate if such operations will succeed or fail, see canWrite
+                 * for that.
+                 */
+                virtual bool isWritable() = 0;
+
+                /**
+                 * Indicates if the stream is capable of seek operations.  This is
+                 * generally false for non-blocking streams.  Some buffered streams may
+                 * support limited in-buffer seeking.
+                 */
+                virtual bool isSeekable() = 0;
 
                 virtual bool isBlocking() = 0;
                 virtual void setBlocking( bool bBlocking=true ) = 0;