Security-55163.44.tar.gz

[apple/security.git] / libsecurity_utilities / lib / bufferfifo.h

diff --git a/libsecurity_utilities/lib/bufferfifo.h b/libsecurity_utilities/lib/bufferfifo.h
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+/*
+ * Copyright (c) 2000-2002,2004 Apple Computer, Inc. All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+//
+// bufferfifo - a Sink that queues data in a FIFO of buffers for retrieval
+//
+#ifndef _H_BUFFERFIFO
+#define _H_BUFFERFIFO
+
+#include "streams.h"
+#include "buffers.h"
+#include <list>
+#include <queue>
+
+
+namespace Security {
+
+
+//
+// A BufferFifo acts as a First-in First-out queue of Buffer objects.
+// This is usually used as a flexible I/O buffer queue mechanism.
+// For convenience, a BufferFifo is a Sink, so you can push data
+// into it directly using the Sink mechanism.
+// Note that there is currently no mechanism for restricting the
+// memory footprint of a BufferFifo.
+//
+class BufferFifo : public Sink {
+public:
+    BufferFifo(size_t es = 4096) : bufferLength(es) { }
+    ~BufferFifo();
+    
+    Buffer *top() const                        { assert(!mBuffers.empty()); return mBuffers.front(); }
+    Buffer *pop();
+    void push(Buffer *b)               { mBuffers.push(b); }
+    
+    bool isEmpty() const               { return mBuffers.empty(); }
+    size_t size() const                        { return mBuffers.size(); }
+    size_t topLength() const   { assert(!isEmpty()); return mBuffers.front()->length(); }
+    
+    // Sink implementation
+    void consume(const void *data, size_t size);
+    void clearBuffer();
+
+private:
+    typedef queue< Buffer *, list<Buffer *> > BufferQueue;
+    BufferQueue mBuffers;
+    const size_t bufferLength;
+};
+
+
+
+}      // end namespace Security
+
+
+#endif /* _H_BUFFERFIFO */