Hide implementation details: SkFrontBufferedStream

include/utils/SkFrontBufferedStream.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-#include "SkStream.h"
-#include "SkTemplates.h"
+#include "SkTypes.h"
+
+class SkStream;
+class SkStreamRewindable;
 
 /**
- *  Specialized stream that only buffers the first X bytes of a stream,
+ *  Specialized stream that buffers the first X bytes of a stream,
  *  where X is passed in by the user. Note that unlike some buffered
- *  stream APIs, once more than those bytes are read, no more buffering
- *  is done. This stream is designed for a use case where the caller
- *  knows that rewind will only be called from within X bytes (inclusive),
- *  and the wrapped stream is not necessarily able to rewind at all.
+ *  stream APIs, once more bytes than can fit in the buffer are read,
+ *  no more buffering is done. This stream is designed for a use case
+ *  where the caller knows that rewind will only be called from within
+ *  X bytes (inclusive), and the wrapped stream is not necessarily
+ *  able to rewind at all.
  */
-class SkFrontBufferedStream : public SkStreamRewindable {
+class SkFrontBufferedStream {
 public:
     /**
-     *  Creates a new stream that wraps and buffers SkStream.
-     *  @param stream SkStream to buffer. If NULL, NULL is returned. After
-     *      this call, unref stream and do not refer to it.
-     *      SkFrontBufferedStream is expected to be its only owner.
-     *  @param bufferSize Exact size of the buffer to be used.
-     *  @return An SkStream that can buffer up to bufferSize.
+     *  Creates a new stream that wraps and buffers an SkStream.
+     *  @param stream SkStream to buffer. If stream is NULL, NULL is
+     *      returned. When this call succeeds (i.e. returns non NULL),
+     *      SkFrontBufferedStream is expected to be the only owner of
+     *      stream, so it should be unreffed and no longer used directly.
+     *  @param minBufferSize Minimum size of buffer required.
+     *  @return An SkStream that can buffer at least minBufferSize, or
+     *      NULL on failure.
      */
-    static SkStreamRewindable* Create(SkStream* stream, size_t bufferSize);
-
-    virtual size_t read(void* buffer, size_t size) SK_OVERRIDE;
-
-    virtual bool isAtEnd() const SK_OVERRIDE;
-
-    virtual bool rewind() SK_OVERRIDE;
-
-    virtual bool hasPosition() const SK_OVERRIDE { return true; }
-
-    virtual size_t getPosition() const SK_OVERRIDE { return fOffset; }
-
-    virtual bool hasLength() const SK_OVERRIDE;
-
-    virtual size_t getLength() const SK_OVERRIDE;
-
-    virtual SkStreamRewindable* duplicate() const SK_OVERRIDE { return NULL; }
-
-private:
-    SkAutoTUnref<SkStream>  fStream;
-    // Current offset into the stream. Always >= 0.
-    size_t                  fOffset;
-    // Amount that has been buffered by calls to read. Will always be less than
-    // fBufferSize.
-    size_t                  fBufferedSoFar;
-    // Total size of the buffer.
-    const size_t            fBufferSize;
-    SkAutoTMalloc<char>     fBuffer;
-
-    // Private. Use Create.
-    SkFrontBufferedStream(SkStream*, size_t bufferSize);
-
-    // Read up to size bytes from already buffered data, and copy to
-    // dst, if non-NULL. Updates fOffset. Assumes that fOffset is less
-    // than fBufferedSoFar.
-    size_t readFromBuffer(char* dst, size_t size);
-
-    // Buffer up to size bytes from the stream, and copy to dst if non-
-    // NULL. Updates fOffset and fBufferedSoFar. Assumes that fOffset is
-    // less than fBufferedSoFar, and size is greater than 0.
-    size_t bufferAndWriteTo(char* dst, size_t size);
-
-    // Read up to size bytes directly from the stream and into dst if non-
-    // NULL. Updates fOffset. Assumes fOffset is at or beyond the buffered
-    // data, and size is greater than 0.
-    size_t readDirectlyFromStream(char* dst, size_t size);
-
-    typedef SkStream INHERITED;
+    static SkStreamRewindable* Create(SkStream* stream, size_t minBufferSize);
 };