1 /*
2  * Copyright 2013 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "SkTypes.h"
9 
10 class SkStream;
11 class SkStreamRewindable;
12 
13 /**
14  *  Specialized stream that buffers the first X bytes of a stream,
15  *  where X is passed in by the user. Note that unlike some buffered
16  *  stream APIs, once more bytes than can fit in the buffer are read,
17  *  no more buffering is done. This stream is designed for a use case
18  *  where the caller knows that rewind will only be called from within
19  *  X bytes (inclusive), and the wrapped stream is not necessarily
20  *  able to rewind at all.
21  */
22 class SkFrontBufferedStream {
23 public:
24     /**
25      *  Creates a new stream that wraps and buffers an SkStream.
26      *  @param stream SkStream to buffer. If stream is NULL, NULL is
27      *      returned. When this call succeeds (i.e. returns non NULL),
28      *      SkFrontBufferedStream is expected to be the only owner of
29      *      stream, so it should no be longer used directly.
30      *      SkFrontBufferedStream will delete stream upon deletion.
31      *  @param minBufferSize Minimum size of buffer required.
32      *  @return An SkStream that can buffer at least minBufferSize, or
33      *      NULL on failure. The caller is required to delete when finished with
34      *      this object.
35      */
36     static SkStreamRewindable* Create(SkStream* stream, size_t minBufferSize);
37 };
38