63fd760a37
Also adds a presubmit to prevent adding trailing whitespace to source code in the future. Change-Id: I41a4df81487f6f00aa19b188f0cac6a3377efde6 Reviewed-on: https://skia-review.googlesource.com/57380 Reviewed-by: Ravi Mistry <rmistry@google.com> Reviewed-by: Mike Reed <reed@google.com> Commit-Queue: Ben Wagner <bungeman@google.com>
112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkRWBuffer_DEFINED
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#define SkRWBuffer_DEFINED
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#include "SkRefCnt.h"
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struct SkBufferBlock;
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struct SkBufferHead;
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class SkRWBuffer;
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class SkStreamAsset;
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/**
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* Contains a read-only, thread-sharable block of memory. To access the memory, the caller must
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* instantiate a local iterator, as the memory is stored in 1 or more contiguous blocks.
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*/
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class SK_API SkROBuffer : public SkRefCnt {
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public:
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/**
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* Return the logical length of the data owned/shared by this buffer. It may be stored in
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* multiple contiguous blocks, accessible via the iterator.
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*/
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size_t size() const { return fAvailable; }
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class SK_API Iter {
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public:
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Iter(const SkROBuffer*);
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Iter(const sk_sp<SkROBuffer>&);
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void reset(const SkROBuffer*);
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/**
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* Return the current continuous block of memory, or nullptr if the iterator is exhausted
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*/
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const void* data() const;
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/**
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* Returns the number of bytes in the current continguous block of memory, or 0 if the
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* iterator is exhausted.
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*/
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size_t size() const;
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/**
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* Advance to the next contiguous block of memory, returning true if there is another
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* block, or false if the iterator is exhausted.
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*/
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bool next();
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private:
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const SkBufferBlock* fBlock;
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size_t fRemaining;
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const SkROBuffer* fBuffer;
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};
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private:
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SkROBuffer(const SkBufferHead* head, size_t available, const SkBufferBlock* fTail);
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virtual ~SkROBuffer();
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const SkBufferHead* fHead;
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const size_t fAvailable;
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const SkBufferBlock* fTail;
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friend class SkRWBuffer;
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};
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/**
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* Accumulates bytes of memory that are "appended" to it, growing internal storage as needed.
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* The growth is done such that at any time in the writer's thread, an RBuffer or StreamAsset
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* can be snapped off (and safely passed to another thread). The RBuffer/StreamAsset snapshot
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* can see the previously stored bytes, but will be unaware of any future writes.
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*/
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class SK_API SkRWBuffer {
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public:
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SkRWBuffer(size_t initialCapacity = 0);
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~SkRWBuffer();
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size_t size() const { return fTotalUsed; }
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/**
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* Append |length| bytes from |buffer|.
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*
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* If the caller knows in advance how much more data they are going to append, they can
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* pass a |reserve| hint (representing the number of upcoming bytes *in addition* to the
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* current append), to minimize the number of internal allocations.
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*/
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void append(const void* buffer, size_t length, size_t reserve = 0);
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sk_sp<SkROBuffer> makeROBufferSnapshot() const {
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return sk_sp<SkROBuffer>(new SkROBuffer(fHead, fTotalUsed, fTail));
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}
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std::unique_ptr<SkStreamAsset> makeStreamSnapshot() const;
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#ifdef SK_DEBUG
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void validate() const;
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#else
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void validate() const {}
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#endif
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private:
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SkBufferHead* fHead;
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SkBufferBlock* fTail;
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size_t fTotalUsed;
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};
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#endif
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