15e9d3e66e
http://codereview.appspot.com/6300114/ git-svn-id: http://skia.googlecode.com/svn/trunk@4291 2bbb7eff-a529-9590-31e7-b0007b416f81
142 lines
3.8 KiB
C++
142 lines
3.8 KiB
C++
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/*
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* Copyright 2011 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 SkData_DEFINED
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#define SkData_DEFINED
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#include "SkRefCnt.h"
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/**
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* SkData holds an immutable data buffer. Not only is the data immutable,
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* but the actual ptr that is returned (by data() or bytes()) is guaranteed
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* to always be the same for the life of this instance.
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*/
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class SkData : public SkRefCnt {
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public:
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SK_DECLARE_INST_COUNT(SkData)
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/**
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* Returns the number of bytes stored.
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*/
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size_t size() const { return fSize; }
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/**
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* Returns the ptr to the data.
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*/
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const void* data() const { return fPtr; }
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/**
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* Like data(), returns a read-only ptr into the data, but in this case
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* it is cast to uint8_t*, to make it easy to add an offset to it.
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*/
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const uint8_t* bytes() const {
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return reinterpret_cast<const uint8_t*>(fPtr);
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}
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/**
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* Helper to copy a range of the data into a caller-provided buffer.
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* Returns the actual number of bytes copied, after clamping offset and
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* length to the size of the data. If buffer is NULL, it is ignored, and
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* only the computed number of bytes is returned.
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*/
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size_t copyRange(size_t offset, size_t length, void* buffer) const;
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/**
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* Function that, if provided, will be called when the SkData goes out
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* of scope, allowing for custom allocation/freeing of the data.
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*/
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typedef void (*ReleaseProc)(const void* ptr, size_t length, void* context);
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/**
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* Create a new dataref by copying the specified data
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*/
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static SkData* NewWithCopy(const void* data, size_t length);
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/**
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* Create a new dataref, taking the data ptr as is, and using the
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* releaseproc to free it. The proc may be NULL.
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*/
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static SkData* NewWithProc(const void* data, size_t length,
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ReleaseProc proc, void* context);
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/**
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* Create a new dataref from a pointer allocated by malloc. The Data object
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* takes ownership of that allocation, and will handling calling sk_free.
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*/
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static SkData* NewFromMalloc(const void* data, size_t length);
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/**
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* Create a new dataref using a subset of the data in the specified
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* src dataref.
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*/
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static SkData* NewSubset(const SkData* src, size_t offset, size_t length);
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/**
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* Returns a new empty dataref (or a reference to a shared empty dataref).
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* New or shared, the caller must see that unref() is eventually called.
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*/
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static SkData* NewEmpty();
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private:
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ReleaseProc fReleaseProc;
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void* fReleaseProcContext;
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const void* fPtr;
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size_t fSize;
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SkData(const void* ptr, size_t size, ReleaseProc, void* context);
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~SkData();
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typedef SkRefCnt INHERITED;
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};
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/**
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* Specialized version of SkAutoTUnref<SkData> for automatically unref-ing a
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* SkData. If the SkData is null, data(), bytes() and size() will return 0.
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*/
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class SkAutoDataUnref : SkNoncopyable {
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public:
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SkAutoDataUnref(SkData* data) : fRef(data) {
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if (data) {
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fData = data->data();
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fSize = data->size();
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} else {
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fData = NULL;
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fSize = 0;
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}
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}
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~SkAutoDataUnref() {
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SkSafeUnref(fRef);
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}
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const void* data() const { return fData; }
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const uint8_t* bytes() const {
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return reinterpret_cast<const uint8_t*> (fData);
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}
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size_t size() const { return fSize; }
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SkData* get() const { return fRef; }
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void release() {
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if (fRef) {
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fRef->unref();
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fRef = NULL;
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fData = NULL;
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fSize = 0;
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}
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}
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private:
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SkData* fRef;
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const void* fData;
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size_t fSize;
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};
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#endif
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