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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkData_DEFINED
#define SkData_DEFINED
#include "SkRefCnt.h"
struct SkFILE;
/**
* SkData holds an immutable data buffer. Not only is the data immutable,
* but the actual ptr that is returned (by data() or bytes()) is guaranteed
* to always be the same for the life of this instance.
*/
class SK_API SkData : public SkRefCnt {
public:
SK_DECLARE_INST_COUNT(SkData)
/**
* Returns the number of bytes stored.
*/
size_t size() const { return fSize; }
bool isEmpty() const { return 0 == fSize; }
/**
* Returns the ptr to the data.
*/
const void* data() const { return fPtr; }
/**
* Like data(), returns a read-only ptr into the data, but in this case
* it is cast to uint8_t*, to make it easy to add an offset to it.
*/
const uint8_t* bytes() const {
return reinterpret_cast<const uint8_t*>(fPtr);
}
/**
* Helper to copy a range of the data into a caller-provided buffer.
* Returns the actual number of bytes copied, after clamping offset and
* length to the size of the data. If buffer is NULL, it is ignored, and
* only the computed number of bytes is returned.
*/
size_t copyRange(size_t offset, size_t length, void* buffer) const;
/**
* Returns true if these two objects have the same length and contents,
* effectively returning 0 == memcmp(...)
*/
bool equals(const SkData* other) const;
/**
* Function that, if provided, will be called when the SkData goes out
* of scope, allowing for custom allocation/freeing of the data.
*/
typedef void (*ReleaseProc)(const void* ptr, size_t length, void* context);
/**
* Create a new dataref by copying the specified data
*/
static SkData* NewWithCopy(const void* data, size_t length);
/**
* Create a new dataref by copying the specified c-string
* (a null-terminated array of bytes). The returned SkData will have size()
* equal to strlen(cstr) + 1. If cstr is NULL, it will be treated the same
* as "".
*/
static SkData* NewWithCString(const char cstr[]);
/**
* Create a new dataref, taking the data ptr as is, and using the
* releaseproc to free it. The proc may be NULL.
*/
static SkData* NewWithProc(const void* data, size_t length,
ReleaseProc proc, void* context);
/**
* Create a new dataref from a pointer allocated by malloc. The Data object
* takes ownership of that allocation, and will handling calling sk_free.
*/
static SkData* NewFromMalloc(const void* data, size_t length);
/**
* Create a new dataref the file with the specified path.
* If the file cannot be opened, this returns NULL.
*/
static SkData* NewFromFileName(const char path[]);
/**
* Create a new dataref from a SkFILE.
* This does not take ownership of the SkFILE, nor close it.
* The caller is free to close the SkFILE at its convenience.
* The SkFILE must be open for reading only.
* Returns NULL on failure.
*/
static SkData* NewFromFILE(SkFILE* f);
/**
* Create a new dataref from a file descriptor.
* This does not take ownership of the file descriptor, nor close it.
* The caller is free to close the file descriptor at its convenience.
* The file descriptor must be open for reading only.
* Returns NULL on failure.
*/
static SkData* NewFromFD(int fd);
/**
* Create a new dataref using a subset of the data in the specified
* src dataref.
*/
static SkData* NewSubset(const SkData* src, size_t offset, size_t length);
/**
* Returns a new empty dataref (or a reference to a shared empty dataref).
* New or shared, the caller must see that unref() is eventually called.
*/
static SkData* NewEmpty();
private:
ReleaseProc fReleaseProc;
void* fReleaseProcContext;
const void* fPtr;
size_t fSize;
SkData(const void* ptr, size_t size, ReleaseProc, void* context);
virtual ~SkData();
// Called the first time someone calls NewEmpty to initialize the singleton.
static SkData* NewEmptyImpl();
static void DeleteEmpty(SkData*);
typedef SkRefCnt INHERITED;
};
/** Typedef of SkAutoTUnref<SkData> for automatically unref-ing a SkData. */
typedef SkAutoTUnref<SkData> SkAutoDataUnref;
#endif
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