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/*
* Copyright 2010 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrTemplates_DEFINED
#define GrTemplates_DEFINED
#include "GrNoncopyable.h"
/**
* Use to cast a ptr to a different type, and maintain strict-aliasing
*/
template <typename Dst, typename Src> Dst GrTCast(Src src) {
union {
Src src;
Dst dst;
} data;
data.src = src;
return data.dst;
}
/**
* takes a T*, saves the value it points to, in and restores the value in the
* destructor
* e.g.:
* {
* GrAutoTRestore<int*> autoCountRestore;
* if (useExtra) {
* autoCountRestore.reset(&fCount);
* fCount += fExtraCount;
* }
* ...
* } // fCount is restored
*/
template <typename T> class GrAutoTRestore : public GrNoncopyable {
public:
GrAutoTRestore() : fPtr(NULL), fVal() {}
GrAutoTRestore(T* ptr) {
fPtr = ptr;
if (NULL != ptr) {
fVal = *ptr;
}
}
~GrAutoTRestore() {
if (NULL != fPtr) {
*fPtr = fVal;
}
}
// restores previously saved value (if any) and saves value for passed T*
void reset(T* ptr) {
if (NULL != fPtr) {
*fPtr = fVal;
}
fPtr = ptr;
fVal = *ptr;
}
private:
T* fPtr;
T fVal;
};
#endif
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