1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/GrTemplates.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,68 @@
1.4 +/*
1.5 + * Copyright 2010 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrTemplates_DEFINED
1.12 +#define GrTemplates_DEFINED
1.13 +
1.14 +#include "SkTypes.h"
1.15 +
1.16 +/**
1.17 + * Use to cast a ptr to a different type, and maintain strict-aliasing
1.18 + */
1.19 +template <typename Dst, typename Src> Dst GrTCast(Src src) {
1.20 + union {
1.21 + Src src;
1.22 + Dst dst;
1.23 + } data;
1.24 + data.src = src;
1.25 + return data.dst;
1.26 +}
1.27 +
1.28 +/**
1.29 + * takes a T*, saves the value it points to, in and restores the value in the
1.30 + * destructor
1.31 + * e.g.:
1.32 + * {
1.33 + * GrAutoTRestore<int*> autoCountRestore;
1.34 + * if (useExtra) {
1.35 + * autoCountRestore.reset(&fCount);
1.36 + * fCount += fExtraCount;
1.37 + * }
1.38 + * ...
1.39 + * } // fCount is restored
1.40 + */
1.41 +template <typename T> class GrAutoTRestore : public SkNoncopyable {
1.42 +public:
1.43 + GrAutoTRestore() : fPtr(NULL), fVal() {}
1.44 +
1.45 + GrAutoTRestore(T* ptr) {
1.46 + fPtr = ptr;
1.47 + if (NULL != ptr) {
1.48 + fVal = *ptr;
1.49 + }
1.50 + }
1.51 +
1.52 + ~GrAutoTRestore() {
1.53 + if (NULL != fPtr) {
1.54 + *fPtr = fVal;
1.55 + }
1.56 + }
1.57 +
1.58 + // restores previously saved value (if any) and saves value for passed T*
1.59 + void reset(T* ptr) {
1.60 + if (NULL != fPtr) {
1.61 + *fPtr = fVal;
1.62 + }
1.63 + fPtr = ptr;
1.64 + fVal = *ptr;
1.65 + }
1.66 +private:
1.67 + T* fPtr;
1.68 + T fVal;
1.69 +};
1.70 +
1.71 +#endif
