98 lines
2.6 KiB
C++
98 lines
2.6 KiB
C++
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// © 2018 and later: Unicode, Inc. and others.
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// License & terms of use: http://www.unicode.org/copyright.html
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#ifndef __CAPI_HELPER_H__
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#define __CAPI_HELPER_H__
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#include "unicode/utypes.h"
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U_NAMESPACE_BEGIN
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/**
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* An internal helper class to help convert between C and C++ APIs.
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*/
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template<typename CType, typename CPPType, int32_t kMagic>
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class IcuCApiHelper {
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public:
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/**
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* Convert from the C type to the C++ type (const version).
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*/
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static const CPPType* validate(const CType* input, UErrorCode& status);
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/**
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* Convert from the C type to the C++ type (non-const version).
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*/
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static CPPType* validate(CType* input, UErrorCode& status);
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/**
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* Convert from the C++ type to the C type (const version).
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*/
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const CType* exportConstForC() const;
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/**
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* Convert from the C++ type to the C type (non-const version).
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*/
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CType* exportForC();
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/**
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* Invalidates the object.
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*/
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~IcuCApiHelper();
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private:
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/**
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* While the object is valid, fMagic equals kMagic.
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*/
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int32_t fMagic = kMagic;
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};
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template<typename CType, typename CPPType, int32_t kMagic>
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const CPPType*
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IcuCApiHelper<CType, CPPType, kMagic>::validate(const CType* input, UErrorCode& status) {
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if (U_FAILURE(status)) {
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return nullptr;
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}
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if (input == nullptr) {
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status = U_ILLEGAL_ARGUMENT_ERROR;
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return nullptr;
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}
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auto* impl = reinterpret_cast<const CPPType*>(input);
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if (static_cast<const IcuCApiHelper<CType, CPPType, kMagic>*>(impl)->fMagic != kMagic) {
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status = U_INVALID_FORMAT_ERROR;
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return nullptr;
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}
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return impl;
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}
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template<typename CType, typename CPPType, int32_t kMagic>
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CPPType*
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IcuCApiHelper<CType, CPPType, kMagic>::validate(CType* input, UErrorCode& status) {
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auto* constInput = static_cast<const CType*>(input);
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auto* validated = validate(constInput, status);
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return const_cast<CPPType*>(validated);
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}
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template<typename CType, typename CPPType, int32_t kMagic>
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const CType*
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IcuCApiHelper<CType, CPPType, kMagic>::exportConstForC() const {
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return reinterpret_cast<const CType*>(static_cast<const CPPType*>(this));
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}
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template<typename CType, typename CPPType, int32_t kMagic>
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CType*
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IcuCApiHelper<CType, CPPType, kMagic>::exportForC() {
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return reinterpret_cast<CType*>(static_cast<CPPType*>(this));
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}
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template<typename CType, typename CPPType, int32_t kMagic>
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IcuCApiHelper<CType, CPPType, kMagic>::~IcuCApiHelper() {
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// head off application errors by preventing use of of deleted objects.
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fMagic = 0;
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}
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U_NAMESPACE_END
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#endif // __CAPI_HELPER_H__
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