将一组类转换为类模板并避免构造函数模棱两可
Converting a set of classes to class templates and avoiding constructor ambiguity
我会尽力使这个问题尽可能短,但是要显示大量的代码,以便一个人了解我要实现的目标以及如何解决我当前的问题。
这是我与所有构造函数的原始类声明:
register.h - 原始版本
#include <bitset>
#include <cassert>
#include <cstdint>
#include <iostream>
typedef std::uint8_t u8;
typedef std::uint16_t u16;
typedef std::uint32_t u32;
typedef std::uint64_t u64;
const u16 BYTE = 0x08, WORD = 0x10, DWORD = 0x20, QWORD = 0x40;
typedef std::bitset<BYTE> Byte;
typedef std::bitset<WORD> Word;
typedef std::bitset<DWORD> DWord;
typedef std::bitset<QWORD> QWord;
template<typename T>
void getByteFrom(T val, u8 idx, u8& res) {
res = ((val >> (idx * 8) & 0xff));
}
template<typename T>
void getWordFrom(T val, u8 idx, u16& res) {
res = ((val >> (idx * 16) & 0xffff));
}
template<typename T>
void getDWordFrom(T val, u8 idx, u32& res) {
res = ((val >> (idx * 32) & 0xffffffff));
}
template<typename T>
struct Register {
T data;
Register() = default;
};
struct Reg8 : public Register<u8> {
u8 value; // must be declared before std::bitset<T>
Byte bits;
// Default 0 Initialized Constructor
Reg8() : value{ 0 }, bits{ value } { this->data = 0; }
// Constructors by Register Sized Values
explicit Reg8(u8 val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg8(u16 val) : value{ static_cast<u8>( val ) }, bits{ value } {
this->data = value;
}
explicit Reg8(u32 val) : value{ static_cast<u8>( val ) }, bits{ value } {
//this->data = value;
}
explicit Reg8(u64 val) : value{ static_cast<u8>( val ) }, bits{ value } {
//this->data = value;
}
Reg8(u16 val, u8 idx ) {
assert( idx == 0 || idx == 1 );
getByteFrom(val, idx, this->value);
bits = value;
this->data = value;
}
Reg8(u32 val, u8 idx) {
assert(idx <= 0 && idx >= 3);
getByteFrom(val, idx, this->value);
bits = value;
this->data = value;
}
Reg8(u64 val, u8 idx) {
assert(idx <= 0 && idx >= 7);
getByteFrom(val, idx, this->value);
bits = value;
this->data = value;
}
// Constructors by Register Types
template<typename T>
explicit Reg8(Register<T>* reg) {
this->value = static_cast<u8>( reg->data );
this->bits = value;
}
};
struct Reg16 : public Register<u16> {
u16 value; // must be declared before std::bitset<T>
Word bits;
// Default 0 Initialized Constructor
Reg16() : value{ 0 }, bits{ value } { this->data = 0; }
// Constructors by Register Sized Values
explicit Reg16(u16& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg16( u8& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg16(u32& val) : value{ static_cast<u16>(val) }, bits{ value } {
this->data = value;
}
explicit Reg16(u64& val) : value{ static_cast<u16>(val) }, bits{ value } {
this->data = value;
}
Reg16( u32 val, u8 idx) {
assert(idx == 0 || idx == 1);
getWordFrom(val, idx, this->value);
bits = value;
this->data = value;
}
Reg16(u64 val, u8 idx) {
assert(idx <= 0 || idx <= 3);
getWordFrom(val, idx, this->value);
bits = value;
this->data = value;
}
// Constructors by Register Types
template<typename T>
explicit Reg16(Register<T>* reg) {
this->value = static_cast<u16>(reg->data);
this->bits = value;
}
};
struct Reg32 : public Register<u32> {
u32 value; // must be declared before std::bitset<T>
DWord bits;
// Default 0 Initialized Constructor
Reg32() : value{ 0 }, bits{ value } { this->data = 0; }
// Constructors by Register Sized Values
explicit Reg32(u32& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg32( u8& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg32(u16& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg32(u64& val) : value{ static_cast<u32>(val) }, bits{ value } {
this->data = value;
}
Reg32(u64 val, u8 idx) {
assert(idx == 0 || idx == 1);
getDWordFrom(val, idx, this->value);
bits = value;
this->data = value;
}
// Constructors by Register Types
template<typename T>
explicit Reg32(Register<T>* reg) {
this->value = static_cast<u32>(reg->data);
this->bits = value;
}
};
struct Reg64 : public Register<u64> {
u64 value; // must be declared before std::bitset<T>
QWord bits;
// Default 0 Initialized Constructor
Reg64() : value{ 0 }, bits{ value } { this->data = 0; }
// Constructors by Register Sized Values
explicit Reg64(u64& val) : value{ val }, bits{ value }{
this->data = value;
}
explicit Reg64( u8& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg64(u16& val) : value{ val }, bits{ value } {
this->data = value;
}
explicit Reg64(u32& val) : value{ val }, bits{ value } {
this->data = value;
}
// Constructors by Register Types
template<typename T>
explicit Reg64(Register<T>* reg) {
this->value = static_cast<u64>(reg->data);
this->bits = value;
}
};
std::ostream& operator<<(std::ostream& os, const Reg8& r);
std::ostream& operator<<(std::ostream& os, const Reg16& r);
std::ostream& operator<<(std::ostream& os, const Reg32& r);
std::ostream& operator<<(std::ostream& os, const Reg64& r);
现在,我去了这些模板类,以减少许多代码重复。这就是我到目前为止所拥有的:
register.h - 新版本
template<typename Ty>
struct Register_t {
static constexpr u16 BitCount = sizeof(Ty) * CHAR_BIT;
Ty currentValue;
Ty previousValue;
std::bitset<BitCount> bits;
Register_t() :
currentValue{ 0 },
previousValue{ 0 },
bits{ 0 }{}
template<typename U>
explicit Register_t(U val) :
currentValue{ static_cast<Ty>(val) },
previousValue{ 0 },
bits{ currentValue } {}
template<typename U>
explicit Register_t(Register_t<U>& r) {
this->currentValue = static_cast<Ty>(r->currentValue);
this->bits = r->bits;
}
};
template<typename Ty>
struct Register : public Register_t<Ty> {
Register() = default;
explicit Register(Ty val) : Register_t<Ty>( val ) {}
// Reg8
template<typename U>
Register( u16 val, u8 idx) {
assert(idx == 0 || idx == 1);
getByteFrom(val, idx, currentValue);
this->bits = this->currentValue;
}
Register(u32 val, u8 idx) {
assert(idx <= 0 && idx >= 3);
getByteFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
Register(u64 val, u8 idx) {
assert(idx <= 0 && idx <= 7);
getByteFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
// Reg16
Register(u32 val, u8 idx) {
assert(idx == 0 || idx == 1);
getWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
Register(u64 val, u8 idx) {
assert(idx <= 0 && idx <= 3);
getWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
// Reg32
Register(u64 val, u8 idx) {
assert(idx == 0 || idx == 1);
getDWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
};
using Reg8 = Register<u8>;
using Reg16 = Register<u16>;
using Reg32 = Register<u32>;
using Reg64 = Register<u64>;
现在,当涉及将使用std::uintx_t
类型以及索引值的构造函数时。例如,某些构造函数声明匹配:
在原始版本中,Reg8
具有Reg8(u32 val, u8 idx)
,Reg16
具有Reg16(u32 val, u8 idx)
。如果您近距离查看Reg8(...)
,则在Reg16(...)
中断言idx <= 0 && idx >= 3
,断言idx == 0 || idx == 1
。
但是,当我尝试在构造函数上模板和端口模板时,这些类和端口现在变得模棱两可。我不知道如何确定要区分它是Reg8
,Reg16
,Reg32
等的主张...
对我来说,您的班级中的所有内容都归结为使用您类型的无符号版本的sizeof
和numeric_limits::max
。
我在我认为班级的外观的粗略草稿下为您写信:
template <typename T>
struct Register {
T data;
T value;
bitset<sizeof(T) * CHAR_BIT> bits;
Register() : data(), value() {}
template <typename P>
explicit Register(const P val) : data(static_cast<T>(val)), value(data), bits(data) {}
template <typename P>
Register(const P val, const unsigned char idx) : data(static_cast<T>((val >> std::size(bits) * idx) & numeric_limits<make_unsigned_t<T>>::max())), value(data), bits(data) {
assert(idx == ' ' || idx < sizeof(P) / sizeof(T));
}
template <typename P>
Register(const Register<P>& reg) : data(static_cast<T>(reg.data)), value(data), bits(data) {}
};
template <typename T>
ostream& operator<<(ostream& os, const Register<T>& r) {
os << "Reg" << size(r.bits) << '(' << r.data << ")nhex: 0x" << uppercase << setfill('0') << setw(sizeof(T) * 2) << hex << r.data << dec << "nbin: ";
for(std::size_t i = 0; i < size(r.bits); ++i) {
cout.put('0' + r.bits[i]);
}
return os << endl << endl;
}
template <>
ostream& operator<<<unsigned char>(ostream& os, const Register<unsigned char>& r) {
os << "Reg" << size(r.bits) << '(' << static_cast<int>(r.data) << ")nhex: 0x" << uppercase << setfill('0') << setw(sizeof(unsigned char) * 2) << hex << static_cast<int>(r.data) << dec << "nbin: ";
for(std::size_t i = 0; i < size(r.bits); ++i) {
cout.put('0' + r.bits[i]);
}
return os << endl << endl;
}
如果要确定类型并做出适当反应,那么为什么要完全使用通用模板?有两个选项,确定类型和分支(通过完全不使用模板,通过专门使用模板或使用SFINAE(或WRITE real 通用代码。前者不是很有用,因为您最终将获得比没有模板更多的锅炉板。
后者取决于您的要求,但看起来像这样:
template <typename T>
T getXFrom(T val, std::uint8_t idx) {
return val >> (idx * CHAR_BIT);
}
template <typename T>
class Register {
public:
template <typename U>
Register(U val, std::uint8_t idx) {
static_assert(std::is_integral_v<U>);
assert(idx >= 0 && idx < sizeof(U));
currentValue = getXFrom(val, idx);
}
private:
T currentValue;
};
按照要求,这是如何专业化的示例(使用基类减少裁员(:
template <typename T>
class Register {
protected:
T currentValue;
};
template <typename>
class RegisterImpl;
template <>
class RegisterImpl<uint8_t> : Register<uint8_t> {
public:
template <typename U>
RegisterImpl(U val, std::uint8_t idx) {
// uint8_t asserts...
}
};
template <>
class RegisterImpl<uint16_t> : Register<uint16_t> {
public:
template <typename U>
RegisterImpl(U val, std::uint8_t idx) {
// uint16_t asserts...
}
};
我认为我已经解决了问题;我能够编译,构建和运行,并且得到了一些预期的结果,但是我没有进行足够的单元测试来验证所有案例是否按预期工作,但这是我到目前为止提出的。我分别将代码分别分为两个文件,以使其工作...
register.h
#pragma once
#include <algorithm>
#include <assert.h>
#include <bitset>
#include <cstdint>
namespace vpc {
typedef std::int8_t i8;
typedef std::int16_t i16;
typedef std::int32_t i32;
typedef std::int64_t i64;
typedef std::uint8_t u8;
typedef std::uint16_t u16;
typedef std::uint32_t u32;
typedef std::uint64_t u64;
const u16 BYTE = 0x08;
const u16 WORD = 0x10;
const u16 DWORD = 0x20;
const u16 QWORD = 0x40;
typedef std::bitset<BYTE> Byte;
typedef std::bitset<WORD> Word;
typedef std::bitset<DWORD> DWord;
typedef std::bitset<QWORD> QWord;
// Helper Functions
template<typename T>
void getByteFrom(T val, u8 idx, u8& res) {
res = ((val >> (idx * 8) & 0xff));
}
template<typename T>
void getWordFrom(T val, u8 idx, u16& res) {
res = ((val >> (idx * 16) & 0xffff));
}
template<typename T>
void getDWordFrom(T val, u8 idx, u32& res) {
res = ((val >> (idx * 32) & 0xffffffff));
}
template<typename T>
struct Register_t {
static constexpr u16 BitCount = sizeof(T) * CHAR_BIT;
T currentValue;
T previousValue;
std::bitset<BitCount> bits;
Register_t() :
currentValue{ 0 },
previousValue{ 0 },
bits{ 0 }
{}
template<typename U>
explicit Register_t(U val) :
currentValue{ static_cast<T>(val) },
previousValue{ 0 },
bits{ currentValue }
{}
template<typename U>
explicit Register_t(Register_t<U>& r) : previousValue{ 0 }
{
this->currentValue = static_cast<T>(r.currentValue);
this->bits = currentValue;
}
};
template<typename T>
struct Register : public Register_t<T> {
Register() : Register_t<T>() {}
explicit Register(T val) : Register_t<T>( val ) {}
template<typename U>
explicit Register(Register_t<U>& r) : Register_t<T>( r ) {}
// These are the constructors with matching declarations
// that were giving me trouble with ambiguous calls
Register(u16 val, u8 idx);
Register(u32 val, u8 idx);
Register(u64 val, u8 idx);
};
using Reg8 = Register<u8>;
using Reg16 = Register<u16>;
using Reg32 = Register<u32>;
using Reg64 = Register<u64>;
std::ostream& operator<<(std::ostream& os, const Reg8& reg);
std::ostream& operator<<(std::ostream& os, const Reg16& reg);
std::ostream& operator<<(std::ostream& os, const Reg32& reg);
std::ostream& operator<<(std::ostream& os, const Reg64& reg);
} // namespace vpc
我现在在Register.cpp
中定义了它们,以防止LNK Error 2005 - object already defined
。
register.cpp
#include "Register.h"
#include <iostream>
#include <iomanip>
namespace vpc {
template<>
Register<u8>::Register(u16 val, u8 idx) {
assert(idx == 0 || idx == 1);
getByteFrom(val, idx, currentValue);
this->bits = this->currentValue;
}
template<>
Register<u8>::Register(u32 val, u8 idx) {
assert(idx >= 0 && idx <= 3);
getByteFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
template<>
Register<u8>::Register(u64 val, u8 idx) {
assert(idx >= 0 && idx <= 7);
getByteFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
// Reg16
template<>
Register<u16>::Register(u32 val, u8 idx) {
assert(idx == 0 || idx == 1);
getWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
template<>
Register<u16>::Register(u64 val, u8 idx) {
assert(idx >= 0 && idx <= 3);
getWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
// Reg32
template<>
Register<u32>::Register(u64 val, u8 idx) {
assert(idx == 0 || idx == 1);
getDWordFrom(val, idx, this->currentValue);
this->bits = this->currentValue;
}
std::ostream& operator<<(std::ostream& os, const Reg8& r) {
os << "Reg8(" << +r.currentValue << ")n"
<< "hex: " << "0x" << std::uppercase
<< std::setfill('0') << std::setw(2) << std::hex
<< +r.currentValue << std::dec << 'n'
<< "bin: " << r.bits << 'n' << std::endl;
return os;
}
std::ostream& operator<<(std::ostream& os, const Reg16& r) {
os << "Reg16(" << r.currentValue << ")n"
<< "hex: " << "0x" << std::uppercase
<< std::setfill('0') << std::setw(4) << std::hex
<< r.currentValue << std::dec << 'n'
<< "bin: " << r.bits << 'n' << std::endl;
return os;
}
std::ostream& operator<<(std::ostream& os, const Reg32& r) {
os << "Reg32(" << r.currentValue << ")n"
<< "hex: " << "0x" << std::uppercase
<< std::setfill('0') << std::setw(8) << std::hex
<< r.currentValue << std::dec << 'n'
<< "bin: " << r.bits << 'n' << std::endl;
return os;
}
std::ostream& operator<<(std::ostream& os, const Reg64& r) {
os << "Reg64(" << r.currentValue << ")n"
<< "hex: " << "0x" << std::uppercase
<< std::setfill('0') << std::setw(16) << std::hex
<< r.currentValue << std::dec << 'n'
<< "bin: " << r.bits << 'n' << std::endl;
return os;
}
} // namespace vpc
现在我的申请程序:
main.cpp
#include <iostream>
#include "Register.h"
int main() {
using namespace vpc;
u16 val = 1420;
Reg16 r16(val); // used to show a 16 bit register
Reg8 r8A(val, 0); // construct an 8 bit register from low byte of val
Reg8 r8B(val, 1); // construct an 8 bit register from high byte of val
std::cout << r16 << r8A << r8B;
return EXIT_SUCCESS;
}
,我正在获得输出:
Reg16(1420)
hex: 0x058C
bin: 0000010110001100
Reg8(140)
hex: 0x8C
bin: 10001100
Reg8(5)
hex: 0x05
bin: 00000101
- "error: no matching function for call to"构造函数错误
- C++17复制构造函数,在std::unordereded_map上进行深度复制
- 如果C++类在类方法中具有动态分配,但没有构造函数/析构函数或任何非静态成员,那么它仍然是POD类型吗
- 为什么在没有显式默认构造函数的情况下,将另一个结构封装在联合中作为成员的结构不能编译
- 为什么在C++中使用私有复制构造函数与删除复制构造函数
- 选择要调用的构造函数
- 如何委托派生类使用其父构造函数?
- 构造函数正在调用一个使用当前类类型的函数
- 没有用于初始化C++中的变量模板的匹配构造函数
- 初始化具有非默认构造函数的std::数组项的更好方法
- 当从函数参数中的临时值调用复制构造函数时
- 在c++构造函数中使用随机字符串生成器
- 一对向量构造函数:初始值设定项列表与显式构造
- 从构造函数抛出异常时如何克服内存泄漏
- 我不明白为什么我声明一个空的内部结构并将其传递给构造函数
- 继承:构造函数,初始化C++11中基类的类C数组成员
- 为什么此C++代码中的构造函数模棱两可以及如何修复它
- 将一组类转换为类模板并避免构造函数模棱两可
- C 汇编错误:对构造函数的引用是模棱两可的
- 为什么我的 T& 和 T&& copy 构造函数模棱两可?