Question

我如何调用这些包装中的任何一个？它们看起来像阵列或者我很困惑的东西

static auto w_printf = [](const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vprintf_s(fmt, args);
    va_end(args);
};

static auto w_printf_s = [](const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vprintf_s(fmt, args);
    va_end(args);
};

static auto w_sprintf = [](char* buf, const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vsprintf(buf, fmt, args);
    va_end(args);
};

static auto w_sprintf_s = [](char* buf, size_t buf_size, const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vsprintf_s(buf, buf_size, fmt, args);
    va_end(args);
};

我试过

char mytext[255] = { 0 };
//sprintf_s(mytext, "old [debug mode]");
w_sprintf(mytext, XorStr("new [debug mode]"));

但无法编译

Error   C3861   'w_sprintf': identifier not found

它说我必须使用这些包装器，因为在sprintf_s中使用XorStr宏会崩溃Visual Studio 2015中的链接器有关Microsoft Compiler / Linker的内容与变量模板无法正常工作，这些包装函数应该可以解决问题但是我不知道怎么称呼他们。

我试图在编译时隐藏程序集中的字符串并且它到目前为止工作正常，但某些事情如sprintf_s崩溃，这个编译时字符串隐藏的创建者说我需要使用这些包装器，但没有给出如何实例。

#pragma once
#include <string>
#include <array>
#include <cstdarg>

#define BEGIN_NAMESPACE( x ) namespace x {
#define END_NAMESPACE }

BEGIN_NAMESPACE(XorCompileTime)

constexpr auto time = __TIME__;
constexpr auto seed = static_cast< int >(time[7]) + static_cast< int >(time[6]) * 10 + static_cast< int >(time[4]) * 60 + static_cast< int >(time[3]) * 600 + static_cast< int >(time[1]) * 3600 + static_cast< int >(time[0]) * 36000;

// 1988, Stephen Park and Keith Miller
// "Random Number Generators: Good Ones Are Hard To Find", considered as "minimal standard"
// Park-Miller 31 bit pseudo-random number generator, implemented with G. Carta's optimisation:
// with 32-bit math and without division

template < int N >
struct RandomGenerator
{
private:
    static constexpr unsigned a = 16807; // 7^5
    static constexpr unsigned m = 2147483647; // 2^31 - 1

    static constexpr unsigned s = RandomGenerator< N - 1 >::value;
    static constexpr unsigned lo = a * (s & 0xFFFF); // Multiply lower 16 bits by 16807
    static constexpr unsigned hi = a * (s >> 16); // Multiply higher 16 bits by 16807
    static constexpr unsigned lo2 = lo + ((hi & 0x7FFF) << 16); // Combine lower 15 bits of hi with lo's upper bits
    static constexpr unsigned hi2 = hi >> 15; // Discard lower 15 bits of hi
    static constexpr unsigned lo3 = lo2 + hi;

public:
    static constexpr unsigned max = m;
    static constexpr unsigned value = lo3 > m ? lo3 - m : lo3;
};

template <>
struct RandomGenerator< 0 >
{
    static constexpr unsigned value = seed;
};

template < int N, int M >
struct RandomInt
{
    static constexpr auto value = RandomGenerator< N + 1 >::value % M;
};

template < int N >
struct RandomChar
{
    static const char value = static_cast< char >(1 + RandomInt< N, 0x7F - 1 >::value);
};

template < size_t N, int K >
struct XorString
{
private:
    const char _key;
    std::array< char, N + 1 > _encrypted;

    constexpr char enc(char c) const
    {
        return c ^ _key;
    }

    char dec(char c) const
    {
        return c ^ _key;
    }

public:
    template < size_t... Is >
    constexpr __forceinline XorString(const char* str, std::index_sequence< Is... >) : _key(RandomChar< K >::value), _encrypted{ enc(str[Is])... }
    {
    }

    __forceinline decltype(auto) decrypt(void)
    {
        for (size_t i = 0; i < N; ++i) {
            _encrypted[i] = dec(_encrypted[i]);
        }
        _encrypted[N] = '\0';
        return _encrypted.data();
    }
};

//--------------------------------------------------------------------------------
//-- Note: XorStr will __NOT__ work directly with functions like printf.
//         To work with them you need a wrapper function that takes a const char*
//         as parameter and passes it to printf and alike.
//
//         The Microsoft Compiler/Linker is not working correctly with variadic 
//         templates!
//  
//         Use the functions below or use std::cout (and similar)!
//--------------------------------------------------------------------------------

static auto w_printf = [](const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vprintf_s(fmt, args);
    va_end(args);
};

static auto w_printf_s = [](const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vprintf_s(fmt, args);
    va_end(args);
};

static auto w_sprintf = [](char* buf, const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vsprintf(buf, fmt, args);
    va_end(args);
};

static auto w_sprintf_s = [](char* buf, size_t buf_size, const char* fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vsprintf_s(buf, buf_size, fmt, args);
    va_end(args);
};

#define XorStr( s ) ( XorCompileTime::XorString< sizeof( s ) - 1, __COUNTER__ >( s, std::make_index_sequence< sizeof( s ) - 1>() ).decrypt() )

END_NAMESPACE

Answer 1

噢，我错过了命名空间嘿嘿

char mytext[255] = { 0 };
//sprintf_s(mytext, "old [debug mode]");
XorCompileTime::w_sprintf(mytext, XorStr("new [debug mode]"));

如何将这些包装用于printf sprintf sprintf_s？

1 个答案: