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关于C#：char []十六进制字符串练习

2023-04-15 17:40:00

char[] to hex string exercise

下面是我当前使用的char *到十六进制字符串的函数。我将其写为位操纵的练习。在AMD Athlon MP 2800上花费约7毫秒来十六进制一千万个字节的阵列。我有什么想念的技巧或其他方式吗？

如何使它更快？

用-O3 in g

编译

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static const char _hex2asciiU_value[256][2] =
{ {'0','0'}, {'0','1'}, /* snip..., */ {'F','E'},{'F','F'} };

std::string char_to_hex( const unsigned char* _pArray, unsigned int _len )
{
std::string str;
str.resize(_len*2);
char* pszHex = &str[0];
const unsigned char* pEnd = _pArray + _len;

clock_t stick, etick;
stick = clock();
for( const unsigned char* pChar = _pArray; pChar != pEnd; pChar++, pszHex += 2 ) {
pszHex[0] = _hex2asciiU_value[*pChar][0];
pszHex[1] = _hex2asciiU_value[*pChar][1];
}
etick = clock();

std::cout <<"ticks to hexify" << etick - stick << std::endl;

return str;
}

更新

添加了计时码

Brian R. Bondy：用堆分配的缓冲区替换std :: string并将ofs * 16更改为ofs << 4-但是堆分配的缓冲区似乎减慢了速度？ -结果?11ms

Antti Syk？ri：用

替换内部循环

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