AsciiUnicodeUtf8.h：

#pragma once
DWORD BytesToHexStr(IN BYTE*nbData,DWORD nbDataSize,OUT char*szpHexBuf); //字节集转十六进制字串
DWORD AnsiToUtf8(LPCSTR Ansi,OUT LPSTR szpUtf8Buf);
char* UniCodeToAscii(IN WCHAR*szpUnicodeStr,OUT char*szpAsciiStr);
char* utf8ToAscii(IN char*szpUtf8/*要转换的utf8字符串*/,OUT char*szpAscii/*转换后的多字节字符串*/); //转码函数

AsciiUnicodeUtf8.cpp：

#include <pch.h>
#include <Windows.h>
#include "AsciiUnicodeUtf8.h"

DWORD BytesToHexStr(IN BYTE*nbData,DWORD nbDataSize,OUT char*szpHexBuf); //字节集转十六进制字串
DWORD AnsiToUtf8(LPCSTR Ansi,OUT LPSTR szpUtf8Buf);
char* UniCodeToAscii(IN WCHAR*szpUnicodeStr,OUT char*szpAsciiStr);
WCHAR* utf8ToUnicode(IN char*szpUtf8 ,OUT WCHAR*szpUniCode);
//注意 此函数 没检测 缓冲区大小
char* utf8ToAscii(IN char*szpUtf8,OUT char*szpAscii);

BOOL CharToHex(OUT char*szpBufHex,BYTE c);

DWORD AnsiToUtf8(LPCSTR Ansi,OUT LPSTR szpUtf8Buf)
{
	int WLength = MultiByteToWideChar(CP_ACP, 0, Ansi, -1, NULL, 0);
	LPWSTR pszW = (LPWSTR) _alloca((WLength+1) * sizeof(WCHAR));
	//Ansi字串转Unicode字串
	MultiByteToWideChar(CP_ACP, 0, Ansi, -1, pszW, WLength);

	//计算UTF8转换所需要空间大小
	int ALength = WideCharToMultiByte(CP_UTF8, 0, pszW, -1, NULL, 0, NULL, NULL);     
	WideCharToMultiByte(CP_UTF8, 0, pszW, -1, szpUtf8Buf, ALength, NULL, NULL);
	szpUtf8Buf[ALength] = 0;
	szpUtf8Buf[ALength+1] = 0;
	return ALength; //返回UTF8字串长度
}



char* UniCodeToAscii(IN WCHAR*szpUnicodeStr,OUT char*szpAsciiStr)
{
	// 预算-缓冲区中多字节的长度    
	//CP_OEMCP
	int ansiiLen = WideCharToMultiByte(CP_ACP, 0,szpUnicodeStr, -1, nullptr, 0, nullptr, nullptr);  
	// 给指向缓冲区的指针变量分配内存    
	// 把 szpUnicodeStr里存放的Unicode编码字串 转成ASCII 存放到  szpAsciiStr缓冲区 
	//CP_OEMCP
	WideCharToMultiByte(CP_ACP, 0, szpUnicodeStr, -1, szpAsciiStr, ansiiLen, nullptr, nullptr);  

	return szpAsciiStr;
}



WCHAR* utf8ToUnicode(IN char*szpUtf8 ,OUT WCHAR*szpUniCode)
{
	// 预算-缓冲区中宽字节的长度    
	//CP_UTF8 963 页码
	int unicodeLen = MultiByteToWideChar(CP_UTF8, 0, szpUtf8, -1, nullptr, 0);  
	// 给指向缓冲区的指针变量分配内存    
	WCHAR *pUnicode = (wchar_t*)malloc(sizeof(wchar_t)*unicodeLen);  
	// 开始向缓冲区转换字节    
	//CP_UTF8 963页码 也可能
	MultiByteToWideChar(CP_UTF8, 0, szpUtf8, -1, pUnicode, unicodeLen);  
	wcscpy_s(  szpUniCode,unicodeLen,pUnicode);  
	free(pUnicode);  
	return szpUniCode;  

}

//注意 此函数 没检测 缓冲区大小
char* utf8ToAscii(IN char*szpUtf8,OUT char*szpAscii)
{
	int iSizeUtf8 = MultiByteToWideChar(CP_UTF8, 0, szpUtf8, -1, nullptr, 0); 
	WCHAR*putf8Buf=(WCHAR*)malloc(sizeof(WCHAR)*iSizeUtf8); //分配了内存 free
	utf8ToUnicode(szpUtf8,putf8Buf);
	UniCodeToAscii(putf8Buf,szpAscii);
	free(putf8Buf);//释放内存
	return szpAscii;
}


BOOL CharToHex(OUT char*szpBufHex,BYTE c)
{
	BYTE bLow=0;
	BYTE bHigh=0;
	bLow=c%16; //取低位0..15
	bHigh=c/16;//取高位0..15
	if (bHigh>9) //A,B,C,D,E,F
	{
		szpBufHex[0]='A'+bHigh-10; //'B'
	}else//0..9
	{
		szpBufHex[0]='0'+bHigh; //'0'+2='2'
	}
	if (bLow>9) //A,B,C,D,E,F
	{
		szpBufHex[1]='A'+bLow-10; //'B'
	}else//0..9
	{
		szpBufHex[1]='0'+bLow; //'0'+2='2'
	}
	szpBufHex[2]=0;//0
	return TRUE;
}
DWORD BytesToHexStr(IN BYTE*nbData,DWORD nbDataSize,OUT char*szpHexBuf) //字节集转十六进制字串
{
	//1 //01
	for (DWORD i=0;i<nbDataSize;i++)
	{   //提高速度
		//sprintf_s(&szpHexBuf[i*2],3,"%02X",nbData[i]);
		CharToHex(&szpHexBuf[i*2],nbData[i]);
	}
	return TRUE;
}