技術標籤：C++筆記

#include <stdio.h>
#include <string.h>
#include <openssl/md5.h>

bool funFileMD5SUM(char* lpcstrFilePath, char *pbymd5Buff)
{
	bool bRet = false;
	
	unsigned char achbyBuff[17] = {0};
	unsigned char *pbyBuff = achbyBuff;
	FILE *inFile = fopen (lpcstrFilePath, "rb");
	MD5_CTX mdContext;
	int bytes;
	unsigned char data[1024];
	
	if (inFile == NULL) {
		printf( "%s can't be opened.\n", lpcstrFilePath);
		return bRet;
	}
	
	MD5_Init (&mdContext);
	while ((bytes = fread (data, 1, 1024, inFile)) != 0)
		MD5_Update (&mdContext, data, bytes);
	MD5_Final (pbyBuff,&mdContext);
	char szBuf[1024] = {0};
	for(int i = 0; i < MD5_DIGEST_LENGTH; i++) 
	{
		sprintf(&szBuf[i*2], "%02x", pbyBuff[i]);
	}
	strcpy((char*)pbymd5Buff, (char*)szBuf);
	strcat(szBuf, "  ");
	strcat(szBuf, lpcstrFilePath);
	printf( "md5sum %d %s\n", MD5_DIGEST_LENGTH,  szBuf);

	fclose (inFile);
	bRet = true;
	
    return bRet;
}

bool funStrMD5SUM(char* lpcstrFilePath,int bytes, char* pbymd5Buff)
{
	bool bRet = false;

	unsigned char achbyBuff[17] = {0};
	unsigned char *pbyBuff = achbyBuff;

	MD5_CTX mdContext;
	
	unsigned char data[1024];

	MD5_Init (&mdContext);

	MD5_Update (&mdContext, lpcstrFilePath, bytes);
	MD5_Final (pbyBuff,&mdContext);
	char szBuf[1024] = {0};
	for(int i = 0; i < MD5_DIGEST_LENGTH; i++) 
	{
		sprintf(&szBuf[i*2], "%02x", pbyBuff[i]);
	}
	strcpy((char*)pbymd5Buff, (char*)szBuf);
	strcat(szBuf, "  ");
	strcat(szBuf, lpcstrFilePath);
	printf( "md5sum %d %s\n", MD5_DIGEST_LENGTH,  szBuf);

	bRet = true;
	return bRet;
}

int main(int argc, char* argv[])  
{  
	char achMd5[100]= {0};
	funStrMD5SUM("hello", 5, achMd5);
	memset(achMd5,0, sizeof(achMd5));
	funFileMD5SUM("./test.cpp",achMd5);
	return 0;
}

執行結果：
[
 
[email protected] root]# g++ -l  crypto test.cpp 
[[email protected] root]# ./a.out 
md5sum 16 5d41402abc4b2a76b9719d911017c592  hello
md5sum 16 b87156248bdddfe954d352fcd38deaeb  ./test.cpp

執行shell命令檢視結果是否正確：
[[email protected] root]# echo -n "hello" |md5sum
5d41402abc4b2a76b9719d911017c592  -
[
 
[email protected] root]# md5sum ./test.cpp 
b87156248bdddfe954d352fcd38deaeb  ./test.cpp
[[email protected] root]# 

編譯的時候要加上庫連線，否則會出現下面的報錯：

[[email protected] root]# g++  test.cpp 
/tmp/cc7OEI36.o：在函式‘funFileMD5SUM(char*, char*)’中：
test.cpp:(.text+0x85)：對‘MD5_Init’未定義的引用
test.cpp:(.text+0xd2)：對‘MD5_Update’未定義的引用
test.cpp:(.text+0xea)：對‘MD5_Final’未定義的引用
/tmp/cc7OEI36.o：在函式‘funStrMD5SUM(char*, int, char*)’中：
test.cpp:(.text+0x239)：對‘MD5_Init’未定義的引用
test.cpp:(.text+0x25b)：對‘MD5_Update’未定義的引用
test.cpp:(.text+0x271)：對‘MD5_Final’未定義的引用
collect2: 錯誤：ld 返回 1