C++获取文件哈希值(hash)和获取torrent(bt种子)磁力链接哈希值

#pragma once
#include "sha1.h"

#define        SIZE_OF_BUFFER         16000

class CHash
{
// Construction
public:
    CString SHA1Hash(CString strHashFile);
};

CString CHash::SHA1Hash(CString strHashFile)
{
    USES_CONVERSION;
    FILE *fileToHash = NULL;
    unsigned long lenRead = 0;
    unsigned char fileBuf[SIZE_OF_BUFFER];
    sha1_ctx m_sha1;
    unsigned char* tempOut = new unsigned char[256];
    CString    tempHash;
    CString outHash;

    sha1_begin(&m_sha1);

    fileToHash = fopen(T2A(strHashFile), "rb");
    do
    {
        lenRead = fread(fileBuf, 1, SIZE_OF_BUFFER, fileToHash);
        if(lenRead != 0)
        {
            sha1_hash(fileBuf, lenRead, &m_sha1);
        }
    } while (lenRead == SIZE_OF_BUFFER);

    fclose(fileToHash); fileToHash = NULL;

    sha1_end(tempOut, &m_sha1);

    for (int i = 0 ; i < 20 ; i++)
    {
        char tmp[3];
        _itoa(tempOut[i], tmp, 16);
        if (strlen(tmp) == 1)
        {
            tmp[1] = tmp[0];
            tmp[0] = '0';
            tmp[2] = '\0';
        }
        tempHash += tmp;   

    }

    delete[] tempOut;

    outHash = tempHash;

    return outHash;
}