std::ifstream读取文件
unsigned char* pFileBytes = nullptr;
unsigned int nTotalSize = 0;
std::ifstream infile("1.dat", std::ios_base::in | std::ios_base::binary);
if (infile.is_open())
{
infile.seekg(0, std::ios_base::end);
unsigned long long nFileSize = infile.tellg();
if (0 == nFileSize)
{
assert(false);
return;
}
pFileBytes = new unsigned char[nFileSize];
infile.seekg(0, std::ios_base::beg);
memset(pFileBytes, 0, nFileSize);
//1、每次读取8K
//do
//{
// infile.read((char*)(pFileBytes + nTotalSize), 8192);
// int nReadBytes = infile.gcount();
// if (nReadBytes > 0) nTotalSize += nReadBytes;
//} while (infile.good());
//2、一次性读取所有,read会阻塞,直到所有的都读取完或出现错误才返回
infile.read((char*)(pFileBytes + nTotalSize), nFileSize);
int nReadBytes = infile.gcount();
if (nReadBytes > 0) nTotalSize += nReadBytes;
infile.close();
}
std::ofstream写文件
与std::ifstream差不多,write也会阻塞,直到所有的都写完或出现错误才返回,代码略