C++像这样将数组从char转换为unsigned int正确且安全吗

C++ Is it proper and safe to convert an array from char to unsigned int like this?

本文关键字：int 安全 unsigned 像这样 数组 转换 char C++      更新时间：2023-10-16

目标：正确快速地将数组从char转换为无符号int。

检查我的工作-请：

...
// NOTE:
// m_chFileBuffer is a member/variable from a class.
// m_nFileSize is also a member/variable from a class.
// iFile is declared locally as std::ifstream
// Calculate the size of iFile and copy the calculated
// value to this->m_nFileSize
iFile.seekg( 0, std::ios::end );
this->m_nFileSize = iFile.tellg( );
iFile.seekg( 0, std::ios::beg );
// Declare this->m_chFileBuffer as a new char array
this->m_chFileBuffer = new char[ this->m_nFileSize ];
// Read iFile into this->m_chFileBuffer
iFile.read( this->m_chFileBuffer, this->m_nFileSize );
// Declare a new local variable
::UINT *nFileBuffer = new ::UINT[ this->m_nFileSize ];
// Convert this->m_chFileBuffer from char to unsigned int (::UINT)
// I might be doing this horribly wrong, but at least I tried and
// will end up learning from my mistakes!
for( ::UINT nIndex = 0; nIndex != this->m_nFileSize; nIndex ++ )
{
    nFileBuffer[ nIndex ] = static_cast< ::UINT >( this->m_chFileBuffer[ nIndex ] );
    // If defined DEBUG, print the value located at nIndex within nFileBuffer
    #ifdef DEBUG
    std::cout << nFileBuffer[ nIndex ] << ' ';
    #endif // DEBUG
}
// Do whatever with nFileBuffer
...
// Clean-up
delete [ ] nFileBuffer;

有什么事吗？：如果有更好的方法来完成目标，请在下面发帖！

更多：有可能将这个概念应用于无符号int std：：向量吗？

对于这样一个简单的任务来说，代码太多了，你只需要这个。

std::vector <unsigned int> v;
std::copy (std::istream_iterator <char> (iFile), 
           std::istream_iterator <char> (), 
           std::back_inserter (v));

或者更短(感谢@1111111(：

std::vector <unsigned int> v 
{ 
       std::istream_iterator <char> (iFile),
       std::istream_iterator <char> ()
};

vector<char> buf(file_size);
/* read file to &buf[0] */
vector<unsigned int> uints(buf.size());
copy(buf.begin(), buf.end(), uints.begin());

您的原始新/删除用法并非异常安全。经验法则：永远不要在代码中写delete，只要你自己没有写析构函数。此外，"char"可能是签名的，不确定您期望的行为。

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