如何直接从char *数组创建一个std :: string而不复制？ [英] How to create a std::string directly from a char* array without copying?

问题描述

假设我有一个字符数组，我已经在堆上分配，我想将其转换为std :: string。目前我正在做以下事情：

Say I have an array of chars, which I have allocated on the heap, and which I want to convert into an std::string. Currently I am doing the following:

char *array = new char[size];
WriteIntoArray(array, size);
std::string mystring(array);
delete[] array;
return mystring; // or whatever

根据我在互联网上阅读的内容（http://www.cplusplus.com / reference / string / string / string /），字符串构造函数执行我传递的缓冲区的副本，让我释放缓冲区（稍后，字符串释放它的内部缓冲区）。我想要做的是分配我的缓冲区，将它的传输控制到字符串，然后让它释放我的缓冲区，当它被破坏。

From what I read on the internet (http://www.cplusplus.com/reference/string/string/string/), the string constructor performs a copy of the buffer I pass it, leaving me to free the buffer (later, the string frees its internal buffer). What I would like to do is to allocate my buffer, transfer control of it to the string, and then have it free my buffer when it is destructed.

问题<一个href =http://stackoverflow.com/questions/361500/initializing-stdstring-from-char-without-copy>初始化std :: string从char *无副本看起来有希望，但我的代码依赖在上面的例子中的API调用（WriteIntoArray），它必须写入一个字符数组，所以我必须创建一个C风格的char *缓冲区，不能转换我的代码只使用内置的字符串操作

The question initializing std::string from char* without copy looked promising, but my code relies on API calls ("WriteIntoArray" in the above example) which have to write into an array of chars, so I have to create a C-style char* buffer, and cannot convert my code to use only built-in string operations (which was the answer suggested).

有没有一些标准的方法来做到这一点，还是我应该写自己的字符串类（ugh）？谢谢！

Is there some standard way to do this, or should I just write my own string class (ugh)? Thanks!

推荐答案

如果你使用一个符合C ++ 0x的实现或许多C ++库中的一个，存储为 std :: string ，那么你可以得到一个 char * 直接指向你的 std :: string 。

If you're using a conforming C++0x implementation, or one of the many C++ libraries that guarantee contiguous storage for std::string, then you can get a char* that points directly to the storage used by your std::string.

例如：

std::string mystring;
mystring.resize(size);
WriteIntoArray(&mystring[0], size);
return mystring;

然而，您可能必须仔细考虑一个空终止符。

You may have to think carefully about a null terminator, however.

这篇关于如何直接从char *数组创建一个std :: string而不复制？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！