解析mmap（）的 - 编辑文件 [英] parsing a mmap()-ed file

问题描述

什么是最好的（最快）的方式通过mmap的-ED文件来分析？它包含了对数据（串INT），但我不能在它们之间persume空格/制表符/换行符号。

What would be the best (fastest) way to parse through a mmap-ed file? It contains pairs of data (string int), but I cannot persume number of whitespaces/tabs/newlines between them.

推荐答案

假设你已经mmaped整个文件（而不是大块 - 因为这将让生活awefully复杂），我会做类似如下..

Assuming you've mmaped the whole file in (rather than chunks - as that would make life awefully complicated), I'd do something like the following...

// Effectively this wraps the mmaped block
std::istringstream str;
str.rdbuf()->pubsetbuf(<pointer to start of mmaped block>, <size of mmaped block>);

std::string sv;
std::string iv;

while(str >> sv >> iv)
{
  // do stuff...
}

我觉得应该工作...

I think that should work...

警告这是实现定义的行为，请参阅这个答案一个更好的共做法。

WARNING This is implementation defined behaviour, see this answer for an altogether better approach.

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