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Efficient Reading of Files into an std::vector
When seeking an optimal method for reading a file into an std::vector
For an optimized solution, the canonical approach involves using iterators:
#include <iterator> std::ifstream testFile("testfile", std::ios::binary); std::vector<char> fileContents((std::istreambuf_iterator<char>(testFile)), std::istreambuf_iterator<char>());
In this approach, two iterators are defined. One points to the beginning of the input file stream, and the other to the end. The vector is then constructed by iterating over the range defined by these iterators.
To mitigate potential reallocations during the read process, the reserve() method can be employed:
#include <iterator> std::ifstream testFile("testfile", std::ios::binary); std::vector<char> fileContents; fileContents.reserve(fileSize); fileContents.assign(std::istreambuf_iterator<char>(testFile), std::istreambuf_iterator<char>());
By reserving space within the vector prior to assigning values, the allocation efficiency is improved, reducing the likelihood of memory fragmentation and performance degradation.
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