Extra Library

Overview

A simple header-only library containing miscellaneous utility macros, functions, and types for C and C++.

Features

xtr::enumerate

A helper function for accessing the index in a range-based for loop.

std::vector<int> vec1{20, 40, 60, 80};

// Keeping track of the index manually with a ranged-based for loop
std::size_t index = 0;
for (auto &&value : vec1) {
  // Access index and value for each element in the vector
  ++index;
}

// Equivalent code with xtr::enumerate
for (auto &&[index, value] : xtr::enumerate(vec1)) {
  // Access index and value for each element in the vector
}

auto make_vec = []() { return std::vector{20, 40, 60, 80}; };

// Works correctly with temporaries
for (auto &&[index, value] : xtr::enumerate(make_vec())) {
  // Access index and value for each element in the vector
}

// Construct the container in place using the variadic overload
for (auto &&[index, value] : xtr::enumerate<std::vector<int>>(20, 40, 60, 80)) {
  // Access index and value for each element in the vector
}

The value in the range-based for loop is a std::tuple storing 2 values, the index and element value respectively. If the container has a member type size_type, then the index is a const qualified value of that type. Otherwise, the index is a const qualified std::size_t. The type of the element value is the same as in a regular range-based for loop.

xtr::multiarray

A type alias to std::array for a more readable multidimensional array syntax.

// 2D array using a C style array
int arr1[5][10] = { 0 };

// 2D array using std::array without type alias
std::array<std::array<int, 10>, 5> arr2;

// 2D array using std::array with xtr::multiarray alias
xtr::multiarray<int, 5, 10> arr3;

static_assert(std::is_same_v<decltype(arr2), decltype(arr3)>);

xtr::is_aligned

A helper function for checking the alignment of memory addresses

char val = 65;

// Always true
assert(xtr::is_aligned<char>(&val));

// Maybe not true
assert(xtr::is_aligned<int>(&val));

Macros for debug logging

• Macro function debug_log prints a message to stdout when in debug mode

Macros for compiler optimization hints

• Macro function assume tells the compiler to assume an expression will always be true
• Macro function assert_assume combines assume behavior with an assertion in debug mode
• Macro functions likely and unlikely hint to the compiler the likelihood of an expression being true
• Macro restrict enables the C language restrict keyword in C++

Additional macro functions

• Macro functions concat_string, literal_string, and macro_string for dealing with string literals and macros

License

Licensed under MIT.