6 Commits

3 changed files with 77 additions and 3 deletions

1
.gitignore vendored
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@@ -1,4 +1,5 @@
build
cmake-build-debug
cmake-build-release
cmake-build-relwithdebinfo
.idea

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@@ -11,8 +11,7 @@ During compile-time, the string to be formatted is preprocessed to the point onl
have to be written (If they are not available at compile time).
For example `One number: {:03}; And another one: {:05.3}` is preprocessed into `One number: 000; And another one: 00.000`.
This is returned as a `std::array<char, N>`, where `N` is automatically evaluated. The only code executed at compile
time then formats the numbers and writes them into their place in the array.
This is returned as a `std::array<char, N>`, where `N` is automatically evaluated. The only code executed at runtime then formats the numbers and writes them into their places in the array.
Disclaimer: The actual formatting code is largely shamelessly stolen from `fmtlib`.
@@ -48,8 +47,11 @@ $ ctest --test-dir build/
## Limitations
For the compile time preprocessing of format strings non non-type template parameters are heavily relied upon,
which means C++20 is required.
Only a relatively limited subset of the `fmtlib` syntax is recognized (for now anyway). In particular,
there is no support for positional arguments, alignment, chrono format specs and custom const_format specifications.
float formatting in decimal and integer formatting in decimal, binary and hexadecimal are supported.
By nature of the library design, which forces compile-time preprocessing of the const_format string, no dynamic width or
dynamic precision can be implemented.

71
const_fmt/std_lib.h Normal file
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@@ -0,0 +1,71 @@
#ifndef CONST_FMT_STD_LIB_H
#define CONST_FMT_STD_LIB_H
#ifdef CONST_FMT_NO_STD_LIB
#include <stdint.h>
namespace std {
using size_t = uint16_t;
// TODO: Is std::size_t really the best bet here?
template <typename data_t, std::size_t t_size>
class array {
public:
// Constructors
array() = default;
array(const array& other) = default;
array(array&& other) = default;
// Operators
array operator=(const array& other) = default;
array operator=(array&& other) = default;
// Element access
data_t& operator[](std::size_t index) {
return m_data[index];
}
const data_t& operator[](std::size_t index) const {
return m_data[index];
}
// Iterators
using iterator = data_t*;
using const_iterator = const data_t*;
iterator begin() {
return &(m_data[0]);
}
iterator end() {
return (&(m_data[t_size-1]) + 1);
}
const iterator cbegin() const {
return &(m_data[0]);
}
const iterator cend() const {
return (&(m_data[t_size-1]) + 1);
}
private:
data_t m_data[t_size];
};
} // namespace std
#endif
#endif // CONST_FMT_STD_LIB_H