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# CharConv
This library is a C++11 compatible implementation of `<charconv>`. The full documentation can be found here: https://www.boost.org/doc/libs/master/libs/charconv/doc/html/charconv.html
# Build Status
| | Master | Develop |
|---------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Github Actions | [](https://github.com/boostorg/charconv/actions/workflows/ci.yml) | [](https://github.com/boostorg/charconv/actions/workflows/ci.yml) |
| Drone | [](https://drone.cpp.al/boostorg/charconv) | [](https://drone.cpp.al/boostorg/charconv) |
| Codecov | [](https://codecov.io/gh/boostorg/charconv/branch/master) | [](https://codecov.io/gh/boostorg/charconv/branch/develop) |
| Fuzzing | [](https://github.com/boostorg/charconv/actions/workflows/fuzz.yml) | [](https://github.com/boostorg/charconv/actions/workflows/fuzz.yml)|
# How to build the library
## B2
````
git clone https://github.com/boostorg/boost
cd boost
git submodule update --init
cd ..
./bootstrap
./b2 cxxstd=11
````
This sets up a complete boost development and allows the tests to be run. To install the development environment run:
````
sudo ./b2 install cxxstd=11
````
# Synopsis
Charconv is a collection of parsing functions that are locale-independent, non-allocating, and non-throwing.
````
namespace boost { namespace charconv {
enum class chars_format : unsigned
{
scientific = 1 << 0,
fixed = 1 << 1,
hex = 1 << 2,
general = fixed | scientific
};
struct from_chars_result
{
const char* ptr;
std::errc ec;
friend constexpr bool operator==(const from_chars_result& lhs, const from_chars_result& rhs) noexcept
friend constexpr bool operator!=(const from_chars_result& lhs, const from_chars_result& rhs) noexcept
constexpr explicit operator bool() const noexcept
}
template <typename Integral>
BOOST_CXX14_CONSTEXPR from_chars_result from_chars(const char* first, const char* last, Integral& value, int base = 10) noexcept;
BOOST_CXX14_CONSTEXPR from_chars_result from_chars<bool>(const char* first, const char* last, bool& value, int base) = delete;
template <typename Real>
from_chars_result from_chars(const char* first, const char* last, Real& value, chars_format fmt = chars_format::general) noexcept;
template <typename Real>
from_chars_result from_chars_erange(const char* first, const char* last, Real& value, chars_format fmt = chars_format::general) noexcept;
struct to_chars_result
{
char* ptr;
std::errc ec;
friend constexpr bool operator==(const to_chars_result& lhs, const to_chars_result& rhs) noexcept;
friend constexpr bool operator!=(const to_chars_result& lhs, const to_chars_result& rhs) noexcept;
constexpr explicit operator bool() const noexcept
};
template <typename Integral>
BOOST_CHARCONV_CONSTEXPR to_chars_result to_chars(char* first, char* last, Integral value, int base = 10) noexcept;
template <typename Integral>
BOOST_CHARCONV_CONSTEXPR to_chars_result to_chars<bool>(char* first, char* last, Integral value, int base) noexcept = delete;
template <typename Real>
to_chars_result to_chars(char* first, char* last, Real value, chars_format fmt = chars_format::general, int precision) noexcept;
}} // Namespace boost::charconv
````
## Notes
- `BOOST_CXX14_CONSTEXPR` is defined as `constexpr` when compiling with C++14 or newer.
- `BOOST_CHARCONV_CONSTEXPR` is defined as `constexpr` when compiling with C++14 or newer, and the compiler has `__builtin_is_constant_evaluated`
- For explanation of `from_chars_erange` see docs under heading: _Usage notes for from_chars for floating point types_
# Examples
## `from_chars`
````
const char* buffer = "42";
int v = 0;
from_chars_result r = boost::charconv::from_chars(buffer, buffer + std::strlen(buffer), v);
assert(r.ec == std::errc());
assert(r); // Equivalent to the above
assert(v == 42);
const char* buffer = "1.2345"
double v = 0;
auto r = boost::charconv::from_chars(buffer, buffer + std::strlen(buffer), v);
assert(r.ec == std::errc());
assert(v == 1.2345);
const char* buffer = "2a";
unsigned v = 0;
auto r = boost::charconv::from_chars(buffer, buffer + std::strlen(buffer), v, 16);
assert(r); // from_chars_result has operator bool()
assert(v == 42);
const char* buffer = "1.3a2bp-10";
double v = 0;
auto r = boost::charconv::from_chars(buffer, buffer + std::strlen(buffer), v, boost::charconv::chars_format::hex);
assert(r);
assert(v == 8.0427e-18);
````
## `to_chars`
````
char buffer[64] {};
int v = 42;
to_chars_result r = boost::charconv::to_chars(buffer, buffer + sizeof(buffer), v);
assert(r.ec == std::errc());
assert(!strcmp(buffer, "42")); // strcmp returns 0 on match
char buffer[64] {};
double v = 1e300;
to_chars_result r = boost::charconv::to_chars(buffer, buffer + sizeof(buffer), v);
assert(r.ec == std::errc());
assert(!strcmp(buffer, "1e+300"));
char buffer[64] {};
int v = 42;
to_chars_result r = boost::charconv::to_chars(buffer, buffer + sizeof(buffer), v, 16);
assert(r); // to_chars_result has operator bool()
assert(!strcmp(buffer, "2a")); // strcmp returns 0 on match
````
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