Write with known number of digits

Writes a value without checking the buffer length with regards to the required number of digits to encode the value. More...

Functions
template<class T >
void	c4::write_dec_unchecked (substr buf, T v, unsigned digits_v) noexcept
template<class T >
void	c4::write_hex_unchecked (substr buf, T v, unsigned digits_v) noexcept
template<class T >
void	c4::write_oct_unchecked (substr buf, T v, unsigned digits_v) noexcept
template<class T >
void	c4::write_bin_unchecked (substr buf, T v, unsigned digits_v) noexcept

Detailed Description

Writes a value without checking the buffer length with regards to the required number of digits to encode the value.

It is the responsibility of the caller to ensure that the provided number of digits is enough to write the given value. Notwithstanding the name, assertions are liberally performed, so this code is safe.

Function Documentation

write_dec_unchecked()

template<class T >

void c4::write_dec_unchecked ( substr  buf, T  v, unsigned  digits_v  )

inlinenoexcept

Definition at line 608 of file charconv.hpp.

{
    C4_STATIC_ASSERT(std::is_integral<T>::value);
    C4_ASSERT(v >= 0);
    C4_ASSERT(buf.len >= digits_v);
    C4_XASSERT(digits_v == digits_dec(v));
    // in bm_xtoa: checkoncelog_singlediv_write2
    while(v >= T(100))
    {
        T quo = v;
        quo /= T(100);
        const auto num = (v - quo * T(100)) << 1u;
        v = quo;
        buf.str[--digits_v] = detail::digits0099[num + 1];
        buf.str[--digits_v] = detail::digits0099[num];
    }
    if(v >= T(10))
    {
        C4_ASSERT(digits_v == 2);
        const auto num = v << 1u;
        buf.str[1] = detail::digits0099[num + 1];
        buf.str[0] = detail::digits0099[num];
    }
    else
    {
        C4_ASSERT(digits_v == 1);
        buf.str[0] = (char)('0' + v);
    }
}

References c4::digits_dec().

Referenced by c4::itoa(), c4::utoa(), and c4::write_dec().

write_hex_unchecked()

template<class T >

void c4::write_hex_unchecked ( substr  buf, T  v, unsigned  digits_v  )

inlinenoexcept

Definition at line 641 of file charconv.hpp.

{
    C4_STATIC_ASSERT(std::is_integral<T>::value);
    C4_ASSERT(v >= 0);
    C4_ASSERT(buf.len >= digits_v);
    C4_XASSERT(digits_v == digits_hex(v));
    do {
        buf.str[--digits_v] = detail::hexchars[v & T(15)];
        v >>= 4;
    } while(v);
    C4_ASSERT(digits_v == 0);
}

References c4::digits_hex().

Referenced by c4::itoa(), c4::utoa(), and c4::write_hex().

write_oct_unchecked()

template<class T >

void c4::write_oct_unchecked ( substr  buf, T  v, unsigned  digits_v  )

inlinenoexcept

Definition at line 657 of file charconv.hpp.

{
    C4_STATIC_ASSERT(std::is_integral<T>::value);
    C4_ASSERT(v >= 0);
    C4_ASSERT(buf.len >= digits_v);
    C4_XASSERT(digits_v == digits_oct(v));
    do {
        buf.str[--digits_v] = (char)('0' + (v & T(7)));
        v >>= 3;
    } while(v);
    C4_ASSERT(digits_v == 0);
}

References c4::digits_oct().

Referenced by c4::itoa(), c4::utoa(), and c4::write_oct().

write_bin_unchecked()

template<class T >

void c4::write_bin_unchecked ( substr  buf, T  v, unsigned  digits_v  )

inlinenoexcept

Definition at line 673 of file charconv.hpp.

{
    C4_STATIC_ASSERT(std::is_integral<T>::value);
    C4_ASSERT(v >= 0);
    C4_ASSERT(buf.len >= digits_v);
    C4_XASSERT(digits_v == digits_bin(v));
    do {
        buf.str[--digits_v] = (char)('0' + (v & T(1)));
        v >>= 1;
    } while(v);
    C4_ASSERT(digits_v == 0);
}

References c4::digits_bin().

Referenced by c4::itoa(), c4::utoa(), and c4::write_bin().