boost::operator>>

Extracts a dynamic_bitset from an input stream.

Synopsis

Declared in <boost/dynamic_bitset/dynamic_bitset.hpp>

template<
    typename CharT,
    typename Traits,
    typename Block,
    typename AllocatorOrContainer>
std::basic_istream<CharT, Traits>&
operator>>(
    std::basic_istream<CharT, Traits>& is,
    dynamic_bitset<Block, AllocatorOrContainer>& b);

Definitions

  • A (non‐eof) character c extracted from is is a bitset digit if and only if either Traits::eq(c, is.widen('0')) or Traits::eq(c, is.widen('1')) return true.

  • If c is a bitset digit, its corresponding bit value is 0 if Tr::eq(c, is.widen('0')) returns true, 1 otherwise.

The extractor begins by constructing a sentry object k as if by `typename std::basic_istream< Char, Traits >::sentry k( is ). If `bool( k ) is true, it calls b.clear()` then attempts to extract characters from `is. For each character c that is a bitset digit, the corresponding bit value is appended to the less significant end of b (appending may throw). If is.width() is greater than zero and smaller than b.max_size() then the maximum number n of bits appended is is.width(); otherwise n = b.max_size(). Unless the extractor is exited via an exception, characters are extracted (and corresponding bits appended) until any of the following occurs:

  • n bits are stored into the bitset;

  • end‐of‐file, or an error, occurs on the input sequence;

  • the next available input character isn't a bitset digit.

If no exception caused the function to exit then is.width( 0 ) is called, regardless of how many characters were actually extracted. The sentry object k is destroyed.

If the function extracts no characters, it calls `is.setstate( std::ios::failbit )`, which may throw `std::ios_base::failure`.

Return Value

is.

Parameters

Name Description

is

The left operand

b

The right operand

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