以二进制格式输出对象基本思路是直接将对象的内存数值以二进制的格式输出,但是如何获取对象内存的二进制结构
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是关键。解决方法是通过位操作找出对象内存的每一个bit的值。并把该方法封装成一个迭代器。 3 \9][S-B
要注意的问题是位操作符只能对整数类型进行操作,为了对所有类型的对象都有效,必须将对 I9s$bRbT
象当作char数组来处理。 RQJ9MGw
template<class Container> ?ZM^%]/+
class bit_iterator : public std::iterator<bidirectional_iterator_tag, K \m4*dOv
void, void> ].c@Gm_(
{ ^"/Dih\_
public: 1uj05aZh}
explicit bit_iterator(Container& c) : m_container(&c) :Q#H(\26r
{ :EaiM J_=
m_size = 8*sizeof(Container); 4]M =q{
m_index = 0; vD"_X"v
} OUKj@~T
explicit bit_iterator() : m_container(0) E-[:.
&
{ {)jk_&c7
m_size = 8*sizeof(Container); $/y%[ .
m_index = m_size; fzOMX
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} y#GCtkhi
bool operator* () ^$?7H>=_ha
{ Hm<M@M$aG
char mask = 1; 7j{Te)"
char* pc = (char*)m_container; 6;[1Jz]?i
int i = (m_size-m_index-1)/8; @<%oIE~]F
int off = (m_size-m_index-1)%8; 4I+.^7d
mask <<=off; jFS'I*1+
return pc & mask; L)=8mF.
} vJzx Py|
bit_iterator<Container>& operator++() ^S:cNRSW"
{ )OS>9
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m_index++; HK=CP0H
return *this; /:Rn"0
} |^\Hv5
bit_iterator<Container>& operator++(int) /6 A:J]Q_
{ B1up^(?
m_index++; 'XG:1Bpm
return *this; wZ}n3R,
} X~`.}
bool operator==(bit_iterator<Container>& bitIt) cG<Q`(5~
{ FL5ibg
return m_index == bitIt.m_index; U=_~{[/
} v_[)FN"]Y.
bool operator!=(bit_iterator<Container>& bitIt) @)S sKk|
{ I>(;bNgNE
return !(*this == bitIt); Jq=X!mTd.
} :K!GR
protected: Q;d+]xj
Container* m_container; U`HXsq
p}
private: ,7WK<0
int m_size; @|jKO5Y
int m_index; BvNl?A@]A
}; +6i7,U
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用该迭代器可以将任意类型对象以二进制格式输出: w50.gr7
double a = 10; &zaW"uy3T
copy(bit_iterator<double>(a), bit_iterator<double> (), ostream_iterator<bool>(cout, ""));