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std_bitset.h: Doxygenate std::bitset<>. 

2002-04-12  Phil Edwards  <pme@gcc.gnu.org>

	* include/std/std_bitset.h:  Doxygenate std::bitset<>.  Clean up
	trailing spaces, indentation, and macro names.  Make exception
	messages more informative.

From-SVN: r52233
parent 0339d239
Showing with 280 additions and 50 deletions
libstdc++-v3/ChangeLog
2002-04-12 Phil Edwards <pme@gcc.gnu.org>
* include/std/std_bitset.h: Doxygenate std::bitset<>. Clean up
trailing spaces, indentation, and macro names. Make exception
messages more informative.
2002-04-11 Richard Henderson <rth@redhat.com>
* include/bits/fstream.tcc (basic_filebuf<>::open): Fix & ordering.
......
libstdc++-v3/include/std/std_bitset.h
......@@ -45,21 +45,11 @@
* in your programs, rather than any of the "st[dl]_*.h" implementation files.
*/
#ifndef __GLIBCPP_BITSET
#define __GLIBCPP_BITSET
#ifndef _GLIBCPP_BITSET_H
#define _GLIBCPP_BITSET_H
#pragma GCC system_header
// A bitset of size N has N % (sizeof(unsigned long) * CHAR_BIT) unused
// bits. (They are the high- order bits in the highest word.) It is
// a class invariant of class bitset<> that those unused bits are
// always zero.
// Most of the actual code isn't contained in bitset<> itself, but in the
// base class _Base_bitset. The base class works with whole words, not with
// individual bits. This allows us to specialize _Base_bitset for the
// important special case where the bitset is only a single word.
#include <cstddef> // for size_t
#include <cstring> // for memset
#include <string>
......@@ -68,8 +58,9 @@
#include <ostream> // for ostream (operator<<)
#include <istream> // for istream (operator>>)
#define _GLIBCPP_BITSET_BITS_PER_WORD (CHAR_BIT*sizeof(unsigned long))
#define __BITSET_WORDS(__n) \
#define _GLIBCPP_BITSET_WORDS(__n) \
((__n) < 1 ? 1 : ((__n) + _GLIBCPP_BITSET_BITS_PER_WORD - 1)/_GLIBCPP_BITSET_BITS_PER_WORD)
namespace std
......@@ -77,13 +68,20 @@ namespace std
extern unsigned char _S_bit_count[256];
extern unsigned char _S_first_one[256];
// Base class: general case.
/**
* @if maint
* Base class, general case. It is a class inveriant that _Nw will be
* nonnegative.
*
* See documentation for bitset.
* @endif
*/
template<size_t _Nw>
struct _Base_bitset
{
typedef unsigned long _WordT;
// 0 is the least significant word.
/// 0 is the least significant word.
_WordT _M_w[_Nw];
_Base_bitset() { _M_do_reset(); }
......@@ -274,7 +272,7 @@ namespace std
{
for (size_t __i = 1; __i < _Nw; ++__i)
if (_M_w[__i])
__throw_overflow_error("bitset");
__throw_overflow_error("bitset -- too large to fit in unsigned long");
return _M_w[0];
}
......@@ -364,7 +362,13 @@ namespace std
} // end _M_do_find_next
// Base class: specialization for a single word.
/**
* @if maint
* Base class, specialization for a single word.
*
* See documentation for bitset.
* @endif
*/
template<>
struct _Base_bitset<1>
{
......@@ -471,26 +475,93 @@ namespace std
struct _Sanitize<0>
{ static void _S_do_sanitize(unsigned long) { } };
// Class bitset.
// _Nb may be any nonzero number of type size_t.
/**
* @brief The %bitset class represents a @e fixed-size sequence of bits.
*
* @ingroup Containers
*
* Meets the requirements of a <a href="tables.html#65">container</a>.
*
* The template argument, @a _Nb, may be any nonzero number of type
* size_t.
*
* A %bitset of size N has N % (sizeof(unsigned long) * CHAR_BIT) unused
* bits. (They are the high-order bits in the highest word.) It is
* a class invariant that those unused bits are always zero.
*
* If you think of %bitset as "a simple array of bits," be aware that
* your mental picture is reversed: a %bitset behaves the same way as
* bits in integers do, with the bit at index 0 in the "least significant
* / right-hand" position, and the bit at index N-1 in the "most
* significant / left-hand" position. Thus, unlike other containers, a
* %bitset's index "counts from right to left," to put it very loosely.
*
* This behavior is preserved when translating to and from strings. For
* example, the first line of the following program probably prints
* "b('a') is 0001100001" on a modern ASCII system.
*
* @code
* #include <bitset>
* #include <iostream>
* #include <sstream>
*
* using namespace std;
*
* int main()
* {
* long a = 'a';
* bitset<10> b(a);
*
* cout << "b('a') is " << b << endl;
*
* ostringstream s;
* s << b;
* string str = s.str();
* cout << "index 3 in the string is " << str[3] << " but\n"
* << "index 3 in the bitset is " << b[3] << endl;
* }
* @endcode
*
* Also see http://gcc.gnu.org/onlinedocs/libstdc++/ext/sgiexts.html#ch23
*
* @if maint
* Most of the actual code isn't contained in %bitset<> itself, but in the
* base class _Base_bitset. The base class works with whole words, not with
* individual bits. This allows us to specialize _Base_bitset for the
* important special case where the %bitset is only a single word.
*
* Extra confusion can result due to the fact that the storage for
* _Base_bitset @e is a regular array, and is indexed as such. This is
* carefully encapsulated.
* @endif
*/
template<size_t _Nb>
class bitset : private _Base_bitset<__BITSET_WORDS(_Nb)>
class bitset : private _Base_bitset<_GLIBCPP_BITSET_WORDS(_Nb)>
{
private:
typedef _Base_bitset<__BITSET_WORDS(_Nb)> _Base;
typedef _Base_bitset<_GLIBCPP_BITSET_WORDS(_Nb)> _Base;
typedef unsigned long _WordT;
void
_M_do_sanitize()
{
_Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::_S_do_sanitize(this->_M_hiword());
_Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::
_S_do_sanitize(this->_M_hiword());
}
public:
// bit reference:
class reference;
friend class reference;
/**
* This encapsulates the concept of a single bit. An instance of this
* class is a proxy for an actual bit; this way the individual bit
* operations are done as faster word-size bitwise instructions.
*
* Most users will never need to use this class directly; conversions
* to and from bool are automatic and should be transparent. Overloaded
* operators help to preserve the illusion.
*
* (On a typical system, this "bit %reference" is 64 times the size of
* an actual bit. Ha.)
*/
class reference
{
friend class bitset;
......@@ -502,7 +573,7 @@ namespace std
reference();
public:
reference( bitset& __b, size_t __pos )
reference(bitset& __b, size_t __pos)
{
_M_wp = &__b._M_getword(__pos);
_M_bpos = _Base::_S_whichbit(__pos);
......@@ -549,33 +620,63 @@ namespace std
return *this;
}
};
friend class reference;
// 23.3.5.1 constructors:
/// All bits set to zero.
bitset() { }
bitset(unsigned long __val) : _Base_bitset<__BITSET_WORDS(_Nb)>(__val)
/// Initial bits bitwise-copied from a single word (others set to zero).
bitset(unsigned long __val) : _Base(__val)
{ _M_do_sanitize(); }
/**
* @brief Use a subset of a string.
* @param s A string of '0' and '1' characters.
* @param pos Index of the first character in @a s to use; defaults
* to zero.
* @throw std::out_of_range If @a pos is bigger the size of @a s.
* @throw std::invalid_argument If a character appears in the string
* which is neither '0' nor '1'.
*/
template<class _CharT, class _Traits, class _Alloc>
explicit bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
size_t __pos = 0) : _Base()
{
if (__pos > __s.size())
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- initial position is larger than "
"the string itself");
_M_copy_from_string(__s, __pos,
basic_string<_CharT, _Traits, _Alloc>::npos);
}
/**
* @brief Use a subset of a string.
* @param s A string of '0' and '1' characters.
* @param pos Index of the first character in @a s to use.
* @param n The number of characters to copy.
* @throw std::out_of_range If @a pos is bigger the size of @a s.
* @throw std::invalid_argument If a character appears in the string
* which is neither '0' nor '1'.
*/
template<class _CharT, class _Traits, class _Alloc>
bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
size_t __pos, size_t __n) : _Base()
{
if (__pos > __s.size())
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- initial position is larger than "
"the string itself");
_M_copy_from_string(__s, __pos, __n);
}
// 23.3.5.2 bitset operations:
//@{
/**
* @brief Operations on bitsets.
* @param rhs A same-sized bitset.
*
* These should be self-explanatory.
*/
bitset<_Nb>&
operator&=(const bitset<_Nb>& __rhs)
{
......@@ -596,7 +697,15 @@ namespace std
this->_M_do_xor(__rhs);
return *this;
}
//@}
//@{
/**
* @brief Operations on bitsets.
* @param pos The number of places to shift.
*
* These should be self-explanatory.
*/
bitset<_Nb>&
operator<<=(size_t __pos)
{
......@@ -612,9 +721,14 @@ namespace std
this->_M_do_sanitize();
return *this;
}
//@}
// Extension:
// Versions of single-bit set, reset, flip, test with no range checking.
//@{
/**
* These versions of single-bit set, reset, flip, and test are
* extensions from the SGI version. They do no range checking.
* @ingroup SGIextensions
*/
bitset<_Nb>&
_Unchecked_set(size_t __pos)
{
......@@ -652,8 +766,12 @@ namespace std
return (this->_M_getword(__pos) & _Base::_S_maskbit(__pos))
!= static_cast<_WordT>(0);
}
//@}
// Set, reset, and flip.
/**
* @brief Sets every bit to true.
*/
bitset<_Nb>&
set()
{
......@@ -662,14 +780,23 @@ namespace std
return *this;
}
/**
* @brief Sets a given bit to a particular value.
* @param pos The index of the bit.
* @param val Either true or false, defaults to true.
* @throw std::out_of_range If @a pos is bigger the size of the %set.
*/
bitset<_Nb>&
set(size_t __pos, bool __val = true)
{
if (__pos >= _Nb)
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- set() argument too large");
return _Unchecked_set(__pos, __val);
}
/**
* @brief Sets every bit to false.
*/
bitset<_Nb>&
reset()
{
......@@ -677,14 +804,24 @@ namespace std
return *this;
}
/**
* @brief Sets a given bit to false.
* @param pos The index of the bit.
* @throw std::out_of_range If @a pos is bigger the size of the %set.
*
* Same as writing @c set(pos,false).
*/
bitset<_Nb>&
reset(size_t __pos)
{
if (__pos >= _Nb)
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- reset() argument too large");
return _Unchecked_reset(__pos);
}
/**
* @brief Toggles every bit to its opposite value.
*/
bitset<_Nb>&
flip()
{
......@@ -693,31 +830,70 @@ namespace std
return *this;
}
/**
* @brief Toggles a given bit to its opposite value.
* @param pos The index of the bit.
* @throw std::out_of_range If @a pos is bigger the size of the %set.
*/
bitset<_Nb>&
flip(size_t __pos)
{
if (__pos >= _Nb)
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- flip() argument too large");
return _Unchecked_flip(__pos);
}
/// See the no-argument flip().
bitset<_Nb>
operator~() const { return bitset<_Nb>(*this).flip(); }
// element access:
//for b[i];
// _GLIBCPP_RESOLVE_LIB_DEFECTS Note that this implementation already
// resolves DR 11 (items 1 and 2), but does not do the range-checking
// required by that DR's resolution. -pme
//@{
/**
* @brief Array-indexing support.
* @param pos Index into the %bitset.
* @return A bool for a 'const %bitset'. For non-const bitsets, an
* instance of the reference proxy class.
* @note These operators do no range checking and throw no exceptions,
* as required by DR 11 to the standard.
*
* @if maint
* _GLIBCPP_RESOLVE_LIB_DEFECTS Note that this implementation already
* resolves DR 11 (items 1 and 2), but does not do the range-checking
* required by that DR's resolution. -pme
* The DR has since been changed: range-checking is a precondition
* (users' responsibility), and these functions must not throw. -pme
* @endif
*/
reference
operator[](size_t __pos) { return reference(*this,__pos); }
bool
operator[](size_t __pos) const { return _Unchecked_test(__pos); }
//@}
/**
* @brief Retuns a numerical interpretation of the %bitset.
* @return The integral equivalent of the bits.
* @throw std::overflow_error If there are too many bits to be
* represented in an @c unsigned @c long.
*/
unsigned long
to_ulong() const { return this->_M_do_to_ulong(); }
/**
* @brief Retuns a character interpretation of the %bitset.
* @return The string equivalent of the bits.
*
* Note the ordering of the bits: decreasing character positions
* correspond to increasing bit positions (see the main class notes for
* an example).
*
* Also note that you must specify the string's template parameters
* explicitly. Given a bitset @c bs and a string @s:
* @code
* s = bs.to_string<char,char_traits<char>,allocator<char> >();
* @endcode
*/
template<class _CharT, class _Traits, class _Alloc>
basic_string<_CharT, _Traits, _Alloc>
to_string() const
......@@ -737,12 +913,16 @@ namespace std
void
_M_copy_to_string(basic_string<_CharT,_Traits,_Alloc>&) const;
/// Returns the number of bits which are set.
size_t
count() const { return this->_M_do_count(); }
/// Returns the total number of bits.
size_t
size() const { return _Nb; }
//@{
/// These comparisons for equality/inequality are, well, @e bitwise.
bool
operator==(const bitset<_Nb>& __rhs) const
{ return this->_M_is_equal(__rhs); }
......@@ -750,21 +930,38 @@ namespace std
bool
operator!=(const bitset<_Nb>& __rhs) const
{ return !this->_M_is_equal(__rhs); }
//@}
/**
* @brief Tests the value of a bit.
* @param pos The index of a bit.
* @return The value at @a pos.
* @throw std::out_of_range If @a pos is bigger the size of the %set.
*/
bool
test(size_t __pos) const
{
if (__pos >= _Nb)
__throw_out_of_range("bitset");
__throw_out_of_range("bitset -- test() argument too large");
return _Unchecked_test(__pos);
}
/**
* @brief Tests whether any of the bits are on.
* @return True if at least one bit is set.
*/
bool
any() const { return this->_M_is_any(); }
/**
* @brief Tests whether any of the bits are on.
* @return True if none of the bits are set.
*/
bool
none() const { return !this->_M_is_any(); }
//@{
/// Self-explanatory.
bitset<_Nb>
operator<<(size_t __pos) const
{ return bitset<_Nb>(*this) <<= __pos; }
......@@ -772,17 +969,23 @@ namespace std
bitset<_Nb>
operator>>(size_t __pos) const
{ return bitset<_Nb>(*this) >>= __pos; }
//@}
// EXTENSIONS: bit-find operations. These operations are
// experimental, and are subject to change or removal in future
// versions.
// find the index of the first "on" bit
/**
* @brief Finds the index of the first "on" bit.
* @ingroup SGIextensions
* @sa _Find_next
*/
size_t
_Find_first() const
{ return this->_M_do_find_first(_Nb); }
// find the index of the next "on" bit after prev
/**
* @brief Finds the index of the next "on" bit after prev.
* @param prev Where to start searching.
* @ingroup SGIextensions
* @sa _Find_first
*/
size_t
_Find_next(size_t __prev ) const
{ return this->_M_do_find_next(__prev, _Nb); }
......@@ -806,7 +1009,8 @@ namespace std
set(__i);
break;
default:
__throw_invalid_argument("bitset");
__throw_invalid_argument("bitset -- string contains characters "
"which are neither 0 nor 1");
}
}
}
......@@ -823,6 +1027,15 @@ namespace std
}
// 23.3.5.3 bitset operations:
//@{
/**
* @brief Global bitwise operations on bitsets.
* @param x A bitset.
* @param y A bitset of the same size as @a x.
* @return A new bitset.
*
* These should be self-explanatory.
*/
template<size_t _Nb>
inline bitset<_Nb>
operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
......@@ -849,7 +1062,17 @@ namespace std
__result ^= __y;
return __result;
}
//@}
//@{
/**
* @brief Global I/O operators for bitsets.
*
* Direct I/O between streams and bitsets is supported. Output is
* straightforward. Input will skip whitespace, only accept '0' and '1'
* characters, and will only extract as many digits as the %bitset will
* hold.
*/
template<class _CharT, class _Traits, size_t _Nb>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
......@@ -906,8 +1129,9 @@ namespace std
__x._M_copy_to_string(__tmp);
return __os << __tmp;
}
//@}
} // namespace std
#undef __BITSET_WORDS
#undef _GLIBCPP_BITSET_WORDS
#endif
#endif /* _GLIBCPP_BITSET_H */
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