Current File : //backups/router/usr/local/include/boost/url/decode_view.hpp
//
// Copyright (c) 2022 Alan de Freitas (alandefreitas@gmail.com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/url
//
#ifndef BOOST_URL_DECODE_VIEW_HPP
#define BOOST_URL_DECODE_VIEW_HPP
#include <boost/url/detail/config.hpp>
#include <boost/core/detail/string_view.hpp>
#include <boost/url/encoding_opts.hpp>
#include <boost/url/pct_string_view.hpp>
#include <type_traits>
#include <iterator>
#include <iosfwd>
namespace boost {
namespace urls {
//------------------------------------------------
#ifndef BOOST_URL_DOCS
class decode_view;
namespace detail {
// unchecked
template<class... Args>
decode_view
make_decode_view(
Args&&... args) noexcept;
} // detail
#endif
//------------------------------------------------
/** A reference to a valid, percent-encoded string
These views reference strings in parts of URLs
or other components that are percent-encoded.
The special characters (those not in the
allowed character set) are stored as three
character escapes that consist of a percent
sign ('%%') followed by a two-digit hexadecimal
number of the corresponding unescaped character
code, which may be part of a UTF-8 code point
depending on the context.
The view refers to the original character
buffer and only decodes escaped sequences when
needed. In particular these operations perform
percent-decoding automatically without the
need to allocate memory:
@li Iteration of the string
@li Accessing the encoded character buffer
@li Comparison to encoded or plain strings
These objects can only be constructed from
strings that have a valid percent-encoding,
otherwise construction fails. The caller is
responsible for ensuring that the lifetime
of the character buffer from which the view
is constructed extends unmodified until the
view is no longer accessed.
@par Operators
The following operators are supported between
@ref decode_view and any object that is convertible
to `core::string_view`
@code
bool operator==( decode_view, decode_view ) noexcept;
bool operator!=( decode_view, decode_view ) noexcept;
bool operator<=( decode_view, decode_view ) noexcept;
bool operator< ( decode_view, decode_view ) noexcept;
bool operator> ( decode_view, decode_view ) noexcept;
bool operator>=( decode_view, decode_view ) noexcept;
@endcode
*/
class decode_view
{
char const* p_ = nullptr;
std::size_t n_ = 0;
std::size_t dn_ = 0;
bool space_as_plus_ = true;
#ifndef BOOST_URL_DOCS
template<class... Args>
friend
decode_view
detail::make_decode_view(
Args&&... args) noexcept;
#endif
// unchecked
BOOST_URL_DECL
explicit
decode_view(
core::string_view s,
std::size_t n,
encoding_opts opt) noexcept;
public:
/** The value type
*/
using value_type = char;
/** The reference type
*/
using reference = char;
/// @copydoc reference
using const_reference = char;
/** The unsigned integer type
*/
using size_type = std::size_t;
/** The signed integer type
*/
using difference_type = std::ptrdiff_t;
/** An iterator of constant, decoded characters.
This iterator is used to access the encoded
string as a bidirectional range of characters
with percent-decoding applied. Escape sequences
are not decoded until the iterator is
dereferenced.
*/
#ifdef BOOST_URL_DOCS
using iterator = __see_below__;
#else
class iterator;
#endif
/// @copydoc iterator
using const_iterator = iterator;
//--------------------------------------------
//
// Special Members
//
//--------------------------------------------
/** Constructor
Default-constructed views represent
empty strings.
@par Example
@code
decode_view ds;
@endcode
@par Postconditions
@code
this->empty() == true
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
decode_view() noexcept = default;
/** Constructor
This constructs a view from the character
buffer `s`, which must remain valid and
unmodified until the view is no longer
accessed.
@par Example
@code
decode_view ds( "Program%20Files" );
@endcode
@par Postconditions
@code
this->encoded() == s
@endcode
@par Complexity
Linear in `s.size()`.
@par Exception Safety
Exceptions thrown on invalid input.
@throw system_error
The string contains an invalid percent encoding.
@param s A percent-encoded string that has
already been validated.
@param opt The options for decoding. If
this parameter is omitted, the default
options are used.
*/
explicit
decode_view(
pct_string_view s,
encoding_opts opt = {}) noexcept
: decode_view(
detail::to_sv(s),
s.decoded_size(),
opt)
{
}
//--------------------------------------------
//
// Observers
//
//--------------------------------------------
/** Return true if the string is empty
@par Example
@code
assert( decode_view( "" ).empty() );
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
bool
empty() const noexcept
{
return n_ == 0;
}
/** Return the number of decoded characters
@par Example
@code
assert( decode_view( "Program%20Files" ).size() == 13 );
@endcode
@par Effects
@code
return std::distance( this->begin(), this->end() );
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
size_type
size() const noexcept
{
return dn_;
}
/** Return an iterator to the beginning
@par Example
@code
auto it = this->begin();
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
iterator
begin() const noexcept;
/** Return an iterator to the end
@par Example
@code
auto it = this->end();
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
iterator
end() const noexcept;
/** Return the first character
@par Example
@code
assert( decode_view( "Program%20Files" ).front() == 'P' );
@endcode
@par Preconditions
@code
not this->empty()
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
reference
front() const noexcept;
/** Return the last character
@par Example
@code
assert( decode_view( "Program%20Files" ).back() == 's' );
@endcode
@par Preconditions
@code
not this->empty()
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
reference
back() const noexcept;
/** Checks if the string begins with the given prefix
@par Example
@code
assert( decode_view( "Program%20Files" ).starts_with("Program") );
@endcode
@par Complexity
Linear.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
bool
starts_with( core::string_view s ) const noexcept;
/** Checks if the string ends with the given prefix
@par Example
@code
assert( decode_view( "Program%20Files" ).ends_with("Files") );
@endcode
@par Complexity
Linear.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
bool
ends_with( core::string_view s ) const noexcept;
/** Checks if the string begins with the given prefix
@par Example
@code
assert( decode_view( "Program%20Files" ).starts_with('P') );
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
bool
starts_with( char ch ) const noexcept;
/** Checks if the string ends with the given prefix
@par Example
@code
assert( decode_view( "Program%20Files" ).ends_with('s') );
@endcode
@par Complexity
Constant.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
bool
ends_with( char ch ) const noexcept;
/** Finds the first occurrence of character in this view
@par Complexity
Linear.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
const_iterator
find( char ch ) const noexcept;
/** Finds the first occurrence of character in this view
@par Complexity
Linear.
@par Exception Safety
Throws nothing.
*/
BOOST_URL_DECL
const_iterator
rfind( char ch ) const noexcept;
/** Remove the first characters
@par Example
@code
decode_view d( "Program%20Files" );
d.remove_prefix( 8 );
assert( d == "Files" );
@endcode
@par Preconditions
@code
not this->empty()
@endcode
@par Complexity
Linear.
*/
BOOST_URL_DECL
void
remove_prefix( size_type n );
/** Remove the last characters
@par Example
@code
decode_view d( "Program%20Files" );
d.remove_prefix( 6 );
assert( d == "Program" );
@endcode
@par Preconditions
@code
not this->empty()
@endcode
@par Complexity
Linear.
*/
BOOST_URL_DECL
void
remove_suffix( size_type n );
/** Return the decoding options
*/
encoding_opts
options() const noexcept
{
encoding_opts opt;
opt.space_as_plus = space_as_plus_;
return opt;
}
//--------------------------------------------
//
// Comparison
//
//--------------------------------------------
/** Return the result of comparing to another string
The length of the sequences to compare is the smaller of
`size()` and `other.size()`.
The function compares the two strings as if by calling
`char_traits<char>::compare(to_string().data(), v.data(), rlen)`.
This means the comparison is performed with
percent-decoding applied to the current string.
@param other string to compare
@return Negative value if this string is less than the other
character sequence, zero if the both character sequences are
equal, positive value if this string is greater than the other
character sequence
*/
BOOST_URL_DECL
int
compare(core::string_view other) const noexcept;
/** Return the result of comparing to another string
The length of the sequences to compare is the smaller of
`size()` and `other.size()`.
The function compares the two strings as if by calling
`char_traits<char>::compare(to_string().data(), v.to_string().data(), rlen)`.
This means the comparison is performed with
percent-decoding applied to the current string.
@param other string to compare
@return Negative value if this string is less than the other
character sequence, zero if the both character sequences are
equal, positive value if this string is greater than the other
character sequence
*/
BOOST_URL_DECL
int
compare(decode_view other) const noexcept;
//--------------------------------------------
// relational operators
#ifndef BOOST_URL_DOCS
private:
template<class S0, class S1>
using is_match = std::integral_constant<bool,
// both decode_view or convertible to core::string_view
(
std::is_same<typename std::decay<S0>::type, decode_view>::value ||
std::is_convertible<S0, core::string_view>::value) &&
(
std::is_same<typename std::decay<S1>::type, decode_view>::value ||
std::is_convertible<S1, core::string_view>::value) &&
// not both are convertible to string view
(
!std::is_convertible<S0, core::string_view>::value ||
!std::is_convertible<S1, core::string_view>::value)>;
static
int
decode_compare(decode_view s0, decode_view s1) noexcept
{
return s0.compare(s1);
}
template <class S>
static
int
decode_compare(decode_view s0, S const& s1) noexcept
{
return s0.compare(s1);
}
template <class S>
static
int
decode_compare(S const& s0, decode_view s1) noexcept
{
return -s1.compare(s0);
}
public:
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator==(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) == 0;
}
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator!=(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) != 0;
}
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator<(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) < 0;
}
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator<=(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) <= 0;
}
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator>(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) > 0;
}
template<class S0, class S1>
BOOST_CXX14_CONSTEXPR friend auto operator>=(
S0 const& s0, S1 const& s1) noexcept ->
typename std::enable_if<
is_match<S0, S1>::value, bool>::type
{
return decode_compare(s0, s1) >= 0;
}
#endif
// hidden friend
friend
std::ostream&
operator<<(
std::ostream& os,
decode_view const& s)
{
// hidden friend
s.write(os);
return os;
}
private:
BOOST_URL_DECL
void
write(std::ostream& os) const;
};
/** Format the string with percent-decoding applied to the output stream
This function serializes the decoded view
to the output stream.
@return A reference to the output stream, for chaining
@param os The output stream to write to
@param s The decoded view to write
*/
inline
std::ostream&
operator<<(
std::ostream& os,
decode_view const& s);
//------------------------------------------------
inline
decode_view
pct_string_view::operator*() const noexcept
{
return decode_view(*this);
}
#ifndef BOOST_URL_DOCS
namespace detail {
template<class... Args>
decode_view
make_decode_view(
Args&&... args) noexcept
{
return decode_view(
std::forward<Args>(args)...);
}
} // detail
#endif
//------------------------------------------------
} // urls
} // boost
#include <boost/url/impl/decode_view.hpp>
#endif
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