catch2/include/internal/catch_stringref.h
Martin Hořeňovský 50cc14c94c
Rework StringRef interface and internals
Now it no longer tries to be this weird hybrid between an owning
and non-owning reference, and is only ever non-owning. This is also
reflected in its interface, for example `StringRef::isNullTerminated`
is now public, and `StringRef::c_str()` has the precondition that it
is true.

Overview of the changes:
* The `StringRef::m_data` member has been completely removed, as it
had no more uses.
* `StringRef::isSubstring()` has been made public and renamed to
`StringRef::isNullTerminated()`, so that the name reflects what the
method actually does.
* `StringRef::currentData()` has been renamed to `StringRef::data()`,
to be in line with common C++ containers and container-alikes.
* `StringRef::c_str()` will no longer silently make copies. It instead
has a precondition that `isNullTerminated()` is true.
* If the user needs a null-terminated string, they should use the
`std::string` conversion operator and call `c_str()` on the resulting
`std::string`.
* Some small optimizations in various places.
* Basic functionality is now `constexpr`.
2019-10-25 13:57:52 +02:00

105 lines
3.4 KiB
C++

/*
* Copyright 2016 Two Blue Cubes Ltd. All rights reserved.
*
* 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)
*/
#ifndef CATCH_STRINGREF_H_INCLUDED
#define CATCH_STRINGREF_H_INCLUDED
#include <cstddef>
#include <string>
#include <iosfwd>
#include <cassert>
namespace Catch {
/// A non-owning string class (similar to the forthcoming std::string_view)
/// Note that, because a StringRef may be a substring of another string,
/// it may not be null terminated.
class StringRef {
public:
using size_type = std::size_t;
using const_iterator = const char*;
private:
static constexpr char const* const s_empty = "";
char const* m_start = s_empty;
size_type m_size = 0;
public: // construction
constexpr StringRef() noexcept = default;
StringRef( char const* rawChars ) noexcept;
constexpr StringRef( char const* rawChars, size_type size ) noexcept
: m_start( rawChars ),
m_size( size )
{}
StringRef( std::string const& stdString ) noexcept
: m_start( stdString.c_str() ),
m_size( stdString.size() )
{}
explicit operator std::string() const {
return std::string(m_start, m_size);
}
public: // operators
auto operator == ( StringRef const& other ) const noexcept -> bool;
auto operator != (StringRef const& other) const noexcept -> bool {
return !(*this == other);
}
auto operator[] ( size_type index ) const noexcept -> char {
assert(index < m_size);
return m_start[index];
}
public: // named queries
constexpr auto empty() const noexcept -> bool {
return m_size == 0;
}
constexpr auto size() const noexcept -> size_type {
return m_size;
}
// Returns the current start pointer. If the StringRef is not
// null-terminated, throws std::domain_exception
auto c_str() const -> char const*;
public: // substrings and searches
// Returns a substring of [start, start + length).
// If start + length > size(), then the substring is [start, size()).
// If start > size(), then the substring is empty.
auto substr( size_type start, size_type length ) const noexcept -> StringRef;
// Returns the current start pointer. May not be null-terminated.
auto data() const noexcept -> char const*;
constexpr auto isNullTerminated() const noexcept -> bool {
return m_start[m_size] == '\0';
}
public: // iterators
constexpr const_iterator begin() const { return m_start; }
constexpr const_iterator end() const { return m_start + m_size; }
};
auto operator += ( std::string& lhs, StringRef const& sr ) -> std::string&;
auto operator << ( std::ostream& os, StringRef const& sr ) -> std::ostream&;
constexpr auto operator "" _sr( char const* rawChars, std::size_t size ) noexcept -> StringRef {
return StringRef( rawChars, size );
}
} // namespace Catch
constexpr auto operator "" _catch_sr( char const* rawChars, std::size_t size ) noexcept -> Catch::StringRef {
return Catch::StringRef( rawChars, size );
}
#endif // CATCH_STRINGREF_H_INCLUDED