Duckstation/dep/rapidyaml/include/c4/std/string.hpp
2024-02-04 16:14:05 +10:00

98 lines
3.9 KiB
C++

#ifndef _C4_STD_STRING_HPP_
#define _C4_STD_STRING_HPP_
/** @file string.hpp */
#ifndef C4CORE_SINGLE_HEADER
#include "c4/substr.hpp"
#endif
#include <string>
namespace c4 {
//-----------------------------------------------------------------------------
/** get a writeable view to an existing std::string.
* When the string is empty, the returned view will be pointing
* at the character with value '\0', but the size will be zero.
* @see https://en.cppreference.com/w/cpp/string/basic_string/operator_at
*/
C4_ALWAYS_INLINE c4::substr to_substr(std::string &s) noexcept
{
#if C4_CPP < 11
#error this function will have undefined behavior
#endif
// since c++11 it is legal to call s[s.size()].
return c4::substr(&s[0], s.size());
}
/** get a readonly view to an existing std::string.
* When the string is empty, the returned view will be pointing
* at the character with value '\0', but the size will be zero.
* @see https://en.cppreference.com/w/cpp/string/basic_string/operator_at
*/
C4_ALWAYS_INLINE c4::csubstr to_csubstr(std::string const& s) noexcept
{
#if C4_CPP < 11
#error this function will have undefined behavior
#endif
// since c++11 it is legal to call s[s.size()].
return c4::csubstr(&s[0], s.size());
}
//-----------------------------------------------------------------------------
C4_ALWAYS_INLINE bool operator== (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) == 0; }
C4_ALWAYS_INLINE bool operator!= (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) != 0; }
C4_ALWAYS_INLINE bool operator>= (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) >= 0; }
C4_ALWAYS_INLINE bool operator> (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) > 0; }
C4_ALWAYS_INLINE bool operator<= (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) <= 0; }
C4_ALWAYS_INLINE bool operator< (c4::csubstr ss, std::string const& s) { return ss.compare(to_csubstr(s)) < 0; }
C4_ALWAYS_INLINE bool operator== (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) == 0; }
C4_ALWAYS_INLINE bool operator!= (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) != 0; }
C4_ALWAYS_INLINE bool operator>= (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) <= 0; }
C4_ALWAYS_INLINE bool operator> (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) < 0; }
C4_ALWAYS_INLINE bool operator<= (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) >= 0; }
C4_ALWAYS_INLINE bool operator< (std::string const& s, c4::csubstr ss) { return ss.compare(to_csubstr(s)) > 0; }
//-----------------------------------------------------------------------------
/** copy an std::string to a writeable string view */
inline size_t to_chars(c4::substr buf, std::string const& s)
{
C4_ASSERT(!buf.overlaps(to_csubstr(s)));
size_t len = buf.len < s.size() ? buf.len : s.size();
// calling memcpy with null strings is undefined behavior
// and will wreak havoc in calling code's branches.
// see https://github.com/biojppm/rapidyaml/pull/264#issuecomment-1262133637
if(len)
{
C4_ASSERT(s.data() != nullptr);
C4_ASSERT(buf.str != nullptr);
memcpy(buf.str, s.data(), len);
}
return s.size(); // return the number of needed chars
}
/** copy a string view to an existing std::string */
inline bool from_chars(c4::csubstr buf, std::string * s)
{
s->resize(buf.len);
C4_ASSERT(!buf.overlaps(to_csubstr(*s)));
// calling memcpy with null strings is undefined behavior
// and will wreak havoc in calling code's branches.
// see https://github.com/biojppm/rapidyaml/pull/264#issuecomment-1262133637
if(buf.len)
{
C4_ASSERT(buf.str != nullptr);
memcpy(&(*s)[0], buf.str, buf.len);
}
return true;
}
} // namespace c4
#endif // _C4_STD_STRING_HPP_