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/*
* This source code is released into the public domain.
*/
#ifndef LFJAIL_STRING_UTILS_HH
#define LFJAIL_STRING_UTILS_HH
#include <algorithm>
#include <ranges>
#include <string>
#include <utility>
#include "ctype.hh"
namespace lfjail {
/*
* Remove leading whitespace from the given string_view.
*/
template<typename Char>
std::basic_string_view<Char>
skipws(std::basic_string_view<Char> text) {
auto isspace = ctype_is(std::ctype_base::space);
auto first_nonws = std::ranges::find_if_not(text, isspace);
return {first_nonws, end(text)};
}
template<typename Char>
void skipws(std::basic_string_view<Char> *text) {
auto ret = skipws(*text);
*text = ret;
}
/*
* Split a string on a predicate. Specifically, divide the string into two
* strings at the first character where the predicate matches, and return
* both strings. If the predicate matched, the matching character will be
* discarded.
*/
template<typename Char,
std::indirect_unary_predicate<
typename std::basic_string_view<Char>::iterator> Pred>
std::pair<std::basic_string_view<Char>, std::basic_string_view<Char>>
split(std::basic_string_view<Char> text, Pred pred)
{
auto split_point = std::ranges::find_if(text, pred);
if (split_point == end(text))
return {text, {}};
else
return {{begin(text), split_point},
{std::next(split_point), end(text)}};
}
template<typename Char,
std::indirect_unary_predicate<
typename std::basic_string_view<Char>::iterator> Pred>
std::basic_string_view<Char>
split(std::basic_string_view<Char> *text, Pred pred)
{
auto [str, rest] = split(*text, pred);
*text = rest;
return str;
}
/*
* Return the next word from a string_view. The by-value version returns
* a pair<next-word, remainder>, while the pointer version returns next-word
* and sets the input string to remainder.
*/
template<typename Char>
std::pair<std::basic_string_view<Char>, std::basic_string_view<Char>>
next_word(std::basic_string_view<Char> text)
{
return (split(skipws(text), ctype_is(std::ctype_base::space)));
}
template<typename Char>
std::basic_string_view<Char>
next_word(std::basic_string_view<Char> *text) {
skipws(text);
return (split(text, ctype_is(std::ctype_base::space)));
}
} // namespace lfjail
#endif // LFJAIL_STRING_UTILS_HH
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