cppdraft_translate/cppdraft/string/view/ops.md

[string.view.ops]

27 Strings library [strings]

27.3 String view classes [string.view]

27.3.3 Class template basic_string_view [string.view.template]

27.3.3.8 String operations [string.view.ops]

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constexpr size_type copy(charT* s, size_type n, size_type pos = 0) const;

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Let rlen be the smaller of n and size() - pos.

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Preconditions: [s, s + rlen) is a valid range.

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Effects: Equivalent to traits​::​copy(s, data() + pos, rlen).

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Returns: rlen.

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Throws: out_of_range if pos > size().

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Complexity: O(rlen).

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constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const; constexpr basic_string_view subview(size_type pos = 0, size_type n = npos) const;

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Let rlen be the smaller of n and size() - pos.

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Effects: Determines rlen, the effective length of the string to reference.

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Returns: basic_string_view(data() + pos, rlen).

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Throws: out_of_range if pos > size().

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constexpr int compare(basic_string_view str) const noexcept;

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Let rlen be the smaller of size() and str.size().

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Effects: Determines rlen, the effective length of the strings to compare.

The function then compares the two strings by calling traits​::​compare(data(), str.data(), rlen).

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Returns: The nonzero result if the result of the comparison is nonzero.

Otherwise, returns a value as indicated in Table 88.

Table 88 — compare() results [tab:string.view.compare]

🔗 Condition	Return Value
🔗 size() < str.size()	< 0
🔗 size() == str.size()	0
🔗 size() > str.size()	> 0

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Complexity: O(rlen).

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constexpr int compare(size_type pos1, size_type n1, basic_string_view str) const;

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Effects: Equivalent to: return substr(pos1, n1).compare(str);

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constexpr int compare(size_type pos1, size_type n1, basic_string_view str, size_type pos2, size_type n2) const;

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Effects: Equivalent to: return substr(pos1, n1).compare(str.substr(pos2, n2));

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constexpr int compare(const charT* s) const;

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Effects: Equivalent to: return compare(basic_string_view(s));

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constexpr int compare(size_type pos1, size_type n1, const charT* s) const;

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Effects: Equivalent to: return substr(pos1, n1).compare(basic_string_view(s));

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constexpr int compare(size_type pos1, size_type n1, const charT* s, size_type n2) const;

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Effects: Equivalent to: return substr(pos1, n1).compare(basic_string_view(s, n2));

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constexpr bool starts_with(basic_string_view x) const noexcept;

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Let rlen be the smaller of size() and x.size().

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Effects: Equivalent to: return basic_string_view(data(), rlen) == x;

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constexpr bool starts_with(charT x) const noexcept;

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Effects: Equivalent to: return !empty() && traits​::​eq(front(), x);

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constexpr bool starts_with(const charT* x) const;

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Effects: Equivalent to: return starts_with(basic_string_view(x));

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constexpr bool ends_with(basic_string_view x) const noexcept;

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Let rlen be the smaller of size() and x.size().

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Effects: Equivalent to:return basic_string_view(data() + (size() - rlen), rlen) == x;

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constexpr bool ends_with(charT x) const noexcept;

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Effects: Equivalent to: return !empty() && traits​::​eq(back(), x);

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constexpr bool ends_with(const charT* x) const;

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Effects: Equivalent to: return ends_with(basic_string_view(x));

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constexpr bool contains(basic_string_view x) const noexcept; constexpr bool contains(charT x) const noexcept; constexpr bool contains(const charT* x) const;

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Effects: Equivalent to: return find(x) != npos;