forked from OSchip/llvm-project
[libc][utils] Add more methods to StringView
Differential Revision: https://reviews.llvm.org/D128908
This commit is contained in:
Guillaume Chatelet
parent
4bb7b6fae3
commit
e0aece276f
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@ -24,7 +24,20 @@ private:
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const char *Data;
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size_t Len;
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static size_t min(size_t A, size_t B) { return A <= B ? A : B; }
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static int compareMemory(const char *Lhs, const char *Rhs, size_t Length) {
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for (size_t I = 0; I < Length; ++I)
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if (int Diff = (int)Lhs[I] - (int)Rhs[I])
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return Diff;
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return 0;
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}
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public:
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// special value equal to the maximum value representable by the type
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// size_type.
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static constexpr size_t npos = -1;
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StringView() : Data(nullptr), Len(0) {}
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// Assumes Str is a null-terminated string. The length of the string does
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@ -41,18 +54,67 @@ public:
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explicit StringView(const char *Str, size_t N)
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: Data(N ? Str : nullptr), Len(Str == nullptr ? 0 : N) {}
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// Ctor for raw literal.
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template <size_t N>
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StringView(const char (&Str)[N]) : StringView(Str, N - 1) {}
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const char *data() const { return Data; }
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size_t size() { return Len; }
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// Returns the size of the StringView.
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size_t size() const { return Len; }
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// Returns whether the StringView is empty.
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bool empty() const { return Len == 0; }
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// Returns an iterator to the first character of the view.
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const char *begin() const { return Data; }
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// Returns an iterator to the character following the last character of the
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// view.
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const char *end() const { return Data + Len; }
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// Returns a const reference to the character at specified location pos.
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// No bounds checking is performed: the behavior is undefined if pos >=
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// size().
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const char &operator[](size_t Index) const { return Data[Index]; }
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/// compare - Compare two strings; the result is -1, 0, or 1 if this string
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/// is lexicographically less than, equal to, or greater than the \p Other.
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int compare(StringView Other) const {
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// Check the prefix for a mismatch.
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if (int Res = compareMemory(Data, Other.Data, min(Len, Other.Len)))
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return Res < 0 ? -1 : 1;
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// Otherwise the prefixes match, so we only need to check the lengths.
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if (Len == Other.Len)
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return 0;
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return Len < Other.Len ? -1 : 1;
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}
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// An equivalent method is not available in std::string_view.
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bool equals(StringView Other) const {
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return (Len == Other.Len &&
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compareMemory(Data, Other.Data, Other.Len) == 0);
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}
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inline bool operator==(StringView Other) const { return equals(Other); }
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inline bool operator!=(StringView Other) const { return !(*this == Other); }
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inline bool operator<(StringView Other) const { return compare(Other) == -1; }
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inline bool operator<=(StringView Other) const { return compare(Other) != 1; }
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inline bool operator>(StringView Other) const { return compare(Other) == 1; }
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inline bool operator>=(StringView Other) const {
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return compare(Other) != -1;
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}
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// Moves the start of the view forward by n characters.
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// The behavior is undefined if n > size().
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StringView remove_prefix(size_t N) const {
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if (N >= Len)
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return StringView();
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return StringView(Data + N, Len - N);
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}
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// Moves the end of the view back by n characters.
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// The behavior is undefined if n > size().
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StringView remove_suffix(size_t N) const {
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if (N >= Len)
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return StringView();
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@ -61,45 +123,134 @@ public:
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// An equivalent method is not available in std::string_view.
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StringView trim(char C) const {
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if (Len == 0)
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return StringView();
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const char *NewStart = Data;
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size_t PrefixLen = 0;
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for (; PrefixLen < Len; ++NewStart, ++PrefixLen) {
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if (*NewStart != C)
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break;
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}
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size_t SuffixLen = 0;
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const char *NewEnd = Data + Len - 1;
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for (; SuffixLen < Len; --NewEnd, ++SuffixLen) {
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if (*NewEnd != C)
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break;
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}
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return remove_prefix(PrefixLen).remove_suffix(SuffixLen);
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StringView Copy = *this;
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while (!Copy.empty() && Copy.front() == C)
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Copy = Copy.drop_front();
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while (!Copy.empty() && Copy.back() == C)
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Copy = Copy.drop_back();
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return Copy;
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}
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// Check if this string starts with the given \p Prefix.
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// Check if this string starts with the given Prefix.
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bool starts_with(StringView Prefix) const {
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if (Len < Prefix.Len)
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return false;
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for (size_t I = 0; I < Prefix.Len; ++I) {
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if (Data[I] != Prefix.Data[I])
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return false;
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return Len >= Prefix.Len &&
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compareMemory(Data, Prefix.Data, Prefix.Len) == 0;
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}
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// Check if this string ends with the given Suffix.
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bool ends_with(StringView Suffix) const {
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return Len >= Suffix.Len &&
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compareMemory(end() - Suffix.Len, Suffix.Data, Suffix.Len) == 0;
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}
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// Return a reference to the substring from [Start, Start + N).
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//
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// Start The index of the starting character in the substring; if the index is
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// npos or greater than the length of the string then the empty substring will
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// be returned.
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//
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// N The number of characters to included in the substring. If N exceeds the
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// number of characters remaining in the string, the string suffix (starting
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// with Start) will be returned.
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StringView substr(size_t Start, size_t N = npos) const {
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Start = min(Start, Len);
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return StringView(Data + Start, min(N, Len - Start));
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}
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// Search for the first character satisfying the predicate Function
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//
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// Returns The index of the first character satisfying Function starting from
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// From, or npos if not found.
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template <typename F> size_t find_if(F Function, size_t From = 0) const {
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StringView S = drop_front(From);
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while (!S.empty()) {
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if (Function(S.front()))
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return size() - S.size();
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S = S.drop_front();
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}
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return npos;
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}
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// Search for the first character not satisfying the predicate Function
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// Returns The index of the first character not satisfying Function starting
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// from From, or npos if not found.
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template <typename F> size_t find_if_not(F Function, size_t From = 0) const {
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return find_if([Function](char c) { return !Function(c); }, From);
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}
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// front - Get the first character in the string.
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char front() const { return Data[0]; }
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// back - Get the last character in the string.
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char back() const { return Data[Len - 1]; }
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// Return a StringView equal to 'this' but with the first N elements
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// dropped.
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StringView drop_front(size_t N = 1) const { return substr(N); }
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// Return a StringView equal to 'this' but with the last N elements
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// dropped.
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StringView drop_back(size_t N = 1) const { return substr(0, size() - N); }
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// Return a StringView equal to 'this' but with only the first N
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// elements remaining. If N is greater than the length of the
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// string, the entire string is returned.
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StringView take_front(size_t N = 1) const {
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if (N >= size())
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return *this;
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return drop_back(size() - N);
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}
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// Return a StringView equal to 'this' but with only the last N
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// elements remaining. If N is greater than the length of the
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// string, the entire string is returned.
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StringView take_back(size_t N = 1) const {
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if (N >= size())
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return *this;
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return drop_front(size() - N);
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}
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// Return the longest prefix of 'this' such that every character
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// in the prefix satisfies the given predicate.
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template <typename F> StringView take_while(F Function) const {
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return substr(0, find_if_not(Function));
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}
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// Return the longest prefix of 'this' such that no character in
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// the prefix satisfies the given predicate.
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template <typename F> StringView take_until(F Function) const {
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return substr(0, find_if(Function));
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}
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// Return a StringView equal to 'this', but with all characters satisfying
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// the given predicate dropped from the beginning of the string.
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template <typename F> StringView drop_while(F Function) const {
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return substr(find_if_not(Function));
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}
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// Return a StringView equal to 'this', but with all characters not
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// satisfying the given predicate dropped from the beginning of the string.
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template <typename F> StringView drop_until(F Function) const {
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return substr(find_if(Function));
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}
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// Returns true if this StringView has the given prefix and removes that
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// prefix.
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bool consume_front(StringView Prefix) {
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if (!starts_with(Prefix))
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return false;
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*this = drop_front(Prefix.size());
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return true;
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}
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// An equivalent method is not available in std::string_view.
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bool equals(StringView Other) const {
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if (Len != Other.Len)
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// Returns true if this StringView has the given suffix and removes that
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// suffix.
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bool consume_back(StringView Suffix) {
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if (!ends_with(Suffix))
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return false;
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for (size_t I = 0; I < Len; ++I) {
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if (Data[I] != Other.Data[I])
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return false;
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}
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*this = drop_back(Suffix.size());
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return true;
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}
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};
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@ -9,65 +9,67 @@
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#include "src/__support/CPP/StringView.h"
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#include "utils/UnitTest/Test.h"
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using __llvm_libc::cpp::StringView;
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TEST(LlvmLibcStringViewTest, InitializeCheck) {
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__llvm_libc::cpp::StringView v;
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StringView v;
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ASSERT_EQ(v.size(), size_t(0));
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ASSERT_TRUE(v.data() == nullptr);
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v = __llvm_libc::cpp::StringView("");
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v = StringView("");
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ASSERT_EQ(v.size(), size_t(0));
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ASSERT_TRUE(v.data() == nullptr);
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v = __llvm_libc::cpp::StringView(nullptr);
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v = StringView(nullptr);
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ASSERT_EQ(v.size(), size_t(0));
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ASSERT_TRUE(v.data() == nullptr);
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v = __llvm_libc::cpp::StringView(nullptr, 10);
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v = StringView(nullptr, 10);
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ASSERT_EQ(v.size(), size_t(0));
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ASSERT_TRUE(v.data() == nullptr);
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v = __llvm_libc::cpp::StringView("abc", 0);
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v = StringView("abc", 0);
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ASSERT_EQ(v.size(), size_t(0));
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ASSERT_TRUE(v.data() == nullptr);
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v = __llvm_libc::cpp::StringView("123456789");
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v = StringView("123456789");
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ASSERT_EQ(v.size(), size_t(9));
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}
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TEST(LlvmLibcStringViewTest, Equals) {
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__llvm_libc::cpp::StringView v("abc");
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ASSERT_TRUE(v.equals(__llvm_libc::cpp::StringView("abc")));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView()));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView("")));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView("123")));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView("abd")));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView("aaa")));
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ASSERT_FALSE(v.equals(__llvm_libc::cpp::StringView("abcde")));
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StringView v("abc");
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ASSERT_TRUE(v.equals(StringView("abc")));
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ASSERT_FALSE(v.equals(StringView()));
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ASSERT_FALSE(v.equals(StringView("")));
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ASSERT_FALSE(v.equals(StringView("123")));
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ASSERT_FALSE(v.equals(StringView("abd")));
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ASSERT_FALSE(v.equals(StringView("aaa")));
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ASSERT_FALSE(v.equals(StringView("abcde")));
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}
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TEST(LlvmLibcStringViewTest, startsWith) {
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__llvm_libc::cpp::StringView v("abc");
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ASSERT_TRUE(v.starts_with(__llvm_libc::cpp::StringView("a")));
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ASSERT_TRUE(v.starts_with(__llvm_libc::cpp::StringView("ab")));
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ASSERT_TRUE(v.starts_with(__llvm_libc::cpp::StringView("abc")));
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ASSERT_TRUE(v.starts_with(__llvm_libc::cpp::StringView()));
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ASSERT_TRUE(v.starts_with(__llvm_libc::cpp::StringView("")));
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ASSERT_FALSE(v.starts_with(__llvm_libc::cpp::StringView("123")));
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ASSERT_FALSE(v.starts_with(__llvm_libc::cpp::StringView("abd")));
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ASSERT_FALSE(v.starts_with(__llvm_libc::cpp::StringView("aaa")));
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ASSERT_FALSE(v.starts_with(__llvm_libc::cpp::StringView("abcde")));
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StringView v("abc");
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ASSERT_TRUE(v.starts_with(StringView("a")));
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ASSERT_TRUE(v.starts_with(StringView("ab")));
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ASSERT_TRUE(v.starts_with(StringView("abc")));
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ASSERT_TRUE(v.starts_with(StringView()));
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ASSERT_TRUE(v.starts_with(StringView("")));
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ASSERT_FALSE(v.starts_with(StringView("123")));
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ASSERT_FALSE(v.starts_with(StringView("abd")));
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ASSERT_FALSE(v.starts_with(StringView("aaa")));
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ASSERT_FALSE(v.starts_with(StringView("abcde")));
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}
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TEST(LlvmLibcStringViewTest, RemovePrefix) {
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__llvm_libc::cpp::StringView v("123456789");
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StringView v("123456789");
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auto p = v.remove_prefix(0);
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ASSERT_EQ(p.size(), size_t(9));
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ASSERT_TRUE(p.equals(__llvm_libc::cpp::StringView("123456789")));
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ASSERT_TRUE(p.equals(StringView("123456789")));
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p = v.remove_prefix(4);
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ASSERT_EQ(p.size(), size_t(5));
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ASSERT_TRUE(p.equals(__llvm_libc::cpp::StringView("56789")));
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ASSERT_TRUE(p.equals(StringView("56789")));
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p = v.remove_prefix(9);
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ASSERT_EQ(p.size(), size_t(0));
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@ -79,15 +81,15 @@ TEST(LlvmLibcStringViewTest, RemovePrefix) {
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}
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TEST(LlvmLibcStringViewTest, RemoveSuffix) {
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__llvm_libc::cpp::StringView v("123456789");
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StringView v("123456789");
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auto p = v.remove_suffix(0);
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ASSERT_EQ(p.size(), size_t(9));
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ASSERT_TRUE(p.equals(__llvm_libc::cpp::StringView("123456789")));
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ASSERT_TRUE(p.equals(StringView("123456789")));
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p = v.remove_suffix(4);
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ASSERT_EQ(p.size(), size_t(5));
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ASSERT_TRUE(p.equals(__llvm_libc::cpp::StringView("12345")));
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ASSERT_TRUE(p.equals(StringView("12345")));
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p = v.remove_suffix(9);
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ASSERT_EQ(p.size(), size_t(0));
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@ -99,42 +101,78 @@ TEST(LlvmLibcStringViewTest, RemoveSuffix) {
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}
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TEST(LlvmLibcStringViewTest, TrimSingleChar) {
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__llvm_libc::cpp::StringView v(" 123456789 ");
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StringView v(" 123456789 ");
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auto t = v.trim(' ');
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ASSERT_EQ(t.size(), size_t(9));
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ASSERT_TRUE(t.equals(__llvm_libc::cpp::StringView("123456789")));
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ASSERT_TRUE(t.equals(StringView("123456789")));
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v = __llvm_libc::cpp::StringView("====12345==");
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v = StringView("====12345==");
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t = v.trim(' ');
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ASSERT_EQ(v.size(), size_t(11));
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ASSERT_TRUE(t.equals(__llvm_libc::cpp::StringView("====12345==")));
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ASSERT_TRUE(t.equals(StringView("====12345==")));
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t = v.trim('=');
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ASSERT_EQ(t.size(), size_t(5));
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ASSERT_TRUE(t.equals(__llvm_libc::cpp::StringView("12345")));
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ASSERT_TRUE(t.equals(StringView("12345")));
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v = __llvm_libc::cpp::StringView("12345===");
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v = StringView("12345===");
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t = v.trim('=');
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ASSERT_EQ(t.size(), size_t(5));
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ASSERT_TRUE(t.equals(__llvm_libc::cpp::StringView("12345")));
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ASSERT_TRUE(t.equals(StringView("12345")));
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v = __llvm_libc::cpp::StringView("===========12345");
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v = StringView("===========12345");
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t = v.trim('=');
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ASSERT_EQ(t.size(), size_t(5));
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ASSERT_TRUE(t.equals(__llvm_libc::cpp::StringView("12345")));
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ASSERT_TRUE(t.equals(StringView("12345")));
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v = __llvm_libc::cpp::StringView("============");
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v = StringView("============");
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t = v.trim('=');
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ASSERT_EQ(t.size(), size_t(0));
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ASSERT_TRUE(t.data() == nullptr);
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v = __llvm_libc::cpp::StringView();
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v = StringView();
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t = v.trim(' ');
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ASSERT_EQ(t.size(), size_t(0));
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ASSERT_TRUE(t.data() == nullptr);
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v = __llvm_libc::cpp::StringView("");
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v = StringView("");
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t = v.trim(' ');
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ASSERT_EQ(t.size(), size_t(0));
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ASSERT_TRUE(t.data() == nullptr);
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}
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TEST(LlvmLibcStringViewTest, Observer) {
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StringView ABC("abc");
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ASSERT_EQ(ABC.size(), size_t(3));
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ASSERT_FALSE(ABC.empty());
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ASSERT_EQ(ABC.front(), 'a');
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ASSERT_EQ(ABC.back(), 'c');
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}
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bool isDigit(char c) { return c >= '0' && c <= '9'; }
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TEST(LlvmLibcStringViewTest, Transform) {
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ASSERT_TRUE(StringView("123abc").drop_back(3).equals("123"));
|
||||
ASSERT_TRUE(StringView("123abc").drop_front(3).equals("abc"));
|
||||
ASSERT_TRUE(StringView("123abc").take_back(3).equals("abc"));
|
||||
ASSERT_TRUE(StringView("123abc").take_front(3).equals("123"));
|
||||
|
||||
ASSERT_TRUE(StringView("123abc").take_while(&isDigit).equals("123"));
|
||||
ASSERT_TRUE(StringView("abc123").take_until(&isDigit).equals("abc"));
|
||||
ASSERT_TRUE(StringView("123abc").drop_while(&isDigit).equals("abc"));
|
||||
ASSERT_TRUE(StringView("abc123").drop_until(&isDigit).equals("123"));
|
||||
}
|
||||
|
||||
TEST(LlvmLibcStringViewTest, ConsumeFront) {
|
||||
StringView Tmp("abc");
|
||||
ASSERT_FALSE(Tmp.consume_front("###"));
|
||||
ASSERT_TRUE(Tmp.consume_front("ab"));
|
||||
ASSERT_TRUE(Tmp.equals("c"));
|
||||
}
|
||||
|
||||
TEST(LlvmLibcStringViewTest, ConsumeBack) {
|
||||
StringView Tmp("abc");
|
||||
ASSERT_FALSE(Tmp.consume_back("###"));
|
||||
ASSERT_TRUE(Tmp.consume_back("bc"));
|
||||
ASSERT_TRUE(Tmp.equals("a"));
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue