1 //===--- StringView.h -------------------------------------------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // FIXME: Use std::string_view instead when we support C++17.
11 //===----------------------------------------------------------------------===//
13 #ifndef DEMANGLE_STRINGVIEW_H
14 #define DEMANGLE_STRINGVIEW_H
16 #include "DemangleConfig.h"
21 DEMANGLE_NAMESPACE_BEGIN
28 static const size_t npos = ~size_t(0);
31 StringView(const char (&Str)[N]) : First(Str), Last(Str + N - 1) {}
32 StringView(const char *First_, const char *Last_)
33 : First(First_), Last(Last_) {}
34 StringView(const char *First_, size_t Len)
35 : First(First_), Last(First_ + Len) {}
36 StringView(const char *Str) : First(Str), Last(Str + std::strlen(Str)) {}
37 StringView() : First(nullptr), Last(nullptr) {}
39 StringView substr(size_t From) const {
40 return StringView(begin() + From, size() - From);
43 size_t find(char C, size_t From = 0) const {
44 size_t FindBegin = std::min(From, size());
45 // Avoid calling memchr with nullptr.
46 if (FindBegin < size()) {
47 // Just forward to memchr, which is faster than a hand-rolled loop.
48 if (const void *P = ::memchr(First + FindBegin, C, size() - FindBegin))
49 return size_t(static_cast<const char *>(P) - First);
54 StringView substr(size_t From, size_t To) const {
59 return StringView(First + From, First + To);
62 StringView dropFront(size_t N = 1) const {
65 return StringView(First + N, Last);
68 StringView dropBack(size_t N = 1) const {
71 return StringView(First, Last - N);
89 bool consumeFront(char C) {
96 bool consumeFront(StringView S) {
99 *this = dropFront(S.size());
103 bool startsWith(char C) const { return !empty() && *begin() == C; }
105 bool startsWith(StringView Str) const {
106 if (Str.size() > size())
108 return std::equal(Str.begin(), Str.end(), begin());
111 const char &operator[](size_t Idx) const { return *(begin() + Idx); }
113 const char *begin() const { return First; }
114 const char *end() const { return Last; }
115 size_t size() const { return static_cast<size_t>(Last - First); }
116 bool empty() const { return First == Last; }
119 inline bool operator==(const StringView &LHS, const StringView &RHS) {
120 return LHS.size() == RHS.size() &&
121 std::equal(LHS.begin(), LHS.end(), RHS.begin());
124 DEMANGLE_NAMESPACE_END