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//===-- Standalone implementation std::string_view --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_UTILS_CPP_STRINGVIEW_H
#define LLVM_LIBC_UTILS_CPP_STRINGVIEW_H
#include <stddef.h>
namespace __llvm_libc {
namespace cpp {
// This is very simple alternate of the std::string_view class. There is no
// bounds check performed in any of the methods. The callers are expected to
// do the checks before invoking the methods.
//
// This class will be extended as needed in future.
class StringView {
private:
const char *Data;
size_t Len;
public:
StringView() : Data(nullptr), Len(0) {}
// Assumes Str is a null-terminated string. The length of the string does
// not include the terminating null character.
explicit StringView(const char *Str) : Data(Str), Len(0) {
if (Str == nullptr)
return;
for (const char *D = Data; *D != '\0'; ++D, ++Len)
;
if (Len == 0)
Data = nullptr;
}
explicit StringView(const char *Str, size_t N)
: Data(N ? Str : nullptr), Len(Str == nullptr ? 0 : N) {}
const char *data() const { return Data; }
size_t size() { return Len; }
const char &operator[](size_t Index) const { return Data[Index]; }
StringView remove_prefix(size_t N) const {
if (N >= Len)
return StringView();
return StringView(Data + N, Len - N);
}
StringView remove_suffix(size_t N) const {
if (N >= Len)
return StringView();
return StringView(Data, Len - N);
}
// An equivalent method is not available in std::string_view.
StringView trim(char C) const {
if (Len == 0)
return StringView();
const char *NewStart = Data;
size_t PrefixLen = 0;
for (; PrefixLen < Len; ++NewStart, ++PrefixLen) {
if (*NewStart != C)
break;
}
size_t SuffixLen = 0;
const char *NewEnd = Data + Len - 1;
for (; SuffixLen < Len; --NewEnd, ++SuffixLen) {
if (*NewEnd != C)
break;
}
return remove_prefix(PrefixLen).remove_suffix(SuffixLen);
}
// An equivalent method is not available in std::string_view.
bool equals(StringView Other) const {
if (Len != Other.Len)
return false;
for (size_t I = 0; I < Len; ++I) {
if (Data[I] != Other.Data[I])
return false;
}
return true;
}
};
} // namespace cpp
} // namespace __llvm_libc
#endif // LLVM_LIBC_UTILS_CPP_STRINGVIEW_H
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