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100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
//===--- OwnedString.h - String storage -------------------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the 'OwnedString' storage wrapper, which can hold its own
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// unique copy of a string, or merely hold a reference to some point in a
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// source buffer, which is assumed to live at least as long as a value of this
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// type.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_BASIC_OWNEDSTRING_H
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#define SWIFT_BASIC_OWNEDSTRING_H
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#include "llvm/ADT/IntrusiveRefCntPtr.h"
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#include "llvm/ADT/StringRef.h"
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using llvm::StringRef;
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namespace swift {
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enum class StringOwnership {
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/// An OwnedString holds a weak reference to the underlying string storage
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/// and will never attempt to free it.
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Unowned,
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/// An OwnedString has its own copy of the underlying string storage and
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/// will free the storage upon its destruction.
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Copied,
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};
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/// Holds a string - either statically allocated or dynamically allocated
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/// and owned by this type.
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class OwnedString {
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const char *Data;
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size_t Length;
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StringOwnership Ownership;
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public:
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OwnedString()
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: Data(nullptr), Length(0), Ownership(StringOwnership::Unowned) {}
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OwnedString(const char *Data, size_t Length, StringOwnership Ownership)
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: Data(Ownership == StringOwnership::Copied ? strndup(Data, Length) : Data),
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Length(Length), Ownership(Ownership) {}
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OwnedString(StringRef Str, StringOwnership Ownership)
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: OwnedString(Ownership == StringOwnership::Copied
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? strndup(Str.data(), Str.size())
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: Str.data(),
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Str.size(), Ownership) {}
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OwnedString(const char *Data)
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: OwnedString(StringRef(Data), StringOwnership::Unowned) {}
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OwnedString(const OwnedString &Other)
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: Data(Other.Ownership == StringOwnership::Copied
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? strndup(Other.Data, Other.Length)
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: Other.Data),
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Length(Other.Length), Ownership(Other.Ownership) {}
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/// Returns the length of the string in bytes.
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size_t size() const {
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return Length;
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}
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/// Returns true if the length is 0.
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bool empty() const {
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return Length == 0;
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}
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/// Returns a StringRef to the underlying data. No copy is made and no
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/// ownership changes take place.
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StringRef str() const {
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return StringRef { Data, Length };
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}
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bool operator==(const OwnedString &Right) const {
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return str() == Right.str();
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}
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~OwnedString() {
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if (Ownership == StringOwnership::Copied)
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free(const_cast<char *>(Data));
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}
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};
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} // end namespace swift
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#endif // SWIFT_BASIC_OWNEDSTRING_H
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