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/*
* Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>
* Copyright (C) 2024 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <span>
#include <string>
#include <type_traits>
#include <wtf/ASCIICType.h>
#include <wtf/Compiler.h>
#include <wtf/Forward.h>
#include <wtf/HashFunctions.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/SuperFastHash.h>
#if USE(CF)
typedef const struct __CFString * CFStringRef;
#endif
OBJC_CLASS NSString;
namespace WTF {
class PrintStream;
class ASCIILiteral final {
public:
constexpr operator const char*() const { return m_charactersWithNullTerminator.data(); }
static constexpr ASCIILiteral fromLiteralUnsafe(const char* string)
{
ASSERT_UNDER_CONSTEXPR_CONTEXT(string);
return ASCIILiteral { unsafeMakeSpan(string, std::char_traits<char>::length(string) + 1) };
}
WTF_EXPORT_PRIVATE void dump(PrintStream& out) const;
ASCIILiteral() = default;
constexpr ASCIILiteral(std::nullptr_t)
: ASCIILiteral()
{ }
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
template<size_t length>
consteval ASCIILiteral(const char (&literal)[length])
: m_charactersWithNullTerminator(unsafeMakeSpan(literal, length))
{
RELEASE_ASSERT_UNDER_CONSTEXPR_CONTEXT(literal[length - 1] == '\0');
}
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
unsigned hash() const;
constexpr bool isNull() const { return m_charactersWithNullTerminator.empty(); }
constexpr const char* characters() const { return m_charactersWithNullTerminator.data(); }
constexpr size_t length() const { return !m_charactersWithNullTerminator.empty() ? m_charactersWithNullTerminator.size() - 1 : 0; }
constexpr std::span<const char> span() const { return m_charactersWithNullTerminator.first(length()); }
std::span<const LChar> span8() const { return byteCast<LChar>(m_charactersWithNullTerminator.first(length())); }
std::span<const char> spanIncludingNullTerminator() const { return m_charactersWithNullTerminator; }
size_t isEmpty() const { return m_charactersWithNullTerminator.size() <= 1; }
constexpr char operator[](size_t index) const { return m_charactersWithNullTerminator[index]; }
constexpr char characterAt(size_t index) const { return m_charactersWithNullTerminator[index]; }
#ifdef __OBJC__
// This function convert null strings to empty strings.
WTF_EXPORT_PRIVATE RetainPtr<NSString> createNSString() const;
#endif
static ASCIILiteral deletedValue();
bool isDeletedValue() const { return characters() == reinterpret_cast<char*>(-1); }
#if USE(CF)
WTF_EXPORT_PRIVATE RetainPtr<CFStringRef> createCFString() const;
#endif
private:
constexpr explicit ASCIILiteral(std::span<const char> spanWithNullTerminator)
: m_charactersWithNullTerminator(spanWithNullTerminator)
{
#if ASSERT_ENABLED
for (size_t i = 0, size = length(); i < size; ++i)
ASSERT_UNDER_CONSTEXPR_CONTEXT(isASCII(m_charactersWithNullTerminator[i]));
#endif
}
std::span<const char> m_charactersWithNullTerminator;
};
inline bool operator==(ASCIILiteral a, ASCIILiteral b)
{
if (!a || !b)
return a.characters() == b.characters();
return equalSpans(a.span(), b.span());
}
inline unsigned ASCIILiteral::hash() const
{
if (isNull())
return 0;
SuperFastHash hasher;
hasher.addCharacters(characters(), length());
return hasher.hash();
}
struct ASCIILiteralHash {
static unsigned hash(const ASCIILiteral& literal) { return literal.hash(); }
static bool equal(const ASCIILiteral& a, const ASCIILiteral& b) { return a == b; }
static constexpr bool safeToCompareToEmptyOrDeleted = false;
};
template<typename T> struct DefaultHash;
template<> struct DefaultHash<ASCIILiteral> : ASCIILiteralHash { };
inline ASCIILiteral ASCIILiteral::deletedValue()
{
ASCIILiteral result;
result.m_charactersWithNullTerminator = { reinterpret_cast<char*>(-1), static_cast<size_t>(0) };
return result;
}
inline namespace StringLiterals {
constexpr ASCIILiteral operator""_s(const char* characters, size_t)
{
auto result = ASCIILiteral::fromLiteralUnsafe(characters);
ASSERT_UNDER_CONSTEXPR_CONTEXT(result.characters() == characters);
return result;
}
constexpr std::span<const char> operator""_span(const char* characters, size_t n)
{
auto span = unsafeMakeSpan(characters, n);
#if ASSERT_ENABLED
for (size_t i = 0, size = span.size(); i < size; ++i)
ASSERT_UNDER_CONSTEXPR_CONTEXT(isASCII(span[i]));
#endif
return span;
}
constexpr std::span<const LChar> operator""_span8(const char* characters, size_t n)
{
auto span = byteCast<LChar>(unsafeMakeSpan(characters, n));
#if ASSERT_ENABLED
for (size_t i = 0, size = span.size(); i < size; ++i)
ASSERT_UNDER_CONSTEXPR_CONTEXT(isASCII(span[i]));
#endif
return span;
}
} // inline StringLiterals
// ASCIILiteral is null terminated
inline const char* safePrintfType(const ASCIILiteral& asciiLiteral) { return asciiLiteral.characters(); }
} // namespace WTF
using namespace WTF::StringLiterals;
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