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//===-- SwiftStringIndex.h --------------------------------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#ifndef liblldb_SwiftStringIndex_h
#define liblldb_SwiftStringIndex_h
#include "lldb/lldb-forward.h"
namespace lldb_private {
namespace formatters {
namespace swift {
// From SwiftIndex.swift
// ┌──────────┬────────────────╥────────────────┬───────╥───────┐
// │ b63:b16 │ b15:b14 ║ b13:b8 │ b7:b4 ║ b3:b0 │
// ├──────────┼────────────────╫────────────────┼───────╫───────┤
// │ position │ transc. offset ║ grapheme cache │ rsvd ║ flags │
// └──────────┴────────────────╨────────────────┴───────╨───────┘
// └────── resilient ───────┘
class StringIndex {
uint64_t _rawBits;
enum Flags : uint8_t {
IsScalarAligned = 1 << 0,
IsCharacterAligned = 1 << 1,
CanBeUTF8 = 1 << 2,
CanBeUTF16 = 1 << 3,
};
public:
StringIndex(uint64_t rawBits) : _rawBits(rawBits) {}
uint64_t encodedOffset() { return _rawBits >> 16; }
const char *encodingName() {
auto flags = _flags();
bool canBeUTF8 = flags & Flags::CanBeUTF8;
bool canBeUTF16 = flags & Flags::CanBeUTF16;
if (canBeUTF8 && canBeUTF16)
return "any";
else if (canBeUTF8)
return "utf8";
else if (canBeUTF16)
return "utf16";
else
return "unknown";
}
uint8_t transcodedOffset() { return (_rawBits >> 14) & 0b11; }
bool matchesEncoding(StringIndex other) {
// Either both are valid utf8 indexes, or valid utf16 indexes.
return (_utfFlags() & other._utfFlags()) != 0;
}
private:
uint8_t _flags() const { return _rawBits & 0b1111; }
uint8_t _utfFlags() const {
return _flags() & (Flags::CanBeUTF8 | Flags::CanBeUTF16);
}
};
}; // namespace swift
}; // namespace formatters
}; // namespace lldb_private
#endif
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