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Emacs assumes .h files are C files by default which is why the tag "-*- C++ -*-" is needed. .cpp files do not have this problem.
88 lines
2.9 KiB
C++
88 lines
2.9 KiB
C++
//===--- PunycodeUTF8.cpp - Unicode to Punycode transcoding ---------------===//
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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 http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#include "swift/Basic/Punycode.h"
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#include <vector>
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using namespace swift;
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static bool isContinuationByte(uint8_t unit) {
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return (unit & 0xC0) == 0x80;
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}
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/// Reencode well-formed UTF-8 as UTF-32.
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///
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/// This entry point is only called from compiler-internal entry points, so does
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/// only minimal validation. In particular, it does *not* check for overlong
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/// encodings.
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static bool convertUTF8toUTF32(StringRef InputUTF8,
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std::vector<uint32_t> &OutUTF32) {
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auto ptr = InputUTF8.begin();
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auto end = InputUTF8.end();
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while (ptr < end) {
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uint8_t first = *ptr++;
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if (first < 0x80) {
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OutUTF32.push_back(first);
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} else if (first < 0xC0) {
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// Invalid continuation byte.
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return false;
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} else if (first < 0xE0) {
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// Two-byte sequence.
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if (ptr == end)
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return false;
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uint8_t second = *ptr++;
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if (!isContinuationByte(second))
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return false;
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OutUTF32.push_back(((first & 0x1F) << 6) | (second & 0x3F));
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} else if (first < 0xF0) {
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// Three-byte sequence.
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if (end - ptr < 2)
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return false;
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uint8_t second = *ptr++;
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uint8_t third = *ptr++;
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if (!isContinuationByte(second) || !isContinuationByte(third))
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return false;
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OutUTF32.push_back(((first & 0xF) << 12) | ((second & 0x3F) << 6)
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| ( third & 0x3F ));
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} else if (first < 0xF8) {
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// Four-byte sequence.
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if (end - ptr < 3)
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return false;
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uint8_t second = *ptr++;
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uint8_t third = *ptr++;
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uint8_t fourth = *ptr++;
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if (!isContinuationByte(second) || !isContinuationByte(third)
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|| !isContinuationByte(fourth))
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return false;
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OutUTF32.push_back(((first & 0x7) << 18) | ((second & 0x3F) << 12)
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| ((third & 0x3F) << 6)
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| ( fourth & 0x3F ));
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} else {
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// Unused sequence length.
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return false;
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}
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}
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return true;
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}
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bool Punycode::encodePunycodeUTF8(StringRef InputUTF8,
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std::string &OutPunycode) {
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std::vector<uint32_t> InputCodePoints;
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InputCodePoints.reserve(InputUTF8.size());
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if (!convertUTF8toUTF32(InputUTF8, InputCodePoints))
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return false;
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return encodePunycode(InputCodePoints, OutPunycode);
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}
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