firefox-main/mfbt/Utf8.cpp (file symbol)

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#define MOZ_PRETEND_NO_JSRUST 1
#include "mozilla/Utf8.h"
#include <stddef.h>
#include "mozilla/HashFunctions.h"
#include "mozilla/Maybe.h"
#include "mozilla/TextUtils.h"
#include "mozilla/Types.h"
#include "mozilla/Utf16.h"
namespace mozilla {
namespace detail {
MFBT_API bool IsValidUtf8(const void* aCodeUnits, size_t aCount) {
const auto* s = reinterpret_cast<const unsigned char*>(aCodeUnits);
const auto* const limit = s + aCount;
while (s < limit) {
unsigned char c = *s++;
// If the first byte is ASCII, it's the only one in the code point. Have a
// fast path that avoids all the rest of the work and looping in that case.
if (IsAscii(c)) {
continue;
}
Maybe<char32_t> maybeCodePoint =
DecodeOneUtf8CodePoint(Utf8Unit(c), &s, limit);
if (maybeCodePoint.isNothing()) {
return false;
}
}
MOZ_ASSERT(s == limit);
return true;
}
} // namespace detail
MFBT_API HashNumber HashUTF8AsUTF16(const char* aUTF8, size_t aLength) {
const auto* s = reinterpret_cast<const unsigned char*>(aUTF8);
const auto* const limit = s + aLength;
detail::UTF16Hasher hasher;
while (s < limit) {
unsigned char c = *s++;
char32_t codePoint;
if (IsAscii(c)) {
codePoint = c;
} else {
codePoint = LossyDecodeOneUtf8CodePoint(Utf8Unit(c), &s, limit);
}
// Split astral code points into a UTF-16 surrogate pair, matching what a
// conversion to UTF-16 followed by HashString() would hash.
if (IsInBMP(codePoint)) {
hasher.Add(static_cast<char16_t>(codePoint));
} else {
hasher.Add(HighSurrogate(codePoint));
hasher.Add(LowSurrogate(codePoint));
}
}
return hasher.Finish();
}
} // namespace mozilla