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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/390223051): Remove C-library calls to fix the errors.
#pragma allow_unsafe_libc_calls
#endif
#include "base/uuid.h"
#include <stddef.h>
#include <stdint.h>
#include <ostream>
#include <string_view>
#include "base/containers/span.h"
#include "base/hash/hash.h"
#include "base/rand_util.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/types/pass_key.h"
namespace base {
namespace {
template <typename Char>
constexpr bool IsLowerHexDigit(Char c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f');
}
constexpr bool IsHyphenPosition(size_t i) {
return i == 8 || i == 13 || i == 18 || i == 23;
}
// Returns a canonical Uuid string given that `input` is validly formatted
// xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, such that x is a hexadecimal digit.
// If `strict`, x must be a lower-case hexadecimal digit.
template <typename StringPieceType>
std::string GetCanonicalUuidInternal(StringPieceType input, bool strict) {
using CharType = typename StringPieceType::value_type;
constexpr size_t kUuidLength = 36;
if (input.length() != kUuidLength) {
return std::string();
}
std::string lowercase_;
lowercase_.resize(kUuidLength);
for (size_t i = 0; i < input.length(); ++i) {
CharType current = input[i];
if (IsHyphenPosition(i)) {
if (current != '-') {
return std::string();
}
lowercase_[i] = '-';
} else {
if (strict ? !IsLowerHexDigit(current) : !IsHexDigit(current)) {
return std::string();
}
lowercase_[i] = static_cast<char>(ToLowerASCII(current));
}
}
return lowercase_;
}
} // namespace
// static
Uuid Uuid::GenerateRandomV4() {
uint8_t sixteen_bytes[kGuidV4InputLength];
// Use base::RandBytes instead of crypto::RandBytes, because crypto calls the
// base version directly, and to prevent the dependency from base/ to crypto/.
RandBytes(sixteen_bytes);
return FormatRandomDataAsV4Impl(sixteen_bytes);
}
// static
Uuid Uuid::FormatRandomDataAsV4Impl(base::span<const uint8_t, 16> input) {
DCHECK_EQ(input.size_bytes(), kGuidV4InputLength);
uint64_t sixteen_bytes[2];
memcpy(&sixteen_bytes, input.data(), sizeof(sixteen_bytes));
// Set the Uuid to version 4 as described in RFC 4122, section 4.4.
// The format of Uuid version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx,
// where y is one of [8, 9, a, b].
// Clear the version bits and set the version to 4:
sixteen_bytes[0] &= 0xffffffff'ffff0fffULL;
sixteen_bytes[0] |= 0x00000000'00004000ULL;
// Clear bit 65 and set bit 64, to set the 'var' field to 0b10 per RFC 9562
// section 5.4.
sixteen_bytes[1] &= 0x3fffffff'ffffffffULL;
sixteen_bytes[1] |= 0x80000000'00000000ULL;
Uuid uuid;
uuid.lowercase_ =
StringPrintf("%08x-%04x-%04x-%04x-%012llx",
static_cast<uint32_t>(sixteen_bytes[0] >> 32),
static_cast<uint32_t>((sixteen_bytes[0] >> 16) & 0x0000ffff),
static_cast<uint32_t>(sixteen_bytes[0] & 0x0000ffff),
static_cast<uint32_t>(sixteen_bytes[1] >> 48),
sixteen_bytes[1] & 0x0000ffff'ffffffffULL);
return uuid;
}
// static
Uuid Uuid::ParseCaseInsensitive(std::string_view input) {
Uuid uuid;
uuid.lowercase_ = GetCanonicalUuidInternal(input, /*strict=*/false);
return uuid;
}
// static
Uuid Uuid::ParseCaseInsensitive(std::u16string_view input) {
Uuid uuid;
uuid.lowercase_ = GetCanonicalUuidInternal(input, /*strict=*/false);
return uuid;
}
// static
Uuid Uuid::ParseLowercase(std::string_view input) {
Uuid uuid;
uuid.lowercase_ = GetCanonicalUuidInternal(input, /*strict=*/true);
return uuid;
}
// static
Uuid Uuid::ParseLowercase(std::u16string_view input) {
Uuid uuid;
uuid.lowercase_ = GetCanonicalUuidInternal(input, /*strict=*/true);
return uuid;
}
Uuid::Uuid() = default;
Uuid::Uuid(const Uuid& other) = default;
Uuid& Uuid::operator=(const Uuid& other) = default;
Uuid::Uuid(Uuid&& other) = default;
Uuid& Uuid::operator=(Uuid&& other) = default;
const std::string& Uuid::AsLowercaseString() const {
return lowercase_;
}
std::ostream& operator<<(std::ostream& out, const Uuid& uuid) {
return out << uuid.AsLowercaseString();
}
size_t UuidHash::operator()(const Uuid& uuid) const {
// TODO(crbug.com/40108138): Avoid converting to string to take the hash when
// the internal type is migrated to a non-string type.
return FastHash(uuid.AsLowercaseString());
}
} // namespace base
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