mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-23 13:22:02 +03:00
258 lines
7.3 KiB
C++
258 lines
7.3 KiB
C++
/*
|
|
* Copyright 2016 Facebook, Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <glog/logging.h>
|
|
#include <sys/types.h>
|
|
#include <algorithm>
|
|
#include <array>
|
|
#include <cstring>
|
|
#include <string>
|
|
#include <type_traits>
|
|
|
|
#include <folly/Conv.h>
|
|
#include <folly/detail/IPAddress.h>
|
|
|
|
// BSDish platforms don't provide standard access to s6_addr16
|
|
#ifndef s6_addr16
|
|
#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || \
|
|
defined(__OpenBSD__)
|
|
#define s6_addr16 __u6_addr.__u6_addr16
|
|
#endif
|
|
#endif
|
|
|
|
namespace folly {
|
|
namespace detail {
|
|
|
|
/**
|
|
* Helper for working with unsigned char* or uint8_t* ByteArray values
|
|
*/
|
|
struct Bytes {
|
|
// mask the values from two byte arrays, returning a new byte array
|
|
template <std::size_t N>
|
|
static std::array<uint8_t, N> mask(
|
|
const std::array<uint8_t, N>& a,
|
|
const std::array<uint8_t, N>& b) {
|
|
static_assert(N > 0, "Can't mask an empty ByteArray");
|
|
std::size_t asize = a.size();
|
|
std::array<uint8_t, N> ba{{0}};
|
|
for (std::size_t i = 0; i < asize; i++) {
|
|
ba[i] = a[i] & b[i];
|
|
}
|
|
return ba;
|
|
}
|
|
|
|
template <std::size_t N>
|
|
static std::pair<std::array<uint8_t, N>, uint8_t> longestCommonPrefix(
|
|
const std::array<uint8_t, N>& one,
|
|
uint8_t oneMask,
|
|
const std::array<uint8_t, N>& two,
|
|
uint8_t twoMask) {
|
|
static constexpr auto kBitCount = N * 8;
|
|
static constexpr std::array<uint8_t, 8> kMasks{{
|
|
0x80, // /1
|
|
0xc0, // /2
|
|
0xe0, // /3
|
|
0xf0, // /4
|
|
0xf8, // /5
|
|
0xfc, // /6
|
|
0xfe, // /7
|
|
0xff // /8
|
|
}};
|
|
if (oneMask > kBitCount || twoMask > kBitCount) {
|
|
throw std::invalid_argument(folly::to<std::string>(
|
|
"Invalid mask "
|
|
"length: ",
|
|
oneMask > twoMask ? oneMask : twoMask,
|
|
". Mask length must be <= ",
|
|
kBitCount));
|
|
}
|
|
|
|
auto mask = std::min(oneMask, twoMask);
|
|
uint8_t byteIndex = 0;
|
|
std::array<uint8_t, N> ba{{0}};
|
|
// Compare a byte at a time. Note - I measured compared this with
|
|
// going multiple bytes at a time (8, 4, 2 and 1). It turns out
|
|
// to be 20 - 25% slower for 4 and 16 byte arrays.
|
|
while (byteIndex * 8 < mask && one[byteIndex] == two[byteIndex]) {
|
|
ba[byteIndex] = one[byteIndex];
|
|
++byteIndex;
|
|
}
|
|
auto bitIndex = std::min(mask, (uint8_t)(byteIndex * 8));
|
|
// Compute the bit up to which the two byte arrays match in the
|
|
// unmatched byte.
|
|
// Here the check is bitIndex < mask since the 0th mask entry in
|
|
// kMasks array holds the mask for masking the MSb in this byte.
|
|
// We could instead make it hold so that no 0th entry masks no
|
|
// bits but thats a useless iteration.
|
|
while (bitIndex < mask && ((one[bitIndex / 8] & kMasks[bitIndex % 8]) ==
|
|
(two[bitIndex / 8] & kMasks[bitIndex % 8]))) {
|
|
ba[bitIndex / 8] = one[bitIndex / 8] & kMasks[bitIndex % 8];
|
|
++bitIndex;
|
|
}
|
|
return {ba, bitIndex};
|
|
}
|
|
|
|
// create an in_addr from an uint8_t*
|
|
static inline in_addr mkAddress4(const uint8_t* src) {
|
|
union {
|
|
in_addr addr;
|
|
uint8_t bytes[4];
|
|
} addr;
|
|
std::memset(&addr, 0, 4);
|
|
std::memcpy(addr.bytes, src, 4);
|
|
return addr.addr;
|
|
}
|
|
|
|
// create an in6_addr from an uint8_t*
|
|
static inline in6_addr mkAddress6(const uint8_t* src) {
|
|
in6_addr addr;
|
|
std::memset(&addr, 0, 16);
|
|
std::memcpy(addr.s6_addr, src, 16);
|
|
return addr;
|
|
}
|
|
|
|
// convert an uint8_t* to its hex value
|
|
static std::string toHex(const uint8_t* src, std::size_t len) {
|
|
static const char* const lut = "0123456789abcdef";
|
|
std::string out(len * 2, 0);
|
|
for (std::size_t i = 0; i < len; i++) {
|
|
const unsigned char c = src[i];
|
|
out[i * 2 + 0] = lut[c >> 4];
|
|
out[i * 2 + 1] = lut[c & 15];
|
|
}
|
|
return out;
|
|
}
|
|
|
|
private:
|
|
Bytes() = delete;
|
|
~Bytes() = delete;
|
|
};
|
|
|
|
//
|
|
// Write a maximum amount of base-converted character digits, of a
|
|
// given base, from an unsigned integral type into a byte buffer of
|
|
// sufficient size.
|
|
//
|
|
// This function does not append null terminators.
|
|
//
|
|
// Output buffer size must be guaranteed by caller (indirectly
|
|
// controlled by DigitCount template parameter).
|
|
//
|
|
// Having these parameters at compile time allows compiler to
|
|
// precompute several of the values, use smaller instructions, and
|
|
// better optimize surrounding code.
|
|
//
|
|
// IntegralType:
|
|
// - Something like uint8_t, uint16_t, etc
|
|
//
|
|
// DigitCount is the maximum number of digits to be printed
|
|
// - This is tied to IntegralType and Base. For example:
|
|
// - uint8_t in base 10 will print at most 3 digits ("255")
|
|
// - uint16_t in base 16 will print at most 4 hex digits ("FFFF")
|
|
//
|
|
// Base is the desired output base of the string
|
|
// - Base 10 will print [0-9], base 16 will print [0-9a-f]
|
|
//
|
|
// PrintAllDigits:
|
|
// - Whether or not leading zeros should be printed
|
|
//
|
|
template <
|
|
class IntegralType,
|
|
IntegralType DigitCount,
|
|
IntegralType Base = 10,
|
|
bool PrintAllDigits = false,
|
|
class = typename std::enable_if<
|
|
std::is_integral<IntegralType>::value &&
|
|
std::is_unsigned<IntegralType>::value,
|
|
bool>::type>
|
|
inline void writeIntegerString(IntegralType val, char** buffer) {
|
|
char* buf = *buffer;
|
|
|
|
if (!PrintAllDigits && val == 0) {
|
|
*(buf++) = '0';
|
|
*buffer = buf;
|
|
return;
|
|
}
|
|
|
|
IntegralType powerToPrint = 1;
|
|
for (int i = 1; i < DigitCount; ++i) {
|
|
powerToPrint *= Base;
|
|
}
|
|
|
|
bool found = PrintAllDigits;
|
|
while (powerToPrint) {
|
|
if (found || powerToPrint <= val) {
|
|
IntegralType value = val / powerToPrint;
|
|
if (Base == 10 || value < 10) {
|
|
value += '0';
|
|
} else {
|
|
value += ('a' - 10);
|
|
}
|
|
*(buf++) = value;
|
|
val %= powerToPrint;
|
|
found = true;
|
|
}
|
|
|
|
powerToPrint /= Base;
|
|
}
|
|
|
|
*buffer = buf;
|
|
}
|
|
|
|
inline std::string fastIpv4ToString(const in_addr& inAddr) {
|
|
const uint8_t* octets = reinterpret_cast<const uint8_t*>(&inAddr.s_addr);
|
|
char str[sizeof("255.255.255.255")];
|
|
char* buf = str;
|
|
|
|
writeIntegerString<uint8_t, 3>(octets[0], &buf);
|
|
*(buf++) = '.';
|
|
writeIntegerString<uint8_t, 3>(octets[1], &buf);
|
|
*(buf++) = '.';
|
|
writeIntegerString<uint8_t, 3>(octets[2], &buf);
|
|
*(buf++) = '.';
|
|
writeIntegerString<uint8_t, 3>(octets[3], &buf);
|
|
|
|
return std::string(str, buf - str);
|
|
}
|
|
|
|
inline std::string fastIpv6ToString(const in6_addr& in6Addr) {
|
|
#ifdef _MSC_VER
|
|
const uint16_t* bytes = reinterpret_cast<const uint16_t*>(&in6Addr.u.Word);
|
|
#else
|
|
const uint16_t* bytes = reinterpret_cast<const uint16_t*>(&in6Addr.s6_addr16);
|
|
#endif
|
|
char str[sizeof("2001:0db8:0000:0000:0000:ff00:0042:8329")];
|
|
char* buf = str;
|
|
|
|
for (int i = 0; i < 8; ++i) {
|
|
writeIntegerString<
|
|
uint16_t,
|
|
4, // at most 4 hex digits per ushort
|
|
16, // base 16 (hex)
|
|
true>(htons(bytes[i]), &buf);
|
|
|
|
if (i != 7) {
|
|
*(buf++) = ':';
|
|
}
|
|
}
|
|
|
|
return std::string(str, buf - str);
|
|
}
|
|
}
|
|
}
|