ClickHouse/dbms/Common/formatIPv6.cpp

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#include <Common/formatIPv6.h>
#include <Common/hex.h>
#include <Common/StringUtils/StringUtils.h>
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#include <ext/range.h>
#include <array>
#include <algorithm>
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namespace DB
{
// To be used in formatIPv4, maps a byte to it's string form prefixed with length (so save strlen call).
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extern const char one_byte_to_string_lookup_table[256][4] =
{
{1, '0'}, {1, '1'}, {1, '2'}, {1, '3'}, {1, '4'}, {1, '5'}, {1, '6'}, {1, '7'}, {1, '8'}, {1, '9'},
{2, '1', '0'}, {2, '1', '1'}, {2, '1', '2'}, {2, '1', '3'}, {2, '1', '4'}, {2, '1', '5'}, {2, '1', '6'}, {2, '1', '7'}, {2, '1', '8'}, {2, '1', '9'},
{2, '2', '0'}, {2, '2', '1'}, {2, '2', '2'}, {2, '2', '3'}, {2, '2', '4'}, {2, '2', '5'}, {2, '2', '6'}, {2, '2', '7'}, {2, '2', '8'}, {2, '2', '9'},
{2, '3', '0'}, {2, '3', '1'}, {2, '3', '2'}, {2, '3', '3'}, {2, '3', '4'}, {2, '3', '5'}, {2, '3', '6'}, {2, '3', '7'}, {2, '3', '8'}, {2, '3', '9'},
{2, '4', '0'}, {2, '4', '1'}, {2, '4', '2'}, {2, '4', '3'}, {2, '4', '4'}, {2, '4', '5'}, {2, '4', '6'}, {2, '4', '7'}, {2, '4', '8'}, {2, '4', '9'},
{2, '5', '0'}, {2, '5', '1'}, {2, '5', '2'}, {2, '5', '3'}, {2, '5', '4'}, {2, '5', '5'}, {2, '5', '6'}, {2, '5', '7'}, {2, '5', '8'}, {2, '5', '9'},
{2, '6', '0'}, {2, '6', '1'}, {2, '6', '2'}, {2, '6', '3'}, {2, '6', '4'}, {2, '6', '5'}, {2, '6', '6'}, {2, '6', '7'}, {2, '6', '8'}, {2, '6', '9'},
{2, '7', '0'}, {2, '7', '1'}, {2, '7', '2'}, {2, '7', '3'}, {2, '7', '4'}, {2, '7', '5'}, {2, '7', '6'}, {2, '7', '7'}, {2, '7', '8'}, {2, '7', '9'},
{2, '8', '0'}, {2, '8', '1'}, {2, '8', '2'}, {2, '8', '3'}, {2, '8', '4'}, {2, '8', '5'}, {2, '8', '6'}, {2, '8', '7'}, {2, '8', '8'}, {2, '8', '9'},
{2, '9', '0'}, {2, '9', '1'}, {2, '9', '2'}, {2, '9', '3'}, {2, '9', '4'}, {2, '9', '5'}, {2, '9', '6'}, {2, '9', '7'}, {2, '9', '8'}, {2, '9', '9'},
{3, '1', '0', '0'}, {3, '1', '0', '1'}, {3, '1', '0', '2'}, {3, '1', '0', '3'}, {3, '1', '0', '4'}, {3, '1', '0', '5'}, {3, '1', '0', '6'}, {3, '1', '0', '7'}, {3, '1', '0', '8'}, {3, '1', '0', '9'},
{3, '1', '1', '0'}, {3, '1', '1', '1'}, {3, '1', '1', '2'}, {3, '1', '1', '3'}, {3, '1', '1', '4'}, {3, '1', '1', '5'}, {3, '1', '1', '6'}, {3, '1', '1', '7'}, {3, '1', '1', '8'}, {3, '1', '1', '9'},
{3, '1', '2', '0'}, {3, '1', '2', '1'}, {3, '1', '2', '2'}, {3, '1', '2', '3'}, {3, '1', '2', '4'}, {3, '1', '2', '5'}, {3, '1', '2', '6'}, {3, '1', '2', '7'}, {3, '1', '2', '8'}, {3, '1', '2', '9'},
{3, '1', '3', '0'}, {3, '1', '3', '1'}, {3, '1', '3', '2'}, {3, '1', '3', '3'}, {3, '1', '3', '4'}, {3, '1', '3', '5'}, {3, '1', '3', '6'}, {3, '1', '3', '7'}, {3, '1', '3', '8'}, {3, '1', '3', '9'},
{3, '1', '4', '0'}, {3, '1', '4', '1'}, {3, '1', '4', '2'}, {3, '1', '4', '3'}, {3, '1', '4', '4'}, {3, '1', '4', '5'}, {3, '1', '4', '6'}, {3, '1', '4', '7'}, {3, '1', '4', '8'}, {3, '1', '4', '9'},
{3, '1', '5', '0'}, {3, '1', '5', '1'}, {3, '1', '5', '2'}, {3, '1', '5', '3'}, {3, '1', '5', '4'}, {3, '1', '5', '5'}, {3, '1', '5', '6'}, {3, '1', '5', '7'}, {3, '1', '5', '8'}, {3, '1', '5', '9'},
{3, '1', '6', '0'}, {3, '1', '6', '1'}, {3, '1', '6', '2'}, {3, '1', '6', '3'}, {3, '1', '6', '4'}, {3, '1', '6', '5'}, {3, '1', '6', '6'}, {3, '1', '6', '7'}, {3, '1', '6', '8'}, {3, '1', '6', '9'},
{3, '1', '7', '0'}, {3, '1', '7', '1'}, {3, '1', '7', '2'}, {3, '1', '7', '3'}, {3, '1', '7', '4'}, {3, '1', '7', '5'}, {3, '1', '7', '6'}, {3, '1', '7', '7'}, {3, '1', '7', '8'}, {3, '1', '7', '9'},
{3, '1', '8', '0'}, {3, '1', '8', '1'}, {3, '1', '8', '2'}, {3, '1', '8', '3'}, {3, '1', '8', '4'}, {3, '1', '8', '5'}, {3, '1', '8', '6'}, {3, '1', '8', '7'}, {3, '1', '8', '8'}, {3, '1', '8', '9'},
{3, '1', '9', '0'}, {3, '1', '9', '1'}, {3, '1', '9', '2'}, {3, '1', '9', '3'}, {3, '1', '9', '4'}, {3, '1', '9', '5'}, {3, '1', '9', '6'}, {3, '1', '9', '7'}, {3, '1', '9', '8'}, {3, '1', '9', '9'},
{3, '2', '0', '0'}, {3, '2', '0', '1'}, {3, '2', '0', '2'}, {3, '2', '0', '3'}, {3, '2', '0', '4'}, {3, '2', '0', '5'}, {3, '2', '0', '6'}, {3, '2', '0', '7'}, {3, '2', '0', '8'}, {3, '2', '0', '9'},
{3, '2', '1', '0'}, {3, '2', '1', '1'}, {3, '2', '1', '2'}, {3, '2', '1', '3'}, {3, '2', '1', '4'}, {3, '2', '1', '5'}, {3, '2', '1', '6'}, {3, '2', '1', '7'}, {3, '2', '1', '8'}, {3, '2', '1', '9'},
{3, '2', '2', '0'}, {3, '2', '2', '1'}, {3, '2', '2', '2'}, {3, '2', '2', '3'}, {3, '2', '2', '4'}, {3, '2', '2', '5'}, {3, '2', '2', '6'}, {3, '2', '2', '7'}, {3, '2', '2', '8'}, {3, '2', '2', '9'},
{3, '2', '3', '0'}, {3, '2', '3', '1'}, {3, '2', '3', '2'}, {3, '2', '3', '3'}, {3, '2', '3', '4'}, {3, '2', '3', '5'}, {3, '2', '3', '6'}, {3, '2', '3', '7'}, {3, '2', '3', '8'}, {3, '2', '3', '9'},
{3, '2', '4', '0'}, {3, '2', '4', '1'}, {3, '2', '4', '2'}, {3, '2', '4', '3'}, {3, '2', '4', '4'}, {3, '2', '4', '5'}, {3, '2', '4', '6'}, {3, '2', '4', '7'}, {3, '2', '4', '8'}, {3, '2', '4', '9'},
{3, '2', '5', '0'}, {3, '2', '5', '1'}, {3, '2', '5', '2'}, {3, '2', '5', '3'}, {3, '2', '5', '4'}, {3, '2', '5', '5'},
};
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/// integer logarithm, return ceil(log(value, base)) (the smallest integer greater or equal than log(value, base)
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static constexpr UInt32 intLog(const UInt32 value, const UInt32 base, const bool carry)
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{
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return value >= base ? 1 + intLog(value / base, base, value % base || carry) : value % base > 1 || carry;
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}
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/// Print integer in desired base, faster than sprintf.
/// NOTE This is not the best way. See https://github.com/miloyip/itoa-benchmark
/// But it doesn't matter here.
template <UInt32 base, typename T>
static void printInteger(char *& out, T value)
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{
if (value == 0)
*out++ = '0';
else
{
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constexpr size_t buffer_size = sizeof(T) * intLog(256, base, false);
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char buf[buffer_size];
auto ptr = buf;
while (value > 0)
{
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*ptr = hexDigitLowercase(value % base);
++ptr;
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value /= base;
}
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/// Copy to out reversed.
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while (ptr != buf)
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{
--ptr;
*out = *ptr;
++out;
}
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}
}
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void formatIPv6(const unsigned char * src, char *& dst, uint8_t zeroed_tail_bytes_count)
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{
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struct { int base, len; } best{-1, 0}, cur{-1, 0};
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std::array<UInt16, IPV6_BINARY_LENGTH / sizeof(UInt16)> words{};
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/** Preprocess:
* Copy the input (bytewise) array into a wordwise array.
* Find the longest run of 0x00's in src[] for :: shorthanding. */
for (const auto i : ext::range(0, IPV6_BINARY_LENGTH - zeroed_tail_bytes_count))
words[i / 2] |= src[i] << ((1 - (i % 2)) << 3);
for (const auto i : ext::range(0, words.size()))
{
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if (words[i] == 0)
{
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if (cur.base == -1)
{
cur.base = i;
cur.len = 1;
}
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else
cur.len++;
}
else
{
if (cur.base != -1)
{
if (best.base == -1 || cur.len > best.len)
best = cur;
cur.base = -1;
}
}
}
if (cur.base != -1)
{
if (best.base == -1 || cur.len > best.len)
best = cur;
}
if (best.base != -1 && best.len < 2)
best.base = -1;
/// Format the result.
for (const int i : ext::range(0, words.size()))
{
/// Are we inside the best run of 0x00's?
if (best.base != -1 && i >= best.base && i < (best.base + best.len))
{
if (i == best.base)
*dst++ = ':';
continue;
}
/// Are we following an initial run of 0x00s or any real hex?
if (i != 0)
*dst++ = ':';
/// Is this address an encapsulated IPv4?
if (i == 6 && best.base == 0 && (best.len == 6 || (best.len == 5 && words[5] == 0xffffu)))
{
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uint8_t ipv4_buffer[IPV4_BINARY_LENGTH] = {0};
memcpy(ipv4_buffer, src + 12, IPV4_BINARY_LENGTH);
// Due to historical reasons formatIPv4() takes ipv4 in BE format, but inside ipv6 we store it in LE-format.
std::reverse(std::begin(ipv4_buffer), std::end(ipv4_buffer));
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formatIPv4(ipv4_buffer, dst, std::min(zeroed_tail_bytes_count, static_cast<uint8_t>(IPV4_BINARY_LENGTH)), "0");
// formatIPv4 has already added a null-terminator for us.
return;
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}
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printInteger<16>(dst, words[i]);
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}
/// Was it a trailing run of 0x00's?
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if (best.base != -1 && size_t(best.base) + size_t(best.len) == words.size())
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*dst++ = ':';
*dst++ = '\0';
}
}