ClickHouse/src/Functions/MatchImpl.h
2021-10-02 10:13:14 +03:00

423 lines
15 KiB
C++

#pragma once
#include <type_traits>
#include <base/types.h>
#include <Common/Volnitsky.h>
#include <Columns/ColumnString.h>
#include "Regexps.h"
#if !defined(ARCADIA_BUILD)
# include "config_functions.h"
# include <Common/config.h>
#endif
#if USE_RE2_ST
# include <re2_st/re2.h>
#else
# include <re2/re2.h>
# define re2_st re2
#endif
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
/// Is the [I]LIKE expression reduced to finding a substring in a string?
static inline bool likePatternIsStrstr(const String & pattern, String & res)
{
res = "";
if (pattern.size() < 2 || pattern.front() != '%' || pattern.back() != '%')
return false;
res.reserve(pattern.size() * 2);
const char * pos = pattern.data();
const char * end = pos + pattern.size();
++pos;
--end;
while (pos < end)
{
switch (*pos)
{
case '%':
case '_':
return false;
case '\\':
++pos;
if (pos == end)
return false;
else
res += *pos;
break;
default:
res += *pos;
break;
}
++pos;
}
return true;
}
/** 'like' - if true, treat pattern as SQL LIKE or ILIKE; if false - treat pattern as re2 regexp.
* NOTE: We want to run regexp search for whole columns by one call (as implemented in function 'position')
* but for that, regexp engine must support \0 bytes and their interpretation as string boundaries.
*/
template <typename Name, bool like, bool revert = false, bool case_insensitive = false>
struct MatchImpl
{
static constexpr bool use_default_implementation_for_constants = true;
static constexpr bool supports_start_pos = false;
static constexpr auto name = Name::name;
using ResultType = UInt8;
using Searcher = std::conditional_t<case_insensitive,
VolnitskyCaseInsensitiveUTF8,
VolnitskyUTF8>;
static void vectorConstant(
const ColumnString::Chars & data,
const ColumnString::Offsets & offsets,
const std::string & pattern,
const ColumnPtr & start_pos,
PaddedPODArray<UInt8> & res)
{
if (start_pos != nullptr)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Function '{}' doesn't support start_pos argument", name);
if (offsets.empty())
return;
String strstr_pattern;
/// A simple case where the [I]LIKE expression reduces to finding a substring in a string
if (like && likePatternIsStrstr(pattern, strstr_pattern))
{
const UInt8 * begin = data.data();
const UInt8 * pos = begin;
const UInt8 * end = pos + data.size();
/// The current index in the array of strings.
size_t i = 0;
/// TODO You need to make that `searcher` is common to all the calls of the function.
Searcher searcher(strstr_pattern.data(), strstr_pattern.size(), end - pos);
/// We will search for the next occurrence in all rows at once.
while (pos < end && end != (pos = searcher.search(pos, end - pos)))
{
/// Let's determine which index it refers to.
while (begin + offsets[i] <= pos)
{
res[i] = revert;
++i;
}
/// We check that the entry does not pass through the boundaries of strings.
if (pos + strstr_pattern.size() < begin + offsets[i])
res[i] = !revert;
else
res[i] = revert;
pos = begin + offsets[i];
++i;
}
/// Tail, in which there can be no substring.
if (i < res.size())
memset(&res[i], revert, (res.size() - i) * sizeof(res[0]));
}
else
{
size_t size = offsets.size();
auto regexp = Regexps::get<like, true, case_insensitive>(pattern);
std::string required_substring;
bool is_trivial;
bool required_substring_is_prefix; /// for `anchored` execution of the regexp.
regexp->getAnalyzeResult(required_substring, is_trivial, required_substring_is_prefix);
if (required_substring.empty())
{
if (!regexp->getRE2()) /// An empty regexp. Always matches.
{
if (size)
memset(res.data(), 1, size * sizeof(res[0]));
}
else
{
size_t prev_offset = 0;
for (size_t i = 0; i < size; ++i)
{
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(reinterpret_cast<const char *>(&data[prev_offset]), offsets[i] - prev_offset - 1),
0,
offsets[i] - prev_offset - 1,
re2_st::RE2::UNANCHORED,
nullptr,
0);
prev_offset = offsets[i];
}
}
}
else
{
/// NOTE This almost matches with the case of LikePatternIsStrstr.
const UInt8 * begin = data.data();
const UInt8 * pos = begin;
const UInt8 * end = pos + data.size();
/// The current index in the array of strings.
size_t i = 0;
Searcher searcher(required_substring.data(), required_substring.size(), end - pos);
/// We will search for the next occurrence in all rows at once.
while (pos < end && end != (pos = searcher.search(pos, end - pos)))
{
/// Determine which index it refers to.
while (begin + offsets[i] <= pos)
{
res[i] = revert;
++i;
}
/// We check that the entry does not pass through the boundaries of strings.
if (pos + strstr_pattern.size() < begin + offsets[i])
{
/// And if it does not, if necessary, we check the regexp.
if (is_trivial)
res[i] = !revert;
else
{
const char * str_data = reinterpret_cast<const char *>(&data[offsets[i - 1]]);
size_t str_size = offsets[i] - offsets[i - 1] - 1;
/** Even in the case of `required_substring_is_prefix` use UNANCHORED check for regexp,
* so that it can match when `required_substring` occurs into the string several times,
* and at the first occurrence, the regexp is not a match.
*/
if (required_substring_is_prefix)
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(str_data, str_size),
reinterpret_cast<const char *>(pos) - str_data,
str_size,
re2_st::RE2::UNANCHORED,
nullptr,
0);
else
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(str_data, str_size), 0, str_size, re2_st::RE2::UNANCHORED, nullptr, 0);
}
}
else
res[i] = revert;
pos = begin + offsets[i];
++i;
}
if (i < res.size())
memset(&res[i], revert, (res.size() - i) * sizeof(res[0]));
}
}
}
/// Very carefully crafted copy-paste.
static void vectorFixedConstant(
const ColumnString::Chars & data, size_t n, const std::string & pattern,
PaddedPODArray<UInt8> & res)
{
if (data.empty())
return;
String strstr_pattern;
/// A simple case where the LIKE expression reduces to finding a substring in a string
if (like && likePatternIsStrstr(pattern, strstr_pattern))
{
const UInt8 * begin = data.data();
const UInt8 * pos = begin;
const UInt8 * end = pos + data.size();
size_t i = 0;
const UInt8 * next_pos = begin;
/// If pattern is larger than string size - it cannot be found.
if (strstr_pattern.size() <= n)
{
Searcher searcher(strstr_pattern.data(), strstr_pattern.size(), end - pos);
/// We will search for the next occurrence in all rows at once.
while (pos < end && end != (pos = searcher.search(pos, end - pos)))
{
/// Let's determine which index it refers to.
while (next_pos + n <= pos)
{
res[i] = revert;
next_pos += n;
++i;
}
next_pos += n;
/// We check that the entry does not pass through the boundaries of strings.
if (pos + strstr_pattern.size() <= next_pos)
res[i] = !revert;
else
res[i] = revert;
pos = next_pos;
++i;
}
}
/// Tail, in which there can be no substring.
if (i < res.size())
memset(&res[i], revert, (res.size() - i) * sizeof(res[0]));
}
else
{
size_t size = data.size() / n;
auto regexp = Regexps::get<like, true>(pattern);
std::string required_substring;
bool is_trivial;
bool required_substring_is_prefix; /// for `anchored` execution of the regexp.
regexp->getAnalyzeResult(required_substring, is_trivial, required_substring_is_prefix);
if (required_substring.empty())
{
if (!regexp->getRE2()) /// An empty regexp. Always matches.
{
if (size)
memset(res.data(), 1, size * sizeof(res[0]));
}
else
{
size_t offset = 0;
for (size_t i = 0; i < size; ++i)
{
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(reinterpret_cast<const char *>(&data[offset]), n),
0,
n,
re2_st::RE2::UNANCHORED,
nullptr,
0);
offset += n;
}
}
}
else
{
/// NOTE This almost matches with the case of LikePatternIsStrstr.
const UInt8 * begin = data.data();
const UInt8 * pos = begin;
const UInt8 * end = pos + data.size();
size_t i = 0;
const UInt8 * next_pos = begin;
/// If required substring is larger than string size - it cannot be found.
if (strstr_pattern.size() <= n)
{
Searcher searcher(required_substring.data(), required_substring.size(), end - pos);
/// We will search for the next occurrence in all rows at once.
while (pos < end && end != (pos = searcher.search(pos, end - pos)))
{
/// Let's determine which index it refers to.
while (next_pos + n <= pos)
{
res[i] = revert;
next_pos += n;
++i;
}
next_pos += n;
if (pos + strstr_pattern.size() <= next_pos)
{
/// And if it does not, if necessary, we check the regexp.
if (is_trivial)
res[i] = !revert;
else
{
const char * str_data = reinterpret_cast<const char *>(next_pos - n);
/** Even in the case of `required_substring_is_prefix` use UNANCHORED check for regexp,
* so that it can match when `required_substring` occurs into the string several times,
* and at the first occurrence, the regexp is not a match.
*/
if (required_substring_is_prefix)
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(str_data, n),
reinterpret_cast<const char *>(pos) - str_data,
n,
re2_st::RE2::UNANCHORED,
nullptr,
0);
else
res[i] = revert
^ regexp->getRE2()->Match(
re2_st::StringPiece(str_data, n), 0, n, re2_st::RE2::UNANCHORED, nullptr, 0);
}
}
else
res[i] = revert;
pos = next_pos;
++i;
}
}
/// Tail, in which there can be no substring.
if (i < res.size())
memset(&res[i], revert, (res.size() - i) * sizeof(res[0]));
}
}
}
template <typename... Args>
static void vectorVector(Args &&...)
{
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Function '{}' doesn't support non-constant needle argument", name);
}
/// Search different needles in single haystack.
template <typename... Args>
static void constantVector(Args &&...)
{
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Function '{}' doesn't support non-constant needle argument", name);
}
};
}