ClickHouse/src/Functions/HasTokenImpl.h

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#pragma once
#include <Columns/ColumnString.h>
namespace DB
{
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namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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}
/** Token search the string, means that needle must be surrounded by some separator chars, like whitespace or puctuation.
*/
template <typename Name, typename TokenSearcher, bool negate>
struct HasTokenImpl
{
using ResultType = UInt8;
static constexpr bool use_default_implementation_for_constants = true;
static constexpr bool supports_start_pos = false;
static constexpr auto name = Name::name;
static void vectorConstant(
const ColumnString::Chars & haystack_data,
const ColumnString::Offsets & haystack_offsets,
const std::string & pattern,
const ColumnPtr & start_pos,
PaddedPODArray<UInt8> & res)
{
if (start_pos != nullptr)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Function '{}' does not support start_pos argument", name);
if (haystack_offsets.empty())
return;
const UInt8 * const begin = haystack_data.data();
const UInt8 * const end = haystack_data.data() + haystack_data.size();
const UInt8 * pos = begin;
/// The current index in the array of strings.
size_t i = 0;
TokenSearcher searcher(pattern.data(), 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 + haystack_offsets[i] <= pos)
{
res[i] = negate;
++i;
}
/// We check that the entry does not pass through the boundaries of strings.
if (pos + pattern.size() < begin + haystack_offsets[i])
res[i] = !negate;
else
res[i] = negate;
pos = begin + haystack_offsets[i];
++i;
}
/// Tail, in which there can be no substring.
if (i < res.size())
memset(&res[i], negate, (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);
}
template <typename... Args>
static void vectorFixedConstant(Args &&...)
{
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Function '{}' doesn't support FixedString haystack argument", name);
}
};
}