ClickHouse/src/Columns/ColumnString.h

311 lines
9.7 KiB
C++

#pragma once
#include <cstring>
#include <cassert>
#include <Columns/IColumn.h>
#include <Columns/IColumnImpl.h>
#include <Common/PODArray.h>
#include <Common/SipHash.h>
#include <Common/memcpySmall.h>
#include <Common/memcmpSmall.h>
#include <Common/assert_cast.h>
#include <Core/Field.h>
class Collator;
namespace DB
{
/** Column for String values.
*/
class ColumnString final : public COWHelper<IColumn, ColumnString>
{
public:
using Char = UInt8;
using Chars = PaddedPODArray<UInt8>;
private:
friend class COWHelper<IColumn, ColumnString>;
/// Maps i'th position to offset to i+1'th element. Last offset maps to the end of all chars (is the size of all chars).
Offsets offsets;
/// Bytes of strings, placed contiguously.
/// For convenience, every string ends with terminating zero byte. Note that strings could contain zero bytes in the middle.
Chars chars;
size_t ALWAYS_INLINE offsetAt(ssize_t i) const { return offsets[i - 1]; }
/// Size of i-th element, including terminating zero.
size_t ALWAYS_INLINE sizeAt(ssize_t i) const { return offsets[i] - offsets[i - 1]; }
template <bool positive>
struct Cmp;
template <bool positive>
struct CmpWithCollation;
ColumnString() = default;
ColumnString(const ColumnString & src);
template <typename Comparator>
void getPermutationImpl(size_t limit, Permutation & res, Comparator cmp) const;
public:
const char * getFamilyName() const override { return "String"; }
TypeIndex getDataType() const override { return TypeIndex::String; }
size_t size() const override
{
return offsets.size();
}
size_t byteSize() const override
{
return chars.size() + offsets.size() * sizeof(offsets[0]);
}
size_t byteSizeAt(size_t n) const override
{
assert(n < size());
return sizeAt(n) + sizeof(offsets[0]);
}
size_t allocatedBytes() const override
{
return chars.allocated_bytes() + offsets.allocated_bytes();
}
void protect() override;
MutableColumnPtr cloneResized(size_t to_size) const override;
Field operator[](size_t n) const override
{
assert(n < size());
return Field(&chars[offsetAt(n)], sizeAt(n) - 1);
}
void get(size_t n, Field & res) const override
{
assert(n < size());
res = std::string_view{reinterpret_cast<const char *>(&chars[offsetAt(n)]), sizeAt(n) - 1};
}
StringRef getDataAt(size_t n) const override
{
assert(n < size());
return StringRef(&chars[offsetAt(n)], sizeAt(n) - 1);
}
StringRef getDataAtWithTerminatingZero(size_t n) const override
{
assert(n < size());
return StringRef(&chars[offsetAt(n)], sizeAt(n));
}
bool isDefaultAt(size_t n) const override
{
assert(n < size());
return sizeAt(n) == 1;
}
/// Suppress gcc 7.3.1 warning: '*((void*)&<anonymous> +8)' may be used uninitialized in this function
#if !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
void insert(const Field & x) override
{
const String & s = DB::get<const String &>(x);
const size_t old_size = chars.size();
const size_t size_to_append = s.size() + 1;
const size_t new_size = old_size + size_to_append;
chars.resize(new_size);
memcpy(chars.data() + old_size, s.c_str(), size_to_append);
offsets.push_back(new_size);
}
#if !defined(__clang__)
#pragma GCC diagnostic pop
#endif
void insertFrom(const IColumn & src_, size_t n) override
{
const ColumnString & src = assert_cast<const ColumnString &>(src_);
const size_t size_to_append = src.offsets[n] - src.offsets[n - 1]; /// -1th index is Ok, see PaddedPODArray.
if (size_to_append == 1)
{
/// shortcut for empty string
chars.push_back(0);
offsets.push_back(chars.size());
}
else
{
const size_t old_size = chars.size();
const size_t offset = src.offsets[n - 1];
const size_t new_size = old_size + size_to_append;
chars.resize(new_size);
memcpySmallAllowReadWriteOverflow15(chars.data() + old_size, &src.chars[offset], size_to_append);
offsets.push_back(new_size);
}
}
void insertData(const char * pos, size_t length) override
{
const size_t old_size = chars.size();
const size_t new_size = old_size + length + 1;
chars.resize(new_size);
if (length)
memcpy(chars.data() + old_size, pos, length);
chars[old_size + length] = 0;
offsets.push_back(new_size);
}
/// Like getData, but inserting data should be zero-ending (i.e. length is 1 byte greater than real string size).
void insertDataWithTerminatingZero(const char * pos, size_t length)
{
const size_t old_size = chars.size();
const size_t new_size = old_size + length;
chars.resize(new_size);
memcpy(chars.data() + old_size, pos, length);
offsets.push_back(new_size);
}
void popBack(size_t n) override
{
size_t nested_n = offsets.back() - offsetAt(offsets.size() - n);
chars.resize(chars.size() - nested_n);
offsets.resize_assume_reserved(offsets.size() - n);
}
StringRef serializeValueIntoArena(size_t n, Arena & arena, char const *& begin) const override;
const char * deserializeAndInsertFromArena(const char * pos) override;
const char * skipSerializedInArena(const char * pos) const override;
void updateHashWithValue(size_t n, SipHash & hash) const override
{
size_t string_size = sizeAt(n);
size_t offset = offsetAt(n);
hash.update(reinterpret_cast<const char *>(&string_size), sizeof(string_size));
hash.update(reinterpret_cast<const char *>(&chars[offset]), string_size);
}
void updateWeakHash32(WeakHash32 & hash) const override;
void updateHashFast(SipHash & hash) const override
{
hash.update(reinterpret_cast<const char *>(offsets.data()), size() * sizeof(offsets[0]));
hash.update(reinterpret_cast<const char *>(chars.data()), size() * sizeof(chars[0]));
}
void insertRangeFrom(const IColumn & src, size_t start, size_t length) override;
ColumnPtr filter(const Filter & filt, ssize_t result_size_hint) const override;
void expand(const Filter & mask, bool inverted) override;
ColumnPtr permute(const Permutation & perm, size_t limit) const override;
ColumnPtr index(const IColumn & indexes, size_t limit) const override;
template <typename Type>
ColumnPtr indexImpl(const PaddedPODArray<Type> & indexes, size_t limit) const;
void insertDefault() override
{
chars.push_back(0);
offsets.push_back(offsets.back() + 1);
}
virtual void insertManyDefaults(size_t length) override
{
chars.resize_fill(chars.size() + length);
for (size_t i = 0; i < length; ++i)
offsets.push_back(offsets.back() + 1);
}
int compareAt(size_t n, size_t m, const IColumn & rhs_, int /*nan_direction_hint*/) const override
{
const ColumnString & rhs = assert_cast<const ColumnString &>(rhs_);
return memcmpSmallAllowOverflow15(chars.data() + offsetAt(n), sizeAt(n) - 1, rhs.chars.data() + rhs.offsetAt(m), rhs.sizeAt(m) - 1);
}
void compareColumn(const IColumn & rhs, size_t rhs_row_num,
PaddedPODArray<UInt64> * row_indexes, PaddedPODArray<Int8> & compare_results,
int direction, int nan_direction_hint) const override;
bool hasEqualValues() const override;
/// Variant of compareAt for string comparison with respect of collation.
int compareAtWithCollation(size_t n, size_t m, const IColumn & rhs_, int, const Collator & collator) const override;
void getPermutation(bool reverse, size_t limit, int nan_direction_hint, Permutation & res) const override;
void updatePermutation(bool reverse, size_t limit, int, Permutation & res, EqualRanges & equal_ranges) const override;
/// Sorting with respect of collation.
void getPermutationWithCollation(const Collator & collator, bool reverse, size_t limit, int, Permutation & res) const override;
void updatePermutationWithCollation(const Collator & collator, bool reverse, size_t limit, int, Permutation & res, EqualRanges & equal_ranges) const override;
ColumnPtr replicate(const Offsets & replicate_offsets) const override;
MutableColumns scatter(ColumnIndex num_columns, const Selector & selector) const override
{
return scatterImpl<ColumnString>(num_columns, selector);
}
void gather(ColumnGathererStream & gatherer_stream) override;
ColumnPtr compress() const override;
void reserve(size_t n) override;
void getExtremes(Field & min, Field & max) const override;
bool canBeInsideNullable() const override { return true; }
bool structureEquals(const IColumn & rhs) const override
{
return typeid(rhs) == typeid(ColumnString);
}
double getRatioOfDefaultRows(double sample_ratio) const override
{
return getRatioOfDefaultRowsImpl<ColumnString>(sample_ratio);
}
void getIndicesOfNonDefaultRows(Offsets & indices, size_t from, size_t limit) const override
{
return getIndicesOfNonDefaultRowsImpl<ColumnString>(indices, from, limit);
}
Chars & getChars() { return chars; }
const Chars & getChars() const { return chars; }
Offsets & getOffsets() { return offsets; }
const Offsets & getOffsets() const { return offsets; }
// Throws an exception if offsets/chars are messed up
void validate() const;
bool isCollationSupported() const override { return true; }
};
}