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#pragma once
#include "indexer/trie.hpp"
#include "coding/reader.hpp"
#include "coding/varint.hpp"
#include "base/assert.hpp"
#include "base/bits.hpp"
#include "base/macros.hpp"
namespace trie
{
template <class TValueList, typename TSerializer>
class LeafIterator0 : public Iterator<TValueList>
{
public:
using TValue = typename TValueList::TValue;
using Iterator<TValueList>::m_valueList;
template <class TReader>
LeafIterator0(TReader const & reader, TSerializer const & serializer)
{
ReaderSource<TReader> src(reader);
m_valueList.Deserialize(src, serializer);
ASSERT_EQUAL(src.Size(), 0, ());
}
// trie::Iterator overrides:
unique_ptr<Iterator<TValueList>> Clone() const override
{
return make_unique<LeafIterator0<TValueList, TSerializer>>(*this);
}
unique_ptr<Iterator<TValueList>> GoToEdge(size_t /* i */) const override
{
ASSERT(false, ());
return nullptr;
}
};
template <typename TReader, typename TValueList, typename TSerializer>
class Iterator0 : public Iterator<TValueList>
{
public:
using TValue = typename TValueList::TValue;
using Iterator<TValueList>::m_valueList;
using Iterator<TValueList>::m_edge;
Iterator0(TReader const & reader, TrieChar baseChar, TSerializer const & serializer)
: m_reader(reader), m_serializer(serializer)
{
ParseNode(baseChar);
}
// trie::Iterator overrides:
unique_ptr<Iterator<TValueList>> Clone() const override
{
return make_unique<Iterator0<TReader, TValueList, TSerializer>>(*this);
}
unique_ptr<Iterator<TValueList>> GoToEdge(size_t i) const override
{
ASSERT_LESS(i, this->m_edge.size(), ());
uint32_t const offset = m_edgeInfo[i].m_offset;
uint32_t const size = m_edgeInfo[i + 1].m_offset - offset;
if (m_edgeInfo[i].m_isLeaf)
{
return make_unique<LeafIterator0<TValueList, TSerializer>>(m_reader.SubReader(offset, size),
m_serializer);
}
return make_unique<Iterator0<TReader, TValueList, TSerializer>>(
m_reader.SubReader(offset, size), this->m_edge[i].m_label.back(), m_serializer);
}
private:
void ParseNode(TrieChar baseChar)
{
ReaderSource<TReader> src(m_reader);
// [1: header]: [2: min(valueCount, 3)] [6: min(childCount, 63)]
uint8_t const header = ReadPrimitiveFromSource<uint8_t>(src);
uint32_t valueCount = (header >> 6);
uint32_t childCount = (header & 63);
// [vu valueCount]: if valueCount in header == 3
if (valueCount == 3)
valueCount = ReadVarUint<uint32_t>(src);
// [vu childCount]: if childCount in header == 63
if (childCount == 63)
childCount = ReadVarUint<uint32_t>(src);
// [valueList]
m_valueList.Deserialize(src, valueCount, m_serializer);
// [childInfo] ... [childInfo]
this->m_edge.resize(childCount);
m_edgeInfo.resize(childCount + 1);
m_edgeInfo[0].m_offset = 0;
for (uint32_t i = 0; i < childCount; ++i)
{
typename Iterator<TValueList>::Edge & e = this->m_edge[i];
// [1: header]: [1: isLeaf] [1: isShortEdge] [6: (edgeChar0 - baseChar) or min(edgeLen-1, 63)]
uint8_t const header = ReadPrimitiveFromSource<uint8_t>(src);
m_edgeInfo[i].m_isLeaf = ((header & 128) != 0);
if (header & 64)
e.m_label.push_back(baseChar + bits::ZigZagDecode(header & 63U));
else
{
// [vu edgeLen-1]: if edgeLen-1 in header == 63
uint32_t edgeLen = (header & 63);
if (edgeLen == 63)
edgeLen = ReadVarUint<uint32_t>(src);
edgeLen += 1;
// [vi edgeChar0 - baseChar] [vi edgeChar1 - edgeChar0] ... [vi edgeCharN - edgeCharN-1]
e.m_label.reserve(edgeLen);
for (uint32_t i = 0; i < edgeLen; ++i)
e.m_label.push_back(baseChar += ReadVarInt<int32_t>(src));
}
// [child size]: if the child is not the last one
m_edgeInfo[i + 1].m_offset = m_edgeInfo[i].m_offset;
if (i != childCount - 1)
m_edgeInfo[i + 1].m_offset += ReadVarUint<uint32_t>(src);
baseChar = e.m_label[0];
}
uint32_t const currentOffset = static_cast<uint32_t>(src.Pos());
for (size_t i = 0; i < m_edgeInfo.size(); ++i)
m_edgeInfo[i].m_offset += currentOffset;
m_edgeInfo.back().m_offset = static_cast<uint32_t>(m_reader.Size());
}
struct EdgeInfo
{
uint32_t m_offset;
bool m_isLeaf;
};
buffer_vector<EdgeInfo, 9> m_edgeInfo;
TReader m_reader;
TSerializer m_serializer;
};
// Returns iterator to the root of the trie.
template <class TReader, class TValueList, class TSerializer>
unique_ptr<Iterator<TValueList>> ReadTrie(TReader const & reader, TSerializer const & serializer)
{
return make_unique<Iterator0<TReader, TValueList, TSerializer>>(reader, kDefaultChar, serializer);
}
} // namespace trie
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