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#pragma once
#include "coding/endianness.hpp"
#include "coding/byte_stream.hpp"
#include "coding/reader.hpp"
#include "coding/varint.hpp"
#include "base/assert.hpp"
#include "base/buffer_vector.hpp"
#include <cstdint>
class IntervalIndexBase
{
public:
#pragma pack(push, 1)
struct Header
{
uint8_t m_Version;
uint8_t m_Levels;
uint8_t m_BitsPerLevel;
uint8_t m_LeafBytes;
};
#pragma pack(pop)
static_assert(sizeof(Header) == 4, "");
static inline uint32_t BitmapSize(uint32_t bitsPerLevel)
{
ASSERT_GREATER(bitsPerLevel, 3, ());
return 1 << (bitsPerLevel - 3);
}
enum { kVersion = 1 };
};
template <class ReaderT, typename Value>
class IntervalIndex : public IntervalIndexBase
{
typedef IntervalIndexBase base_t;
public:
explicit IntervalIndex(ReaderT const & reader) : m_Reader(reader)
{
ReaderSource<ReaderT> src(reader);
src.Read(&m_Header, sizeof(Header));
CHECK_EQUAL(m_Header.m_Version, static_cast<uint8_t>(kVersion), ());
if (m_Header.m_Levels != 0)
for (int i = 0; i <= m_Header.m_Levels + 1; ++i)
m_LevelOffsets.push_back(ReadPrimitiveFromSource<uint32_t>(src));
}
uint64_t KeyEnd() const
{
return 1ULL << (m_Header.m_Levels * m_Header.m_BitsPerLevel + m_Header.m_LeafBytes * 8);
}
template <typename F>
void ForEach(F const & f, uint64_t beg, uint64_t end) const
{
if (m_Header.m_Levels != 0 && beg != end)
{
// ASSERT_LESS_OR_EQUAL(beg, KeyEnd(), (end));
// ASSERT_LESS_OR_EQUAL(end, KeyEnd(), (beg));
if (beg > KeyEnd())
beg = KeyEnd();
if (end > KeyEnd())
end = KeyEnd();
--end; // end is inclusive in ForEachImpl().
ForEachNode(f, beg, end, m_Header.m_Levels, 0,
m_LevelOffsets[m_Header.m_Levels + 1] - m_LevelOffsets[m_Header.m_Levels]);
}
}
private:
template <typename F>
void ForEachLeaf(F const & f, uint64_t const beg, uint64_t const end,
uint32_t const offset, uint32_t const size) const
{
buffer_vector<uint8_t, 1024> data;
data.resize_no_init(size);
m_Reader.Read(offset, &data[0], size);
ArrayByteSource src(&data[0]);
void const * pEnd = &data[0] + size;
Value value = 0;
while (src.Ptr() < pEnd)
{
uint32_t key = 0;
src.Read(&key, m_Header.m_LeafBytes);
key = SwapIfBigEndian(key);
if (key > end)
break;
value += ReadVarInt<int64_t>(src);
if (key >= beg)
f(value);
}
}
template <typename F>
void ForEachNode(F const & f, uint64_t beg, uint64_t end, int level,
uint32_t offset, uint32_t size) const
{
offset += m_LevelOffsets[level];
if (level == 0)
{
ForEachLeaf(f, beg, end, offset, size);
return;
}
uint8_t const skipBits = (m_Header.m_LeafBytes << 3) + (level - 1) * m_Header.m_BitsPerLevel;
ASSERT_LESS_OR_EQUAL(beg, end, (skipBits));
uint64_t const levelBytesFF = (1ULL << skipBits) - 1;
uint32_t const beg0 = static_cast<uint32_t>(beg >> skipBits);
uint32_t const end0 = static_cast<uint32_t>(end >> skipBits);
ASSERT_LESS(end0, (1U << m_Header.m_BitsPerLevel), (beg, end, skipBits));
buffer_vector<uint8_t, 576> data;
data.resize_no_init(size);
m_Reader.Read(offset, &data[0], size);
ArrayByteSource src(&data[0]);
uint32_t const offsetAndFlag = ReadVarUint<uint32_t>(src);
uint32_t childOffset = offsetAndFlag >> 1;
if (offsetAndFlag & 1)
{
// Reading bitmap.
uint8_t const * pBitmap = static_cast<uint8_t const *>(src.Ptr());
src.Advance(BitmapSize(m_Header.m_BitsPerLevel));
for (uint32_t i = 0; i <= end0; ++i)
{
if (bits::GetBit(pBitmap, i))
{
uint32_t childSize = ReadVarUint<uint32_t>(src);
if (i >= beg0)
{
uint64_t const beg1 = (i == beg0) ? (beg & levelBytesFF) : 0;
uint64_t const end1 = (i == end0) ? (end & levelBytesFF) : levelBytesFF;
ForEachNode(f, beg1, end1, level - 1, childOffset, childSize);
}
childOffset += childSize;
}
}
ASSERT(end0 != (static_cast<uint32_t>(1) << m_Header.m_BitsPerLevel) - 1 ||
static_cast<uint8_t const *>(src.Ptr()) - &data[0] == size,
(beg, end, beg0, end0, offset, size, src.Ptr(), &data[0]));
}
else
{
void const * pEnd = &data[0] + size;
while (src.Ptr() < pEnd)
{
uint8_t const i = src.ReadByte();
if (i > end0)
break;
uint32_t childSize = ReadVarUint<uint32_t>(src);
if (i >= beg0)
{
uint64_t const beg1 = (i == beg0) ? (beg & levelBytesFF) : 0;
uint64_t const end1 = (i == end0) ? (end & levelBytesFF) : levelBytesFF;
ForEachNode(f, beg1, end1, level - 1, childOffset, childSize);
}
childOffset += childSize;
}
}
}
ReaderT m_Reader;
Header m_Header;
buffer_vector<uint32_t, 7> m_LevelOffsets;
};
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