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#include "coding/varint_vector.hpp"
/*
#include "coding/writer.hpp"
#include "coding/reader.hpp"
#include "base/assert.hpp"
namespace varint
{
namespace
{
void VarintEncode(vector<uint8_t> & dst, uint64_t n)
{
if (n == 0)
{
dst.push_back(0);
}
else
{
while (n != 0)
{
uint8_t b = n & 0x7F;
n >>= 7;
b |= (n == 0) ? 0 : 0x80;
dst.push_back(b);
}
}
}
uint64_t VarintDecode(Reader * reader, uint64_t & offset)
{
uint64_t n = 0;
int shift = 0;
while (1)
{
uint8_t b = 0;
reader->Read(offset, &b, 1);
n |= uint64_t(b & 0x7F) << shift;
++offset;
if ((b & 0x80) == 0)
break;
shift += 7;
}
return n;
}
}
VectorBuilder::VectorBuilder(uint64_t numElemPerTableEntry)
: m_numElemPerTableEntry(numElemPerTableEntry), m_numsCount(0), m_sum(0)
{
}
void VectorBuilder::AddNum(uint64_t num)
{
if (m_numsCount % m_numElemPerTableEntry == 0)
{
TableEntry tableEntry;
tableEntry.pos = m_serialNums.size();
tableEntry.sum = m_sum;
m_selectTable.push_back(tableEntry);
}
VarintEncode(m_serialNums, num);
++m_numsCount;
m_sum += num;
}
void VectorBuilder::Finalize(Writer * writer)
{
vector<uint8_t> header;
VarintEncode(header, m_numsCount);
VarintEncode(header, m_numElemPerTableEntry);
VarintEncode(header, m_selectTable.size());
VarintEncode(header, m_serialNums.size());
writer->Write(header.data(), header.size());
writer->Write(m_selectTable.data(), m_selectTable.size() * sizeof(m_selectTable.front()));
writer->Write(m_serialNums.data(), m_serialNums.size());
}
void VectorBuilderDelayedLast::AddLast()
{
if (m_hasLast)
{
BaseT::AddNum(m_last);
m_hasLast = false;
}
}
void VectorBuilderDelayedLast::AddNum(uint64_t num)
{
AddLast();
m_last = num;
m_hasLast = true;
}
void VectorBuilderDelayedLast::ReplaceLast(uint64_t num)
{
ASSERT(m_hasLast, ());
m_last = num;
}
void VectorBuilderDelayedLast::Finalize(Writer * writer)
{
AddLast();
BaseT::Finalize(writer);
}
Vector::Vector(Reader * reader)
: m_reader(reader), m_numsCount(0), m_numElemPerTableEntry(0), m_numTableEntries(0),
m_serialNumsSize(0), m_selectTableOffset(0), m_serialNumsOffset(0)
{
uint64_t parseOffset = 0;
m_numsCount = VarintDecode(m_reader, parseOffset);
m_numElemPerTableEntry = VarintDecode(m_reader, parseOffset);
m_numTableEntries = VarintDecode(m_reader, parseOffset);
m_serialNumsSize = VarintDecode(m_reader, parseOffset);
m_selectTableOffset = parseOffset;
m_serialNumsOffset = m_selectTableOffset + sizeof(TableEntry) * m_numTableEntries;
}
void Vector::FindByIndex(uint64_t index, uint32_t & serialPos, uint64_t & sumBefore)
{
ASSERT_LESS(index, m_numsCount, ());
uint64_t tableEntryIndex = index / m_numElemPerTableEntry;
ASSERT_LESS(tableEntryIndex, m_numTableEntries, ());
uint64_t tableEntryOffset = m_selectTableOffset + tableEntryIndex * sizeof(TableEntry);
uint64_t indexWithinRange = index % m_numElemPerTableEntry;
TableEntry tableEntry;
m_reader->Read(tableEntryOffset, &tableEntry, sizeof(TableEntry));
uint64_t sum = tableEntry.sum;
uint64_t numOffset = m_serialNumsOffset + tableEntry.pos;
for (uint64_t i = 0; i < indexWithinRange; ++i)
{
uint64_t num = VarintDecode(m_reader, numOffset);
sum += num;
}
serialPos = numOffset - m_serialNumsOffset;
sumBefore = sum;
}
void Vector::FindBySum(uint64_t sum, uint32_t & serialPos, uint64_t & sumBefore, uint64_t & countBefore)
{
// First do binary search over select table to find the biggest
// sum that is less or equal to our.
uint64_t l = 0, r = m_numTableEntries;
uint64_t countBinarySearchCycles = 0;
while (r - l > 1)
{
++countBinarySearchCycles;
uint64_t m = (l + r) / 2;
uint64_t tableEntryOffset = m_selectTableOffset + m * sizeof(TableEntry);
TableEntry tableEntry;
m_reader->Read(tableEntryOffset, &tableEntry, sizeof(TableEntry));
if (sum >= tableEntry.sum)
l = m;
else
r = m;
}
uint64_t tableEntryIndex = l;
countBefore = tableEntryIndex * m_numElemPerTableEntry;
uint64_t tableEntryOffset = m_selectTableOffset + tableEntryIndex * sizeof(TableEntry);
TableEntry tableEntry;
m_reader->Read(tableEntryOffset, &tableEntry, sizeof(TableEntry));
uint64_t numsSum = tableEntry.sum;
// At this point nums_sum <= sum.
uint64_t numOffset = m_serialNumsOffset + tableEntry.pos;
while (numsSum <= sum && countBefore < m_numsCount)
{
uint64_t nextOffset = numOffset;
uint64_t num = VarintDecode(m_reader, nextOffset);
if (numsSum + num > sum)
break;
numOffset = nextOffset;
numsSum += num;
++countBefore;
}
serialPos = numOffset - m_serialNumsOffset;
sumBefore = numsSum;
}
void Vector::Read(uint32_t & serialPos, uint64_t & num)
{
ASSERT_LESS(serialPos, m_serialNumsSize, ());
uint64_t numOffset = m_serialNumsOffset + serialPos;
num = VarintDecode(m_reader, numOffset);
serialPos = numOffset - m_serialNumsOffset;
}
}
*/
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