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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "countcompression.h"
#include <vespa/searchlib/index/postinglistcounts.h>
#include <cassert>
namespace search::bitcompression {
#define K_VALUE_COUNTFILE_LASTDOCID 22
#define K_VALUE_COUNTFILE_NUMCHUNKS 1
#define K_VALUE_COUNTFILE_CHUNKNUMDOCS 18
#define K_VALUE_COUNTFILE_SPNUMDOCS 0
void
PostingListCountFileDecodeContext::
readCounts(PostingListCounts &counts)
{
UC64_DECODECONTEXT_CONSTRUCTOR(o, _);
uint32_t length;
uint64_t val64;
const uint64_t *valE = _valE;
uint32_t numDocs;
counts._segments.clear();
UC64BE_DECODEEXPGOLOMB_NS(o,
K_VALUE_COUNTFILE_SPNUMDOCS,
EC);
numDocs = static_cast<uint32_t>(val64) + 1;
counts._numDocs = numDocs;
if (numDocs != 0) {
uint64_t expVal = numDocs * static_cast<uint64_t>(_avgBitsPerDoc);
uint32_t kVal = (expVal < 4) ? 1 : EC::asmlog2(expVal);
UC64BE_DECODEEXPGOLOMB_NS(o,
kVal,
EC);
counts._bitLength = val64;
} else
counts._bitLength = 0;
if (__builtin_expect(oCompr >= valE, false)) {
UC64_DECODECONTEXT_STORE(o, _);
_readContext->readComprBuffer();
valE = _valE;
UC64_DECODECONTEXT_LOAD(o, _);
}
uint32_t numChunks = 0;
if (numDocs >= _minChunkDocs) {
UC64BE_DECODEEXPGOLOMB_NS(o,
K_VALUE_COUNTFILE_NUMCHUNKS,
EC);
numChunks = static_cast<uint32_t>(val64);
if (__builtin_expect(oCompr >= valE, false)) {
UC64_DECODECONTEXT_STORE(o, _);
_readContext->readComprBuffer();
valE = _valE;
UC64_DECODECONTEXT_LOAD(o, _);
}
}
if (numChunks != 0) {
uint32_t prevLastDoc = 0u;
counts._segments.reserve(numChunks);
for (uint32_t chunk = 0; chunk < numChunks; ++chunk) {
if (__builtin_expect(oCompr >= valE, false)) {
UC64_DECODECONTEXT_STORE(o, _);
_readContext->readComprBuffer();
valE = _valE;
UC64_DECODECONTEXT_LOAD(o, _);
}
PostingListCounts::Segment seg;
UC64BE_DECODEEXPGOLOMB_NS(o,
K_VALUE_COUNTFILE_CHUNKNUMDOCS,
EC);
seg._numDocs = static_cast<uint32_t>(val64) + 1;
UC64BE_DECODEEXPGOLOMB_NS(o,
K_VALUE_COUNTFILE_POSOCCBITS,
EC);
seg._bitLength = val64;
UC64BE_DECODEEXPGOLOMB_NS(o,
K_VALUE_COUNTFILE_LASTDOCID,
EC);
seg._lastDoc =
static_cast<uint32_t>(val64) + seg._numDocs + prevLastDoc;
prevLastDoc = seg._lastDoc;
counts._segments.push_back(seg);
}
}
UC64_DECODECONTEXT_STORE(o, _);
if (__builtin_expect(oCompr >= valE, false)) {
_readContext->readComprBuffer();
}
}
void
PostingListCountFileDecodeContext::
copyParams(const PostingListCountFileDecodeContext &rhs)
{
_avgBitsPerDoc = rhs._avgBitsPerDoc;
_minChunkDocs = rhs._minChunkDocs;
_docIdLimit = rhs._docIdLimit;
_numWordIds = rhs._numWordIds;
}
void
PostingListCountFileEncodeContext::
writeCounts(const PostingListCounts &counts)
{
assert(counts._segments.empty() ||
counts._numDocs >= _minChunkDocs);
uint32_t numDocs = counts._numDocs;
assert(numDocs > 0);
encodeExpGolomb(numDocs - 1, K_VALUE_COUNTFILE_SPNUMDOCS);
if (numDocs == 0) {
if (__builtin_expect(_valI >= _valE, false)) {
_writeContext->writeComprBuffer(false);
}
return;
}
uint64_t encodeVal = counts._bitLength;
uint64_t expVal = numDocs * static_cast<uint64_t>(_avgBitsPerDoc);
uint32_t kVal = (expVal < 4) ? 1 : asmlog2(expVal);
encodeExpGolomb(encodeVal, kVal);
uint32_t numChunks = counts._segments.size();
if (numDocs >= _minChunkDocs) {
encodeExpGolomb(numChunks, K_VALUE_COUNTFILE_NUMCHUNKS);
}
if (numChunks != 0) {
using segit = std::vector<PostingListCounts::Segment>::const_iterator;
segit ite = counts._segments.end();
uint32_t prevLastDoc = 0u;
for (segit it = counts._segments.begin(); it != ite; ++it) {
if (__builtin_expect(_valI >= _valE, false)) {
_writeContext->writeComprBuffer(false);
}
encodeExpGolomb(it->_numDocs - 1,
K_VALUE_COUNTFILE_CHUNKNUMDOCS);
encodeExpGolomb(it->_bitLength,
K_VALUE_COUNTFILE_POSOCCBITS);
encodeExpGolomb(it->_lastDoc - prevLastDoc - it->_numDocs,
K_VALUE_COUNTFILE_LASTDOCID);
prevLastDoc = it->_lastDoc;
}
}
if (__builtin_expect(_valI >= _valE, false)) {
_writeContext->writeComprBuffer(false);
}
}
void
PostingListCountFileEncodeContext::
copyParams(const PostingListCountFileEncodeContext &rhs)
{
_avgBitsPerDoc = rhs._avgBitsPerDoc;
_minChunkDocs = rhs._minChunkDocs;
_docIdLimit = rhs._docIdLimit;
_numWordIds = rhs._numWordIds;
}
}
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