jaisonbi commented on a change in pull request #2213: URL: https://github.com/apache/lucene-solr/pull/2213#discussion_r564272513
########## File path: lucene/core/src/java/org/apache/lucene/codecs/lucene80/Lucene80DocValuesConsumer.java ########## @@ -791,6 +806,107 @@ private void addTermsDict(SortedSetDocValues values) throws IOException { writeTermsIndex(values); } + private void addCompressedTermsDict(SortedSetDocValues values) throws IOException { + final long size = values.getValueCount(); + meta.writeVLong(size); + meta.writeInt(Lucene80DocValuesFormat.TERMS_DICT_BLOCK_LZ4_CODE); + + ByteBuffersDataOutput addressBuffer = new ByteBuffersDataOutput(); + ByteBuffersIndexOutput addressOutput = + new ByteBuffersIndexOutput(addressBuffer, "temp", "temp"); + meta.writeInt(DIRECT_MONOTONIC_BLOCK_SHIFT); + long numBlocks = + (size + Lucene80DocValuesFormat.TERMS_DICT_BLOCK_LZ4_MASK) + >>> Lucene80DocValuesFormat.TERMS_DICT_BLOCK_LZ4_SHIFT; + DirectMonotonicWriter writer = + DirectMonotonicWriter.getInstance( + meta, addressOutput, numBlocks, DIRECT_MONOTONIC_BLOCK_SHIFT); + + LZ4.FastCompressionHashTable ht = new LZ4.FastCompressionHashTable(); + ByteArrayDataOutput bufferedOutput = new ByteArrayDataOutput(termsDictBuffer); + long ord = 0; + long start = data.getFilePointer(); + int maxLength = 0; + TermsEnum iterator = values.termsEnum(); + int maxBlockLength = 0; + BytesRefBuilder previous = new BytesRefBuilder(); + for (BytesRef term = iterator.next(); term != null; term = iterator.next()) { + int termLength = term.length; + if ((ord & Lucene80DocValuesFormat.TERMS_DICT_BLOCK_LZ4_MASK) == 0) { + if (bufferedOutput.getPosition() > 0) { + int uncompressedLength = bufferedOutput.getPosition(); + data.writeVInt(uncompressedLength); + maxBlockLength = Math.max(maxBlockLength, uncompressedLength); + long before = data.getFilePointer(); + // Compress block + LZ4.compress(termsDictBuffer, 0, uncompressedLength, data, ht); + int compressedLength = (int) (data.getFilePointer() - before); + // Corner case: Compressed length might be bigger than un-compressed length. + maxBlockLength = Math.max(maxBlockLength, compressedLength); + bufferedOutput.reset(termsDictBuffer); + } + + writer.add(data.getFilePointer() - start); + data.writeVInt(termLength); + data.writeBytes(term.bytes, term.offset, termLength); + } else { + final int prefixLength = StringHelper.bytesDifference(previous.get(), term); + final int suffixLength = term.length - prefixLength; + assert suffixLength > 0; // terms are unique + int reservedSize = suffixLength + 11; // 1 byte + 2 vint. + bufferedOutput = maybeGrowBuffer(bufferedOutput, reservedSize); + bufferedOutput.writeByte( + (byte) (Math.min(prefixLength, 15) | (Math.min(15, suffixLength - 1) << 4))); + + if (prefixLength >= 15) { + bufferedOutput.writeVInt(prefixLength - 15); + } + if (suffixLength >= 16) { + bufferedOutput.writeVInt(suffixLength - 16); + } + bufferedOutput.writeBytes(term.bytes, term.offset + prefixLength, suffixLength); + } + maxLength = Math.max(maxLength, termLength); + previous.copyBytes(term); + ++ord; + } + + // Compress and write out the last block + if (bufferedOutput.getPosition() > 0) { + int uncompressedLength = bufferedOutput.getPosition(); + data.writeVInt(uncompressedLength); + maxBlockLength = Math.max(maxBlockLength, uncompressedLength); + long before = data.getFilePointer(); + LZ4.compress(termsDictBuffer, 0, uncompressedLength, data, ht); + int compressedLength = (int) (data.getFilePointer() - before); + maxBlockLength = Math.max(maxBlockLength, compressedLength); + } + + writer.finish(); + meta.writeInt(maxLength); + // Write one more int for storing max block length. For compressed terms dict only. + meta.writeInt(maxBlockLength); + meta.writeLong(start); + meta.writeLong(data.getFilePointer() - start); + start = data.getFilePointer(); + addressBuffer.copyTo(data); + meta.writeLong(start); + meta.writeLong(data.getFilePointer() - start); + + // Now write the reverse terms index + writeTermsIndex(values); + } + + private ByteArrayDataOutput maybeGrowBuffer(ByteArrayDataOutput bufferedOutput, int termLength) { + int pos = bufferedOutput.getPosition(), originalLength = termsDictBuffer.length; + if (pos + termLength >= originalLength - 1) { + int newLength = (originalLength + termLength) << 1; Review comment: Makes sense. Call ArrayUtil.grow is enough. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org