emkornfield commented on a change in pull request #10379: URL: https://github.com/apache/arrow/pull/10379#discussion_r654006657
########## File path: go/parquet/internal/encoding/delta_bit_packing.go ########## @@ -0,0 +1,515 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package encoding + +import ( + "bytes" + "math" + "math/bits" + "reflect" + + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" + "github.com/apache/arrow/go/parquet" + "github.com/apache/arrow/go/parquet/internal/utils" + "golang.org/x/xerrors" +) + +// see the deltaBitPack encoder for a description of the encoding format that is +// used for delta-bitpacking. +type deltaBitPackDecoder struct { + decoder + + mem memory.Allocator + + usedFirst bool + bitdecoder *utils.BitReader + blockSize uint64 + currentBlockVals uint64 + miniBlocks uint64 + valsPerMini uint64 + currentMiniBlockVals uint64 + minDelta int64 + miniBlockIdx uint64 + + deltaBitWidths *memory.Buffer + deltaBitWidth byte + + lastVal int64 +} + +// returns the number of bytes read so far +func (d *deltaBitPackDecoder) bytesRead() int64 { + return d.bitdecoder.CurOffset() +} + +func (d *deltaBitPackDecoder) Allocator() memory.Allocator { return d.mem } + +// SetData sets the bytes and the expected number of values to decode +// into the decoder, updating the decoder and allowing it to be reused. +func (d *deltaBitPackDecoder) SetData(nvalues int, data []byte) { + // set our data into the underlying decoder for the type + d.decoder.SetData(nvalues, data) + // create a bit reader for our decoder's values + d.bitdecoder = utils.NewBitReader(bytes.NewReader(d.data)) + d.currentBlockVals = 0 + d.currentMiniBlockVals = 0 + if d.deltaBitWidths == nil { + d.deltaBitWidths = memory.NewResizableBuffer(d.mem) + } + + var ok bool + d.blockSize, ok = d.bitdecoder.GetVlqInt() + if !ok { + panic("parquet: eof exception") + } + + if d.miniBlocks, ok = d.bitdecoder.GetVlqInt(); !ok { + panic("parquet: eof exception") + } + + var totalValues uint64 + if totalValues, ok = d.bitdecoder.GetVlqInt(); !ok { + panic("parquet: eof exception") + } + + if int(totalValues) != d.nvals { + panic("parquet: mismatch between number of values and count in data header") + } + + if d.lastVal, ok = d.bitdecoder.GetZigZagVlqInt(); !ok { + panic("parquet: eof exception") + } + + d.valsPerMini = uint64(d.blockSize / d.miniBlocks) Review comment: This is my intuition. I believe values per page are limited to 2^32 - 1. I was assuming at worst 1 mini block per value. ########## File path: go/parquet/internal/encoding/delta_bit_packing.go ########## @@ -0,0 +1,515 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package encoding + +import ( + "bytes" + "math" + "math/bits" + "reflect" + + "github.com/apache/arrow/go/arrow" + "github.com/apache/arrow/go/arrow/memory" + "github.com/apache/arrow/go/parquet" + "github.com/apache/arrow/go/parquet/internal/utils" + "golang.org/x/xerrors" +) + +// see the deltaBitPack encoder for a description of the encoding format that is +// used for delta-bitpacking. +type deltaBitPackDecoder struct { + decoder + + mem memory.Allocator + + usedFirst bool + bitdecoder *utils.BitReader + blockSize uint64 + currentBlockVals uint64 + miniBlocks uint64 + valsPerMini uint64 + currentMiniBlockVals uint64 + minDelta int64 + miniBlockIdx uint64 + + deltaBitWidths *memory.Buffer + deltaBitWidth byte + + lastVal int64 +} + +// returns the number of bytes read so far +func (d *deltaBitPackDecoder) bytesRead() int64 { + return d.bitdecoder.CurOffset() +} + +func (d *deltaBitPackDecoder) Allocator() memory.Allocator { return d.mem } + +// SetData sets the bytes and the expected number of values to decode +// into the decoder, updating the decoder and allowing it to be reused. +func (d *deltaBitPackDecoder) SetData(nvalues int, data []byte) { + // set our data into the underlying decoder for the type + d.decoder.SetData(nvalues, data) + // create a bit reader for our decoder's values + d.bitdecoder = utils.NewBitReader(bytes.NewReader(d.data)) + d.currentBlockVals = 0 + d.currentMiniBlockVals = 0 + if d.deltaBitWidths == nil { + d.deltaBitWidths = memory.NewResizableBuffer(d.mem) + } + + var ok bool + d.blockSize, ok = d.bitdecoder.GetVlqInt() + if !ok { + panic("parquet: eof exception") + } + + if d.miniBlocks, ok = d.bitdecoder.GetVlqInt(); !ok { + panic("parquet: eof exception") + } + + var totalValues uint64 + if totalValues, ok = d.bitdecoder.GetVlqInt(); !ok { + panic("parquet: eof exception") + } + + if int(totalValues) != d.nvals { + panic("parquet: mismatch between number of values and count in data header") + } + + if d.lastVal, ok = d.bitdecoder.GetZigZagVlqInt(); !ok { + panic("parquet: eof exception") + } + + d.valsPerMini = uint64(d.blockSize / d.miniBlocks) Review comment: https://github.com/apache/parquet-format/blob/master/src/main/thrift/parquet.thrift#L555 limits number of values. -- This is an automated message from the Apache Git Service. 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