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// 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 (
"errors"
"fmt"
"math"
"github.com/apache/arrow-go/v18/internal/utils"
"github.com/apache/arrow-go/v18/parquet"
"golang.org/x/xerrors"
)
// PlainFixedLenByteArrayDecoder is a plain encoding decoder for Fixed Length Byte Arrays
type PlainFixedLenByteArrayDecoder struct {
decoder
}
// Type returns the physical type this decoder operates on, FixedLength Byte Arrays
func (PlainFixedLenByteArrayDecoder) Type() parquet.Type {
return parquet.Types.FixedLenByteArray
}
func (pflba *PlainFixedLenByteArrayDecoder) Discard(n int) (int, error) {
n = min(n, pflba.nvals)
numBytesNeeded := n * pflba.typeLen
if numBytesNeeded > len(pflba.data) || numBytesNeeded > math.MaxInt32 {
return 0, errors.New("parquet: eof exception")
}
pflba.data = pflba.data[numBytesNeeded:]
pflba.nvals -= n
return n, nil
}
// Decode populates out with fixed length byte array values until either there are no more
// values to decode or the length of out has been filled. Then returns the total number of values
// that were decoded.
func (pflba *PlainFixedLenByteArrayDecoder) Decode(out []parquet.FixedLenByteArray) (int, error) {
max := utils.Min(len(out), pflba.nvals)
numBytesNeeded := max * pflba.typeLen
if numBytesNeeded > len(pflba.data) || numBytesNeeded > math.MaxInt32 {
return 0, xerrors.New("parquet: eof exception")
}
for idx := range out[:max] {
out[idx] = pflba.data[:pflba.typeLen]
pflba.data = pflba.data[pflba.typeLen:]
}
pflba.nvals -= max
return max, nil
}
// DecodeSpaced does the same as Decode but spaces out the resulting slice according to the bitmap leaving space for null values
func (pflba *PlainFixedLenByteArrayDecoder) DecodeSpaced(out []parquet.FixedLenByteArray, nullCount int, validBits []byte, validBitsOffset int64) (int, error) {
toRead := len(out) - nullCount
valuesRead, err := pflba.Decode(out[:toRead])
if err != nil {
return valuesRead, err
}
if valuesRead != toRead {
return valuesRead, xerrors.New("parquet: number of values / definitions levels read did not match")
}
return spacedExpand(out, nullCount, validBits, validBitsOffset), nil
}
// ByteStreamSplitFixedLenByteArrayDecoder is a decoder for BYTE_STREAM_SPLIT-encoded
// bytes representing FixedLenByteArray values
type ByteStreamSplitFixedLenByteArrayDecoder struct {
decoder
stride int
}
func (dec *ByteStreamSplitFixedLenByteArrayDecoder) Type() parquet.Type {
return parquet.Types.FixedLenByteArray
}
func (dec *ByteStreamSplitFixedLenByteArrayDecoder) SetData(nvals int, data []byte) error {
if nvals*dec.typeLen < len(data) {
return fmt.Errorf("data size (%d) is too small for the number of values in in BYTE_STREAM_SPLIT (%d)", len(data), nvals)
}
if len(data)%dec.typeLen != 0 {
return fmt.Errorf("ByteStreamSplit data size %d not aligned with type %s and byte_width: %d", len(data), dec.Type(), dec.typeLen)
}
nvals = len(data) / dec.typeLen
dec.stride = nvals
return dec.decoder.SetData(nvals, data)
}
func (dec *ByteStreamSplitFixedLenByteArrayDecoder) Discard(n int) (int, error) {
n = min(n, dec.nvals)
numBytesNeeded := n * dec.typeLen
if numBytesNeeded > len(dec.data) || numBytesNeeded > math.MaxInt32 {
return 0, errors.New("parquet: eof exception")
}
dec.nvals -= n
dec.data = dec.data[n:]
return n, nil
}
func (dec *ByteStreamSplitFixedLenByteArrayDecoder) Decode(out []parquet.FixedLenByteArray) (int, error) {
toRead := min(len(out), dec.nvals)
numBytesNeeded := toRead * dec.typeLen
if numBytesNeeded > len(dec.data) || numBytesNeeded > math.MaxInt32 {
return 0, xerrors.New("parquet: eof exception")
}
for i := range out {
if cap(out[i]) < dec.typeLen {
out[i] = make(parquet.FixedLenByteArray, dec.typeLen)
} else {
out[i] = out[i][:dec.typeLen]
}
}
switch dec.typeLen {
case 2:
decodeByteStreamSplitBatchFLBAWidth2(dec.data, toRead, dec.stride, out)
case 4:
decodeByteStreamSplitBatchFLBAWidth4(dec.data, toRead, dec.stride, out)
case 8:
decodeByteStreamSplitBatchFLBAWidth8(dec.data, toRead, dec.stride, out)
default:
decodeByteStreamSplitBatchFLBA(dec.data, toRead, dec.stride, dec.typeLen, out)
}
dec.nvals -= toRead
dec.data = dec.data[toRead:]
return toRead, nil
}
func (dec *ByteStreamSplitFixedLenByteArrayDecoder) DecodeSpaced(out []parquet.FixedLenByteArray, nullCount int, validBits []byte, validBitsOffset int64) (int, error) {
toRead := len(out) - nullCount
valuesRead, err := dec.Decode(out[:toRead])
if err != nil {
return valuesRead, err
}
if valuesRead != toRead {
return valuesRead, xerrors.New("parquet: number of values / definitions levels read did not match")
}
return spacedExpand(out, nullCount, validBits, validBitsOffset), nil
}
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