github.com/apache/arrow/go/v7@v7.0.1/parquet/internal/utils/bit_packing_avx2_amd64.go (about)

     1  // Licensed to the Apache Software Foundation (ASF) under one
     2  // or more contributor license agreements.  See the NOTICE file
     3  // distributed with this work for additional information
     4  // regarding copyright ownership.  The ASF licenses this file
     5  // to you under the Apache License, Version 2.0 (the
     6  // "License"); you may not use this file except in compliance
     7  // with the License.  You may obtain a copy of the License at
     8  //
     9  // http://www.apache.org/licenses/LICENSE-2.0
    10  //
    11  // Unless required by applicable law or agreed to in writing, software
    12  // distributed under the License is distributed on an "AS IS" BASIS,
    13  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14  // See the License for the specific language governing permissions and
    15  // limitations under the License.
    16  
    17  // +build !noasm
    18  
    19  package utils
    20  
    21  import (
    22  	"bytes"
    23  	"io"
    24  	"sync"
    25  	"unsafe"
    26  )
    27  
    28  var bufferPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
    29  
    30  //go:noescape
    31  func _unpack32_avx2(in, out unsafe.Pointer, batchSize, nbits int) (num int)
    32  
    33  func unpack32Avx2(in io.Reader, out []uint32, nbits int) int {
    34  	batch := len(out) / 32 * 32
    35  	if batch <= 0 {
    36  		return 0
    37  	}
    38  
    39  	n := batch * nbits / 8
    40  
    41  	buffer := bufferPool.Get().(*bytes.Buffer)
    42  	defer bufferPool.Put(buffer)
    43  	buffer.Reset()
    44  	buffer.Grow(n)
    45  	io.CopyN(buffer, in, int64(n))
    46  
    47  	var (
    48  		input  = unsafe.Pointer(&buffer.Bytes()[0])
    49  		output = unsafe.Pointer(&out[0])
    50  	)
    51  
    52  	return _unpack32_avx2(input, output, len(out), nbits)
    53  }