ceph/src/arrow/go/arrow/type_traits_float16.go

   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 package arrow
  18
  19 import (
  20         "reflect"
  21         "unsafe"
  22
  23         "github.com/apache/arrow/go/v6/arrow/float16"
  24         "github.com/apache/arrow/go/v6/arrow/endian"
  25 )
  26
  27 // Float16 traits
  28 var Float16Traits float16Traits
  29
  30 const (
  31         // Float16SizeBytes specifies the number of bytes required to store a single float16 in memory
  32         Float16SizeBytes = int(unsafe.Sizeof(uint16(0)))
  33 )
  34
  35 type float16Traits struct{}
  36
  37 // BytesRequired returns the number of bytes required to store n elements in memory.
  38 func (float16Traits) BytesRequired(n int) int { return Float16SizeBytes * n }
  39
  40 // PutValue
  41 func (float16Traits) PutValue(b []byte, v float16.Num) {
  42         endian.Native.PutUint16(b, uint16(v.Uint16()))
  43 }
  44
  45 // CastFromBytes reinterprets the slice b to a slice of type uint16.
  46 //
  47 // NOTE: len(b) must be a multiple of Uint16SizeBytes.
  48 func (float16Traits) CastFromBytes(b []byte) []float16.Num {
  49         h := (*reflect.SliceHeader)(unsafe.Pointer(&b))
  50
  51         var res []float16.Num
  52         s := (*reflect.SliceHeader)(unsafe.Pointer(&res))
  53         s.Data = h.Data
  54         s.Len = h.Len / Float16SizeBytes
  55         s.Cap = h.Cap / Float16SizeBytes
  56
  57         return res
  58 }
  59
  60 // CastToBytes reinterprets the slice b to a slice of bytes.
  61 func (float16Traits) CastToBytes(b []float16.Num) []byte {
  62         h := (*reflect.SliceHeader)(unsafe.Pointer(&b))
  63
  64         var res []byte
  65         s := (*reflect.SliceHeader)(unsafe.Pointer(&res))
  66         s.Data = h.Data
  67         s.Len = h.Len * Float16SizeBytes
  68         s.Cap = h.Cap * Float16SizeBytes
  69
  70         return res
  71 }
  72
  73 // Copy copies src to dst.
  74 func (float16Traits) Copy(dst, src []float16.Num) { copy(dst, src) }