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ASF GitHub Bot logged work on BEAM-3910: ---------------------------------------- Author: ASF GitHub Bot Created on: 22/Mar/18 23:55 Start Date: 22/Mar/18 23:55 Worklog Time Spent: 10m Work Description: herohde commented on a change in pull request #4941: BEAM-3910: Add float support for the Go SDK. URL: https://github.com/apache/beam/pull/4941#discussion_r176606245 ########## File path: sdks/go/pkg/beam/core/runtime/coderx/float.go ########## @@ -0,0 +1,75 @@ +// 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 coderx + +import ( + "fmt" + "math" + "math/bits" + "reflect" + + "github.com/apache/beam/sdks/go/pkg/beam/core/graph/coder" + "github.com/apache/beam/sdks/go/pkg/beam/core/runtime" + "github.com/apache/beam/sdks/go/pkg/beam/core/typex" + "github.com/apache/beam/sdks/go/pkg/beam/core/util/reflectx" +) + +func init() { + runtime.RegisterFunction(encFloat) + runtime.RegisterFunction(decFloat) +} + +func encFloat(v typex.T) []byte { + var val float64 + switch n := v.(type) { + case float32: + val = float64(n) + case float64: + val = n + default: + panic(fmt.Sprintf("received unknown value type: want a float, got %T", n)) + } + + return encVarUintZ(bits.ReverseBytes64(math.Float64bits(val))) +} + +func decFloat(t reflect.Type, data []byte) (typex.T, error) { + uval, err := decVarUintZ(reflectx.Uint64, data) + if err != nil { + return nil, fmt.Errorf("invalid float encoding for: %v", data) + } + + n := math.Float64frombits(bits.ReverseBytes64(uval.(uint64))) + switch t.Kind() { + case reflect.Float64: + return n, nil + case reflect.Float32: + return float32(n), nil + default: + panic(fmt.Sprintf("unreachable statement: expected a float, got %v", t)) + } +} + +// NewFloat returns a coder for the given float type. It uses the same +// encoding scheme as the gob package. +func NewFloat(t reflect.Type) (*coder.CustomCoder, error) { Review comment: Given there are only 2 types, perhaps do them separately to avoid the reflect.Type everywhere? I.e., NewFloat32 NewFloat64 encFloat32 etc Presumably faster, too, but not sure if it matters. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on 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 Issue Time Tracking ------------------- Worklog Id: (was: 83389) Time Spent: 0.5h (was: 20m) Remaining Estimate: 23.5h (was: 23h 40m) > Support floating point values in Go SDK > --------------------------------------- > > Key: BEAM-3910 > URL: https://issues.apache.org/jira/browse/BEAM-3910 > Project: Beam > Issue Type: New Feature > Components: sdk-go > Reporter: Bill Neubauer > Assignee: Bill Neubauer > Priority: Major > Original Estimate: 24h > Time Spent: 0.5h > Remaining Estimate: 23.5h > > The Go SDK supports all the integer types of the language, but does not > support floats. > My plan for coding is to use the same technique the gob package uses, which > results in a compact encoding for simple values. > [https://golang.org/src/encoding/gob/encode.go?#L210|https://golang.org/src/encoding/gob/encode.go#L210] > with rationale explained in > https://golang.org/pkg/encoding/gob/#hdr-Encoding_Details > The resulting uint is then encoded using the existing coders in coderx. -- This message was sent by Atlassian JIRA (v7.6.3#76005)