Compact Float

A go implementation of compact float.

Library Usage


import (
	"fmt"

	"github.com/cockroachdb/apd/v2"
	"github.com/kstenerud/go-compact-float"
)

func demonstrateEncodeDecodeDFloat() {
	originalValue := DFloat{
		Exponent:    100,
		Coefficient: 863994506,
	}

	buffer := &bytes.Buffer{}
	_, err := Encode(originalValue, buffer)
	if err != nil {
		// TODO: Handle error
	}
	fmt.Printf("%v encoded = %v\n", originalValue, buffer.Bytes())

	fmt.Printf("%v decoded ", buffer.Bytes())
	value, _, bytesDecoded, err := Decode(buffer)
	if err != nil {
		// TODO: Handle error
	}
	fmt.Printf("(%v bytes) = %v\n", bytesDecoded, value)

	// Prints:
	// 8.63994506e+108 encoded = [144 3 138 133 254 155 3]
	// [144 3 138 133 254 155 3] decoded (7 bytes) = 8.63994506e+108
}

func demonstrateEncodeDecodeBig() {
	// This value is too big to fit into a float64 or DFloat.
	originalValue, _, err := apd.NewFromString("-9.4452837206285466345998345667683453466347345e-5000")
	if err != nil {
		// TODO: Handle error
	}

	buffer := &bytes.Buffer{}
	if _, err = EncodeBig(originalValue, buffer); err != nil {
		// TODO: Handle error
	}
	fmt.Printf("%v encoded = %v\n", originalValue, buffer.Bytes())

	fmt.Printf("%v decoded ", buffer.Bytes())
	_, bigValue, bytesDecoded, err := Decode(buffer)
	if err != nil {
		// TODO: Handle error
	}
	fmt.Printf("(%v bytes) = %v\n", bytesDecoded, bigValue)

	// Prints:
	// -9.4452837206285466345998345667683453466347345E-5000 encoded = [207 157 1 209 142 162 230 131 138 191 193 187 225 243 223 252 238 172 229 254 225 143 226 67]
	// [207 157 1 209 142 162 230 131 138 191 193 187 225 243 223 252 238 172 229 254 225 143 226 67] decoded (24 bytes) = -9.4452837206285466345998345667683453466347345E-5000
}

func demonstrateEncodeDecodeFloat64() {
	originalValue := 0.1473445219134543
	significantDigits := 6
	buffer := &bytes.Buffer{}
	value, err := DFloatFromFloat64(originalValue, significantDigits)
	if err != nil {
		// TODO: Handle error (which might be RoundingError, in which case value is the rounded result)
	}
	_, err = Encode(value, buffer)
	if err != nil {
		// TODO: Handle error
	}
	fmt.Printf("%v encoded using %d significant digits = %v\n", originalValue, significantDigits, buffer.Bytes())

	fmt.Printf("%v decoded ", buffer.Bytes())
	decodedValue, _, bytesDecoded, err := Decode(buffer)
	if err != nil {
		// TODO: Handle error
	}
	fmt.Printf("(%v bytes) = %v\n", bytesDecoded, decodedValue.Float())

	// Prints:
	// 0.1473445219134543 encoded using 6 significant digits = [26 145 255 8]
	// [26 145 255 8] decoded (4 bytes) = 0.147345
}

License

MIT License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# README

Compact Float

Library Usage

License