vendor/github.com/lunixbochs/struc/custom_float16_test.go

   1 package struc
   2
   3 import (
   4         "bytes"
   5         "encoding/binary"
   6         "fmt"
   7         "math"
   8         "strconv"
   9         "strings"
  10         "testing"
  11 )
  12
  13 func TestFloat16(t *testing.T) {
  14         // test cases from https://en.wikipedia.org/wiki/Half-precision_floating-point_format#Half_precision_examples
  15         tests := []struct {
  16                 B string
  17                 F float64
  18         }{
  19                 //s expnt significand
  20                 {"0 01111 0000000000", 1},
  21                 {"0 01111 0000000001", 1.0009765625},
  22                 {"1 10000 0000000000", -2},
  23                 {"0 11110 1111111111", 65504},
  24                 // {"0 00001 0000000000", 0.0000610352},
  25                 // {"0 00000 1111111111", 0.0000609756},
  26                 // {"0 00000 0000000001", 0.0000000596046},
  27                 {"0 00000 0000000000", 0},
  28                 // {"1 00000 0000000000", -0},
  29                 {"0 11111 0000000000", math.Inf(1)},
  30                 {"1 11111 0000000000", math.Inf(-1)},
  31                 {"0 01101 0101010101", 0.333251953125},
  32         }
  33         for _, test := range tests {
  34                 var buf bytes.Buffer
  35                 f := Float16(test.F)
  36                 if err := Pack(&buf, &f); err != nil {
  37                         t.Error("pack failed:", err)
  38                         continue
  39                 }
  40                 bitval, _ := strconv.ParseUint(strings.Replace(test.B, " ", "", -1), 2, 16)
  41                 tmp := binary.BigEndian.Uint16(buf.Bytes())
  42                 if tmp != uint16(bitval) {
  43                         t.Errorf("incorrect pack: %s != %016b (%f)", test.B, tmp, test.F)
  44                         continue
  45                 }
  46                 var f2 Float16
  47                 if err := Unpack(&buf, &f2); err != nil {
  48                         t.Error("unpack failed:", err)
  49                         continue
  50                 }
  51                 // let sprintf deal with (im)precision for me here
  52                 if fmt.Sprintf("%f", f) != fmt.Sprintf("%f", f2) {
  53                         t.Errorf("incorrect unpack: %016b %f != %f", bitval, f, f2)
  54                 }
  55         }
  56 }