go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/data/text/units/units.go (about)

     1  // Copyright 2015 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package units
    16  
    17  import (
    18  	"flag"
    19  	"fmt"
    20  	"strconv"
    21  )
    22  
    23  var units = []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"}
    24  
    25  // Size represents a size in bytes that knows how to print itself.
    26  //
    27  // Size implements flag.Value interface.
    28  type Size int64
    29  
    30  var _ flag.Value = (*Size)(nil)
    31  
    32  // String returns pretty printed file size.
    33  func (s Size) String() string {
    34  	return SizeToString(int64(s))
    35  }
    36  
    37  // Set sets Size from a given flag args.
    38  func (s *Size) Set(str string) error {
    39  	n, err := strconv.ParseInt(str, 10, 64)
    40  	if err != nil {
    41  		return err
    42  	}
    43  	*s = Size(n)
    44  	return nil
    45  }
    46  
    47  // SizeToString pretty prints file size (given as number of bytes).
    48  func SizeToString(s int64) string {
    49  	v := float64(s)
    50  	i := 0
    51  	for ; i < len(units); i++ {
    52  		if v < 1024. {
    53  			break
    54  		}
    55  		v /= 1024.
    56  	}
    57  	if i == 0 {
    58  		return fmt.Sprintf("%d%s", s, units[i])
    59  	}
    60  	if v >= 10 {
    61  		return fmt.Sprintf("%.1f%s", v, units[i])
    62  	}
    63  	return fmt.Sprintf("%.2f%s", v, units[i])
    64  }