github.com/keysonzzz/kmg@v0.0.0-20151121023212-05317bfd7d39/encoding/kmgYaml/sorter.go (about)

     1  package kmgYaml
     2  
     3  import (
     4  	"reflect"
     5  	//"unicode"
     6  )
     7  
     8  type keyList []reflect.Value
     9  
    10  func (l keyList) Len() int      { return len(l) }
    11  func (l keyList) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
    12  func (l keyList) Less(i, j int) bool {
    13  	a := l[i]
    14  	b := l[j]
    15  	ak := a.Kind()
    16  	bk := b.Kind()
    17  	for (ak == reflect.Interface || ak == reflect.Ptr) && !a.IsNil() {
    18  		a = a.Elem()
    19  		ak = a.Kind()
    20  	}
    21  	for (bk == reflect.Interface || bk == reflect.Ptr) && !b.IsNil() {
    22  		b = b.Elem()
    23  		bk = b.Kind()
    24  	}
    25  	af, aok := keyFloat(a)
    26  	bf, bok := keyFloat(b)
    27  	if aok && bok {
    28  		if af != bf {
    29  			return af < bf
    30  		}
    31  		if ak != bk {
    32  			return ak < bk
    33  		}
    34  		return numLess(a, b)
    35  	}
    36  	if ak != reflect.String || bk != reflect.String {
    37  		return ak < bk
    38  	}
    39  	return a.String() < b.String()
    40  	/*
    41  		too complex stuff and lots of bugs, just compare string by bytes.
    42  		ar, br := []rune(a.String()), []rune(b.String())
    43  		for i := 0; i < len(ar) && i < len(br); i++ {
    44  			if ar[i] == br[i] {
    45  				continue
    46  			}
    47  			al := unicode.IsLetter(ar[i])
    48  			bl := unicode.IsLetter(br[i])
    49  			if al && bl {
    50  				return ar[i] < br[i]
    51  			}
    52  			if al || bl {
    53  				return bl
    54  			}
    55  			var ai, bi int
    56  			var an, bn int64
    57  			for ai = i; ai < len(ar) && unicode.IsDigit(ar[ai]); ai++ {
    58  				an = an*10 + int64(ar[ai]-'0')
    59  			}
    60  			for bi = i; bi < len(br) && unicode.IsDigit(br[bi]); bi++ {
    61  				bn = bn*10 + int64(br[bi]-'0')
    62  			}
    63  			if an != bn {
    64  				return an < bn
    65  			}
    66  			if ai != bi {
    67  				return ai < bi
    68  			}
    69  			return ar[i] < br[i]
    70  		}
    71  		return len(ar) < len(br)
    72  	*/
    73  }
    74  
    75  // keyFloat returns a float value for v if it is a number/bool
    76  // and whether it is a number/bool or not.
    77  func keyFloat(v reflect.Value) (f float64, ok bool) {
    78  	switch v.Kind() {
    79  	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
    80  		return float64(v.Int()), true
    81  	case reflect.Float32, reflect.Float64:
    82  		return v.Float(), true
    83  	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
    84  		return float64(v.Uint()), true
    85  	case reflect.Bool:
    86  		if v.Bool() {
    87  			return 1, true
    88  		}
    89  		return 0, true
    90  	}
    91  	return 0, false
    92  }
    93  
    94  // numLess returns whether a < b.
    95  // a and b must necessarily have the same kind.
    96  func numLess(a, b reflect.Value) bool {
    97  	switch a.Kind() {
    98  	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
    99  		return a.Int() < b.Int()
   100  	case reflect.Float32, reflect.Float64:
   101  		return a.Float() < b.Float()
   102  	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
   103  		return a.Uint() < b.Uint()
   104  	case reflect.Bool:
   105  		return !a.Bool() && b.Bool()
   106  	}
   107  	panic("not a number")
   108  }