/
slices.go
450 lines (420 loc) · 11.9 KB
/
slices.go
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// Copyright (c) 2018, The GoKi Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package kit
import (
"fmt"
"log"
"reflect"
"sort"
"strings"
"time"
"github.com/goki/ki/floats"
"github.com/goki/ki/ints"
)
// This file contains helpful functions for dealing with slices, in the reflect
// system
// SliceElType returns the type of the elements for the given slice (which can be
// a pointer to a slice or a direct slice) -- just Elem() of slice type, but using
// this function makes it more explicit what is going on.
func SliceElType(sl interface{}) reflect.Type {
return NonPtrType(reflect.TypeOf(sl)).Elem()
}
// SliceNewAt inserts a new blank element at given index in the slice -- -1
// means the end
func SliceNewAt(sl interface{}, idx int) {
sltyp := SliceElType(sl)
slptr := sltyp.Kind() == reflect.Ptr
svl := reflect.ValueOf(sl)
svnp := NonPtrValue(svl)
nval := reflect.New(NonPtrType(sltyp)) // make the concrete el
if !slptr {
nval = nval.Elem() // use concrete value
}
sz := svnp.Len()
svnp = reflect.Append(svnp, nval)
if idx >= 0 && idx < sz {
reflect.Copy(svnp.Slice(idx+1, sz+1), svnp.Slice(idx, sz))
svnp.Index(idx).Set(nval)
}
svl.Elem().Set(svnp)
}
// SliceDeleteAt deletes element at given index from slice
func SliceDeleteAt(sl interface{}, idx int) {
svl := reflect.ValueOf(sl)
svnp := NonPtrValue(svl)
svtyp := svnp.Type()
nval := reflect.New(svtyp.Elem())
sz := svnp.Len()
reflect.Copy(svnp.Slice(idx, sz-1), svnp.Slice(idx+1, sz))
svnp.Index(sz - 1).Set(nval.Elem())
svl.Elem().Set(svnp.Slice(0, sz-1))
}
// SliceSort sorts a slice of basic values (see StructSliceSort for sorting a
// slice-of-struct using a specific field), trying floats.Floater Float(),
// ints.Inter Int(), interfaces first, and then falling back on reflect.Kind
// float, int, string conversions (first fmt.Stringer String()) and supporting
// time.Time directly as well.
func SliceSort(sl interface{}, ascending bool) error {
sv := reflect.ValueOf(sl)
svnp := NonPtrValue(sv)
if svnp.Len() == 0 {
return nil
}
eltyp := SliceElType(sl)
elnptyp := NonPtrType(eltyp)
vk := elnptyp.Kind()
elval := OnePtrValue(svnp.Index(0))
elif := elval.Interface()
switch elif.(type) {
case floats.Floater:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Interface().(floats.Floater).Float()
jv := NonPtrValue(svnp.Index(j)).Interface().(floats.Floater).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case ints.Inter:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Interface().(ints.Inter).Int()
jv := NonPtrValue(svnp.Index(j)).Interface().(ints.Inter).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// try all the numeric types first!
switch {
case vk >= reflect.Int && vk <= reflect.Int64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Int()
jv := NonPtrValue(svnp.Index(j)).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Uint && vk <= reflect.Uint64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Uint()
jv := NonPtrValue(svnp.Index(j)).Uint()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Float32 && vk <= reflect.Float64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Float()
jv := NonPtrValue(svnp.Index(j)).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk == reflect.Struct && FullTypeName(elnptyp) == "time.Time":
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Interface().(time.Time)
jv := NonPtrValue(svnp.Index(j)).Interface().(time.Time)
if ascending {
return iv.Before(jv)
} else {
return jv.Before(iv)
}
})
}
// this stringer case will likely pick up most of the rest
switch elif.(type) {
case fmt.Stringer:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).Interface().(fmt.Stringer).String()
jv := NonPtrValue(svnp.Index(j)).Interface().(fmt.Stringer).String()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// last resort!
switch {
case vk == reflect.String:
sort.Slice(svnp.Interface(), func(i, j int) bool {
iv := NonPtrValue(svnp.Index(i)).String()
jv := NonPtrValue(svnp.Index(j)).String()
if ascending {
return strings.ToLower(iv) < strings.ToLower(jv)
} else {
return strings.ToLower(iv) > strings.ToLower(jv)
}
})
return nil
}
err := fmt.Errorf("SortSlice: unable to sort elements of type: %v", eltyp.String())
log.Println(err)
return err
}
// StructSliceSort sorts a slice of a struct according to the given field
// indexes and sort direction, trying floats.Floater Float(), ints.Inter Int(),
// interfaces first, and then falling back on reflect.Kind float, int, string
// conversions (first fmt.Stringer String()) and supporting time.Time directly
// as well. There is no direct method for checking the field indexes so those
// are assumed to be accurate -- will panic if not!
func StructSliceSort(struSlice interface{}, fldIdx []int, ascending bool) error {
sv := reflect.ValueOf(struSlice)
svnp := NonPtrValue(sv)
if svnp.Len() == 0 {
return nil
}
struTyp := SliceElType(struSlice)
struNpTyp := NonPtrType(struTyp)
fld := struNpTyp.FieldByIndex(fldIdx) // not easy to check.
vk := fld.Type.Kind()
struVal := OnePtrValue(svnp.Index(0))
fldVal := struVal.Elem().FieldByIndex(fldIdx)
fldIf := fldVal.Interface()
switch fldIf.(type) {
case floats.Floater:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Interface().(floats.Floater).Float()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Interface().(floats.Floater).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case ints.Inter:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Interface().(ints.Inter).Int()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Interface().(ints.Inter).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// try all the numeric types first!
switch {
case vk >= reflect.Int && vk <= reflect.Int64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Int()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Uint && vk <= reflect.Uint64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Uint()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Uint()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Float32 && vk <= reflect.Float64:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Float()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk == reflect.Struct && FullTypeName(fld.Type) == "time.Time":
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Interface().(time.Time)
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Interface().(time.Time)
if ascending {
return iv.Before(jv)
} else {
return jv.Before(iv)
}
})
}
// this stringer case will likely pick up most of the rest
switch fldIf.(type) {
case fmt.Stringer:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).Interface().(fmt.Stringer).String()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).Interface().(fmt.Stringer).String()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// last resort!
switch {
case vk == reflect.String:
sort.Slice(svnp.Interface(), func(i, j int) bool {
ival := OnePtrValue(svnp.Index(i))
iv := ival.Elem().FieldByIndex(fldIdx).String()
jval := OnePtrValue(svnp.Index(j))
jv := jval.Elem().FieldByIndex(fldIdx).String()
if ascending {
return strings.ToLower(iv) < strings.ToLower(jv)
} else {
return strings.ToLower(iv) > strings.ToLower(jv)
}
})
return nil
}
err := fmt.Errorf("SortStructSlice: unable to sort on field of type: %v\n", fld.Type.String())
log.Println(err)
return err
}
// ValueSliceSort sorts a slice of reflect.Values using basic types where possible
func ValueSliceSort(sl []reflect.Value, ascending bool) error {
if len(sl) == 0 {
return nil
}
felval := sl[0] // reflect.Value
eltyp := felval.Type()
elnptyp := NonPtrType(eltyp)
vk := elnptyp.Kind()
elval := OnePtrValue(felval)
elif := elval.Interface()
switch elif.(type) {
case floats.Floater:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Interface().(floats.Floater).Float()
jv := NonPtrValue(sl[j]).Interface().(floats.Floater).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case ints.Inter:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Interface().(ints.Inter).Int()
jv := NonPtrValue(sl[j]).Interface().(ints.Inter).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// try all the numeric types first!
switch {
case vk >= reflect.Int && vk <= reflect.Int64:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Int()
jv := NonPtrValue(sl[j]).Int()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Uint && vk <= reflect.Uint64:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Uint()
jv := NonPtrValue(sl[j]).Uint()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk >= reflect.Float32 && vk <= reflect.Float64:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Float()
jv := NonPtrValue(sl[j]).Float()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
case vk == reflect.Struct && FullTypeName(elnptyp) == "time.Time":
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Interface().(time.Time)
jv := NonPtrValue(sl[j]).Interface().(time.Time)
if ascending {
return iv.Before(jv)
} else {
return jv.Before(iv)
}
})
}
// this stringer case will likely pick up most of the rest
switch elif.(type) {
case fmt.Stringer:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).Interface().(fmt.Stringer).String()
jv := NonPtrValue(sl[j]).Interface().(fmt.Stringer).String()
if ascending {
return iv < jv
} else {
return iv > jv
}
})
return nil
}
// last resort!
switch {
case vk == reflect.String:
sort.Slice(sl, func(i, j int) bool {
iv := NonPtrValue(sl[i]).String()
jv := NonPtrValue(sl[j]).String()
if ascending {
return strings.ToLower(iv) < strings.ToLower(jv)
} else {
return strings.ToLower(iv) > strings.ToLower(jv)
}
})
return nil
}
err := fmt.Errorf("ValueSliceSort: unable to sort elements of type: %v", eltyp.String())
log.Println(err)
return err
}