can someone attach the improved and efficient code?
On Friday, March 30, 2012 at 5:29:52 PM UTC+5:30, Luke Mauldin wrote:
>
> I have the the task of comparing two structs (of the same type) for
> equality and returning the field level differences. One of the
> restrictions is that I only have to support the types int, bool, float,
> string, and time.Time. I have built the following reflection routine and
> it works correctly for int, float, bool and string but I cannot figure out
> how do the comparison for time.Time because I am getting the compiler error
> "type time.Time is not an expression". Does anyone have any suggestions?
> Also, looking at the overall code, is there a better or more efficient way
> I can solve this problem?
>
> type CompareResult struct {
> FieldName string
> Value1 string
> Value2 string
> }
>
> func Compare (struct1 interface{}, struct2 interface{}) ([]*CompareResult,
> error) {
> if struct1 == nil || struct2 == nil {
> return nil, errors.New("One of the inputs cannot be nil.")
> }
> structVal1 := reflect.ValueOf(struct1)
> structVal2 := reflect.ValueOf(struct2)
> structType := reflect.TypeOf(struct1)
> if !(structVal1.Kind() == reflect.Struct && structVal2.Kind() ==
> reflect.Struct) {
> return nil, errors.New("Types must both be structs.")
> }
> if structVal1.Type() != structVal2.Type() {
> return nil, errors.New("Structs must be the same type.")
> }
> //if structVal1.IsNil() || structVal2.IsNil() {
> // return nil, errors.New("Structs cannot be nil.")
> //}
> numFields := structVal1.NumField()
> results := make([]*CompareResult, 0, numFields)
> for i := 0; i < numFields; i++ {
> //Get values of the structure's fields
> val1 := structVal1.Field(i)
> val2 := structVal2.Field(i)
> //If the values are pointers, get the value of the pointers
> isPtr := val1.Kind() == reflect.Ptr
> isVal1Nil := false
> isVal2Nil := false
> if isPtr {
> isVal1Nil = val1.IsNil()
> isVal2Nil = val2.IsNil()
> val1 = val1.Elem()
> val2 = val2.Elem()
> }
> //If the type is a pointer and both values are nil, continue the loop
> if isPtr && isVal1Nil && isVal2Nil {
> continue;
> }
> switch val1.Kind() {
> case reflect.Int:
> int1 := val1.Int()
> int2 := val2.Int()
> if int1 != int2 {
> result := &CompareResult{structType.Field(i).Name, strconv.FormatInt(int1,
> 10), strconv.FormatInt(int2, 10) }
> results = append(results, result)
> }
> break;
> case reflect.Bool:
> bool1 := val1.Bool()
> bool2 := val2.Bool()
> if bool1 != bool2 {
> result := &CompareResult{structType.Field(i).Name,
> strconv.FormatBool(bool1), strconv.FormatBool(bool2) }
> results = append(results, result)
> }
> break;
> case reflect.Float32, reflect.Float64:
> float1 := val1.Float()
> float2 := val2.Float()
> if float1 != float2 {
> result := &CompareResult{structType.Field(i).Name,
> strconv.FormatFloat(float1, 'f', 2, 64), strconv.FormatFloat(float2, 'f',
> 2, 64) }
> results = append(results, result)
> }
> case reflect.Struct:
> //Handle time.Time
> timeType := reflect.TypeOf(time.Time) //This gives me a "type time.Time
> is not an expression"
> if val1.Type() == timeType {
> }
> break;
> case reflect.String:
> str1 := val1.String()
> str2 := val2.String()
> if str1 != str2 {
> result := &CompareResult{structType.Field(i).Name, str1, str2 }
> results = append(results, result)
> }
> break;
> default:
> return nil, errors.New(fmt.Sprintf("Unsupported kind: %v", val1.Kind()))
> }
> }
> return results, nil
> }
>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
