path: root/ethutil/value.go

package ethutil

import (
    "fmt"
    "math/big"
    "reflect"
)

// Data values are returned by the rlp decoder. The data values represents
// one item within the rlp data structure. It's responsible for all the casting
// It always returns something valid
type Value struct {
    Val  interface{}
    kind reflect.Value
}

func (val *Value) String() string {
    return fmt.Sprintf("%x", val.Val)
}

func NewValue(val interface{}) *Value {
    t := val
    if v, ok := val.(*Value); ok {
        t = v.Val
    }

    return &Value{Val: t}
}

func (val *Value) Type() reflect.Kind {
    return reflect.TypeOf(val.Val).Kind()
}

func (val *Value) IsNil() bool {
    return val.Val == nil
}

func (val *Value) Len() int {
    //return val.kind.Len()
    if data, ok := val.Val.([]interface{}); ok {
        return len(data)
    }

    return len(val.Bytes())
}

func (val *Value) Raw() interface{} {
    return val.Val
}

func (val *Value) Interface() interface{} {
    return val.Val
}

func (val *Value) Uint() uint64 {
    if Val, ok := val.Val.(uint8); ok {
        return uint64(Val)
    } else if Val, ok := val.Val.(uint16); ok {
        return uint64(Val)
    } else if Val, ok := val.Val.(uint32); ok {
        return uint64(Val)
    } else if Val, ok := val.Val.(uint64); ok {
        return Val
    } else if Val, ok := val.Val.(int); ok {
        return uint64(Val)
    } else if Val, ok := val.Val.(uint); ok {
        return uint64(Val)
    } else if Val, ok := val.Val.([]byte); ok {
        return new(big.Int).SetBytes(Val).Uint64()
    } else if Val, ok := val.Val.(*big.Int); ok {
        return Val.Uint64()
    }

    return 0
}

func (val *Value) Byte() byte {
    if Val, ok := val.Val.(byte); ok {
        return Val
    }

    return 0x0
}

func (val *Value) BigInt() *big.Int {
    if a, ok := val.Val.([]byte); ok {
        b := new(big.Int).SetBytes(a)

        return b
    } else if a, ok := val.Val.(*big.Int); ok {
        return a
    } else {
        return big.NewInt(int64(val.Uint()))
    }

    return big.NewInt(0)
}

func (val *Value) Str() string {
    if a, ok := val.Val.([]byte); ok {
        return string(a)
    } else if a, ok := val.Val.(string); ok {
        return a
    } else if a, ok := val.Val.(byte); ok {
        return string(a)
    }

    return ""
}

func (val *Value) Bytes() []byte {
    if a, ok := val.Val.([]byte); ok {
        return a
    } else if s, ok := val.Val.(byte); ok {
        return []byte{s}
    } else if s, ok := val.Val.(string); ok {
        return []byte(s)
    } else if s, ok := val.Val.(*big.Int); ok {
        return s.Bytes()
    }

    return []byte{}
}

func (val *Value) Slice() []interface{} {
    if d, ok := val.Val.([]interface{}); ok {
        return d
    }

    return []interface{}{}
}

func (val *Value) SliceFrom(from int) *Value {
    slice := val.Slice()

    return NewValue(slice[from:])
}

func (val *Value) SliceTo(to int) *Value {
    slice := val.Slice()

    return NewValue(slice[:to])
}

func (val *Value) SliceFromTo(from, to int) *Value {
    slice := val.Slice()

    return NewValue(slice[from:to])
}

// TODO More type checking methods
func (val *Value) IsSlice() bool {
    return val.Type() == reflect.Slice
}

func (val *Value) IsStr() bool {
    return val.Type() == reflect.String
}

// Special list checking function. Something is considered
// a list if it's of type []interface{}. The list is usually
// used in conjunction with rlp decoded streams.
func (val *Value) IsList() bool {
    _, ok := val.Val.([]interface{})

    return ok
}

func (val *Value) IsEmpty() bool {
    return val.Val == nil || ((val.IsSlice() || val.IsStr()) && val.Len() == 0)
}

// Threat the value as a slice
func (val *Value) Get(idx int) *Value {
    if d, ok := val.Val.([]interface{}); ok {
        // Guard for oob
        if len(d) <= idx {
            return NewValue(nil)
        }

        if idx < 0 {
            return NewValue(nil)
        }

        return NewValue(d[idx])
    }

    // If this wasn't a slice you probably shouldn't be using this function
    return NewValue(nil)
}

func (self *Value) Copy() *Value {
    switch val := self.Val.(type) {
    case *big.Int:
        return NewValue(new(big.Int).Set(val))
    case []byte:
        return NewValue(CopyBytes(val))
    default:
        return NewValue(self.Val)
    }

    return nil
}

func (val *Value) Cmp(o *Value) bool {
    return reflect.DeepEqual(val.Val, o.Val)
}

func (self *Value) DeepCmp(o *Value) bool {
    a := NewValue(self.BigInt())
    b := NewValue(o.BigInt())

    return a.Cmp(b)
}

func (val *Value) Encode() []byte {
    return Encode(val.Val)
}

// Assume that the data we have is encoded
func (self *Value) Decode() {
    v, _ := Decode(self.Bytes(), 0)
    self.Val = v
}

func NewValueFromBytes(data []byte) *Value {
    if len(data) != 0 {
        data, _ := Decode(data, 0)
        return NewValue(data)
    }

    return NewValue(nil)
}

// Value setters
func NewSliceValue(s interface{}) *Value {
    list := EmptyValue()

    if s != nil {
        if slice, ok := s.([]interface{}); ok {
            for _, val := range slice {
                list.Append(val)
            }
        } else if slice, ok := s.([]string); ok {
            for _, val := range slice {
                list.Append(val)
            }
        }
    }

    return list
}

func EmptyValue() *Value {
    return NewValue([]interface{}{})
}

func (val *Value) AppendList() *Value {
    list := EmptyValue()
    val.Val = append(val.Slice(), list)

    return list
}

func (val *Value) Append(v interface{}) *Value {
    val.Val = append(val.Slice(), v)

    return val
}

const (
    valOpAdd = iota
    valOpDiv
    valOpMul
    valOpPow
    valOpSub
)

// Math stuff
func (self *Value) doOp(op int, other interface{}) *Value {
    left := self.BigInt()
    right := NewValue(other).BigInt()

    switch op {
    case valOpAdd:
        self.Val = left.Add(left, right)
    case valOpDiv:
        self.Val = left.Div(left, right)
    case valOpMul:
        self.Val = left.Mul(left, right)
    case valOpPow:
        self.Val = left.Exp(left, right, Big0)
    case valOpSub:
        self.Val = left.Sub(left, right)
    }

    return self
}

func (self *Value) Add(other interface{}) *Value {
    return self.doOp(valOpAdd, other)
}

func (self *Value) Sub(other interface{}) *Value {
    return self.doOp(valOpSub, other)
}

func (self *Value) Div(other interface{}) *Value {
    return self.doOp(valOpDiv, other)
}

func (self *Value) Mul(other interface{}) *Value {
    return self.doOp(valOpMul, other)
}

func (self *Value) Pow(other interface{}) *Value {
    return self.doOp(valOpPow, other)
}

type ValueIterator struct {
    value        *Value
    currentValue *Value
    idx          int
}

func (val *Value) NewIterator() *ValueIterator {
    return &ValueIterator{value: val}
}

func (it *ValueIterator) Next() bool {
    if it.idx >= it.value.Len() {
        return false
    }

    it.currentValue = it.value.Get(it.idx)
    it.idx++

    return true
}

func (it *ValueIterator) Value() *Value {
    return it.currentValue
}

func (it *ValueIterator) Idx() int {
    return it.idx
}