package abi
import (
"fmt"
"reflect"
"regexp"
"strconv"
"github.com/ethereum/go-ethereum/common"
)
const (
IntTy byte = iota
UintTy
BoolTy
SliceTy
AddressTy
RealTy
)
// Type is the reflection of the supported argument type
type Type struct {
Kind reflect.Kind
Type reflect.Type
Size int
T byte // Our own type checking
stringKind string // holds the unparsed string for deriving signatures
}
// New type returns a fully parsed Type given by the input string or an error if it can't be parsed.
//
// Strings can be in the format of:
//
// Input = Type [ "[" [ Number ] "]" ] Name .
// Type = [ "u" ] "int" [ Number ] .
//
// Examples:
//
// string int uint real
// string32 int8 uint8 uint[]
// address int256 uint256 real[2]
func NewType(t string) (typ Type, err error) {
// 1. full string 2. type 3. (opt.) is slice 4. (opt.) size
freg, err := regexp.Compile("([a-zA-Z0-9]+)(\\[([0-9]*)?\\])?")
if err != nil {
return Type{}, err
}
res := freg.FindAllStringSubmatch(t, -1)[0]
var (
isslice bool
size int
)
switch {
case res[3] != "":
// err is ignored. Already checked for number through the regexp
size, _ = strconv.Atoi(res[3])
isslice = true
case res[2] != "":
isslice = true
size = -1
case res[0] == "":
return Type{}, fmt.Errorf("type parse error for `%s`", t)
}
treg, err := regexp.Compile("([a-zA-Z]+)([0-9]*)?")
if err != nil {
return Type{}, err
}
parsedType := treg.FindAllStringSubmatch(res[1], -1)[0]
vsize, _ := strconv.Atoi(parsedType[2])
vtype := parsedType[1]
// substitute canonical representation
if vsize == 0 && (vtype == "int" || vtype == "uint") {
vsize = 256
t += "256"
}
if isslice {
typ.Kind = reflect.Slice
typ.Size = size
switch vtype {
case "int":
typ.Type = big_ts
case "uint":
typ.Type = ubig_ts
default:
return Type{}, fmt.Errorf("unsupported arg slice type: %s", t)
}
} else {
switch vtype {
case "int":
typ.Kind = reflect.Ptr
typ.Type = big_t
typ.Size = 256
typ.T = IntTy
case "uint":
typ.Kind = reflect.Ptr
typ.Type = ubig_t
typ.Size = 256
typ.T = UintTy
case "bool":
typ.Kind = reflect.Bool
case "real": // TODO
typ.Kind = reflect.Invalid
case "address":
typ.Kind = reflect.Slice
typ.Type = byte_ts
typ.Size = 20
typ.T = AddressTy
case "string":
typ.Kind = reflect.String
typ.Size = -1
if vsize > 0 {
typ.Size = 32
}
default:
return Type{}, fmt.Errorf("unsupported arg type: %s", t)
}
}
typ.stringKind = t
return
}
func (t Type) String() (out string) {
return t.stringKind
}
// Test the given input parameter `v` and checks if it matches certain
// criteria
// * Big integers are checks for ptr types and if the given value is
// assignable
// * Integer are checked for size
// * Strings, addresses and bytes are checks for type and size
func (t Type) pack(v interface{}) ([]byte, error) {
value := reflect.ValueOf(v)
switch kind := value.Kind(); kind {
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if t.Type != ubig_t {
return nil, fmt.Errorf("type mismatch: %s for %T", t.Type, v)
}
return packNum(value, t.T), nil
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if t.Type != ubig_t {
return nil, fmt.Errorf("type mismatch: %s for %T", t.Type, v)
}
return packNum(value, t.T), nil
case reflect.Ptr:
// If the value is a ptr do a assign check (only used by
// big.Int for now)
if t.Type == ubig_t && value.Type() != ubig_t {
return nil, fmt.Errorf("type mismatch: %s for %T", t.Type, v)
}
return packNum(value, t.T), nil
case reflect.String:
if t.Size > -1 && value.Len() > t.Size {
return nil, fmt.Errorf("%v out of bound. %d for %d", value.Kind(), value.Len(), t.Size)
}
return []byte(common.LeftPadString(t.String(), 32)), nil
case reflect.Slice:
if t.Size > -1 && value.Len() > t.Size {
return nil, fmt.Errorf("%v out of bound. %d for %d", value.Kind(), value.Len(), t.Size)
}
// Address is a special slice. The slice acts as one rather than a list of elements.
if t.T == AddressTy {
return common.LeftPadBytes(v.([]byte), 32), nil
}
// Signed / Unsigned check
if (t.T != IntTy && isSigned(value)) || (t.T == UintTy && isSigned(value)) {
return nil, fmt.Errorf("slice of incompatible types.")
}
var packed []byte
for i := 0; i < value.Len(); i++ {
packed = append(packed, packNum(value.Index(i), t.T)...)
}
return packed, nil
case reflect.Bool:
if value.Bool() {
return common.LeftPadBytes(common.Big1.Bytes(), 32), nil
} else {
return common.LeftPadBytes(common.Big0.Bytes(), 32), nil
}
}
panic("unreached")
}