neo-go/pkg/core/transaction/input.go
2020-03-03 17:21:42 +03:00

94 lines
2.2 KiB
Go

package transaction
import (
"sort"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util"
)
// Input represents a Transaction input (CoinReference).
type Input struct {
// The hash of the previous transaction.
PrevHash util.Uint256 `json:"txid"`
// The index of the previous transaction.
PrevIndex uint16 `json:"vout"`
}
// DecodeBinary implements Serializable interface.
func (in *Input) DecodeBinary(br *io.BinReader) {
br.ReadBytes(in.PrevHash[:])
in.PrevIndex = br.ReadU16LE()
}
// EncodeBinary implements Serializable interface.
func (in *Input) EncodeBinary(bw *io.BinWriter) {
bw.WriteBytes(in.PrevHash[:])
bw.WriteU16LE(in.PrevIndex)
}
// Cmp compares two Inputs by their hash and index allowing to make a set of
// transactions ordered.
func (in *Input) Cmp(other *Input) int {
hashcmp := in.PrevHash.CompareTo(other.PrevHash)
if hashcmp == 0 {
return int(in.PrevIndex) - int(other.PrevIndex)
}
return hashcmp
}
// MapInputsToSorted maps given slice of inputs into a new slice of pointers
// to inputs sorted by their PrevHash and PrevIndex.
func MapInputsToSorted(ins []Input) []*Input {
ptrs := make([]*Input, len(ins))
for i := range ins {
ptrs[i] = &ins[i]
}
sort.Slice(ptrs, func(i, j int) bool {
return ptrs[i].Cmp(ptrs[j]) < 0
})
return ptrs
}
// GroupInputsByPrevHash groups all TX inputs by their previous hash into
// several slices (which actually are subslices of one new slice with pointers).
// Each of these slices contains at least one element.
func GroupInputsByPrevHash(ins []Input) [][]*Input {
if len(ins) == 0 {
return nil
}
ptrs := MapInputsToSorted(ins)
var first int
res := make([][]*Input, 0)
currentHash := ptrs[0].PrevHash
for i := range ptrs {
if !currentHash.Equals(ptrs[i].PrevHash) {
res = append(res, ptrs[first:i])
first = i
currentHash = ptrs[i].PrevHash
}
}
res = append(res, ptrs[first:])
return res
}
// HaveDuplicateInputs checks inputs for duplicates and returns true if there are
// any.
func HaveDuplicateInputs(ins []Input) bool {
if len(ins) < 2 {
return false
}
if len(ins) == 2 {
return ins[0] == ins[1]
}
ptrs := MapInputsToSorted(ins)
for i := 1; i < len(ptrs); i++ {
if *ptrs[i] == *ptrs[i-1] {
return true
}
}
return false
}