76 lines
1.6 KiB
Go
76 lines
1.6 KiB
Go
package main
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import (
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"crypto/sha256"
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"fmt"
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"log"
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"strconv"
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"time"
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)
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// Block keeps block headers
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type Block struct {
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Timestamp int64
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Data []byte
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PrevBlock []byte
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hash []byte
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}
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// SetHash calculates and sets block hash
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func (b *Block) SetHash() {
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h := sha256.New()
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timestamp := []byte(strconv.FormatInt(b.Timestamp, 10))
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var data []byte
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data = append(data, b.PrevBlock...)
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data = append(data, b.Data...)
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data = append(data, timestamp...)
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_, err := h.Write(data)
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if err != nil {
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log.Panic(err)
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}
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b.hash = h.Sum(nil)
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}
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// NewBlock creates and returns Block
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func NewBlock(data string, prevBlock []byte) *Block {
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block := &Block{time.Now().Unix(), []byte(data), prevBlock, []byte("")}
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block.SetHash()
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return block
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}
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// NewGenesisBlock creates and returns genesis Block
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func NewGenesisBlock() *Block {
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return NewBlock("Genesis Block", []byte("0"))
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}
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// Blockchain keeps a sequence of Blocks
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type Blockchain struct {
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blocks []*Block
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}
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// AddBlock saves provided data as a block in the blockchain
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func (bc *Blockchain) AddBlock(data string) {
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prevBlock := bc.blocks[len(bc.blocks)-1]
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newBlock := &Block{time.Now().Unix(), []byte(data), prevBlock.hash, []byte("")}
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newBlock.SetHash()
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bc.blocks = append(bc.blocks, newBlock)
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}
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// NewBlockchain creates a new Blockchain with genesis Block
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func NewBlockchain() *Blockchain {
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return &Blockchain{[]*Block{NewGenesisBlock()}}
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}
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func main() {
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bc := NewBlockchain()
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bc.AddBlock("Send 1 BTC to Ivan")
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bc.AddBlock("Send 2 more BTC to Ivan")
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for _, block := range bc.blocks {
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fmt.Printf("%s\n", block.Data)
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fmt.Printf("%x\n", block.hash)
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}
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}
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