Add BSV20Mint contract.

src/contracts/bsv20Mint.ts

@@ -0,0 +1,168 @@
+import { assert } from 'console'
+import {
+ ByteString,
+ FixedArray,
+ OpCode,
+ PubKeyHash,
+ SmartContract,
+ Utils,
+ byteString2Int,
+ hash256,
+ int2ByteString,
+ len,
+ lshift,
+ method,
+ prop,
+ slice,
+ toByteString,
+} from 'scrypt-ts'
+import { Shift10 } from 'scrypt-ts-lib'
+
+export class BSV20Mint extends SmartContract {
+ @prop()
+ totalSupply: bigint
+
+ @prop(true)
+ alreadyMinted: bigint
+
+ @prop(true)
+ isFirstMint: boolean
+
+ @prop(true)
+ tokenId: ByteString
+
+ @prop()
+ static readonly hexAsciiTable: FixedArray<ByteString, 16> = [
+ toByteString('0', true),
+ toByteString('1', true),
+ toByteString('2', true),
+ toByteString('3', true),
+ toByteString('4', true),
+ toByteString('5', true),
+ toByteString('6', true),
+ toByteString('7', true),
+ toByteString('8', true),
+ toByteString('9', true),
+ toByteString('a', true),
+ toByteString('b', true),
+ toByteString('c', true),
+ toByteString('d', true),
+ toByteString('e', true),
+ toByteString('f', true),
+ ]
+
+ constructor(totalSupply: bigint) {
+ super(...arguments)
+ this.totalSupply = totalSupply
+ this.alreadyMinted = 0n
+ this.isFirstMint = false
+ this.tokenId = toByteString('')
+ }
+
+ @method()
+ public mint(dest: PubKeyHash, amount: bigint) {
+ // If first mint, parse token id and store it in a state var
+ if (this.isFirstMint) {
+ this.tokenId =
+ BSV20Mint.txId2Ascii(this.ctx.utxo.outpoint.txid) +
+ toByteString('_', true) +
+ BSV20Mint.int2Ascii(this.ctx.utxo.outpoint.outputIndex)
+ this.isFirstMint = false
+ }
+
+ // Check if tokens still available.
+ assert(
+ this.totalSupply - this.alreadyMinted >= amount,
+ 'not enough tokens left to mint'
+ )
+
+ // Update already minted amount.
+ this.alreadyMinted += amount
+
+ // Build state output inscribed with leftover tokens.
+ const leftover = this.totalSupply - this.alreadyMinted
+ const script0 =
+ BSV20Mint.getTransferInsciption(this.tokenId, leftover) +
+ this.getStateScript()
+ let outputs = Utils.buildOutput(script0, 1n)
+
+ // Build P2PKH output to dest paying specified amount of tokens.
+ const script1 =
+ BSV20Mint.getTransferInsciption(this.tokenId, leftover) +
+ Utils.buildPublicKeyHashScript(dest)
+ outputs += Utils.buildOutput(script1, 1n)
+
+ // Build change output.
+ outputs += this.buildChangeOutput()
+
+ assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+ }
+
+ // OP_FALSE OP_IF OP_DATA3 "ord" OP_1 OP_DATA18 "application/bsv-20" OP_FALSE <transfer-json> OP_ENDIF
+ // Transfer JSON example:
+ //{
+ // "p": "bsv-20",
+ // "op": "transfer",
+ // "id": "3b313338fa0555aebeaf91d8db1ffebd74773c67c8ad5181ff3d3f51e21e0000_1"
+ // "amt": "10000"
+ //}
+ @method()
+ static getTransferInsciption(tokenId: ByteString, amt: bigint): ByteString {
+ const transferJson =
+ toByteString('{"p":"bsv-20","op":"transfer","id":"', true) +
+ toByteString('","amt":"', true) +
+ BSV20Mint.int2Ascii(amt) +
+ toByteString('"}', true)
+
+ return (
+ toByteString(
+ '0063036f726451126170706c69636174696f6e2f6273762d323000'
+ ) +
+ int2ByteString(len(transferJson)) +
+ transferJson +
+ OpCode.OP_ENDIF
+ )
+ }
+
+ // Converts integer to hex-encoded ASCII.
+ // 1000 -> '31303030'
+ // Input cannot be larger than 2^64-1.
+ @method()
+ static int2Ascii(n: bigint): ByteString {
+ // Max 2^64-1
+ assert(n < lshift(1n, 64n), 'n is larger than 2^64-1')
+
+ let res = toByteString('')
+ let done = false
+
+ for (let i = 0; i < 20; i++) {
+ if (!done) {
+ // Get ith digit: n // 10^i % 10
+ const denominator = Shift10.pow(BigInt(i))
+
+ if (n < denominator) {
+ done = true
+ } else {
+ const ithDigit = (n / denominator) % 10n
+
+ // Transform digit to ASCII (hex encoded) and prepend to result.
+ res = int2ByteString(48n + ithDigit, 1n) + res
+ }
+ }
+ }
+
+ return res
+ }
+
+ @method()
+ static txId2Ascii(txId: ByteString): ByteString {
+ let res = toByteString('')
+
+ for (let i = 0; i < 64; i++) {
+ const char = slice(txId, BigInt(i), BigInt(i + 1))
+ const charInt = byteString2Int(char)
+ res += BSV20Mint.hexAsciiTable[Number(charInt)]
+ }
+ return res
+ }
+}