Merge pull request #14 from sCrypt-Inc/txParser

add txParser

src/index.ts

@@ -27,3 +27,16 @@ export { MerklePath } from './merklePath'
 export { Shift10 } from './shift10'
 export { ArrayUtils } from './arrayUtils'
 export { Schnorr } from './schnorr'
+export {
+    TxParser,
+    Output,
+    Input,
+    MAX_TX_INPUT_COUNT,
+    MAX_TX_OUTPUT_COUNT,
+} from './txParser'
+export {
+    TxParserBTC,
+    MAX_BTC_TX_INPUT_COUNT,
+    MAX_BTC_TX_OUTPUT_COUNT,
+    MAX_WITNESS_ITEM_COUNT,
+} from './txParserBTC'

src/txParser.ts

@@ -0,0 +1,187 @@
+import {
+    prop,
+    method,
+    SmartContractLib,
+    FixedArray,
+    assert,
+    ByteString,
+    toByteString,
+    slice,
+    fill,
+    Utils,
+} from 'scrypt-ts'
+
+export interface Output {
+    satoshis: bigint
+    script: ByteString
+}
+
+export interface Input {
+    txId: ByteString
+    vout: bigint
+    scriptSig: ByteString
+    nSequence: bigint
+}
+
+export const MAX_TX_INPUT_COUNT = 5
+
+export const MAX_TX_OUTPUT_COUNT = 5
+
+export class TxParser extends SmartContractLib {
+    @prop()
+    buf: ByteString
+
+    @prop()
+    pos: bigint
+
+    @prop()
+    inputs: FixedArray<Input, typeof MAX_TX_INPUT_COUNT>
+
+    @prop()
+    outputs: FixedArray<Output, typeof MAX_TX_OUTPUT_COUNT>
+
+    @prop()
+    inputsCount: bigint
+
+    @prop()
+    outputsCount: bigint
+
+    @prop()
+    version: bigint
+
+    @prop()
+    nLockTime: bigint
+
+    constructor(raw: ByteString) {
+        super(raw)
+        this.buf = raw
+        this.pos = 0n
+        this.inputsCount = 0n
+        this.outputsCount = 0n
+        this.version = 0n
+        this.nLockTime = 0n
+
+        this.inputs = fill(
+            {
+                txId: toByteString(''),
+                vout: 0n,
+                scriptSig: toByteString(''),
+                nSequence: 1n,
+            },
+            MAX_TX_INPUT_COUNT
+        )
+        this.outputs = fill(
+            { satoshis: 0n, script: toByteString('') },
+            MAX_TX_OUTPUT_COUNT
+        )
+    }
+
+    @method()
+    readVarInt(): bigint {
+        const n: bigint = Utils.fromLEUnsigned(
+            slice(this.buf, this.pos, this.pos + 1n)
+        )
+        this.pos++
+
+        let ret = 0n
+
+        if (n < 0xfdn) {
+            ret = n
+        } else if (n == 0xfdn) {
+            ret = Utils.fromLEUnsigned(slice(this.buf, this.pos, this.pos + 2n))
+            this.pos += 2n
+        } else if (n == 0xfen) {
+            ret = Utils.fromLEUnsigned(slice(this.buf, this.pos, this.pos + 4n))
+            this.pos += 4n
+        } else if (n == 0xffn) {
+            ret = Utils.fromLEUnsigned(slice(this.buf, this.pos, this.pos + 8n))
+            this.pos += 8n
+        }
+
+        return ret
+    }
+
+    @method()
+    readBytes(l: bigint): ByteString {
+        const ret = slice(this.buf, this.pos, this.pos + l)
+        this.pos += l
+        return ret
+    }
+
+    @method()
+    readUInt32(): bigint {
+        return Utils.fromLEUnsigned(this.readBytes(4n))
+    }
+
+    @method()
+    readInput(): Input {
+        // Previous Transaction hash, 32 bytes
+        const txid: ByteString = this.readBytes(32n)
+        // Previous Txout-index, 4 bytes
+        const vout: bigint = Utils.fromLEUnsigned(this.readBytes(4n))
+        // Txin-script length, 1 - 9 bytes
+        const scriptSigLen: bigint = this.readVarInt()
+        // Txin-script / scriptSig, 	<in-script length>-many bytes
+        const scriptSig: ByteString =
+            scriptSigLen > 0n ? this.readBytes(scriptSigLen) : toByteString('')
+        // Sequence_no, 4 bytes
+        const nSequence: bigint = Utils.fromLEUnsigned(this.readBytes(4n))
+        return {
+            txId: txid,
+            vout: vout,
+            scriptSig: scriptSig,
+            nSequence: nSequence,
+        }
+    }
+
+    @method()
+    readOutput(): Output {
+        // Satoshi value, 8 bytes
+        const satoshis: bigint = Utils.fromLEUnsigned(this.readBytes(8n))
+        // Txout-script length, 1 - 9 bytes
+        const scriptLen: bigint = this.readVarInt()
+        // Txout-script / scriptPubKey, <out-script length>-many bytes
+        const script: ByteString = this.readBytes(scriptLen)
+        return {
+            script: script,
+            satoshis: satoshis,
+        }
+    }
+
+    @method()
+    parse(): boolean {
+        this.version = this.readUInt32()
+
+        this.inputsCount = this.readVarInt()
+        assert(this.inputsCount < MAX_TX_INPUT_COUNT, 'too much inputs')
+
+        for (let i = 0; i < MAX_TX_INPUT_COUNT; i++) {
+            if (i < this.inputsCount) {
+                this.inputs[i] = this.readInput()
+            }
+        }
+
+        this.outputsCount = this.readVarInt()
+        assert(this.outputsCount < MAX_TX_OUTPUT_COUNT, 'too much outputs')
+
+        for (let i = 0; i < MAX_TX_OUTPUT_COUNT; i++) {
+            if (i < this.outputsCount) {
+                this.outputs[i] = this.readOutput()
+            }
+        }
+
+        this.nLockTime = this.readUInt32()
+
+        return true
+    }
+
+    @method()
+    getInputs(): FixedArray<Input, typeof MAX_TX_INPUT_COUNT> {
+        return this.inputs
+    }
+
+    @method()
+    getOutputs(): FixedArray<Output, typeof MAX_TX_OUTPUT_COUNT> {
+        return this.outputs
+    }
+}