git ssb

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const BN = require('bn.js')
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const ethUtil = require('ethereumjs-util')
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module.exports = class U256 {
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  constructor (value) {
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    // bn.js still doesn't support hex prefixes...
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    if ((typeof value === 'string') && ethUtil.isHexPrefixed(value)) {
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      this._value = new BN(ethUtil.stripHexPrefix(value), 16)
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    } else {
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      this._value = new BN(value, 10)
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    }
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  }
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  // This assumes Uint8Array in LSB (WASM code)
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  static fromMemory (value) {
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    return new U256(new BN(value, 16, 'be'))
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  }
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  // This assumes Uint8Array in LSB (WASM code)
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  toMemory (width) {
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    return this._value.toBuffer('be', width || 32)
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  }
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  toString (radix = 10) {
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    if (radix === 16) {
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      return '0x' + this._value.toString(16)
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    }
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    return this._value.toString(radix)
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  }
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  toBuffer (width = 32) {
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    if (width <= 0 || width > 32) {
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      throw new Error('Invalid U256 width')
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    }
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    return this._value.toBuffer('be', width)
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  }
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  toArray () {
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    return [...this.toBuffer()]
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  }
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  isZero () {
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    return this._value.isZero()
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  }
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  sub (u256) {
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    return new U256(this._value.sub(u256._value))
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  }
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  add (u256) {
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    return new U256(this._value.add(u256._value))
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  }
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  mul (u256) {
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    return new U256(this._value.mul(u256._value))
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  }
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  div (u256) {
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    return new U256(this._value.div(u256._value))
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  }
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  lt (u256) {
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    return this._value.lt(u256._value)
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  }
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  gt (u256) {
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    return this._value.gt(u256._value)
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  }
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}
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