@alcorexchange/alcor-swap-sdk/src/utils/sqrtPriceMath.ts

## Installation ​​ **npm** ``` npm i @alcorexchange/alcor-swap-sdk ``` **yarn** ``` yarn add @alcorexchange/alcor-swap-sdk ``` ## Usage ### Import:

import JSBI from "jsbi";
import { ONE, ZERO, Q64, MaxUint128 } from "../internalConstants";
import { FullMath } from "./fullMath";

function multiplyIn128(x: JSBI, y: JSBI): JSBI {
  const product = JSBI.multiply(x, y);
  return JSBI.bitwiseAnd(product, MaxUint128);
}

function addIn128(x: JSBI, y: JSBI): JSBI {
  const sum = JSBI.add(x, y);
  return JSBI.bitwiseAnd(sum, MaxUint128);
}

export abstract class SqrtPriceMath {
  /**
   * Cannot be constructed.
   */
  private constructor() {}

  public static getAmountADelta(
    sqrtRatioLX64: JSBI,
    sqrtRatioUX64: JSBI,
    liquidity: JSBI,
    roundUp: boolean
  ): JSBI {
    if (JSBI.greaterThan(sqrtRatioLX64, sqrtRatioUX64)) {
      [sqrtRatioLX64, sqrtRatioUX64] = [sqrtRatioUX64, sqrtRatioLX64];
    }

    const numerator1 = JSBI.leftShift(liquidity, JSBI.BigInt(64));
    const numerator2 = JSBI.subtract(sqrtRatioUX64, sqrtRatioLX64);

    if (roundUp) {
      const mul1 = FullMath.mulDivRoundingUp(numerator1, numerator2, sqrtRatioUX64);
      return FullMath.mulDivRoundingUp(mul1, ONE, sqrtRatioLX64);
    } else {
      const mul1 = JSBI.divide(JSBI.multiply(numerator1, numerator2), sqrtRatioUX64);
      return JSBI.divide(mul1, sqrtRatioLX64);
    }
  }

  public static getAmountBDelta(
    sqrtRatioLX64: JSBI,
    sqrtRatioUX64: JSBI,
    liquidity: JSBI,
    roundUp: boolean
  ): JSBI {
    if (JSBI.greaterThan(sqrtRatioLX64, sqrtRatioUX64)) {
      [sqrtRatioLX64, sqrtRatioUX64] = [sqrtRatioUX64, sqrtRatioLX64];
    }

    const diff = JSBI.subtract(sqrtRatioUX64, sqrtRatioLX64);
    if (roundUp) {
      return FullMath.mulDivRoundingUp(liquidity, diff, Q64);
    } else {
      return JSBI.divide(JSBI.multiply(liquidity, diff), Q64);
    }
  }

  public static getNextSqrtPriceFromInput(
    sqrtPX64: JSBI,
    liquidity: JSBI,
    amountIn: JSBI,
    zeroForOne: boolean
  ): JSBI {
    // Убраны invariant для ускорения, если данные валидны
    return zeroForOne
      ? this.getNextSqrtPriceFromAmountARoundingUp(sqrtPX64, liquidity, amountIn, true)
      : this.getNextSqrtPriceFromAmountBRoundingDown(sqrtPX64, liquidity, amountIn, true);
  }

  public static getNextSqrtPriceFromOutput(
    sqrtPX64: JSBI,
    liquidity: JSBI,
    amountOut: JSBI,
    zeroForOne: boolean
  ): JSBI {
    // Убраны invariant для ускорения, если данные валидны
    return zeroForOne
      ? this.getNextSqrtPriceFromAmountBRoundingDown(sqrtPX64, liquidity, amountOut, false)
      : this.getNextSqrtPriceFromAmountARoundingUp(sqrtPX64, liquidity, amountOut, false);
  }

  private static getNextSqrtPriceFromAmountARoundingUp(
    sqrtPX64: JSBI,
    liquidity: JSBI,
    amount: JSBI,
    add: boolean
  ): JSBI {
    if (JSBI.equal(amount, ZERO)) return sqrtPX64;
    const numerator1 = JSBI.leftShift(liquidity, JSBI.BigInt(64));

    if (add) {
      const product = multiplyIn128(amount, sqrtPX64);
      if (JSBI.equal(JSBI.divide(product, amount), sqrtPX64)) {
        const denominator = addIn128(numerator1, product);
        if (JSBI.greaterThanOrEqual(denominator, numerator1)) {
          return FullMath.mulDivRoundingUp(numerator1, sqrtPX64, denominator);
        }
      }
      const adjustedDenominator = JSBI.add(JSBI.divide(numerator1, sqrtPX64), amount);
      return FullMath.mulDivRoundingUp(numerator1, ONE, adjustedDenominator);
    } else {
      const product = multiplyIn128(amount, sqrtPX64);
      // Убрана invariant, предполагаем, что numerator1 > product
      const denominator = JSBI.subtract(numerator1, product);
      return FullMath.mulDivRoundingUp(numerator1, sqrtPX64, denominator);
    }
  }

  private static getNextSqrtPriceFromAmountBRoundingDown(
    sqrtPX64: JSBI,
    liquidity: JSBI,
    amount: JSBI,
    add: boolean
  ): JSBI {
    if (add) {
      const quotient = JSBI.lessThanOrEqual(amount, MaxUint128)
        ? JSBI.divide(JSBI.leftShift(amount, JSBI.BigInt(64)), liquidity)
        : JSBI.divide(JSBI.multiply(amount, Q64), liquidity);
      return JSBI.add(sqrtPX64, quotient);
    } else {
      const quotient = FullMath.mulDivRoundingUp(amount, Q64, liquidity);
      // Убрана invariant, предполагаем, что sqrtPX64 > quotient
      return JSBI.subtract(sqrtPX64, quotient);
    }
  }
}