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contracts/SmartRoute/lib/DODOSellHelper.sol
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227
contracts/SmartRoute/lib/DODOSellHelper.sol
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/**
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*Submitted for verification at Etherscan.io on 2020-10-10
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*/
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// File: contracts/intf/IDODO.sol
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/*
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Copyright 2020 DODO ZOO.
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SPDX-License-Identifier: Apache-2.0
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*/
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pragma solidity 0.6.9;
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pragma experimental ABIEncoderV2;
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import {IDODOV1} from "../intf/IDODOV1.sol";
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import {SafeMath} from "../../lib/SafeMath.sol";
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import {DecimalMath} from "../../lib/DecimalMath.sol";
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// import {DODOMath} from "../lib/DODOMath.sol";
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library DODOMath {
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using SafeMath for uint256;
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/*
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Integrate dodo curve fron V1 to V2
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require V0>=V1>=V2>0
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res = (1-k)i(V1-V2)+ikV0*V0(1/V2-1/V1)
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let V1-V2=delta
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res = i*delta*(1-k+k(V0^2/V1/V2))
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*/
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function _GeneralIntegrate(
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uint256 V0,
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uint256 V1,
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uint256 V2,
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uint256 i,
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uint256 k
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) internal pure returns (uint256) {
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uint256 fairAmount = DecimalMath.mulFloor(i, V1.sub(V2)); // i*delta
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uint256 V0V0V1V2 = DecimalMath.divCeil(V0.mul(V0).div(V1), V2);
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uint256 penalty = DecimalMath.mulFloor(k, V0V0V1V2); // k(V0^2/V1/V2)
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return DecimalMath.mulFloor(fairAmount, DecimalMath.ONE.sub(k).add(penalty));
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}
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/*
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The same with integration expression above, we have:
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i*deltaB = (Q2-Q1)*(1-k+kQ0^2/Q1/Q2)
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Given Q1 and deltaB, solve Q2
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This is a quadratic function and the standard version is
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aQ2^2 + bQ2 + c = 0, where
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a=1-k
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-b=(1-k)Q1-kQ0^2/Q1+i*deltaB
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c=-kQ0^2
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and Q2=(-b+sqrt(b^2+4(1-k)kQ0^2))/2(1-k)
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note: another root is negative, abondan
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if deltaBSig=true, then Q2>Q1
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if deltaBSig=false, then Q2<Q1
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*/
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function _SolveQuadraticFunctionForTrade(
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uint256 Q0,
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uint256 Q1,
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uint256 ideltaB,
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bool deltaBSig,
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uint256 k
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) internal pure returns (uint256) {
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// calculate -b value and sig
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// -b = (1-k)Q1-kQ0^2/Q1+i*deltaB
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uint256 kQ02Q1 = DecimalMath.mulFloor(k, Q0).mul(Q0).div(Q1); // kQ0^2/Q1
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uint256 b = DecimalMath.mulFloor(DecimalMath.ONE.sub(k), Q1); // (1-k)Q1
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bool minusbSig = true;
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if (deltaBSig) {
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b = b.add(ideltaB); // (1-k)Q1+i*deltaB
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} else {
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kQ02Q1 = kQ02Q1.add(ideltaB); // i*deltaB+kQ0^2/Q1
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}
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if (b >= kQ02Q1) {
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b = b.sub(kQ02Q1);
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minusbSig = true;
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} else {
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b = kQ02Q1.sub(b);
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minusbSig = false;
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}
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// calculate sqrt
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uint256 squareRoot = DecimalMath.mulFloor(
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DecimalMath.ONE.sub(k).mul(4),
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DecimalMath.mulFloor(k, Q0).mul(Q0)
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); // 4(1-k)kQ0^2
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squareRoot = b.mul(b).add(squareRoot).sqrt(); // sqrt(b*b+4(1-k)kQ0*Q0)
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// final res
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uint256 denominator = DecimalMath.ONE.sub(k).mul(2); // 2(1-k)
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uint256 numerator;
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if (minusbSig) {
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numerator = b.add(squareRoot);
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} else {
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numerator = squareRoot.sub(b);
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}
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if (deltaBSig) {
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return DecimalMath.divFloor(numerator, denominator);
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} else {
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return DecimalMath.divCeil(numerator, denominator);
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}
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}
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/*
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Start from the integration function
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i*deltaB = (Q2-Q1)*(1-k+kQ0^2/Q1/Q2)
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Assume Q2=Q0, Given Q1 and deltaB, solve Q0
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let fairAmount = i*deltaB
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*/
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function _SolveQuadraticFunctionForTarget(
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uint256 V1,
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uint256 k,
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uint256 fairAmount
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) internal pure returns (uint256 V0) {
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// V0 = V1+V1*(sqrt-1)/2k
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uint256 sqrt = DecimalMath.divCeil(DecimalMath.mulFloor(k, fairAmount).mul(4), V1);
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sqrt = sqrt.add(DecimalMath.ONE).mul(DecimalMath.ONE).sqrt();
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uint256 premium = DecimalMath.divCeil(sqrt.sub(DecimalMath.ONE), k.mul(2));
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// V0 is greater than or equal to V1 according to the solution
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return DecimalMath.mulFloor(V1, DecimalMath.ONE.add(premium));
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}
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}
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contract DODOSellHelper {
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using SafeMath for uint256;
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enum RStatus {ONE, ABOVE_ONE, BELOW_ONE}
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uint256 constant ONE = 10**18;
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struct DODOState {
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uint256 oraclePrice;
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uint256 K;
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uint256 B;
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uint256 Q;
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uint256 baseTarget;
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uint256 quoteTarget;
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RStatus rStatus;
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}
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function querySellBaseToken(address dodo, uint256 amount) public view returns (uint256) {
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return IDODOV1(dodo).querySellBaseToken(amount);
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}
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function querySellQuoteToken(address dodo, uint256 amount) public view returns (uint256) {
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DODOState memory state;
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(state.baseTarget, state.quoteTarget) = IDODOV1(dodo).getExpectedTarget();
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state.rStatus = RStatus(IDODOV1(dodo)._R_STATUS_());
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state.oraclePrice = IDODOV1(dodo).getOraclePrice();
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state.Q = IDODOV1(dodo)._QUOTE_BALANCE_();
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state.B = IDODOV1(dodo)._BASE_BALANCE_();
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state.K = IDODOV1(dodo)._K_();
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uint256 boughtAmount;
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// Determine the status (RStatus) and calculate the amount
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// based on the state
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if (state.rStatus == RStatus.ONE) {
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boughtAmount = _ROneSellQuoteToken(amount, state);
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} else if (state.rStatus == RStatus.ABOVE_ONE) {
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boughtAmount = _RAboveSellQuoteToken(amount, state);
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} else {
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uint256 backOneBase = state.B.sub(state.baseTarget);
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uint256 backOneQuote = state.quoteTarget.sub(state.Q);
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if (amount <= backOneQuote) {
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boughtAmount = _RBelowSellQuoteToken(amount, state);
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} else {
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boughtAmount = backOneBase.add(
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_ROneSellQuoteToken(amount.sub(backOneQuote), state)
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);
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}
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}
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// Calculate fees
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return
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DecimalMath.divFloor(
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boughtAmount,
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DecimalMath.ONE.add(IDODOV1(dodo)._MT_FEE_RATE_()).add(
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IDODOV1(dodo)._LP_FEE_RATE_()
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)
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);
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}
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function _ROneSellQuoteToken(uint256 amount, DODOState memory state)
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internal
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pure
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returns (uint256 receiveBaseToken)
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{
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uint256 i = DecimalMath.divFloor(ONE, state.oraclePrice);
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uint256 B2 = DODOMath._SolveQuadraticFunctionForTrade(
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state.baseTarget,
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state.baseTarget,
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DecimalMath.mulFloor(i, amount),
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false,
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state.K
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);
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return state.baseTarget.sub(B2);
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}
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function _RAboveSellQuoteToken(uint256 amount, DODOState memory state)
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internal
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pure
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returns (uint256 receieBaseToken)
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{
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uint256 i = DecimalMath.divFloor(ONE, state.oraclePrice);
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uint256 B2 = DODOMath._SolveQuadraticFunctionForTrade(
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state.baseTarget,
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state.B,
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DecimalMath.mulFloor(i, amount),
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false,
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state.K
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);
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return state.B.sub(B2);
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}
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function _RBelowSellQuoteToken(uint256 amount, DODOState memory state)
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internal
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pure
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returns (uint256 receiveBaseToken)
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{
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uint256 Q1 = state.Q.add(amount);
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uint256 i = DecimalMath.divFloor(ONE, state.oraclePrice);
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return DODOMath._GeneralIntegrate(state.quoteTarget, Q1, state.Q, i, state.K);
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}
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}
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