Update for buys

packages/asset-swapper/contracts/src/BalancerSampler.sol

@@ -130,6 +130,29 @@ contract BalancerSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Balancer.
+    /// @param poolAddress Address of the Balancer pool to query.
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromBalancerGlobal(
+        address poolAddress,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromBalancer(
+            poolAddress,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Balancer.
     /// @param poolAddress Address of the Balancer pool to query.
     /// @param takerToken Address of the taker token (what to sell).
@@ -137,13 +160,13 @@ contract BalancerSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromBalancer(
+    function _sampleBuysFromBalancer(
         address poolAddress,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/BalancerV2Sampler.sol

@@ -135,6 +135,28 @@ contract BalancerV2Sampler is
         }
     }
 
+    /// @dev Sample buy quotes from Balancer V2.
+    /// @param poolInfo Struct with pool related data
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromBalancerV2Global(
+        BalancerV2PoolInfo memory poolInfo,
+        address takerToken,
+        address makerToken
+    )
+        public
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromBalancerV2(
+            poolInfo,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Balancer V2.
     /// @param poolInfo Struct with pool related data
     /// @param takerToken Address of the taker token (what to sell).
@@ -142,13 +164,13 @@ contract BalancerV2Sampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromBalancerV2(
+    function _sampleBuysFromBalancerV2(
         BalancerV2PoolInfo memory poolInfo,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal 
         returns (uint256[] memory takerTokenAmounts)
     {
         _assertValidPair(makerToken, takerToken);

packages/asset-swapper/contracts/src/BancorSampler.sol

@@ -112,21 +112,20 @@ contract BancorSampler is
     /// @param opts BancorSamplerOpts The Bancor registry contract address and paths
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
-    /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return bancorNetwork the Bancor Network address
     /// @return path the selected conversion path from bancor
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromBancor(
+    function sampleBuysFromBancorGlobal(
         BancorSamplerOpts memory opts,
         address takerToken,
-        address makerToken,
+        address makerToken
-        uint256[] memory makerTokenAmounts
     )
         public
         view
         returns (address bancorNetwork, address[] memory path, uint256[] memory takerTokenAmounts)
     {
+        takerTokenAmounts = new uint256[](SAMPLE_VALUES.length);
     }
 
     function _findBestPath(

packages/asset-swapper/contracts/src/CompoundSampler.sol

@@ -86,13 +86,30 @@ contract CompoundSampler is
         }
     }
 
-    function sampleBuysFromCompound(
+    function sampleBuysFromCompoundGlobal(
+        ICToken cToken,
+        IERC20TokenV06 takerToken,
+        IERC20TokenV06 makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromCompound(
+            cToken,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
+    function _sampleBuysFromCompound(
         ICToken cToken,
         IERC20TokenV06 takerToken,
         IERC20TokenV06 makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/CurveSampler.sol

@@ -105,6 +105,29 @@ contract CurveSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Curve.
+    /// @param curveInfo Curve information specific to this token pair.
+    /// @param fromTokenIdx Index of the taker token (what to sell).
+    /// @param toTokenIdx Index of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromCurveGlobal(
+        CurveInfo memory curveInfo,
+        int128 fromTokenIdx,
+        int128 toTokenIdx
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromCurve(
+            curveInfo,
+            fromTokenIdx,
+            toTokenIdx,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Curve.
     /// @param curveInfo Curve information specific to this token pair.
     /// @param fromTokenIdx Index of the taker token (what to sell).
@@ -112,13 +135,13 @@ contract CurveSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromCurve(
+    function _sampleBuysFromCurve(
         CurveInfo memory curveInfo,
         int128 fromTokenIdx,
         int128 toTokenIdx,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/DODOSampler.sol

@@ -134,6 +134,31 @@ contract DODOSampler is
         }
     }
 
+    /// @dev Sample buy quotes from DODO.
+    /// @param opts DODOSamplerOpts DODO Registry and helper addresses
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return sellBase whether the bridge needs to sell the base token
+    /// @return pool the DODO pool address
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromDODOGlobal(
+        DODOSamplerOpts memory opts,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
+    {
+        (sellBase, pool, takerTokenAmounts) = _sampleBuysFromDODO(
+            opts,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from DODO.
     /// @param opts DODOSamplerOpts DODO Registry and helper addresses
     /// @param takerToken Address of the taker token (what to sell).
@@ -143,13 +168,13 @@ contract DODOSampler is
     /// @return pool the DODO pool address
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromDODO(
+    function _sampleBuysFromDODO(
         DODOSamplerOpts memory opts,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/DODOV2Sampler.sol

@@ -125,6 +125,34 @@ contract DODOV2Sampler is
         }
     }
 
+    /// @dev Sample buy quotes from DODO.
+    /// @param registry Address of the registry to look up.
+    /// @param offset offset index for the pool in the registry.
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return sellBase whether the bridge needs to sell the base token
+    /// @return pool the DODO pool address
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromDODOV2Global(
+        address registry,
+        uint256 offset,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
+    {
+        (sellBase, pool, takerTokenAmounts) = _sampleBuysFromDODOV2(
+            registry,
+            offset,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from DODO.
     /// @param registry Address of the registry to look up.
     /// @param offset offset index for the pool in the registry.
@@ -135,14 +163,14 @@ contract DODOV2Sampler is
     /// @return pool the DODO pool address
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromDODOV2(
+    function _sampleBuysFromDODOV2(
         address registry,
         uint256 offset,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/KyberDmmSampler.sol

@@ -122,6 +122,27 @@ contract KyberDmmSampler is
         }
     }
 
+    /// @dev Sample buy quotes from KyberDmm.
+    /// @param router Router to look up tokens and amounts
+    /// @param path Token route. Should be takerToken -> makerToken.
+    /// @return pools The pool addresses involved in the multi path trade
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromKyberDmmGlobal(
+        address router,
+        address[] memory path
+    )
+        public
+        view
+        returns (address[] memory pools, uint256[] memory takerTokenAmounts)
+    {
+        (pools, takerTokenAmounts) = _sampleBuysFromKyberDmm(
+            router,
+            path,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from KyberDmm.
     /// @param router Router to look up tokens and amounts
     /// @param path Token route. Should be takerToken -> makerToken.
@@ -129,12 +150,12 @@ contract KyberDmmSampler is
     /// @return pools The pool addresses involved in the multi path trade
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromKyberDmm(
+    function _sampleBuysFromKyberDmm(
         address router,
         address[] memory path,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (address[] memory pools, uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/KyberSampler.sol

@@ -111,6 +111,30 @@ contract KyberSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Kyber.
+    /// @param opts KyberSamplerOpts The nth reserve
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return reserveId The id of the reserve found at reserveOffset
+    /// @return hint The hint for the selected reserve
+    /// @return takerTokenAmounts Taker amounts sold at each maker token amount.
+    function sampleBuysFromKyberNetworkGlobal(
+        KyberSamplerOpts memory opts,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (bytes32 reserveId, bytes memory hint, uint256[] memory takerTokenAmounts)
+    {
+        (reserveId, hint, takerTokenAmounts) = _sampleBuysFromKyberNetwork(
+            opts,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Kyber.
     /// @param opts KyberSamplerOpts The nth reserve
     /// @param takerToken Address of the taker token (what to sell).
@@ -119,13 +143,13 @@ contract KyberSampler is
     /// @return reserveId The id of the reserve found at reserveOffset
     /// @return hint The hint for the selected reserve
     /// @return takerTokenAmounts Taker amounts sold at each maker token amount.
-    function sampleBuysFromKyberNetwork(
+    function _sampleBuysFromKyberNetwork(
         KyberSamplerOpts memory opts,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (bytes32 reserveId, bytes memory hint, uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/LidoSampler.sol

@@ -85,6 +85,29 @@ contract LidoSampler is
         return takerTokenAmounts;
     }
 
+    /// @dev Sample buy quotes from Lido.
+    /// @param lidoInfo Info regarding a specific Lido deployment
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromLidoGlobal(
+        LidoInfo memory lidoInfo,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromLido(
+            lidoInfo,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Lido.
     /// @param lidoInfo Info regarding a specific Lido deployment
     /// @param takerToken Address of the taker token (what to sell).
@@ -92,13 +115,13 @@ contract LidoSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromLido(
+    function _sampleBuysFromLido(
         LidoInfo memory lidoInfo,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         pure
         returns (uint256[] memory)
     {

packages/asset-swapper/contracts/src/LiquidityProviderSampler.sol

@@ -102,6 +102,29 @@ contract LiquidityProviderSampler is
         }
     }
 
+    /// @dev Sample buy quotes from an arbitrary on-chain liquidity provider.
+    /// @param providerAddress Address of the liquidity provider.
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromLiquidityProviderGlobal(
+        address providerAddress,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        (takerTokenAmounts) = _sampleBuysFromLiquidityProvider(
+            providerAddress,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from an arbitrary on-chain liquidity provider.
     /// @param providerAddress Address of the liquidity provider.
     /// @param takerToken Address of the taker token (what to sell).
@@ -109,13 +132,13 @@ contract LiquidityProviderSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromLiquidityProvider(
+    function _sampleBuysFromLiquidityProvider(
         address providerAddress,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/MStableSampler.sol

@@ -97,6 +97,29 @@ contract MStableSampler is
         }
     }
 
+    /// @dev Sample buy quotes from MStable contract
+    /// @param router Address of the mStable contract
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromMStableGlobal(
+        address router,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        (takerTokenAmounts) = _sampleBuysFromMStable(
+            router,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from MStable contract
     /// @param router Address of the mStable contract
     /// @param takerToken Address of the taker token (what to sell).
@@ -104,13 +127,13 @@ contract MStableSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromMStable(
+    function _sampleBuysFromMStable(
         address router,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/MakerPSMSampler.sol

@@ -157,13 +157,30 @@ contract MakerPSMSampler is
         }
     }
 
-    function sampleBuysFromMakerPsm(
+    function sampleBuysFromMakerPsmGlobal(
+        MakerPsmInfo memory psmInfo,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        (takerTokenAmounts) = _sampleBuysFromMakerPsm(
+            psmInfo,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
+    function _sampleBuysFromMakerPsm(
         MakerPsmInfo memory psmInfo,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/MooniswapSampler.sol

@@ -138,6 +138,30 @@ contract MooniswapSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Mooniswap.
+    /// @param registry Address of the Mooniswap Registry.
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return pool The contract address for the pool
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromMooniswapGlobal(
+        address registry,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (IMooniswap pool, uint256[] memory takerTokenAmounts)
+    {
+        (pool, takerTokenAmounts) = _sampleBuysFromMooniswap(
+            registry,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Mooniswap.
     /// @param registry Address of the Mooniswap Registry.
     /// @param takerToken Address of the taker token (what to sell).
@@ -146,13 +170,13 @@ contract MooniswapSampler is
     /// @return pool The contract address for the pool
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromMooniswap(
+    function _sampleBuysFromMooniswap(
         address registry,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (IMooniswap pool, uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/ShellSampler.sol

@@ -98,6 +98,29 @@ contract ShellSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Shell pool contract
+    /// @param pool Address of the Shell pool contract
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromShellGlobal(
+        address pool,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromShell(
+            pool,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Shell pool contract
     /// @param pool Address of the Shell pool contract
     /// @param takerToken Address of the taker token (what to sell).
@@ -105,13 +128,13 @@ contract ShellSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromShell(
+    function _sampleBuysFromShell(
         address pool,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/SmoothySampler.sol

@@ -123,6 +123,29 @@ contract SmoothySampler is
         }
     }
 
+    /// @dev Sample buy quotes from Smoothy.
+    /// @param smoothyInfo Smoothy information specific to this token pair.
+    /// @param fromTokenIdx Index of the taker token (what to sell).
+    /// @param toTokenIdx Index of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromSmoothyGlobal(
+        SmoothyInfo memory smoothyInfo,
+        int128 fromTokenIdx,
+        int128 toTokenIdx
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromSmoothy(
+            smoothyInfo,
+            fromTokenIdx,
+            toTokenIdx,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Smoothy.
     /// @param smoothyInfo Smoothy information specific to this token pair.
     /// @param fromTokenIdx Index of the taker token (what to sell).
@@ -130,13 +153,13 @@ contract SmoothySampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromSmoothy(
+    function _sampleBuysFromSmoothy(
         SmoothyInfo memory smoothyInfo,
         int128 fromTokenIdx,
         int128 toTokenIdx,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/TwoHopSampler.sol

@@ -86,7 +86,8 @@ contract TwoHopSampler is
         bytes[] memory firstHopCalls,
         bytes[] memory secondHopCalls,
         uint256 buyAmount
-    )
+    ) 
+        resetsSampleValues()
         public
         returns (
             HopInfo memory firstHop,
@@ -96,8 +97,11 @@ contract TwoHopSampler is
     {
         sellAmount = uint256(-1);
         uint256 intermediateAssetAmount = uint256(-1);
+        uint256[] memory tmpSampleValues = new uint256[](1);
         for (uint256 j = 0; j != secondHopCalls.length; ++j) {
-            secondHopCalls[j].writeUint256(secondHopCalls[j].length - 32, buyAmount);
+            // Set the temporary global sample values
+            tmpSampleValues[0] = buyAmount;
+            SAMPLE_VALUES = tmpSampleValues;
             (bool didSucceed, bytes memory returnData) = address(this).call(secondHopCalls[j]);
             if (didSucceed) {
                 uint256 amount = returnData.readUint256(returnData.length - 32);
@@ -115,7 +119,9 @@ contract TwoHopSampler is
             return (firstHop, secondHop, sellAmount);
         }
         for (uint256 i = 0; i != firstHopCalls.length; ++i) {
-            firstHopCalls[i].writeUint256(firstHopCalls[i].length - 32, intermediateAssetAmount);
+            // Set the temporary global sample values
+            tmpSampleValues[0] = intermediateAssetAmount;
+            SAMPLE_VALUES = tmpSampleValues;
             (bool didSucceed, bytes memory returnData) = address(this).call(firstHopCalls[i]);
             if (didSucceed) {
                 uint256 amount = returnData.readUint256(returnData.length - 32);

packages/asset-swapper/contracts/src/UniswapSampler.sol

@@ -128,19 +128,41 @@ contract UniswapSampler is
         }
     }
 
+    /// @dev Sample buy quotes from Uniswap.
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromUniswapGlobal(
+        address router,
+        address takerToken,
+        address makerToken
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromUniswap(
+            router,
+            takerToken,
+            makerToken,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from Uniswap.
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token sell amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromUniswap(
+    function _sampleBuysFromUniswap(
         address router,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/UniswapV2Sampler.sol

@@ -86,18 +86,38 @@ contract UniswapV2Sampler is
         }
     }
 
+    /// @dev Sample buy quotes from UniswapV2.
+    /// @param router Router to look up tokens and amounts
+    /// @param path Token route. Should be takerToken -> makerToken.
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromUniswapV2Global(
+        address router,
+        address[] memory path
+    )
+        public
+        view
+        returns (uint256[] memory takerTokenAmounts)
+    {
+        takerTokenAmounts = _sampleBuysFromUniswapV2(
+            router,
+            path,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from UniswapV2.
     /// @param router Router to look up tokens and amounts
     /// @param path Token route. Should be takerToken -> makerToken.
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromUniswapV2(
+    function _sampleBuysFromUniswapV2(
         address router,
         address[] memory path,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         view
         returns (uint256[] memory takerTokenAmounts)
     {

packages/asset-swapper/contracts/src/UniswapV3Sampler.sol

@@ -128,6 +128,29 @@ contract UniswapV3Sampler is
         }
     }
 
+    /// @dev Sample buy quotes from UniswapV3.
+    /// @param quoter UniswapV3 Quoter contract.
+    /// @param path Token route. Should be takerToken -> makerToken.
+    /// @return uniswapPaths The encoded uniswap path for each sample.
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromUniswapV3Global(
+        IUniswapV3Quoter quoter,
+        IERC20TokenV06[] memory path
+    )
+        public
+        returns (
+            bytes[] memory uniswapPaths,
+            uint256[] memory takerTokenAmounts
+        )
+    {
+        (uniswapPaths, takerTokenAmounts) = _sampleBuysFromUniswapV3(
+            quoter,
+            path,
+            SAMPLE_VALUES
+        );
+    }
+
     /// @dev Sample buy quotes from UniswapV3.
     /// @param quoter UniswapV3 Quoter contract.
     /// @param path Token route. Should be takerToken -> makerToken.
@@ -135,12 +158,12 @@ contract UniswapV3Sampler is
     /// @return uniswapPaths The encoded uniswap path for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
-    function sampleBuysFromUniswapV3(
+    function _sampleBuysFromUniswapV3(
         IUniswapV3Quoter quoter,
         IERC20TokenV06[] memory path,
         uint256[] memory makerTokenAmounts
     )
-        public
+        internal
         returns (
             bytes[] memory uniswapPaths,
             uint256[] memory takerTokenAmounts

packages/asset-swapper/src/utils/market_operation_utils/sampler_operations.ts

@@ -286,17 +286,17 @@ export class SamplerOperations {
         reserveOffset: BigNumber,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Kyber,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromKyberNetwork,
+            function: this._samplerContract.sampleBuysFromKyberNetworkGlobal,
-            params: [{ ...kyberOpts, reserveOffset, hint: NULL_BYTES }, takerToken, makerToken, makerFillAmounts],
+            params: [{ ...kyberOpts, reserveOffset, hint: NULL_BYTES }, takerToken, makerToken],
             callback: (callResults: string, fillData: KyberFillData): BigNumber[] => {
                 const [reserveId, hint, samples] = this._samplerContract.getABIDecodedReturnData<
                     [string, string, BigNumber[]]
-                >('sampleBuysFromKyberNetwork', callResults);
+                >('sampleBuysFromKyberNetworkGlobal', callResults);
                 fillData.hint = hint;
                 fillData.reserveId = reserveId;
                 fillData.networkProxy = kyberOpts.networkProxy;
@@ -331,16 +331,16 @@ export class SamplerOperations {
     public getKyberDmmBuyQuotes(
         router: string,
         tokenAddressPath: string[],
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<KyberDmmFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.KyberDmm,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromKyberDmm,
+            function: this._samplerContract.sampleBuysFromKyberDmmGlobal,
-            params: [router, tokenAddressPath, makerFillAmounts],
+            params: [router, tokenAddressPath],
             callback: (callResults: string, fillData: KyberDmmFillData): BigNumber[] => {
                 const [pools, samples] = this._samplerContract.getABIDecodedReturnData<[string[], BigNumber[]]>(
-                    'sampleBuysFromKyberDmm',
+                    'sampleBuysFromKyberDmmGlobal',
                     callResults,
                 );
                 fillData.poolsPath = pools;
@@ -373,7 +373,7 @@ export class SamplerOperations {
         router: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<GenericRouterFillData> {
         // Uniswap uses ETH instead of WETH, represented by address(0)
         const uniswapTakerToken = takerToken === NATIVE_FEE_TOKEN_BY_CHAIN_ID[this.chainId] ? NULL_ADDRESS : takerToken;
@@ -382,8 +382,8 @@ export class SamplerOperations {
             source: ERC20BridgeSource.Uniswap,
             fillData: { router },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromUniswap,
+            function: this._samplerContract.sampleBuysFromUniswapGlobal,
-            params: [router, uniswapTakerToken, uniswapMakerToken, makerFillAmounts],
+            params: [router, uniswapTakerToken, uniswapMakerToken],
         });
     }
 
@@ -405,15 +405,15 @@ export class SamplerOperations {
     public getUniswapV2BuyQuotes(
         router: string,
         tokenAddressPath: string[],
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         source: ERC20BridgeSource = ERC20BridgeSource.UniswapV2,
     ): SourceQuoteOperation<UniswapV2FillData> {
         return new SamplerContractOperation({
             source,
             fillData: { tokenAddressPath, router },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromUniswapV2,
+            function: this._samplerContract.sampleBuysFromUniswapV2Global,
-            params: [router, tokenAddressPath, makerFillAmounts],
+            params: [router, tokenAddressPath],
         });
     }
 
@@ -441,7 +441,7 @@ export class SamplerOperations {
         providerAddress: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         gasCost: number,
         source: ERC20BridgeSource = ERC20BridgeSource.LiquidityProvider,
     ): SourceQuoteOperation<LiquidityProviderFillData> {
@@ -452,8 +452,8 @@ export class SamplerOperations {
                 gasCost,
             },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromLiquidityProvider,
+            function: this._samplerContract.sampleBuysFromLiquidityProviderGlobal,
-            params: [providerAddress, takerToken, makerToken, makerFillAmounts],
+            params: [providerAddress, takerToken, makerToken],
         });
     }
 
@@ -489,7 +489,7 @@ export class SamplerOperations {
         pool: CurveInfo,
         fromTokenIdx: number,
         toTokenIdx: number,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         source: ERC20BridgeSource = ERC20BridgeSource.Curve,
     ): SourceQuoteOperation<CurveFillData> {
         return new SamplerContractOperation({
@@ -500,7 +500,7 @@ export class SamplerOperations {
                 toTokenIdx,
             },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromCurve,
+            function: this._samplerContract.sampleBuysFromCurveGlobal,
             params: [
                 {
                     poolAddress: pool.poolAddress,
@@ -509,7 +509,6 @@ export class SamplerOperations {
                 },
                 new BigNumber(fromTokenIdx),
                 new BigNumber(toTokenIdx),
-                makerFillAmounts,
             ],
         });
     }
@@ -545,7 +544,7 @@ export class SamplerOperations {
         pool: CurveInfo,
         fromTokenIdx: number,
         toTokenIdx: number,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<CurveFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Smoothy,
@@ -555,7 +554,7 @@ export class SamplerOperations {
                 toTokenIdx,
             },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromSmoothy,
+            function: this._samplerContract.sampleBuysFromSmoothyGlobal,
             params: [
                 {
                     poolAddress: pool.poolAddress,
@@ -564,7 +563,6 @@ export class SamplerOperations {
                 },
                 new BigNumber(fromTokenIdx),
                 new BigNumber(toTokenIdx),
-                makerFillAmounts,
             ],
         });
     }
@@ -589,15 +587,15 @@ export class SamplerOperations {
         poolInfo: BalancerV2PoolInfo,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         source: ERC20BridgeSource,
     ): SourceQuoteOperation<BalancerV2FillData> {
         return new SamplerContractOperation({
             source,
             fillData: poolInfo,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromBalancerV2,
+            function: this._samplerContract.sampleBuysFromBalancerV2Global,
-            params: [poolInfo, takerToken, makerToken, makerFillAmounts],
+            params: [poolInfo, takerToken, makerToken],
         });
     }
 
@@ -621,15 +619,15 @@ export class SamplerOperations {
         poolAddress: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         source: ERC20BridgeSource,
     ): SourceQuoteOperation<BalancerFillData> {
         return new SamplerContractOperation({
             source,
             fillData: { poolAddress },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromBalancer,
+            function: this._samplerContract.sampleBuysFromBalancerGlobal,
-            params: [poolAddress, takerToken, makerToken, makerFillAmounts],
+            params: [poolAddress, takerToken, makerToken],
         });
     }
 
@@ -652,14 +650,14 @@ export class SamplerOperations {
         router: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<GenericRouterFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.MStable,
             fillData: { router },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromMStable,
+            function: this._samplerContract.sampleBuysFromMStableGlobal,
-            params: [router, takerToken, makerToken, makerFillAmounts],
+            params: [router, takerToken, makerToken],
         });
     }
 
@@ -691,17 +689,17 @@ export class SamplerOperations {
         registry: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<BancorFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Bancor,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromBancor,
+            function: this._samplerContract.sampleBuysFromBancorGlobal,
-            params: [{ registry, paths: [] }, takerToken, makerToken, makerFillAmounts],
+            params: [{ registry, paths: [] }, takerToken, makerToken],
             callback: (callResults: string, fillData: BancorFillData): BigNumber[] => {
                 const [networkAddress, path, samples] = this._samplerContract.getABIDecodedReturnData<
                     [string, string[], BigNumber[]]
-                >('sampleBuysFromBancor', callResults);
+                >('sampleBuysFromBancorGlobal', callResults);
                 fillData.networkAddress = networkAddress;
                 fillData.path = path;
                 return samples;
@@ -740,7 +738,7 @@ export class SamplerOperations {
         registry: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<MooniswapFillData> {
         // Mooniswap uses ETH instead of WETH, represented by address(0)
         const mooniswapTakerToken =
@@ -750,11 +748,11 @@ export class SamplerOperations {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Mooniswap,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromMooniswap,
+            function: this._samplerContract.sampleBuysFromMooniswapGlobal,
-            params: [registry, mooniswapTakerToken, mooniswapMakerToken, makerFillAmounts],
+            params: [registry, mooniswapTakerToken, mooniswapMakerToken],
             callback: (callResults: string, fillData: MooniswapFillData): BigNumber[] => {
                 const [poolAddress, samples] = this._samplerContract.getABIDecodedReturnData<[string, BigNumber[]]>(
-                    'sampleBuysFromMooniswap',
+                    'sampleBuysFromMooniswapGlobal',
                     callResults,
                 );
                 fillData.poolAddress = poolAddress;
@@ -801,11 +799,11 @@ export class SamplerOperations {
         return new SamplerContractOperation({
             source,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromUniswapV3,
+            function: this._samplerContract.sampleBuysFromUniswapV3Global,
-            params: [quoter, tokenAddressPath, makerFillAmounts],
+            params: [quoter, tokenAddressPath],
             callback: (callResults: string, fillData: UniswapV3FillData): BigNumber[] => {
                 const [paths, samples] = this._samplerContract.getABIDecodedReturnData<[string[], BigNumber[]]>(
-                    'sampleBuysFromUniswapV3',
+                    'sampleBuysFromUniswapV3Global',
                     callResults,
                 );
                 fillData.router = router;
@@ -952,15 +950,15 @@ export class SamplerOperations {
         poolAddress: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
         source: ERC20BridgeSource = ERC20BridgeSource.Shell,
     ): SourceQuoteOperation {
         return new SamplerContractOperation({
             source,
             fillData: { poolAddress },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromShell,
+            function: this._samplerContract.sampleBuysFromShellGlobal,
-            params: [poolAddress, takerToken, makerToken, makerFillAmounts],
+            params: [poolAddress, takerToken, makerToken],
         });
     }
 
@@ -978,7 +976,7 @@ export class SamplerOperations {
             callback: (callResults: string, fillData: DODOFillData): BigNumber[] => {
                 const [isSellBase, pool, samples] = this._samplerContract.getABIDecodedReturnData<
                     [boolean, string, BigNumber[]]
-                >('sampleSellsFromDODO', callResults);
+                >('sampleSellsFromDODOGlobal', callResults);
                 fillData.isSellBase = isSellBase;
                 fillData.poolAddress = pool;
                 fillData.helperAddress = opts.helper;
@@ -991,17 +989,17 @@ export class SamplerOperations {
         opts: { registry: string; helper: string },
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<DODOFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Dodo,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromDODO,
+            function: this._samplerContract.sampleBuysFromDODOGlobal,
-            params: [opts, takerToken, makerToken, makerFillAmounts],
+            params: [opts, takerToken, makerToken],
             callback: (callResults: string, fillData: DODOFillData): BigNumber[] => {
                 const [isSellBase, pool, samples] = this._samplerContract.getABIDecodedReturnData<
                     [boolean, string, BigNumber[]]
-                >('sampleBuysFromDODO', callResults);
+                >('sampleBuysFromDODOGlobal', callResults);
                 fillData.isSellBase = isSellBase;
                 fillData.poolAddress = pool;
                 fillData.helperAddress = opts.helper;
@@ -1038,17 +1036,17 @@ export class SamplerOperations {
         offset: BigNumber,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<DODOFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.DodoV2,
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromDODOV2,
+            function: this._samplerContract.sampleBuysFromDODOV2Global,
-            params: [registry, offset, takerToken, makerToken, makerFillAmounts],
+            params: [registry, offset, takerToken, makerToken],
             callback: (callResults: string, fillData: DODOFillData): BigNumber[] => {
                 const [isSellBase, pool, samples] = this._samplerContract.getABIDecodedReturnData<
                     [boolean, string, BigNumber[]]
-                >('sampleSellsFromDODOV2', callResults);
+                >('sampleSellsFromDODOV2Global', callResults);
                 fillData.isSellBase = isSellBase;
                 fillData.poolAddress = pool;
                 return samples;
@@ -1080,7 +1078,7 @@ export class SamplerOperations {
         psmInfo: PsmInfo,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<MakerPsmFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.MakerPsm,
@@ -1091,8 +1089,8 @@ export class SamplerOperations {
                 ...psmInfo,
             },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromMakerPsm,
+            function: this._samplerContract.sampleBuysFromMakerPsmGlobal,
-            params: [psmInfo, takerToken, makerToken, makerFillAmounts],
+            params: [psmInfo, takerToken, makerToken],
         });
     }
 
@@ -1118,7 +1116,7 @@ export class SamplerOperations {
         lidoInfo: LidoInfo,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<LidoFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Lido,
@@ -1127,8 +1125,8 @@ export class SamplerOperations {
                 stEthTokenAddress: lidoInfo.stEthToken,
             },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromLido,
+            function: this._samplerContract.sampleBuysFromLidoGlobal,
-            params: [lidoInfo, takerToken, makerToken, makerFillAmounts],
+            params: [lidoInfo, takerToken, makerToken],
         });
     }
 
@@ -1179,14 +1177,14 @@ export class SamplerOperations {
         cToken: string,
         makerToken: string,
         takerToken: string,
-        makerFillAmounts: BigNumber[],
+        _makerFillAmounts: BigNumber[],
     ): SourceQuoteOperation<CompoundFillData> {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Compound,
             fillData: { cToken, takerToken, makerToken },
             contract: this._samplerContract,
-            function: this._samplerContract.sampleBuysFromCompound,
+            function: this._samplerContract.sampleBuysFromCompoundGlobal,
-            params: [cToken, takerToken, makerToken, makerFillAmounts],
+            params: [cToken, takerToken, makerToken],
         });
     }