Add scalingFactor to Buffers (wip)

balancer · Jan 20, 2025 · 28eb39b · 28eb39b
1 parent 0b0f96b
commit 28eb39b
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Showing 3 changed files with 36 additions and 8 deletions.
diff --git a/typescript/src/buffer/bufferMath.ts b/typescript/src/buffer/bufferMath.ts
@@ -18,24 +18,45 @@ export function calculateBufferAmounts(
     kind: SwapKind,
     amountRaw: bigint,
     rate: bigint,
+    scalingFactor: bigint,
 ): bigint {
     if (direction === WrappingDirection.WRAP) {
         // Amount in is underlying tokens, amount out is wrapped tokens
         if (kind === SwapKind.GivenIn) {
             // previewDeposit
-            return _convertToShares(amountRaw, rate, Rounding.DOWN);
+            return _convertToShares(
+                amountRaw,
+                rate,
+                scalingFactor,
+                Rounding.DOWN,
+            );
         } else {
             // previewMint
-            return _convertToAssets(amountRaw, rate, Rounding.UP);
+            return _convertToAssets(
+                amountRaw,
+                rate,
+                scalingFactor,
+                Rounding.UP,
+            );
         }
     } else {
         // Amount in is wrapped tokens, amount out is underlying tokens
         if (kind === SwapKind.GivenIn) {
             // previewRedeem
-            return _convertToAssets(amountRaw, rate, Rounding.DOWN);
+            return _convertToAssets(
+                amountRaw,
+                rate,
+                scalingFactor,
+                Rounding.DOWN,
+            );
         } else {
             // previewWithdraw
-            return _convertToShares(amountRaw, rate, Rounding.UP);
+            return _convertToShares(
+                amountRaw,
+                rate,
+                scalingFactor,
+                Rounding.UP,
+            );
         }
     }
 }
@@ -44,17 +65,22 @@ export function calculateBufferAmounts(
 function _convertToShares(
     assets: bigint,
     rate: bigint,
+    scalingFactor: bigint,
     rounding: Rounding,
 ): bigint {
-    if (rounding === Rounding.UP) return MathSol.divUpFixed(assets, rate);
-    return MathSol.divDownFixed(assets, rate);
+    const assetsScale18 = assets * scalingFactor;
+    if (rounding === Rounding.UP)
+        return MathSol.divUpFixed(assetsScale18, rate);
+    return MathSol.divDownFixed(assetsScale18, rate);
 }
 
 function _convertToAssets(
     shares: bigint,
     rate: bigint,
+    scalingFactor: bigint,
     rounding: Rounding,
 ): bigint {
-    if (rounding === Rounding.UP) return MathSol.mulUpFixed(shares, rate);
-    return MathSol.mulDownFixed(shares, rate);
+    const sharesRaw = shares / scalingFactor; // TODO: think a bit about rounding direction
+    if (rounding === Rounding.UP) return MathSol.mulUpFixed(sharesRaw, rate);
+    return MathSol.mulDownFixed(sharesRaw, rate);
 }
diff --git a/typescript/src/buffer/data.ts b/typescript/src/buffer/data.ts
@@ -7,6 +7,7 @@ export type BufferMutable = {
 export type BufferImmutable = {
     poolAddress: string;
     tokens: string[];
+    scalingFactor: bigint; // between wrapped/underlying
 };
 
 /**

diff --git a/typescript/src/buffer/erc4626BufferWrapOrUnwrap.ts b/typescript/src/buffer/erc4626BufferWrapOrUnwrap.ts
@@ -28,5 +28,6 @@ export function erc4626BufferWrapOrUnwrap(
         input.swapKind,
         input.amountRaw,
         poolState.rate,
+        poolState.scalingFactor,
     );
 }