> For the complete documentation index, see [llms.txt](https://defivaults.gitbook.io/amphor/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://defivaults.gitbook.io/amphor/technical/v1/syncsynthvault.md).

# SyncSynthVault

## Solidity version

```solidity
0.8.21
```

***

## Inheritance

* `Ownable2StepUpgradeable` of [OpenZeppelin](https://github.com/OpenZeppelin/openzeppelin-contracts).
* `ERC20PermitUpgradeable` of [OpenZeppelin](https://github.com/OpenZeppelin/openzeppelin-contracts).
* `ERC20PausableUpgradeable` of [OpenZeppelin](https://github.com/OpenZeppelin/openzeppelin-contracts).
* `IERC4626` of [OpenZeppelin](https://github.com/OpenZeppelin/openzeppelin-contracts).

***

## Global Variables

### PermitParams

```solidity
struct PermitParams {
    uint256 value;
    uint256 deadline;
    uint8 v;
    bytes32 r;
    bytes32 s;
}
```

### BPS\_DIVIDER

```solidity
uint256 constant BPS_DIVIDER = 10_000;
```

### MAX\_FEES

```solidity
uint16 constant MAX_FEES = 3000; // 30%
```

## State Variables

### feesInBps

```solidity
uint16 public feesInBps;
```

<table><thead><tr><th width="118.33333333333331">Type</th><th width="196">Scope</th><th>Description</th></tr></thead><tbody><tr><td><code>uint16</code></td><td><code>public</code></td><td>Performance fees are applied on the absolute returns of the underlying strategy.</td></tr></tbody></table>

### vaultIsOpen

```solidity
bool public vaultIsOpen; // vault is open or closed
```

<table><thead><tr><th width="130.33333333333331">Type</th><th width="105">Scope</th><th>Description</th></tr></thead><tbody><tr><td><code>bool</code></td><td><code>public</code></td><td>The locking status of the vault.</td></tr></tbody></table>

## lastSavedBalance

```solidity
uint256 public lastSavedBalance; // last saved balance
```

<table><thead><tr><th width="118.33333333333331">Type</th><th width="196">Scope</th><th>Description</th></tr></thead><tbody><tr><td><code>uint16</code></td><td><code>public</code></td><td>Performance fees are applied on the absolute returns of the underlying strategy.</td></tr></tbody></table>

***

## Events

### EpochStart

```solidity
event EpochStart(
    uint256 indexed timestamp,
    uint256 lastSavedBalance,
    uint256 totalShares
)
```

Emitted when an epoch starts.

<table><thead><tr><th width="210.33333333333331">Name</th><th width="186">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>timestamp</code></td><td><code>uint256 indexed</code></td><td>The block timestamp of the epoch starts.</td></tr><tr><td><code>lastSavedBalance</code></td><td><code>uint256</code></td><td>The <code>lastSavedBalance</code> when the vault starts.</td></tr><tr><td><code>totalShares</code></td><td><code>uint256</code></td><td>The total number of shares when the vault starts.</td></tr></tbody></table>

### EpochEnd

```solidity
event EpochEnd(
    uint256 indexed timestamp,
    uint256 lastSavedBalance,
    uint256 returnedAssets,
    uint256 fees,
    uint256 totalShares
)
```

Emitted when an epoch ends.

<table><thead><tr><th width="210.33333333333331">Name</th><th width="186">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>timestamp</code></td><td><code>uint256 indexed</code></td><td>The block timestamp of the epoch terminates.</td></tr><tr><td><code>lastSavedBalance</code></td><td><code>uint256</code></td><td>The <code>lastSavedBalance</code> from the current epoch starts.</td></tr><tr><td><code>returnedAssets</code></td><td><code>uint256</code></td><td>The total amount of underlying assets returned to the vault before collecting fees.</td></tr><tr><td><code>fees</code></td><td><code>uint256</code></td><td>The amount of fees collected.</td></tr><tr><td><code>totalShares</code></td><td><code>uint256</code></td><td>The total amount of shares when the vault terminates.</td></tr></tbody></table>

### FeesChanged

```solidity
event FeesChanged(uint16 oldFees, uint16 newFees)
```

Emitted when fees are changed.

<table><thead><tr><th width="191.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>oldFees</code></td><td><code>uint16</code></td><td>The previous performance fees (in bps).</td></tr><tr><td><code>newFees</code></td><td><code>uint16</code></td><td>The newly applied performance fees (in bps).</td></tr><tr><td><code>returnedAssets</code></td><td><code>uint256</code></td><td>The total amount of underlying assets returned to the vault before collecting fees.</td></tr></tbody></table>

***

## Errors

### VaultIsClosed

```solidity
error VaultIsClosed();
```

The vault is in a locked state. Emitted if the transaction cannot happen in this state.

### VaultIsOpen

```solidity
error VaultIsOpen()
```

The vault is in an open state. Emitted if the transaction cannot happen in this state.

### CannotClaimAsset

```solidity
error CannotClaimAsset()
```

Claiming the underlying assets is not allowed.

### ERC4626ExceededMaxDeposit

```solidity
error ERC4626ExceededMaxDeposit(
    address receiver,
    uint256 assets,
    uint256 max
)
```

Attempt to deposit more underlying assets than the maximum allowed amount for `receiver`.

<table><thead><tr><th width="134.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>receiver</code>.</td></tr><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets asked for deposit.</td></tr><tr><td><code>max</code></td><td><code>uint256</code></td><td>Number of shares  (LP tokens) received in exchange for the specified amount of underlying assets.</td></tr></tbody></table>

### ERC4626ExceededMaxMint

```solidity
error ERC4626ExceededMaxMint(address receiver, uint256 shares, uint256 max)
```

Attempt to mint more shares (LP tokens) than the maximum allowed amount for `receiver`.

<table><thead><tr><th width="117.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The amount of underlying assets asked to mint shares (LP tokens).</td></tr><tr><td><code>max</code></td><td><code>uint256</code></td><td>The maximum number of withdrawable shares (LP tokens).</td></tr></tbody></table>

### ERC4626ExceededMaxWithdraw

```solidity
error ERC4626ExceededMaxWithdraw(
    address owner,
    uint256 assets,
    uint256 max
)
```

Attempt to withdraw more underlying assets than the maximum allowed amount for `receiver`.

<table><thead><tr><th width="117.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The number of underlying assets asked for withdrawal.</td></tr><tr><td><code>max</code></td><td><code>uint256</code></td><td>The maximum amount of withdrawable underlying assets.</td></tr></tbody></table>

### ERC4626ExceededMaxRedeem

```solidity
 error ERC4626ExceededMaxRedeem(address owner, uint256 shares, uint256 max)
```

Attempt to redeem more shares(LP tokens) than the maximum allowed amount for `receiver`.

<table><thead><tr><th width="114.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The number of shares (LP tokens) asked to be redeemed.</td></tr><tr><td><code>max</code></td><td><code>uint256</code></td><td>The maximum number of redeemable shares (LP tokens).</td></tr></tbody></table>

***

## Functions

### asset

```solidity
function asset() public view returns (address)
```

The `asset` function is used to return the `address` of the underlying asset.

{% tabs %}
{% tab title="Returned Value" %}

<table><thead><tr><th width="125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>address</code></td><td><code>address</code> of the underlying asset.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### decimals

```solidity
function decimals() public view override(ERC20, IERC20Metadata) returns (uint8)
```

See `{IERC20-decimals}`. The `_decimalShares` is equal to underlying asset decimals + `decimalsOffset`. See Constructor for more details about this.

{% tabs %}
{% tab title="Returned value" %}

<table><thead><tr><th width="104">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint8</code></td><td>Amount of decimals of the share (LP) token.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### totalAssets

```solidity
function totalAssets() public view returns (uint256)
```

The `totalAssets` function is used to calculate the theoretical total underlying assets owned by the vault. If the vault is locked, the last saved balance is added to the current balance.

{% tabs %}
{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of the total underlying assets in the vault.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### convertToShares

```solidity
function convertToShares(uint256 assets) public view returns (uint256)
```

See {IERC4626-convertToShares}.\
The `convertToShares` function is used to calculate the number of shares (LP tokens) received in exchange for the specified amount of underlying assets.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="116.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be converted into shares .</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="126">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares (LP tokens) received in exchange for the specified number of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### convertToAssets

```solidity
function convertToAssets(uint256 shares) public view returns (uint256)
```

See {IERC4626-convertToAssets}.\
The `convertToAssets` function is used to calculate the amount of underlying assets received in exchange for the specified number of shares (LP tokens).

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="116.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The number of shares (LP tokens) to be converted into underlying assets.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="126">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of underlying assets received in exchange for the specified number of shares (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### maxDeposit

```solidity
function maxMint(address) public view returns (uint256)
```

The `maxDeposit` function is used to calculate the maximum deposit.\
If the vault is locked or paused, users are not allowed to mint, the `maxMint` is `0`.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="92.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td>_</td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="126">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of the maximum underlying assets deposit.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### maxMint

```solidity
function maxMint(address) public view returns (uint256)
```

The `maxMint` function is used to calculate the maximum number of shares (LP tokens) you can mint. If the vault is locked or paused, the `maxMint` is `0`.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="94.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td>_</td><td><code>address</code></td><td>The <code>address</code> of the <code>receiver</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Maximum number of shares (LP tokens) mintable for the specified <code>address</code>.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### maxWithdraw

```solidity
function maxWithdraw(address owner) public view returns (uint256)
```

The `maxWithdraw` function is used to calculate the maximum amount of withdrawable underlying assets. If the function is called during the lock period the `maxWithdraw` is `0`.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="105.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>The maximum amount of withdrawable underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### maxRedeem

```solidity
function maxRedeem(address owner) public view returns (uint256)
```

The `maxRedemm` function is used to calculate the maximum number of redeemable shares (LP tokens). If the function is called during the lock period, the `maxRedeem` is `0`.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="104.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>The maximum number of redeemable shares (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### previewDeposit

```solidity
function previewDeposit(uint256 assets) public view returns (uint256)
```

The `previewDeposit` function is used to calculate the number of shares (LP tokens) received in exchange for the specified underlying asset.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="114.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be converted into shares (LP tokens).</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="125">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares (LP tokens) received in exchange for the specified amount of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### previewMint

```solidity
function previewMint(uint256 shares) public view returns (uint256)
```

The `previewMint` function is used to calculate the amount of underlying assets received in exchange for the specified number of shares (LP tokens).

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="114.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The number of shares (LP tokens) to be converted into underlying assets.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of underlying assets received in exchange for the specified number of shares (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### previewWithdraw

```solidity
function previewWithdraw(uint256 assets) public view returns (uint256)
```

The `previewWithdraw` function is used to calculate the number of shares (LP tokens) received in exchange for the specified underlying asset.

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="114.33333333333331">Name</th><th width="109">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be converted into shares (LP tokens).</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares (LP tokens) received in exchange of the specified amount of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### previewRedeem

```solidity
function previewRedeem(uint256 shares) public view returns (uint256)
```

The `previewRedeem` function is used to calculate the amount of underlying assets received in exchange for the specified number of shares (LP token).

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="115.33333333333331">Name</th><th width="111">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The number of shares (LP tokens) to be converted into underlying assets.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of underlying assets received in exchange for the specified number of shares (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### sharesBalanceInAsset

```solidity
function sharesBalanceInAsset(address owner) public view returns (uint256)
```

Given the address of an owner, returns the amount of shares of an user, converted in assets.

The `previewRedeem` function is used to calculate the amount of underlying assets received in exchange for the specified number of shares (LP token).

{% tabs %}
{% tab title="Parameter" %}

<table><thead><tr><th width="115.33333333333331">Name</th><th width="111">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>owner</code></td><td><code>address</code></td><td>The owner <code>address</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of shares converted to underlying assets owner by the user (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### deposit

```solidity
function deposit(uint256 assets, address receiver) public returns (uint256)
```

The `deposit` function is used to deposit underlying assets into the vault.

{% tabs %}
{% tab title="Parameters" %}

<table><thead><tr><th width="144.33333333333331">Name</th><th width="110">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be converted into shares (LP tokens).</td></tr><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares (LP tokens) received in exchange for the specified amount of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### depositWithPermit

```solidity
function depositWithPermit(
        uint256 assets,
        address receiver,
        PermitParams calldata permitParams
) external returns (uint256)
```

The `depositWithPermit` function is used to deposit underlying assets into the vault by using permit feature **if the underlying asset support it**.

{% tabs %}
{% tab title="Parameters" %}

<table><thead><tr><th width="174.33333333333331">Name</th><th width="157">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be converted into shares (LP tokens).</td></tr><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr><tr><td><code>permitParams</code></td><td><code>PermitParams</code></td><td>Permit functionality parameters.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares (LP tokens) received in exchange for the specified amount of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### depositWithPermit

### mint

```solidity
function mint(uint256 shares, address receiver) public returns (uint256)
```

The `mint` function is used to mint the specified number of shares (LP tokens) in exchange for the corresponding amount of underlying assets from `owner`.

{% tabs %}
{% tab title="Parameters" %}

<table><thead><tr><th width="134.33333333333331">Name</th><th width="111">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The number of shares (LP tokens) to be converted into underlying assets.</td></tr><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Amount of underlying assets received in exchange of the specified number of shares (LP tokens).</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### withdraw

```solidity
function withdraw(uint256 assets, address receiver, address owner) external returns (uint256)
```

The `withdraw` function is used to withdraw the specified amount of underlying assets in exchange for a proportional number of shares (LP tokens).

{% tabs %}
{% tab title="Parameters" %}

<table><thead><tr><th width="134.33333333333331">Name</th><th width="111">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>assets</code></td><td><code>uint256</code></td><td>The amount of underlying assets to be withdrawn.</td></tr><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr></tbody></table>
{% endtab %}

{% tab title="Returned value" %}

<table><thead><tr><th width="124">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>uint256</code></td><td>Number of shares received in exchange for the specified amount of underlying assets.</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

### redeem

```solidity
function redeem(uint256 shares, address receiver, address owner) external returns (uint256)
```

The `redeem` function is used to redeem the specified number of shares (LP tokens) in exchange for the corresponding amount of underlying assets from `owner`.

<table><thead><tr><th width="134.33333333333331">Name</th><th width="111">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>shares</code></td><td><code>uint256</code></td><td>The amount of  shares to be redeemed.</td></tr><tr><td><code>receiver</code></td><td><code>address</code></td><td>The <code>address</code> of the shares (LP tokens) <code>receiver</code>.</td></tr><tr><td><code>owner</code></td><td><code>address</code></td><td>The <code>address</code> of the <code>owner</code>.</td></tr></tbody></table>