Discounter

This interface defines the functions and events of the Discounter contract

Chain Type	Name	ID	Contract Address
Mainnet	Base	8453	0x3d2337823Debc69a8317783697765715265A9DD8
Testnet	Base Sepolia	84532	0x423CAd69d1Dc4E6F4b3EB0c4d714df772B914E99

Buy

event Buy(address from, uint256 amount, uint256 minted, bytes data)

Emitted when a user buys sTokens with base tokens

Parameters

Name	Type	Description
from	address	The address of the buyer
amount	uint256	The amount of base tokens used for the purchase
minted	uint256	The amount of sTokens minted to the buyer
data	bytes	Additional metadata for the transaction

Redeem

event Redeem(address to, uint256 amount, uint256 burned, bytes data)

Emitted when a user redeems sTokens for base tokens

Parameters

Name	Type	Description
to	address	The address of the redeemer
amount	uint256	The amount of base tokens redeemed
burned	uint256	The amount of sTokens burned during redemption
data	bytes	Additional metadata for the transaction

Sell

event Sell(address to, uint256 amount, bytes data)

Emitted when base tokens are sold from the reserve

Parameters

Name	Type	Description
to	address	The address of the recipient of the sold tokens
amount	uint256	The amount of base tokens sold
data	bytes	Additional metadata for the transaction

Settle

event Settle(address from, uint256 amount, bytes data)

Emitted when debt is settled using base tokens

Parameters

Name	Type	Description
from	address	The address of the account settling the debt
amount	uint256	The amount of base tokens used to settle the debt
data	bytes	Additional metadata for the transaction

DiscountChange

event DiscountChange(uint256 discountRateBase, uint256 discountRateSlope)

Emitted when the discount rate parameters are updated

Parameters

Name	Type	Description
discountRateBase	uint256	The new base discount rate (per second)
discountRateSlope	uint256	The new discount rate slope (per second)

ReserveFactorChange

event ReserveFactorChange(uint256 minReserveFactor, uint256 maxReserveFactor)

Emitted when the reserve factor parameters are updated

Parameters

Name	Type	Description
minReserveFactor	uint256	The new minimum reserve factor
maxReserveFactor	uint256	The new maximum reserve factor

Accrue

event Accrue(uint256 timeElapsed, uint256 baseTotalSoldStart, uint256 baseTotalSoldEnd, uint256 baseTotalReserve)

Emitted when accrual of the discount rate is processed

Parameters

Name	Type	Description
timeElapsed	uint256	The time elapsed since the last accrual (in seconds)
baseTotalSoldStart	uint256	The total base tokens sold at the start of the accrual period
baseTotalSoldEnd	uint256	The total base tokens sold at the end of the accrual period
baseTotalReserve	uint256	The total base tokens in reserve at the end of the accrual period

TimestampTooLarge

error TimestampTooLarge(uint256 timestamp)

Error thrown when the timestamp exceeds the maximum value that can be stored

Parameters

Name	Type	Description
timestamp	uint256	The timestamp that caused the error

DiscounterInsufficientBalance

error DiscounterInsufficientBalance(address sender, uint256 balance, uint256 needed)

Error thrown when an account tries to redeem more tokens than their balance allows

Parameters

Name	Type	Description
sender	address	The address attempting the redemption
balance	uint256	The actual balance of the sender (in base token units)
needed	uint256	The amount the sender attempted to redeem (in base token units)

DiscounterSettleExceedsSold

error DiscounterSettleExceedsSold(uint256 sold, uint256 needed)

Error thrown when attempting to settle more debt than has been sold

Parameters

Name	Type	Description
sold	uint256	The current amount of base tokens sold
needed	uint256	The amount attempted to settle

DiscounterUnsupportedERC1155Contract

error DiscounterUnsupportedERC1155Contract(address supported, address needed)

Error thrown when interacting with an unsupported ERC1155 contract

Parameters

Name	Type	Description
supported	address	The address of the supported contract
needed	address	The address of the contract that was attempted to be used

DiscounterUnsupportedERC1155Token

error DiscounterUnsupportedERC1155Token(uint256 supported, uint256 needed)

Error thrown when interacting with an unsupported ERC1155 token ID

Parameters

Name	Type	Description
supported	uint256	The supported token ID
needed	uint256	The token ID that was attempted to be used

DiscounterInvalidERC1155TransferBatch

error DiscounterInvalidERC1155TransferBatch()

Error thrown when an invalid ERC1155 batch transfer is detected

DiscounterAmountExceedsBuyable

error DiscounterAmountExceedsBuyable(uint256 buyable, uint256 amount)

Error thrown when attempting to buy more tokens than are available

Parameters

Name	Type	Description
buyable	uint256	The maximum amount of base tokens that can be used for buying
amount	uint256	The amount that was attempted to be used

DiscounterAmountExceedsSellable

error DiscounterAmountExceedsSellable(uint256 sellable, uint256 amount)

Error thrown when attempting to sell more tokens from the reserve than are available

Parameters

Name	Type	Description
sellable	uint256	The maximum amount of base tokens that can be sold from the reserve
amount	uint256	The amount that was attempted to be sold

baseToken

function baseToken() external view returns (address)

Returns the address of the base token used for purchases and redemptions (e.g., USDC, USDT)

Return Values

Name	Type	Description
[0]	address	The address of the base token

discountRateSlope

function discountRateSlope() external view returns (uint64)

The slope component of the discount rate (per second)

Adjusted by dividing annual rate by SECONDS_PER_YEAR

discountRateBase

function discountRateBase() external view returns (uint64)

The base component of the discount rate (per second)

Adjusted by dividing annual rate by SECONDS_PER_YEAR

minReserveFactor

function minReserveFactor() external view returns (uint64)

The minimum reserve factor, representing the minimum percentage of total supplied tokens that must remain in reserve

Scaled by FACTOR_SCALE (1e18)

maxReserveFactor

function maxReserveFactor() external view returns (uint64)

The maximum reserve factor, representing the maximum percentage of total supplied tokens that should remain in reserve

Scaled by FACTOR_SCALE (1e18)

lastAccrualTime

function lastAccrualTime() external view returns (uint40)

The timestamp of the last accrual calculation

Stored as uint40 to save gas, can represent timestamps until year 36812

baseIndex

function baseIndex() external view returns (uint256)

Returns the current base index used for token conversions between base tokens and sTokens
also known as the exchange rate or price of sToken in base currency

The base index scales with the total supplied base tokens and token supply

Return Values

Name	Type	Description
[0]	uint256	The current base index value

baseValue

function baseValue(uint256 amount) external view returns (uint256)

tokenValue

function tokenValue(uint256 amount) external view returns (uint256)

baseSold

function baseSold() external view returns (uint256)

Returns the current amount of base tokens that have been sold

Projects the current sold amount by applying interest accrual since last update

Return Values

Name	Type	Description
[0]	uint256	The current total amount of base tokens sold (in base token units)

baseBalanceOf

function baseBalanceOf(address account) external view returns (uint256)

Returns the base token equivalent of a token balance

Converts an sToken balance to its equivalent value in base tokens

Parameters

Name	Type	Description
account	address	The account to check the balance for

Return Values

Name	Type	Description
[0]	uint256	The base token value of the account's sToken balance (in base token units)

accrueRate

function accrueRate(uint256 utilization_) external view returns (uint256)

Calculates the accrual rate of sold receivables based on current utilization

The accrual rate is used to determine how the discount increases over time

Parameters

Name	Type	Description
utilization_	uint256	The current utilization factor (ratio of sold to total supplied)

Return Values

Name	Type	Description
[0]	uint256	The calculated accrual rate including base rate plus slope component

discountRate

function discountRate() external view returns (uint256, uint256, uint256, uint256)

Returns the current discount rate information and related values

Calculates the time elapsed since last accrual and projects the current state

Return Values

Name	Type	Description
[0]	uint256	timeElapsed The time elapsed since last accrual in seconds
[1]	uint256	baseTotalSoldStart The base total sold at the start of the period (in base token units)
[2]	uint256	baseTotalSoldEnd The projected base total sold at the current time (in base token units)
[3]	uint256	baseTotalReserve_ The current base total reserve (in base token units)

buyable

function buyable() external view returns (uint256)

Returns the amount of base tokens that can be used to buy sTokens

Calculates the buyable amount based on current reserves and reserve factor constraints

Return Values

Name	Type	Description
[0]	uint256	The amount of base tokens available for buying (in base token units)

buy

function buy(uint256 amount, bytes data) external returns (uint256)

Buys receivable tokens (sTokens) with base tokens

Transfers base tokens from sender to contract and mints sTokens
Emits a Buy event after the purchase is complete When paused, this function will revert

Parameters

Name	Type	Description
amount	uint256	The amount of base tokens to use for buying, or max uint to use all available
data	bytes	Additional metadata for the transaction

Return Values

Name	Type	Description
[0]	uint256	The amount of receivable tokens (sTokens) minted

redeem

function redeem(uint256 amount, bytes data) external returns (uint256)

Redeems receivable tokens (sTokens) for base tokens

Burns sTokens and transfers base tokens to the redeemer
Emits a Redeem event after the redemption is complete When paused, this function will revert

Parameters

Name	Type	Description
amount	uint256	The amount of base tokens to redeem, or max uint to redeem all available
data	bytes	Additional metadata for the transaction

Return Values

Name	Type	Description
[0]	uint256	The amount of sTokens burned during redemption