BatchAuction.sol

Integrated with OrderBook — handles the clearing algorithm.

clearBatch(marketId)

Permissionless. Callable by anyone (typically keepers).

Algorithm

1. Check interval: block.timestamp >= lastClearTime + batchInterval

2. Read aggregates: cumulative bid volume (descending from tick 99) and ask volume (ascending from tick 1) via segment trees

3. Find clearing tick: highest tick where cumulative bids ≥ cumulative asks (maximizes matched quantity)

4. Tie-break: midpoint of tied ticks

5. Fill fractions: calculate BPS fill fraction for oversubscribed side at clearing tick

6. Store result: write BatchResult(batchId, clearingTick, bidFillBps, askFillBps, totalVolume)

7. Skip if empty: if no crossing orders, return without writing (save gas)

BatchResult Struct

struct BatchResult {
    uint256 batchId;
    uint8 clearingTick;
    uint16 bidFillFractionBps;
    uint16 askFillFractionBps;
    uint256 totalVolume;
    uint256 timestamp;
}

Gas Efficiency

• Segment tree traversal: O(log N) for 99 ticks (~7 levels)

• Clearing writes: O(1) — only the batch result struct

• No per-order iteration during clearing

• IOC and batch-only orders are marked expired (not iterated — claimed/pruned later)

Events

event BatchCleared(uint256 indexed marketId, uint256 batchId, uint8 clearingTick, uint256 volume);