44 lines
1.9 KiB
Rust
44 lines
1.9 KiB
Rust
//! Constants for Block Subsidy, Funding Streams, and Founders’ Reward
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use zebra_chain::{amount::COIN, block::Height};
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/// An initial period from Genesis to this Height where the block subsidy is gradually incremented. [What is slow-start mining][slow-mining]
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///
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/// [slow-mining]: https://z.cash/support/faq/#what-is-slow-start-mining
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pub const SLOW_START_INTERVAL: Height = Height(20_000);
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/// `SlowStartShift()` as described in [protocol specification §7.7][7.7]
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///
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/// [7.7]: https://zips.z.cash/protocol/protocol.pdf#subsidies
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///
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/// This calculation is exact, because `SLOW_START_INTERVAL` is divisible by 2.
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pub const SLOW_START_SHIFT: Height = Height(SLOW_START_INTERVAL.0 / 2);
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/// The largest block subsidy, used before the first halving.
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///
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/// We use `25 / 2` instead of `12.5`, so that we can calculate the correct value without using floating-point.
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/// This calculation is exact, because COIN is divisible by 2, and the division is done last.
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pub const MAX_BLOCK_SUBSIDY: u64 = ((25 * COIN) / 2) as u64;
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/// Used as a multiplier to get the new halving interval after Blossom.
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///
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/// Calculated as `PRE_BLOSSOM_POW_TARGET_SPACING / POST_BLOSSOM_POW_TARGET_SPACING`
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/// in the Zcash specification.
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pub const BLOSSOM_POW_TARGET_SPACING_RATIO: u64 = 2;
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/// Halving is at about every 4 years, before Blossom block time is 150 seconds.
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///
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/// `(60 * 60 * 24 * 365 * 4) / 150 = 840960`
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pub const PRE_BLOSSOM_HALVING_INTERVAL: Height = Height(840_000);
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/// After Blossom the block time is reduced to 75 seconds but halving period should remain around 4 years.
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pub const POST_BLOSSOM_HALVING_INTERVAL: Height =
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Height((PRE_BLOSSOM_HALVING_INTERVAL.0 as u64 * BLOSSOM_POW_TARGET_SPACING_RATIO) as u32);
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/// The divisor used to calculate the FoundersFraction.
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///
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/// Derivation: FOUNDERS_FRACTION_DIVISOR = 1/FoundersFraction
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///
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/// Usage: founders_reward = block_subsidy / FOUNDERS_FRACTION_DIVISOR
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pub const FOUNDERS_FRACTION_DIVISOR: u64 = 5;
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