27 lines
1.1 KiB
Rust
27 lines
1.1 KiB
Rust
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//! Block difficulty data structures and calculations
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//!
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//! The block difficulty "target threshold" is stored in the block header as a
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//! 32-bit "compact bits" value. The `BlockHeaderHash` must be less than or equal
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//! to the expanded target threshold, when represented as a 256-bit integer in
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//! little-endian order.
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//!
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//! The target threshold is also used to calculate the "work" for each block.
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//! The block work is used to find the chain with the greatest total work. Each
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//! block's work value depends on the fixed threshold in the block header, not
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//! the actual work represented by the block header hash.
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#[cfg(test)]
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use proptest_derive::Arbitrary;
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/// A 32-bit "compact bits" value, which represents the difficulty threshold for
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/// a block header.
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///
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/// Used for:
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/// - checking the `difficulty_threshold` value in the block header,
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/// - calculating the 256-bit `ExpandedDifficulty` threshold, for comparison
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/// with the block header hash, and
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/// - calculating the block work.
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#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize)]
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#[cfg_attr(test, derive(Arbitrary))]
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pub struct CompactDifficulty(pub u32);
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