Added module with consensus parameters (#93)

src/network/consensus_params.rs

@@ -0,0 +1,129 @@
+// Rust Bitcoin Library
+// Written in 2014 by
+//   Andrew Poelstra <apoelstra@wpsoftware.net>
+//
+// To the extent possible under law, the author(s) have dedicated all
+// copyright and related and neighboring rights to this software to
+// the public domain worldwide. This software is distributed without
+// any warranty.
+//
+// You should have received a copy of the CC0 Public Domain Dedication
+// along with this software.
+// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+//
+
+//! # Consensus parameters
+//!
+//! This module provides predefined set of parameters for different chains.
+//!
+
+use network::constants::Network;
+use util::uint::Uint256;
+
+/// Lowest possible difficulty for Mainnet.
+const MAX_BITS_BITCOIN: Uint256 = Uint256([
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0x00000000ffffffffu64,
+]);
+/// Lowest possible difficulty for Testnet.
+const MAX_BITS_TESTNET: Uint256 = Uint256([
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0x00000000ffffffffu64,
+]);
+/// Lowest possible difficulty for Regtest.
+const MAX_BITS_REGTEST: Uint256 = Uint256([
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0xffffffffffffffffu64,
+    0x7fffffffffffffffu64,
+]);
+
+#[derive(Debug, Clone)]
+/// Parameters that influence chain consensus.
+pub struct ConsensusParams {
+    /// Network for which parameters are valid.
+    pub network: Network,
+    /// Time when BIP16 becomes active.
+    pub bip16_time: u32,
+    /// Block height at which BIP34 becomes active.
+    pub bip34_height: u32,
+    /// Block height at which BIP65 becomes active.
+    pub bip65_height: u32,
+    /// Block height at which BIP66 becomes active.
+    pub bip66_height: u32,
+    /// Minimum blocks including miner confirmation of the total of 2016 blocks in a retargeting period,
+    /// (nPowTargetTimespan / nPowTargetSpacing) which is also used for BIP9 deployments.
+    /// Examples: 1916 for 95%, 1512 for testchains.
+    pub rule_change_activation_threshold: u32,
+    /// Number of blocks with the same set of rules.
+    pub miner_confirmation_window: u32,
+    /// Proof of work limit value. It cointans the lowest possible difficulty.
+    pub pow_limit: Uint256,
+    /// Expected amount of time to mine one block.
+    pub pow_target_spacing: u64,
+    /// Difficulty recalculation interval.
+    pub pow_target_timespan: u64,
+    /// Determines whether minimal difficulty may be used for blocks or not.
+    pub allow_min_difficulty_blocks: bool,
+    /// Determines whether retargeting is disabled for this network or not.
+    pub no_pow_retargeting: bool,
+}
+
+impl ConsensusParams {
+    /// Creates parameters set for the given network.
+    pub fn new(network: Network) -> Self {
+        match network {
+            Network::Bitcoin => ConsensusParams {
+                network: Network::Bitcoin,
+                bip16_time: 1333238400,                 // Apr 1 2012
+                bip34_height: 227931, // 000000000000024b89b42a942fe0d9fea3bb44ab7bd1b19115dd6a759c0808b8
+                bip65_height: 388381, // 000000000000000004c2b624ed5d7756c508d90fd0da2c7c679febfa6c4735f0
+                bip66_height: 363725, // 00000000000000000379eaa19dce8c9b722d46ae6a57c2f1a988119488b50931
+                rule_change_activation_threshold: 1916, // 95%
+                miner_confirmation_window: 2016,
+                pow_limit: MAX_BITS_BITCOIN.clone(),
+                pow_target_spacing: 10 * 60,            // 10 minutes.
+                pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks.
+                allow_min_difficulty_blocks: false,
+                no_pow_retargeting: false,
+            },
+            Network::Testnet => ConsensusParams {
+                network: Network::Testnet,
+                bip16_time: 1333238400,                 // Apr 1 2012
+                bip34_height: 21111, // 0000000023b3a96d3484e5abb3755c413e7d41500f8e2a5c3f0dd01299cd8ef8
+                bip65_height: 581885, // 00000000007f6655f22f98e72ed80d8b06dc761d5da09df0fa1dc4be4f861eb6
+                bip66_height: 330776, // 000000002104c8c45e99a8853285a3b592602a3ccde2b832481da85e9e4ba182
+                rule_change_activation_threshold: 1512, // 75%
+                miner_confirmation_window: 2016,
+                pow_limit: MAX_BITS_TESTNET.clone(),
+                pow_target_spacing: 10 * 60,            // 10 minutes.
+                pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks.
+                allow_min_difficulty_blocks: true,
+                no_pow_retargeting: false,
+            },
+            Network::Regtest => ConsensusParams {
+                network: Network::Regtest,
+                bip16_time: 1333238400,  // Apr 1 2012
+                bip34_height: 100000000, // not activated on regtest
+                bip65_height: 1351,
+                bip66_height: 1251,                    // used only in rpc tests
+                rule_change_activation_threshold: 108, // 75%
+                miner_confirmation_window: 144,
+                pow_limit: MAX_BITS_REGTEST.clone(),
+                pow_target_spacing: 10 * 60,            // 10 minutes.
+                pow_target_timespan: 14 * 24 * 60 * 60, // 2 weeks.
+                allow_min_difficulty_blocks: true,
+                no_pow_retargeting: true,
+            },
+        }
+    }
+
+    /// Calculates the number of blocks between difficulty adjustments.
+    pub fn difficulty_adjustment_interval(&self) -> u64 {
+        self.pow_target_timespan / self.pow_target_spacing
+    }
+}

src/network/mod.rs

@@ -19,6 +19,7 @@
 //!
 
 pub mod constants;
+pub mod consensus_params;
 pub mod encodable;
 pub mod socket;
 pub mod serialize;