Add 'zcash_history/' from commit 'e2c131fdc308265adcab774e54d4d5804c23b368'

git-subtree-dir: zcash_history
git-subtree-mainline: be0ee9eb82
git-subtree-split: e2c131fdc3

zcash_history/examples/lib/main.rs

@@ -0,0 +1,4 @@
+// dummy example
+pub fn main() {
+
+}

zcash_history/examples/lib/shared.rs

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+use zcash_mmr:: {NodeData, Tree, Entry, EntryLink};
+
+pub struct NodeDataIterator {
+    return_stack: Vec<NodeData>,
+    tree: Tree,
+    cursor: usize,
+    leaf_cursor: usize,
+}
+
+impl Iterator for NodeDataIterator {
+    type Item = NodeData;
+
+    fn next(&mut self) -> Option<NodeData> {
+        let result = if self.cursor == 1 {
+            self.leaf_cursor = 2;
+            Some(leaf(1))
+        } else if self.cursor == 2 {
+            self.leaf_cursor = 3;
+            Some(leaf(2))
+        } else if self.cursor == 3 {
+            Some(self.tree.root_node().expect("always exists").data().clone())
+        } else if self.return_stack.len() > 0 {
+            self.return_stack.pop()
+        } else {
+            for n_append in
+                self.tree.append_leaf(leaf(self.leaf_cursor as u32))
+                    .expect("full tree cannot fail").into_iter().rev()
+            {
+                self.return_stack.push(self.tree.resolve_link(n_append).expect("just pushed").data().clone())
+            }
+            self.leaf_cursor += 1;
+            self.return_stack.pop()
+        };
+
+        self.cursor += 1;
+        result
+    }
+}
+
+impl NodeDataIterator {
+    pub fn new() -> Self {
+        let root = Entry::new(
+            NodeData::combine(&leaf(1), &leaf(2)),
+            EntryLink::Stored(0),
+            EntryLink::Stored(1)
+        );
+        let tree =
+            Tree::new(
+                3,
+                vec![(2, root)],
+                vec![(0, leaf(1).into()), (1, leaf(2).into())]
+            );
+
+        NodeDataIterator {
+            return_stack: Vec::new(),
+            tree,
+            cursor: 1,
+            leaf_cursor: 1,
+        }
+    }
+}
+
+fn leaf(height: u32) -> NodeData {
+    NodeData {
+        consensus_branch_id: 0,
+        subtree_commitment: [0u8; 32],
+        start_time: height*10+1,
+        end_time: (height+1)*10,
+        start_target: 100 + height*10,
+        end_target: 100 + (height+1)*10,
+        start_sapling_root: [0u8; 32],
+        end_sapling_root: [0u8; 32],
+        subtree_total_work: 0.into(),
+        start_height: height as u64,
+        end_height: height as u64,
+        shielded_tx: 5 + height as u64,
+    }
+}

zcash_history/examples/long.rs

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+use zcash_mmr::{Entry, EntryLink, NodeData, Tree};
+
+#[path= "lib/shared.rs"]
+mod share;
+
+fn draft(into: &mut Vec<(u32, Entry)>, vec: &Vec<NodeData>, peak_pos: usize, h: u32) {
+    let node_data = vec[peak_pos-1].clone();
+    let peak: Entry = match h {
+        0 => node_data.into(),
+        _ => Entry::new(
+            node_data,
+            EntryLink::Stored((peak_pos - (1 << h) - 1) as u32),
+            EntryLink::Stored((peak_pos - 2) as u32),
+        ),
+    };
+
+    println!("Entry #{}: {}", into.len(), peak);
+
+    into.push(((peak_pos-1) as u32, peak));
+}
+
+fn prepare_tree(vec: &Vec<NodeData>) -> Tree {
+
+    assert!(vec.len() > 0);
+
+    // integer log2 of (vec.len()+1), -1
+    let mut h = (32 - ((vec.len()+1) as u32).leading_zeros() - 1)-1;
+    let mut peak_pos = (1 << (h+1)) - 1;
+    let mut nodes = Vec::new();
+
+    // used later
+    let mut last_peak_pos = 0;
+    let mut last_peak_h = 0;
+
+    loop {
+
+        if peak_pos > vec.len() {
+            // left child, -2^h
+            peak_pos = peak_pos - (1<<h);
+            h = h - 1;
+        }
+
+        if peak_pos <= vec.len() {
+            draft(&mut nodes, vec, peak_pos, h);
+
+            // save to be used in next loop
+            last_peak_pos = peak_pos;
+            last_peak_h = h;
+
+            // right sibling
+            peak_pos = peak_pos + (1 << (h+1)) - 1;
+        }
+
+        if h == 0 {
+            break;
+        }
+    }
+
+    // for deletion, everything on the right slope of the last peak should be pre-loaded
+    let mut extra = Vec::new();
+    let mut h = last_peak_h;
+    let mut peak_pos = last_peak_pos;
+
+    while h > 0 {
+        let left_pos = peak_pos - (1<<h);
+        let right_pos = peak_pos - 1;
+        h = h - 1;
+
+        // drafting left child
+        draft(&mut extra, vec, left_pos, h);
+
+        // drafting right child
+        draft(&mut extra, vec, right_pos, h);
+
+        // continuing on right slope
+        peak_pos = right_pos;
+    }
+
+    println!("Total extra of {} required for deletion!", extra.len());
+
+    Tree::new(vec.len() as u32, nodes, extra)
+}
+
+fn main() {
+    let number= match std::env::args().skip(1).next() {
+        None => { eprintln!("writer <number of nodes> [<out_file>]"); std::process::exit(1); },
+        Some(number) => {
+            number.parse::<usize>().expect("invalid number")
+        }
+    };
+
+    let long_vec = share::NodeDataIterator::new().take(number)
+        .collect::<Vec<NodeData>>();
+
+    let now = std::time::Instant::now();
+
+    let tree = prepare_tree(&long_vec);
+    let elapsed = now.elapsed();
+
+    println!("Tree final root: {}-{}",
+        tree.root_node().expect("root").data().start_height,
+        tree.root_node().expect("root").data().end_height,
+    );
+
+    println!("Prepare tree of {} length: {} ns / {} mcs / {} ms",
+        number,
+        elapsed.as_nanos(), elapsed.as_micros(), elapsed.as_millis()
+    );
+}

zcash_history/examples/write.rs

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+#[path= "lib/shared.rs"]
+mod share;
+
+// Test data generator
+// $ cargo run --example writer -- 16 nodes.dat
+// or
+// $ cargo run --example writer -- 16
+// to preview
+
+fn main() {
+    let mut args = std::env::args().skip(1);
+
+    let (number, out_file) = match args.next() {
+        None => { eprintln!("writer <number of nodes> [<out_file>]"); std::process::exit(1); },
+        Some(number) => {
+            (number.parse::<usize>().expect("invalid number"), args.next())
+        }
+    };
+
+    let iterator = share::NodeDataIterator::new().take(number);
+
+    if let Some(out_file_path) = out_file {
+        use std::io::Write;
+
+        let mut buf = Vec::new();
+
+        for node in iterator{
+            node.write(&mut buf).expect("Failed to write data");
+        }
+
+        let mut file = std::fs::File::create(&out_file_path)
+            .expect("Failed to create output file");
+
+        file.write_all(&buf[..])
+            .expect("Failed to write data to file");
+    } else {
+        for n in iterator {
+            println!("{:?}", n);
+        }
+    }
+}