124 lines
5.0 KiB
Rust
124 lines
5.0 KiB
Rust
// Rust Bitcoin Library
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// Written in 2014 by
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// Andrew Poelstra <apoelstra@wpsoftware.net>
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//
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// To the extent possible under law, the author(s) have dedicated all
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// copyright and related and neighboring rights to this software to
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// the public domain worldwide. This software is distributed without
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// any warranty.
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//
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// You should have received a copy of the CC0 Public Domain Dedication
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// along with this software.
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// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
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//
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//! Miscellaneous functions
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//!
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//! Various utility functions
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use hashes::{sha256d, Hash, HashEngine};
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use blockdata::opcodes;
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use consensus::{encode, Encodable};
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static MSG_SIGN_PREFIX: &[u8] = b"\x18Bitcoin Signed Message:\n";
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/// Search for `needle` in the vector `haystack` and remove every
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/// instance of it, returning the number of instances removed.
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/// Loops through the vector opcode by opcode, skipping pushed data.
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pub fn script_find_and_remove(haystack: &mut Vec<u8>, needle: &[u8]) -> usize {
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if needle.len() > haystack.len() { return 0; }
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if needle.is_empty() { return 0; }
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let mut top = haystack.len() - needle.len();
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let mut n_deleted = 0;
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let mut i = 0;
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while i <= top {
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if &haystack[i..(i + needle.len())] == needle {
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for j in i..top {
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haystack.swap(j + needle.len(), j);
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}
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n_deleted += 1;
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// This is ugly but prevents infinite loop in case of overflow
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let overflow = top < needle.len();
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top = top.wrapping_sub(needle.len());
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if overflow { break; }
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} else {
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i += match opcodes::All::from((*haystack)[i]).classify() {
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opcodes::Class::PushBytes(n) => n as usize + 1,
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opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA1) => 2,
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opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA2) => 3,
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opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA4) => 5,
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_ => 1
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};
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}
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}
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haystack.truncate(top.wrapping_add(needle.len()));
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n_deleted
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}
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/// Hash message for signature using Bitcoin's message signing format
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pub fn signed_msg_hash(msg: &str) -> sha256d::Hash {
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let mut engine = sha256d::Hash::engine();
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engine.input(MSG_SIGN_PREFIX);
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let msg_len = encode::VarInt(msg.len() as u64);
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msg_len.consensus_encode(&mut engine).unwrap();
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engine.input(msg.as_bytes());
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sha256d::Hash::from_engine(engine)
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}
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#[cfg(test)]
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mod tests {
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use hashes::hex::ToHex;
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use super::script_find_and_remove;
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use super::signed_msg_hash;
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#[test]
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fn test_script_find_and_remove() {
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let mut v = vec![101u8, 102, 103, 104, 102, 103, 104, 102, 103, 104, 105, 106, 107, 108, 109];
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assert_eq!(script_find_and_remove(&mut v, &[]), 0);
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assert_eq!(script_find_and_remove(&mut v, &[105, 105, 105]), 0);
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assert_eq!(v, vec![101, 102, 103, 104, 102, 103, 104, 102, 103, 104, 105, 106, 107, 108, 109]);
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assert_eq!(script_find_and_remove(&mut v, &[105, 106, 107]), 1);
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assert_eq!(v, vec![101, 102, 103, 104, 102, 103, 104, 102, 103, 104, 108, 109]);
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assert_eq!(script_find_and_remove(&mut v, &[104, 108, 109]), 1);
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assert_eq!(v, vec![101, 102, 103, 104, 102, 103, 104, 102, 103]);
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assert_eq!(script_find_and_remove(&mut v, &[101]), 1);
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assert_eq!(v, vec![102, 103, 104, 102, 103, 104, 102, 103]);
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assert_eq!(script_find_and_remove(&mut v, &[102]), 3);
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assert_eq!(v, vec![103, 104, 103, 104, 103]);
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assert_eq!(script_find_and_remove(&mut v, &[103, 104]), 2);
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assert_eq!(v, vec![103]);
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assert_eq!(script_find_and_remove(&mut v, &[105, 105, 5]), 0);
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assert_eq!(script_find_and_remove(&mut v, &[105]), 0);
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assert_eq!(script_find_and_remove(&mut v, &[103]), 1);
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assert_eq!(v, Vec::<u8>::new());
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assert_eq!(script_find_and_remove(&mut v, &[105, 105, 5]), 0);
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assert_eq!(script_find_and_remove(&mut v, &[105]), 0);
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}
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#[test]
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fn test_script_codesep_remove() {
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let mut s = vec![33u8, 3, 132, 121, 160, 250, 153, 140, 211, 82, 89, 162, 239, 10, 122, 92, 104, 102, 44, 20, 116, 248, 140, 203, 109, 8, 167, 103, 123, 190, 199, 242, 32, 65, 173, 171, 33, 3, 132, 121, 160, 250, 153, 140, 211, 82, 89, 162, 239, 10, 122, 92, 104, 102, 44, 20, 116, 248, 140, 203, 109, 8, 167, 103, 123, 190, 199, 242, 32, 65, 173, 171, 81];
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assert_eq!(script_find_and_remove(&mut s, &[171]), 2);
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assert_eq!(s, vec![33, 3, 132, 121, 160, 250, 153, 140, 211, 82, 89, 162, 239, 10, 122, 92, 104, 102, 44, 20, 116, 248, 140, 203, 109, 8, 167, 103, 123, 190, 199, 242, 32, 65, 173, 33, 3, 132, 121, 160, 250, 153, 140, 211, 82, 89, 162, 239, 10, 122, 92, 104, 102, 44, 20, 116, 248, 140, 203, 109, 8, 167, 103, 123, 190, 199, 242, 32, 65, 173, 81]);
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}
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#[test]
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fn test_signed_msg_hash() {
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let hash = signed_msg_hash("test");
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assert_eq!(hash.to_hex(), "a6f87fe6d58a032c320ff8d1541656f0282c2c7bfcc69d61af4c8e8ed528e49c");
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}
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}
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