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refactor: use match for OP_N push in push_int_unchecked

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Chris Hyunhum Cho 2024-09-26 09:56:12 +09:00 committed by GitHub
parent d7ee177f17
commit c9988ba8cb
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1 changed files with 17 additions and 14 deletions
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31
bitcoin/src/blockdata/script/builder.rs
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@ -5,7 +5,7 @@ use core::fmt;
use super::{opcode_to_verify, write_scriptint, Error, PushBytes, Script, ScriptBuf};
use crate::locktime::absolute;
use crate::opcodes::all::*;
use crate::opcodes::{self, Opcode};
use crate::opcodes::Opcode;
use crate::prelude::Vec;
use crate::script::{ScriptBufExt as _, ScriptBufExtPriv as _, ScriptExtPriv as _};
use crate::Sequence;
@ -46,20 +46,23 @@ impl Builder {
///
/// Integers are encoded as little-endian signed-magnitude numbers, but there are dedicated
/// opcodes to push some small integers.
/// It doesn't check whether the integer in the range of [-2^31 +1...2^31 -1].
///
/// This function implements `CScript::push_int64` from Core `script.h`.
///
/// > Numeric opcodes (OP_1ADD, etc) are restricted to operating on 4-byte integers.
/// > The semantics are subtle, though: operands must be in the range [-2^31 +1...2^31 -1],
/// > but results may overflow (and are valid as long as they are not used in a subsequent
/// > numeric operation). CScriptNum enforces those semantics by storing results as
/// > an int64 and allowing out-of-range values to be returned as a vector of bytes but
/// > throwing an exception if arithmetic is done or the result is interpreted as an integer.
///
/// Does not check whether `n` is in the range of [-2^31 +1...2^31 -1].
pub fn push_int_unchecked(self, n: i64) -> Builder {
// We can special-case -1, 1-16
if n == -1 || (1..=16).contains(&n) {
let opcode = Opcode::from((n - 1 + opcodes::OP_TRUE.to_u8() as i64) as u8);
self.push_opcode(opcode)
}
// We can also special-case zero
else if n == 0 {
self.push_opcode(opcodes::OP_0)
}
// Otherwise encode it as data
else {
self.push_int_non_minimal(n)
match n {
-1 => self.push_opcode(OP_PUSHNUM_NEG1),
0 => self.push_opcode(OP_PUSHBYTES_0),
1..=16 => self.push_opcode(Opcode::from(n as u8 + (OP_PUSHNUM_1.to_u8() - 1))),
_ => self.push_int_non_minimal(n),
}
}