98 lines
2.9 KiB
Rust
98 lines
2.9 KiB
Rust
// Copyright 2015-2018 Parity Technologies (UK) Ltd.
|
|
// This file is part of Parity.
|
|
|
|
// Parity is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
|
|
// Parity is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with Parity. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
use std::fmt;
|
|
use instructions;
|
|
|
|
/// Stack trait with VM-friendly API
|
|
pub trait Stack<T> {
|
|
/// Returns `Stack[len(Stack) - no_from_top]`
|
|
fn peek(&self, no_from_top: usize) -> &T;
|
|
/// Swaps Stack[len(Stack)] and Stack[len(Stack) - no_from_top]
|
|
fn swap_with_top(&mut self, no_from_top: usize);
|
|
/// Returns true if Stack has at least `no_of_elems` elements
|
|
fn has(&self, no_of_elems: usize) -> bool;
|
|
/// Get element from top and remove it from Stack. Panics if stack is empty.
|
|
fn pop_back(&mut self) -> T;
|
|
/// Get (up to `instructions::MAX_NO_OF_TOPICS`) elements from top and remove them from Stack. Panics if stack is empty.
|
|
fn pop_n(&mut self, no_of_elems: usize) -> &[T];
|
|
/// Add element on top of the Stack
|
|
fn push(&mut self, elem: T);
|
|
/// Get number of elements on Stack
|
|
fn size(&self) -> usize;
|
|
/// Returns all data on stack.
|
|
fn peek_top(&self, no_of_elems: usize) -> &[T];
|
|
}
|
|
|
|
pub struct VecStack<S> {
|
|
stack: Vec<S>,
|
|
logs: [S; instructions::MAX_NO_OF_TOPICS]
|
|
}
|
|
|
|
impl<S : Copy> VecStack<S> {
|
|
pub fn with_capacity(capacity: usize, zero: S) -> Self {
|
|
VecStack {
|
|
stack: Vec::with_capacity(capacity),
|
|
logs: [zero; instructions::MAX_NO_OF_TOPICS]
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<S : fmt::Display> Stack<S> for VecStack<S> {
|
|
fn peek(&self, no_from_top: usize) -> &S {
|
|
&self.stack[self.stack.len() - no_from_top - 1]
|
|
}
|
|
|
|
fn swap_with_top(&mut self, no_from_top: usize) {
|
|
let len = self.stack.len();
|
|
self.stack.swap(len - no_from_top - 1, len - 1);
|
|
}
|
|
|
|
fn has(&self, no_of_elems: usize) -> bool {
|
|
self.stack.len() >= no_of_elems
|
|
}
|
|
|
|
fn pop_back(&mut self) -> S {
|
|
let val = self.stack.pop();
|
|
match val {
|
|
Some(x) => x,
|
|
None => panic!("Tried to pop from empty stack.")
|
|
}
|
|
}
|
|
|
|
fn pop_n(&mut self, no_of_elems: usize) -> &[S] {
|
|
assert!(no_of_elems <= instructions::MAX_NO_OF_TOPICS);
|
|
|
|
for i in 0..no_of_elems {
|
|
self.logs[i] = self.pop_back();
|
|
}
|
|
&self.logs[0..no_of_elems]
|
|
}
|
|
|
|
fn push(&mut self, elem: S) {
|
|
self.stack.push(elem);
|
|
}
|
|
|
|
fn size(&self) -> usize {
|
|
self.stack.len()
|
|
}
|
|
|
|
fn peek_top(&self, no_from_top: usize) -> &[S] {
|
|
assert!(self.stack.len() >= no_from_top, "peek_top asked for more items than exist.");
|
|
&self.stack[self.stack.len() - no_from_top .. self.stack.len()]
|
|
}
|
|
}
|