Will Hawkins
65 lines
2.0 KiB
Swift
65 lines
2.0 KiB
Swift
// p4rse, Copyright 2026, Will Hawkins
|
|
//
|
|
// This file is part of p4rse.
|
|
//
|
|
// This file 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.
|
|
//
|
|
// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
import Common
|
|
import Lang
|
|
|
|
/// The runtime for a parser
|
|
public class ParserRuntime: CustomStringConvertible {
|
|
var execution: ParserInstance
|
|
|
|
init(execution: ParserInstance) {
|
|
self.execution = execution
|
|
}
|
|
|
|
/// Create a parser runtime from a P4 program
|
|
public static func create(program: Lang.Program) -> Result<ParserRuntime> {
|
|
return switch program.starting_parser() {
|
|
case .Ok(let parser):
|
|
switch ParserInstance.create(parser) {
|
|
case .Ok(let execution): .Ok(Runtime.ParserRuntime(execution: execution))
|
|
case .Error(let error): .Error(error)
|
|
}
|
|
case .Error(let error): .Error(error)
|
|
}
|
|
}
|
|
|
|
/// Run the P4 parser on a given packet
|
|
public func run(input: Packet) -> Result<(ParserState, ProgramExecution)> {
|
|
execution.scopes.enter()
|
|
return .Ok(execution.execute())
|
|
}
|
|
|
|
public var description: String {
|
|
return "Runtime:\nExecution: \(execution)"
|
|
}
|
|
}
|
|
|
|
/// Instances of parsers are executable
|
|
extension ParserInstance: Execution {
|
|
public func execute() -> (ParserState, ProgramExecution) {
|
|
var execution = self as ProgramExecution
|
|
var state = self.state
|
|
|
|
// Evaluate until the state is either accept or reject.
|
|
while state != accept && state != reject {
|
|
(state, execution) = self.state.evaluate(execution: execution)
|
|
}
|
|
return (state, execution)
|
|
}
|
|
}
|