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package firrtl

import org.antlr.v4.runtime._;
import org.antlr.v4.runtime.atn._;
import com.typesafe.scalalogging.LazyLogging
import Utils.{time}
import antlr._

class ParserException(message: String) extends Exception(message)
case class ParameterNotSpecifiedException(message: String) extends ParserException(message)
case class ParameterRedefinedException(message: String) extends ParserException(message)
case class InvalidStringLitException(message: String) extends ParserException(message)
case class InvalidEscapeCharException(message: String) extends ParserException(message)

object Parser extends LazyLogging
{
  /** Takes Iterator over lines of FIRRTL, returns AST (root node is Circuit) */
  def parse(lines: Iterator[String], infoMode: InfoMode = UseInfo): Circuit = {
    val fixedInput = time("Translator") { Translator.addBrackets(lines) }
    val antlrStream = new ANTLRInputStream(fixedInput.result)
    val lexer = new FIRRTLLexer(antlrStream)
    val tokens = new CommonTokenStream(lexer)
    val parser = new FIRRTLParser(tokens)

    time("ANTLR Parser") { parser.getInterpreter.setPredictionMode(PredictionMode.SLL) }

    // Concrete Syntax Tree
    val cst = parser.circuit

    val numSyntaxErrors = parser.getNumberOfSyntaxErrors
    if (numSyntaxErrors > 0) throw new ParserException(s"${numSyntaxErrors} syntax error(s) detected")

    val visitor = new Visitor(infoMode)
    val ast = time("Visitor") { visitor.visit(cst) } match {
      case c: Circuit => c
      case x => throw new ClassCastException("Error! AST not rooted with Circuit node!")
    }

    ast
  }

  def parse(lines: Seq[String]): Circuit = parse(lines.iterator)

  sealed abstract class InfoMode
  case object IgnoreInfo extends InfoMode
  case object UseInfo extends InfoMode
  case class GenInfo(filename: String) extends InfoMode
  case class AppendInfo(filename: String) extends InfoMode
}
