lila/modules/video/src/main/CsvParser.scala

/*
 * Copyright 2013 Toshiyuki Takahashi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.github.tototoshi.csv

import scala.annotation.switch

object CSVParser {

  class MalformedCSVException(message: String) extends Exception(message)

  private type State = Int
  final private val Start       = 0
  final private val Field       = 1
  final private val Delimiter   = 2
  final private val End         = 3
  final private val QuoteStart  = 4
  final private val QuoteEnd    = 5
  final private val QuotedField = 6

  def apply(input: String, escapeChar: Char, delimiter: Char, quoteChar: Char): Option[List[String]] = {
    val buf: Array[Char]       = input.toCharArray
    var fields: Vector[String] = Vector()
    var field                  = new StringBuilder
    var state: State           = Start
    var pos                    = 0
    val buflen                 = buf.length

    if (buf.length > 0 && buf(0) == '\uFEFF') {
      pos += 1
    }

    while (state != End && pos < buflen) {
      val c = buf(pos)
      (state: @switch) match {
        case Start => {
          c match {
            case `quoteChar` => {
              state = QuoteStart
              pos += 1
            }
            case `delimiter` => {
              fields :+= field.toString
              field = new StringBuilder
              state = Delimiter
              pos += 1
            }
            case '\n' | '\u2028' | '\u2029' | '\u0085' => {
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case '\r' => {
              if (pos + 1 < buflen && buf(1) == '\n') {
                pos += 1
              }
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case x => {
              field += x
              state = Field
              pos += 1
            }
          }
        }
        case Delimiter => {
          c match {
            case `quoteChar` => {
              state = QuoteStart
              pos += 1
            }
            case `escapeChar` => {
              if (
                pos + 1 < buflen
                && (buf(pos + 1) == escapeChar || buf(pos + 1) == delimiter)
              ) {
                field += buf(pos + 1)
                state = Field
                pos += 2
              } else {
                throw new MalformedCSVException(buf.mkString)
              }
            }
            case `delimiter` => {
              fields :+= field.toString
              field = new StringBuilder
              state = Delimiter
              pos += 1
            }
            case '\n' | '\u2028' | '\u2029' | '\u0085' => {
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case '\r' => {
              if (pos + 1 < buflen && buf(1) == '\n') {
                pos += 1
              }
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case x => {
              field += x
              state = Field
              pos += 1
            }
          }
        }
        case Field => {
          c match {
            case `escapeChar` => {
              if (pos + 1 < buflen) {
                if (
                  buf(pos + 1) == escapeChar
                  || buf(pos + 1) == delimiter
                ) {
                  field += buf(pos + 1)
                  state = Field
                  pos += 2
                } else {
                  throw new MalformedCSVException(buf.mkString)
                }
              } else {
                state = QuoteEnd
                pos += 1
              }
            }
            case `delimiter` => {
              fields :+= field.toString
              field = new StringBuilder
              state = Delimiter
              pos += 1
            }
            case '\n' | '\u2028' | '\u2029' | '\u0085' => {
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case '\r' => {
              if (pos + 1 < buflen && buf(1) == '\n') {
                pos += 1
              }
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case x => {
              field += x
              state = Field
              pos += 1
            }
          }
        }
        case QuoteStart => {
          c match {
            case `escapeChar` if escapeChar != quoteChar => {
              if (pos + 1 < buflen) {
                if (
                  buf(pos + 1) == escapeChar
                  || buf(pos + 1) == quoteChar
                ) {
                  field += buf(pos + 1)
                  state = QuotedField
                  pos += 2
                } else {
                  throw new MalformedCSVException(buf.mkString)
                }
              } else {
                throw new MalformedCSVException(buf.mkString)
              }
            }
            case `quoteChar` => {
              if (pos + 1 < buflen && buf(pos + 1) == quoteChar) {
                field += quoteChar
                state = QuotedField
                pos += 2
              } else {
                state = QuoteEnd
                pos += 1
              }
            }
            case x => {
              field += x
              state = QuotedField
              pos += 1
            }
          }
        }
        case QuoteEnd => {
          c match {
            case `delimiter` => {
              fields :+= field.toString
              field = new StringBuilder
              state = Delimiter
              pos += 1
            }
            case '\n' | '\u2028' | '\u2029' | '\u0085' => {
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case '\r' => {
              if (pos + 1 < buflen && buf(1) == '\n') {
                pos += 1
              }
              fields :+= field.toString
              field = new StringBuilder
              state = End
              pos += 1
            }
            case _ => {
              throw new MalformedCSVException(buf.mkString)
            }
          }
        }
        case QuotedField => {
          c match {
            case `escapeChar` if escapeChar != quoteChar => {
              if (pos + 1 < buflen) {
                if (
                  buf(pos + 1) == escapeChar
                  || buf(pos + 1) == quoteChar
                ) {
                  field += buf(pos + 1)
                  state = QuotedField
                  pos += 2
                } else {
                  field += buf(pos)
                  field += buf(pos + 1)
                  state = QuotedField
                  pos += 2
                }
              } else {
                throw new MalformedCSVException(buf.mkString)
              }
            }
            case `quoteChar` => {
              if (pos + 1 < buflen && buf(pos + 1) == quoteChar) {
                field += quoteChar
                state = QuotedField
                pos += 2
              } else {
                state = QuoteEnd
                pos += 1
              }
            }
            case x => {
              field += x
              state = QuotedField
              pos += 1
            }
          }
        }
        case End => {
          sys.error("unexpected error")
        }
      }
    }
    (state: @switch) match {
      case Delimiter => {
        fields :+= ""
        Some(fields.toList)
      }
      case QuotedField => {
        None
      }
      case _ => {
        // When no crlf at end of file
        state match {
          case Field | QuoteEnd => {
            fields :+= field.toString
          }
          case _ => {}
        }
        Some(fields.toList)
      }
    }
  }
}