swim.json.ArrayParser Maven / Gradle / Ivy

Go to download
// Copyright 2015-2019 SWIM.AI inc.
//
// 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 swim.json;

import swim.codec.Diagnostic;
import swim.codec.Input;
import swim.codec.Parser;
import swim.util.Builder;

final class ArrayParser extends Parser {
  final JsonParser json;
  final Builder builder;
  final Parser valueParser;
  final int step;

  ArrayParser(JsonParser json, Builder builder, Parser valueParser, int step) {
    this.json = json;
    this.builder = builder;
    this.valueParser = valueParser;
    this.step = step;
  }

  ArrayParser(JsonParser json) {
    this(json, null, null, 1);
  }

  @Override
  public Parser feed(Input input) {
    return parse(input, this.json, this.builder, this.valueParser, this.step);
  }

  static  Parser parse(Input input, JsonParser json, Builder builder,
                                Parser valueParser, int step) {
    int c = 0;
    if (step == 1) {
      while (input.isCont()) {
        c = input.head();
        if (Json.isWhitespace(c)) {
          input = input.step();
        } else {
          break;
        }
      }
      if (input.isCont()) {
        if (c == '[') {
          input = input.step();
          step = 2;
        } else {
          return error(Diagnostic.expected('[', input));
        }
      } else if (input.isDone()) {
        return error(Diagnostic.expected('[', input));
      }
    }
    if (step == 2) {
      while (input.isCont()) {
        c = input.head();
        if (Json.isWhitespace(c)) {
          input = input.step();
        } else {
          break;
        }
      }
      if (input.isCont()) {
        if (builder == null) {
          builder = json.arrayBuilder();
        }
        if (c == ']') {
          input = input.step();
          return done(builder.bind());
        } else {
          step = 3;
        }
      } else if (input.isDone()) {
        return error(Diagnostic.expected(']', input));
      }
    }
    while (step >= 3 && !input.isEmpty()) {
      if (step == 3) {
        if (valueParser == null) {
          valueParser = json.parseValue(input);
        }
        while (valueParser.isCont() && !input.isEmpty()) {
          valueParser = valueParser.feed(input);
        }
        if (valueParser.isDone()) {
          builder.add(json.item(valueParser.bind()));
          valueParser = null;
          step = 4;
        } else if (valueParser.isError()) {
          return valueParser;
        } else {
          break;
        }
      }
      if (step == 4) {
        while (input.isCont()) {
          c = input.head();
          if (Json.isWhitespace(c)) {
            input = input.step();
          } else {
            break;
          }
        }
        if (input.isCont()) {
          if (c == ',') {
            input = input.step();
            step = 3;
          } else if (c == ']') {
            input = input.step();
            return done(builder.bind());
          } else {
            return error(Diagnostic.expected("',' or ']'", input));
          }
        } else if (input.isDone()) {
          return error(Diagnostic.expected(']', input));
        } else {
          break;
        }
      }
    }
    if (input.isError()) {
      return error(input.trap());
    }
    return new ArrayParser(json, builder, valueParser, step);
  }

  static  Parser parse(Input input, JsonParser json) {
    return parse(input, json, null, null, 1);
  }
}