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uniVocity's open source parsers for processing different text formats using a consistent API
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/*******************************************************************************
 * Copyright 2014 uniVocity Software Pty Ltd
 *
 * 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.univocity.parsers.fixed;

import com.univocity.parsers.common.*;

/**
 * A fast and flexible fixed-with parser implementation.
 *
 * @see FixedWidthFormat
 * @see FixedWidthFieldLengths
 * @see FixedWidthParserSettings
 * @see FixedWidthWriter
 * @see AbstractParser
 *
 * @author uniVocity Software Pty Ltd - [email protected]
 *
 */
public class FixedWidthParser extends AbstractParser {

	private final int[] lengths;

	private final boolean ignoreLeadingWhitespace;
	private final boolean ignoreTrailingWhitespace;
	private final boolean skipToNewLine;
	private final boolean recordEndsOnNewLine;
	private final boolean skipEmptyLines;

	private final char padding;
	private final char newLine;

	private int length;

	/**
	 * The FixedWidthParser supports all settings provided by {@link FixedWidthParserSettings}, and requires this configuration to be properly initialized.
	 * @param settings the parser configuration
	 */
	public FixedWidthParser(FixedWidthParserSettings settings) {
		super(settings);
		ignoreLeadingWhitespace = settings.getIgnoreLeadingWhitespaces();
		ignoreTrailingWhitespace = settings.getIgnoreTrailingWhitespaces();
		skipToNewLine = settings.getSkipTrailingCharsUntilNewline();
		recordEndsOnNewLine = settings.getRecordEndsOnNewline();
		skipEmptyLines = settings.getSkipEmptyLines();
		lengths = settings.getFieldLengths();

		FixedWidthFormat format = settings.getFormat();
		padding = format.getPadding();
		newLine = format.getNormalizedNewline();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void parseRecord() {
		if (ch == newLine && skipEmptyLines) {
			return;
		}

		int i;
		for (i = 0; i < lengths.length; i++) {
			length = lengths[i];

			skipPadding();

			if (ignoreLeadingWhitespace) {
				skipWhitespace();
			}

			if (recordEndsOnNewLine) {
				readValueUntilNewLine();
				if (ch == newLine) {
					output.valueParsed();
					return;
				}
			} else {
				readValue();
			}
			output.valueParsed();
		}

		if (skipToNewLine) {
			skipToNewLine();
		}

	}

	private void skipToNewLine() {
		while (ch != newLine) {
			ch = input.nextChar();
		}
	}

	private void skipPadding() {
		while (ch == padding && length-- > 0) {
			ch = input.nextChar();
		}
	}

	private void skipWhitespace() {
		while (ch <= ' ' && length-- > 0) {
			ch = input.nextChar();
		}
	}

	private void readValueUntilNewLine() {
		if (ignoreTrailingWhitespace) {
			while (length-- > 0 && ch != newLine) {
				output.appender.appendIgnoringWhitespaceAndPadding(ch);
				ch = input.nextChar();
			}
		} else {
			while (length-- > 0 && ch != newLine) {
				output.appender.appendIgnoringPadding(ch);
				ch = input.nextChar();
			}
		}
	}

	private void readValue() {
		if (ignoreTrailingWhitespace) {
			while (length-- > 0) {
				output.appender.appendIgnoringWhitespaceAndPadding(ch);
				ch = input.nextChar();
			}
		} else {
			while (length-- > 0) {
				output.appender.appendIgnoringPadding(ch);
				ch = input.nextChar();
			}
		}
	}
}