Implemented enhancement to allow configuring the number of sample row…

…s to use when trying to detect the CSV format (#408)

src/main/java/com/univocity/parsers/csv/CsvParser.java

@@ -59,6 +59,7 @@ public final class CsvParser extends AbstractParser<CsvParserSettings> {
 	private final boolean trimQuotedTrailing;
 	private char[] delimiters;
 	private int match = 0;
+	private int formatDetectorRowSampleCount;
 
 	/**
 	 * The CsvParser supports all settings provided by {@link CsvParserSettings}, and requires this configuration to be properly initialized.
@@ -78,7 +79,7 @@ public CsvParser(CsvParserSettings settings) {
 		maxColumnLength = settings.getMaxCharsPerColumn();
 		trimQuotedTrailing = settings.getIgnoreTrailingWhitespacesInQuotes();
 		trimQuotedLeading = settings.getIgnoreLeadingWhitespacesInQuotes();
-
+		formatDetectorRowSampleCount = settings.getFormatDetectorRowSampleCount();
 		updateFormat(settings.getFormat());
 
 		whitespaceAppender = new ExpandingCharAppender(10, "", whitespaceRangeStart);
@@ -463,7 +464,7 @@ private void parseQuotedValue() {
 	@Override
 	protected final InputAnalysisProcess getInputAnalysisProcess() {
 		if (settings.isDelimiterDetectionEnabled() || settings.isQuoteDetectionEnabled()) {
-			return new CsvFormatDetector(20, settings, whitespaceRangeStart) {
+			return new CsvFormatDetector(formatDetectorRowSampleCount, settings, whitespaceRangeStart) {
 				@Override
 				void apply(char delimiter, char quote, char quoteEscape) {
 					if (settings.isDelimiterDetectionEnabled()) {

src/main/java/com/univocity/parsers/csv/CsvParserSettings.java

@@ -52,6 +52,7 @@ public class CsvParserSettings extends CommonParserSettings<CsvFormat> {
 	private boolean quoteDetectionEnabled = false;
 	private UnescapedQuoteHandling unescapedQuoteHandling = null;
 	private char[] delimitersForDetection = null;
+	private int formatDetectorRowSampleCount = 20;
 
 	/**
 	 * Returns the String representation of an empty value (defaults to null)
@@ -487,4 +488,22 @@ public final void trimQuotedValues(boolean trim) {
 		setIgnoreTrailingWhitespacesInQuotes(trim);
 		setIgnoreLeadingWhitespacesInQuotes(trim);
 	}
+
+	/**
+	 * Returns the number of sample rows used in the CSV format auto-detection process (defaults to 20)
+	 *
+	 * @return the number of sample rows used in the CSV format auto-detection process
+	 */
+	public int getFormatDetectorRowSampleCount() {
+		return formatDetectorRowSampleCount;
+	}
+
+	/**
+	 * Updates the number of sample rows used in the CSV format auto-detection process (defaults to 20)
+	 *
+	 * @param formatDetectorRowSampleCount the number of sample rows used in the CSV format auto-detection process
+	 */
+	public void setFormatDetectorRowSampleCount(int formatDetectorRowSampleCount) {
+		this.formatDetectorRowSampleCount = formatDetectorRowSampleCount <= 0 ? 20 : formatDetectorRowSampleCount;
+	}
 }