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copied!<p>Here's a rough implementation that guesses the line ending type based on a simple majority and falls back on unknown in a worst-case scenario:</p> <pre><code>import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.util.EnumMap; import java.util.Map; import java.util.Scanner; class LineEndings { private enum ExitState { SUCCESS, FAILURE; } public enum LineEndingType { DOS("Windows"), MAC("Mac OS Classic"), UNIX("Unix/Linux/Mac OS X"), UNKNOWN("Unknown"); private final String name; private LineEndingType(String name) { this.name = name; } public String toString() { if (null == this.name) { return super.toString(); } else { return this.name; } } } public static void main(String[] arguments) { ExitState exitState = ExitState.SUCCESS; File inputFile = getInputFile(); if (null == inputFile) { exitState = ExitState.FAILURE; System.out.println("Error: No input file specified."); } else { System.out.println("Determining line endings for: " + inputFile.getName()); try { LineEndingType lineEndingType = getLineEndingType(inputFile); System.out.println("Determined line endings: " + lineEndingType); } catch (java.io.IOException exception) { exitState = ExitState.FAILURE; System.out.println("Error: " + exception.getMessage()); } } switch (exitState) { case SUCCESS: System.exit(0); break; case FAILURE: System.exit(1); break; } } private static File getInputFile() { File inputFile = null; Scanner stdinScanner = new Scanner(System.in); while (true) { System.out.println("Enter the input file name:"); System.out.print(">> "); if (stdinScanner.hasNext()) { String inputFileName = stdinScanner.next(); inputFile = new File(inputFileName); if (!inputFile.exists()) { System.out.println("File not found.\n"); } else if (!inputFile.canRead()) { System.out.println("Could not read file.\n"); } else { break; } } else { inputFile = null; break; } } System.out.println(); return inputFile; } private static LineEndingType getLineEndingType(File inputFile) throws java.io.IOException, java.io.FileNotFoundException { EnumMap<LineEndingType, Integer> lineEndingTypeCount = new EnumMap<LineEndingType, Integer>(LineEndingType.class); BufferedReader inputReader = new BufferedReader(new FileReader(inputFile)); LineEndingType currentLineEndingType = null; while (inputReader.ready()) { int token = inputReader.read(); if ('\n' == token) { currentLineEndingType = LineEndingType.UNIX; } else if ('\r' == token) { if (inputReader.ready()) { int nextToken = inputReader.read(); if ('\n' == nextToken) { currentLineEndingType = LineEndingType.DOS; } else { currentLineEndingType = LineEndingType.MAC; } } } if (null != currentLineEndingType) { incrementLineEndingType(lineEndingTypeCount, currentLineEndingType); currentLineEndingType = null; } } return getMostFrequentLineEndingType(lineEndingTypeCount); } private static void incrementLineEndingType(Map<LineEndingType, Integer> lineEndingTypeCount, LineEndingType targetLineEndingType) { Integer targetLineEndingCount = lineEndingTypeCount.get(targetLineEndingType); if (null == targetLineEndingCount) { targetLineEndingCount = 0; } else { targetLineEndingCount++; } lineEndingTypeCount.put(targetLineEndingType, targetLineEndingCount); } private static LineEndingType getMostFrequentLineEndingType(Map<LineEndingType, Integer> lineEndingTypeCount) { Integer maximumEntryCount = Integer.MIN_VALUE; Map.Entry<LineEndingType, Integer> mostFrequentEntry = null; for (Map.Entry<LineEndingType, Integer> entry : lineEndingTypeCount.entrySet()) { int entryCount = entry.getValue(); if (entryCount > maximumEntryCount) { mostFrequentEntry = entry; maximumEntryCount = entryCount; } } if (null != mostFrequentEntry) { return mostFrequentEntry.getKey(); } else { return LineEndingType.UNKNOWN; } } } </code></pre>

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