Probably Trailing new lines not supported/Line Break Issue

[ogawaffm]

I browsed the code on github and think colorize(String text, String ansiCode) will not handle trailing new lines correctly, because split will not return them. See https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split(java.lang.String)
" ... Trailing empty strings are therefore not included in the resulting array. ... "

I think the code gets in trouble with:

"a\n\n\n" because split will result in ["a"]
"a\n\n\b" because endsWithLine is set to false and therefore no new lines are added in the loop

[ogawaffm]

As assumed, the code did not work for both examples. It also has problems, if the newline to be output is not the newline of the current jre/os, which can occure in a multi-platform environment, where for example messages are logged into files with a fix new line for all os.

The code below solves the three issues and can replace the existing method in class Ansi:

    // Windows, Unix or old Classic Mac OS
    static Pattern newLinePattern = Pattern.compile("((\\r?\\n)|\\r)", Pattern.MULTILINE);

    static StringBuilder output = new StringBuilder();

    static public String colorize(String text, String ansiCode) {

        output.setLength(0);

        // assure at least one newline for logic simplicity
        text = text + "\n";

        Matcher newLineMatcher = newLinePattern.matcher(text);

        int nextLineBegin = 0;
        String line = null;
        String newLine = null;

        while (newLineMatcher.find()) {

            line = text.substring(nextLineBegin, newLineMatcher.start());

            // determine the exact new line (which can be different from line to line)
            // to assure identical new lines output
            newLine = text.substring(newLineMatcher.start(), newLineMatcher.end());

            if (! line.isEmpty())
            {

                output.append(ansiCode);
                output.append(line);
                output.append(RESET);

            // ELSE: no text => no ansiCode output => no RESET => keep effect of last RESET

            }

            // Not at last line?
            if (newLineMatcher.end() != text.length()) {

                // yes, there is more to come, output new line
                output.append(newLine);
                nextLineBegin = newLineMatcher.end();

            }

        }

        return output.toString();

    }

If a line is empty, the code neither sets attributes nor resets the terminal. The last state is keept to reduce output, because last reset (of none-empty line output) still is active. If this assumption is wrong, just remove IF to make reset unconditional again.

I assure this code was written by me and only by me and I contribute it under MIT License to the project.

[dialex]

Apologies for my silence in the last days, I've been struggling with some personal issues. I'll try to review your issue and code asap. If you want, you can create a PR in the meantime, that will speed up the review process, you will also be listed as a contributor to this project :)

[dialex]

I have a PR that solves the bug you found. I tested your code and it worked, however I found it too complex and hard to understand. I achieved the same thing just by changing a few lines.

I'll push this in a new release (v5.0.1)

[ogawaffm]

The replace function always uses the same (plattform specific) NEWLINE. I think the original text passed to colorize should only be attributed by ansiCode, but kept as it is. If you are using different NEWLINEs in a string or consistently a fix NEWLINE, which is not the plattform-specific NEWLINE the result is not what I expect. The source of text to be attributed maybe is not under control of the caller and the text is just received as it is.