private static int validatePemByRegexParser()

in src/main/java/software/amazon/awssdk/crt/utils/PemUtils.java [243:288]
40 lines of code
11 McCabe index (conditional complexity)

    private static int validatePemByRegexParser(String pem, String expectedPemTypeSubString, int maxChainDepth) {
        int beginCount = 0;
        int endCount = 0;
        int objCount = 0;
        Matcher beginMatcher = PEM_BEGIN_PATTERN.matcher(pem);
        Matcher endMatcher = PEM_END_PATTERN.matcher(pem);
        Matcher objMatcher = PEM_OBJECT_PATTERN.matcher(pem);

        while (beginMatcher.find()) {
            beginCount++;
        }
        while (endMatcher.find()) {
            endCount++;
        }
        while (objMatcher.find()) {
            String beginType = objMatcher.group(1);
            String base64Contents = objMatcher.group(2);
            String endType = objMatcher.group(3);

            if (!beginType.contains(expectedPemTypeSubString) || !endType.contains(expectedPemTypeSubString)) {
                throw new IllegalArgumentException(
                        "PEM Object does not have expected type. " + "Expected Type: " + expectedPemTypeSubString
                                + ", Actual BEGIN Type: " + beginType + ", Actual END Type: " + endType);
            }
            if (base64Contents.length() == 0) {
                throw new IllegalArgumentException("PEM Objet does not have any contents");
            }
            objCount++;
        }

        if (objCount == 0) {
            throw new IllegalArgumentException("PEM contains no objects, or is not a PEM");
        }

        if (beginCount != endCount || beginCount != objCount) {
            throw new IllegalArgumentException("PEM has mismatching BEGIN and END Delimiters. BeginCount: " + beginCount
                    + ", EndCount: " + endCount + ", ObjCount: " + objCount);
        }

        if (beginCount > maxChainDepth) {
            throw new IllegalArgumentException(
                    "PEM has greater than expected depth, ExpectedMax: " + maxChainDepth + ", Actual: " + beginCount);
        }

        return beginCount;
    }