+ * A version-part consists of up to four parts, all of which are optional:
+ *
+ * <number-a><string-b><number-c>
+ * <string-d (everything else)>
+ *
+ * A version-part may also consist of a single asterisk "*" which indicates + * "infinity". + *
+ * Numbers are base-10, and are zero if left out. + * Strings are compared bytewise. + *
+ * For additional backwards compatibility, if "string-b" is "+" then + * "number-a" is incremented by 1 and "string-b" becomes "pre". + *
+ * 1.0pre1 + * < 1.0pre2 + * < 1.0 == 1.0.0 == 1.0.0.0 + * < 1.1pre == 1.1pre0 == 1.0+ + * < 1.1pre1a + * < 1.1pre1 + * < 1.1pre10a + * < 1.1pre10 + *+ * Although not required by this interface, it is recommended that + * numbers remain within the limits of a signed char, i.e. -127 to 128. + */ +public class VersionComparator implements nsIVersionComparator { + + public nsISupports queryInterface(String aIID) { + return Mozilla.queryInterface(this, aIID); + } + + /** + * Compare two version strings + * @param A a version string + * @param B a version string + * @return a value less than 0 if A < B; + * the value 0 if A == B; + * or a value greater than 0 if A > B + */ + public int compare(String A, String B) { + int result; + String a = A, b = B; + + do { + VersionPart va = new VersionPart(); + VersionPart vb = new VersionPart(); + a = parseVersionPart(a, va); + b = parseVersionPart(b, vb); + + result = compareVersionPart(va, vb); + if (result != 0) { + break; + } + } while (a != null || b != null); + + return result; + } + + private class VersionPart { + int numA = 0; + String strB; + int numC = 0; + String extraD; + } + + private static String parseVersionPart(String aVersion, VersionPart result) { + if (aVersion == null || aVersion.length() == 0) { + return aVersion; + } + + StringTokenizer tok = new StringTokenizer(aVersion.trim(), "."); + String part = tok.nextToken(); + + if (part.equals("*")) { + result.numA = Integer.MAX_VALUE; + result.strB = ""; + } else { + VersionPartTokenizer vertok = new VersionPartTokenizer(part); + try { + result.numA = Integer.parseInt(vertok.nextToken()); + } catch (NumberFormatException e) { + // parsing error; default to zero like 'strtol' C function + result.numA = 0; + } + + if (vertok.hasMoreElements()) { + String str = vertok.nextToken(); + + // if part is of type "
+ * <number-a><string-b><number-c>
+ * <string-d (everything else)>.
+ */
+class VersionPartTokenizer implements Enumeration {
+
+ String part;
+
+ public VersionPartTokenizer(String aPart) {
+ part = aPart;
+ }
+
+ public boolean hasMoreElements() {
+ return part.length() != 0;
+ }
+
+ public boolean hasMoreTokens() {
+ return part.length() != 0;
+ }
+
+ public Object nextElement() {
+ if (part.matches("[\\+\\-]?[0-9].*")) {
+ // if string starts with a number...
+ int index = 0;
+ if (part.charAt(0) == '+' || part.charAt(0) == '-') {
+ index = 1;
+ }
+
+ while (index < part.length() && Character.isDigit(part.charAt(index))) {
+ index++;
+ }
+
+ String numPart = part.substring(0, index);
+ part = part.substring(index);
+ return numPart;
+ } else {
+ // ... or if this is the non-numeric part of version string
+ int index = 0;
+ while (index < part.length() && !Character.isDigit(part.charAt(index))) {
+ index++;
+ }
+
+ String alphaPart = part.substring(0, index);
+ part = part.substring(index);
+ return alphaPart;
+ }
+ }
+
+ public String nextToken() {
+ return (String) nextElement();
+ }
+
+ /**
+ * Returns what remains of the original string, without tokenization. This
+ * method is useful for getting the <string-d (everything else)>
+ * section of a version string.
+ *
+ * @return remaining version string
+ */
+ public String getRemainder() {
+ return part;
+ }
+
+}
+