Refactor Argeo APIs

[gpl/argeo-suite.git] / org.argeo.api.app / src / org / argeo / api / app / IdRange.java

diff --git a/org.argeo.api.app/src/org/argeo/api/app/IdRange.java b/org.argeo.api.app/src/org/argeo/api/app/IdRange.java
new file mode 100644 (file)
index 0000000..c70e96a
--- /dev/null
+++ b/org.argeo.api.app/src/org/argeo/api/app/IdRange.java
@@ -0,0 +1,133 @@
+package org.argeo.api.app;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ThreadLocalRandom;
+
+/** A range of numerical IDs (typically numerical uid or gid). */
+public class IdRange {
+       // see https://systemd.io/UIDS-GIDS/#special-distribution-uid-ranges
+       final static long MIN_INCLUDED = Long.parseUnsignedLong("66000");
+       final static long MAX_EXCLUDED = Long.parseUnsignedLong("4294967294");
+
+       // We use long as a de facto unsigned int
+       
+       /** included */
+       private final long min;
+       /** included */
+       private final long max;
+
+       public IdRange(long min, long max) {
+               this.min = min;
+               this.max = max;
+       }
+
+       public IdRange(long minPow10) {
+               this(minPow10, maxFromMinPow10(minPow10));
+       }
+
+       public long getMin() {
+               return min;
+       }
+
+       public long getMax() {
+               return max;
+       }
+
+       @Override
+       public int hashCode() {
+               return (int) min;
+       }
+
+       @Override
+       public boolean equals(Object obj) {
+               if (obj instanceof IdRange idRange) {
+                       return min == idRange.min && max == idRange.max;
+               } else
+                       return false;
+       }
+
+       @Override
+       public String toString() {
+               return "[" + Long.toUnsignedString(min) + "," + Long.toUnsignedString(max) + "]";
+       }
+
+       /*
+        * RANGE GENERATION
+        */
+       public static synchronized Set<IdRange> randomRanges10000(int count, Set<IdRange> forbiddenRanges) {
+               Set<IdRange> res = new HashSet<>();
+
+               for (int i = 0; i < count; i++) {
+                       IdRange newRange = null;
+                       do {
+                               newRange = randomRange10000();
+                       } while (overlap(newRange, res) || overlap(newRange, forbiddenRanges));
+                       res.add(newRange);
+               }
+               return res;
+       }
+
+       public static synchronized IdRange randomRange10000() {
+               // TODO make it more generic
+               long minPred = 7l;
+               long maxPred = 429496l;
+
+               long rand = ThreadLocalRandom.current().nextLong(minPred, maxPred);
+               long min = rand * 10000l;
+               return new IdRange(min);
+       }
+
+       public static boolean overlap(IdRange idRange, Set<IdRange> idRanges) {
+               for (IdRange other : idRanges) {
+                       if (overlap(idRange, other))
+                               return true;
+               }
+               return false;
+       }
+
+       public static boolean overlap(IdRange idRange, IdRange other) {
+               // see
+               // https://stackoverflow.com/questions/3269434/whats-the-most-efficient-way-to-test-if-two-ranges-overlap
+               return idRange.min <= other.max && other.min <= idRange.max;
+       }
+
+       /*
+        * UTILITIES
+        */
+
+       private static long maxFromMinPow10(long minPow10) {
+               if ((minPow10 % 100) != 0) {
+                       throw new IllegalArgumentException(minPow10 + " must at least ends with two zeroes");
+               }
+               int exp = 2;
+               exp: for (int i = exp + 1; i < 10; i++) {
+                       if ((minPow10 % pow10(i)) != 0)
+                               break exp;
+                       exp++;
+               }
+//             System.out.println(exp);
+
+               long max = minPow10 + pow10(exp) - 1;
+               return max;
+       }
+
+       /** Power of 10. */
+       private static long pow10(int exp) {
+               if (exp == 0)
+                       return 1;
+               else
+                       return 10 * pow10(exp - 1);
+       }
+
+       public static void main(String... args) {
+               System.out.println(maxFromMinPow10(100));
+               System.out.println(maxFromMinPow10(78500));
+               System.out.println(maxFromMinPow10(716850000));
+
+//             System.out.println(pow10(6));
+//             System.out.println(maxFromMinPow10(12));
+//             System.out.println(maxFromMinPow10(124));
+//             System.out.println(maxFromMinPow10(99814565));
+       }
+}