X-Git-Url: https://git.argeo.org/?p=gpl%2Fargeo-suite.git;a=blobdiff_plain;f=org.argeo.api.app%2Fsrc%2Forg%2Fargeo%2Fapi%2Fapp%2FIdRange.java;fp=org.argeo.api.app%2Fsrc%2Forg%2Fargeo%2Fapi%2Fapp%2FIdRange.java;h=c70e96a5c5779522aa2c41e2688ee6fc406825c7;hp=0000000000000000000000000000000000000000;hb=616a062e9d061ce91589556624ed622298a21ac7;hpb=c4cecb1f3b6cbe1b25dafae79e3f17d50d90b9c8

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
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));
+	}
+}