From: Mathieu Baudier <mbaudier@argeo.org>
Date: Sat, 24 Sep 2022 10:39:20 +0000 (+0200)
Subject: ID range generation
X-Git-Tag: v2.3.8~29
X-Git-Url: https://git.argeo.org/?p=gpl%2Fargeo-suite.git;a=commitdiff_plain;h=68e87a1f35f88460fafe476521a6e5fa7f2fd22b

ID range generation
---

diff --git a/org.argeo.app.api/src/org/argeo/app/api/IdRange.java b/org.argeo.app.api/src/org/argeo/app/api/IdRange.java
index d96c789..e47eb5e 100644
--- a/org.argeo.app.api/src/org/argeo/app/api/IdRange.java
+++ b/org.argeo.app.api/src/org/argeo/app/api/IdRange.java
@@ -1,9 +1,20 @@
 package org.argeo.app.api;
 
+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) {
@@ -23,6 +34,68 @@ public class IdRange {
 		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");
@@ -33,7 +106,7 @@ public class IdRange {
 				break exp;
 			exp++;
 		}
-		System.out.println(exp);
+//		System.out.println(exp);
 
 		long max = minPow10 + pow10(exp) - 1;
 		return max;