CLDR-17298 Add parts per billion (#3716)

Author: macchiati

common/main/en.xml

@@ -6886,6 +6886,11 @@ annotations.
 				<unitPattern count="one">{0} part per million</unitPattern>
 				<unitPattern count="other">{0} parts per million</unitPattern>
 			</unit>
+			<unit type="concentr-portion-per-1e9">
+				<displayName>parts per billion</displayName>
+				<unitPattern count="one">{0} part per billion</unitPattern>
+				<unitPattern count="other">{0} parts per billion</unitPattern>
+			</unit>
 			<unit type="concentr-percent">
 				<displayName>percent</displayName>
 				<unitPattern count="one">{0} percent</unitPattern>
@@ -7970,6 +7975,11 @@ annotations.
 				<unitPattern count="one">{0} ppm</unitPattern>
 				<unitPattern count="other">{0} ppm</unitPattern>
 			</unit>
+			<unit type="concentr-portion-per-1e9">
+				<displayName>parts/billion</displayName>
+				<unitPattern count="one">{0} ppb</unitPattern>
+				<unitPattern count="other">{0} ppb</unitPattern>
+			</unit>
 			<unit type="concentr-percent">
 				<displayName>percent</displayName>
 				<unitPattern count="one">{0}%</unitPattern>
@@ -9051,6 +9061,11 @@ annotations.
 				<unitPattern count="one">{0}ppm</unitPattern>
 				<unitPattern count="other">{0}ppm</unitPattern>
 			</unit>
+			<unit type="concentr-portion-per-1e9">
+				<displayName>ppb</displayName>
+				<unitPattern count="one">{0}ppb</unitPattern>
+				<unitPattern count="other">{0}ppb</unitPattern>
+			</unit>
 			<unit type="concentr-percent">
 				<displayName>%</displayName>
 				<unitPattern count="one">{0}%</unitPattern>

common/main/root.xml

@@ -5101,6 +5101,10 @@ Warnings: All cp values have U+FE0F characters removed. See /annotationsDerived/
 				<displayName>ppm</displayName>
 				<unitPattern count="other">{0} ppm</unitPattern>
 			</unit>
+			<unit type="concentr-portion-per-1e9">
+				<displayName>ppb</displayName>
+				<unitPattern count="other">{0} ppb</unitPattern>
+			</unit>
 			<unit type="concentr-percent">
 				<displayName>%</displayName>
 				<unitPattern count="other">{0}%</unitPattern>

common/validity/unit.xml

@@ -239,6 +239,7 @@ For terms of use, see http://www.unicode.org/copyright.html
 			volume-sai
 			volume-to-jp
 			volume-koku
+			concentr-portion-per-1e9
 			mass-fun
 			duration-night
 			speed-light-speed

tools/cldr-code/src/main/java/org/unicode/cldr/util/DtdData.java

@@ -1871,6 +1871,7 @@ private static final class UnitOrderHolder {
                                         "volume-koku",
                                         "speed-light-speed",
                                         "mass-fun",
+                                        "concentr-portion-per-1e9",
                                         "duration-night"))
                         .freeze();
     }

tools/cldr-code/src/main/java/org/unicode/cldr/util/UnitConverter.java

@@ -1073,6 +1073,7 @@ public int compare(String o1, String o2) {
     }
 
     Comparator<String> UNIT_COMPARATOR = new UnitComparator();
+    static final Pattern TRAILING_ZEROS = Pattern.compile("0+$");
 
     /** Only handles the canonical units; no kilo-, only normalized, etc. */
     // Thus we do not need to handle specials here
@@ -1174,7 +1175,7 @@ public String toString() {
             for (int i = 1; i >= 0; --i) { // two passes, numerator then den.
                 boolean positivePass = i > 0;
                 if (positivePass && !factor.numerator.equals(BigInteger.ONE)) {
-                    builder.append(factor.numerator);
+                    builder.append(shortConstant(factor.numerator));
                 }
 
                 Map<String, Integer> target = positivePass ? numUnitsToPowers : denUnitsToPowers;
@@ -1190,7 +1191,7 @@ public String toString() {
                             firstDenominator = false;
                             builder.append("per-");
                             if (!factor.denominator.equals(BigInteger.ONE)) {
-                                builder.append(factor.denominator).append('-');
+                                builder.append(shortConstant(factor.denominator)).append('-');
                             }
                         }
                     }
@@ -1213,10 +1214,35 @@ public String toString() {
                     }
                     builder.append(unit);
                 }
+                if (!positivePass
+                        && firstDenominator
+                        && !factor.denominator.equals(BigInteger.ONE)) {
+                    builder.append("-per-").append(shortConstant(factor.denominator));
+                }
             }
             return builder.toString();
         }
 
+        /**
+         * Return a string format. If larger than 7 digits, use 1eN format.
+         *
+         * @param source
+         * @return
+         */
+        public String shortConstant(BigInteger source) {
+            // don't bother optimizing
+            String result = source.toString();
+            if (result.length() < 8) {
+                return result;
+            }
+            Matcher matcher = TRAILING_ZEROS.matcher(result);
+            if (matcher.find()) {
+                int zeroCount = matcher.group().length();
+                return result.substring(0, result.length() - zeroCount) + "e" + zeroCount;
+            }
+            return result;
+        }
+
         public String toString(
                 LocaleStringProvider resolvedFile,
                 String width,

tools/cldr-code/src/test/java/org/unicode/cldr/unittest/TestUnits.java

@@ -3197,6 +3197,10 @@ public void TestUnitOrder() {
 
         checkNormalization("test case", "newton-meter");
         checkNormalization("test case", "acre-foot");
+        checkNormalization("test case", "portion-per-1e9");
+        checkNormalization("test case", "portion-per-1000");
+        checkNormalization("test case", "1e9-meter");
+        checkNormalization("test case", "1000-meter");
 
         String stdAcre = converter.getStandardUnit("acre");