From e3e7183663e297a35e5c3ae79246792af1161fec Mon Sep 17 00:00:00 2001
From: George Rhoten <grhoten@users.noreply.github.com>
Date: Wed, 26 Aug 2015 10:42:17 +0000
Subject: [PATCH] ICU-11818 Implement PluralRules in fractional RBNF

X-SVN-Rev: 37823
---
 icu4c/source/i18n/nfrule.cpp          | 12 ++++++++++--
 icu4c/source/test/intltest/itrbnf.cpp | 25 +++++++++++++++++++++++--
 icu4c/source/test/intltest/itrbnf.h   |  1 +
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/icu4c/source/i18n/nfrule.cpp b/icu4c/source/i18n/nfrule.cpp
index da55a212e53..f0e0953d802 100644
--- a/icu4c/source/i18n/nfrule.cpp
+++ b/icu4c/source/i18n/nfrule.cpp
@@ -792,8 +792,16 @@ NFRule::doFormat(double number, UnicodeString& toInsertInto, int32_t pos, int32_
         if (pluralRuleEnd < ruleText.length() - 1) {
             toInsertInto.insert(pos, ruleText.tempSubString(pluralRuleEnd + 2));
         }
-        toInsertInto.insert(pos,
-            rulePatternFormat->format((int32_t)(number/uprv_pow(radix, exponent)), status));
+        double pluralVal = number;
+        if (0 <= pluralVal && pluralVal < 1) {
+            // We're in a fractional rule, and we have to match the NumeratorSubstitution behavior.
+            // 2.3 can become 0.2999999999999998 for the fraction due to rounding errors.
+            pluralVal = uprv_round(pluralVal * uprv_pow(radix, exponent));
+        }
+        else {
+            pluralVal = pluralVal / uprv_pow(radix, exponent);
+        }
+        toInsertInto.insert(pos, rulePatternFormat->format((int32_t)(pluralVal), status));
         if (pluralRuleStart > 0) {
             toInsertInto.insert(pos, ruleText.tempSubString(0, pluralRuleStart));
         }
diff --git a/icu4c/source/test/intltest/itrbnf.cpp b/icu4c/source/test/intltest/itrbnf.cpp
index c92d8536e6c..66ee2b8fca6 100644
--- a/icu4c/source/test/intltest/itrbnf.cpp
+++ b/icu4c/source/test/intltest/itrbnf.cpp
@@ -354,11 +354,17 @@ void IntlTestRBNF::TestMultiplePluralRules() {
     UnicodeString rules("%spellout-cardinal-feminine-genitive:"
                 "0: zero;"
                 "1: ono;"
+                "2: two;"
                 "1000: << $(cardinal,one{thousand}few{thousanF}other{thousanO})$[ >>];"
                 "%spellout-cardinal-feminine:"
+                "x.x: [<< $(cardinal,one{singleton}other{plurality})$ ]>%%fractions>;"
                 "0: zero;"
                 "1: one;"
-                "1000: << $(cardinal,one{thousand}few{thousanF}other{thousanO})$[ >>];");
+                "2: two;"
+                "1000: << $(cardinal,one{thousand}few{thousanF}other{thousanO})$[ >>];"
+                "%%fractions:"
+                "10: <%spellout-cardinal-feminine< $(cardinal,one{oneth}other{tenth})$;"
+                "100: <%spellout-cardinal-feminine< $(cardinal,one{1hundredth}other{hundredth})$;");
     UErrorCode status = U_ZERO_ERROR;
     UParseError pError;
     RuleBasedNumberFormat formatter(rules, Locale("ru"), pError, status);
@@ -388,6 +394,21 @@ void IntlTestRBNF::TestMultiplePluralRules() {
         errln("RuleBasedNumberFormat(spellout-cardinal-feminine) did not return the correct value. Got: %d", result.getLong());
         errln(resultStr);
     }
+    static const char* const testData[][2] = {
+        { "0", "zero" },
+        { "1", "one" },
+        { "2", "two" },
+        { "0.1", "one oneth" },
+        { "0.2", "two tenth" },
+        { "1.1", "one singleton one oneth" },
+        { "1.2", "one singleton two tenth" },
+        { "2.1", "two plurality one oneth" },
+        { "2.2", "two plurality two tenth" },
+        { "0.01", "one 1hundredth" },
+        { "0.02", "two hundredth" },
+        { NULL, NULL }
+    };
+    doTest(&formatter, testData, TRUE);
 }
 
 void IntlTestRBNF::TestFractionalRuleSet()
@@ -475,7 +496,7 @@ void IntlTestRBNF::TestFractionalRuleSet()
             { "1.2856", "1 2/7" },
             { NULL, NULL }
         };
-       doTest(&formatter, testData, FALSE); // exact values aren't parsable from fractions
+        doTest(&formatter, testData, FALSE); // exact values aren't parsable from fractions
     }
 }
 
diff --git a/icu4c/source/test/intltest/itrbnf.h b/icu4c/source/test/intltest/itrbnf.h
index f84ff9eb5e7..8d52555aba4 100644
--- a/icu4c/source/test/intltest/itrbnf.h
+++ b/icu4c/source/test/intltest/itrbnf.h
@@ -142,6 +142,7 @@ class IntlTestRBNF : public IntlTest {
 
     void TestInfinityNaN();
     void TestVariableDecimalPoint();
+    void TestRounding();
 
 protected:
   virtual void doTest(RuleBasedNumberFormat* formatter, const char* const testData[][2], UBool testParsing);
-- 
2.40.0