From d0d8535066a7b53ab307b84986e228b756b40303 Mon Sep 17 00:00:00 2001
From: Shane Carr <shane@unicode.org>
Date: Wed, 23 May 2018 04:03:19 +0000
Subject: [PATCH] ICU-13717 Adds fast path for RBNF, which is not affect by
 min/max integer digits.

X-SVN-Rev: 41439
---
 icu4c/source/i18n/smpdtfmt.cpp        | 16 +++++++++++++---
 icu4c/source/test/intltest/itrbnf.cpp | 16 ++++++++++++++++
 icu4c/source/test/intltest/itrbnf.h   |  1 +
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/icu4c/source/i18n/smpdtfmt.cpp b/icu4c/source/i18n/smpdtfmt.cpp
index cc5da8b9d8..210e7db1a2 100644
--- a/icu4c/source/i18n/smpdtfmt.cpp
+++ b/icu4c/source/i18n/smpdtfmt.cpp
@@ -53,6 +53,7 @@
 #include "unicode/vtzone.h"
 #include "unicode/udisplaycontext.h"
 #include "unicode/brkiter.h"
+#include "unicode/rbnf.h"
 #include "uresimp.h"
 #include "olsontz.h"
 #include "patternprops.h"
@@ -2069,7 +2070,6 @@ SimpleDateFormat::zeroPaddingNumber(
             }
         }
     }
-
     if (fastFormatter != nullptr) {
         // Can use fast path
         number::impl::UFormattedNumberData result;
@@ -2080,9 +2080,19 @@ SimpleDateFormat::zeroPaddingNumber(
             return;
         }
         appendTo.append(result.string.toTempUnicodeString());
+        return;
+    }
 
-    } else if (currentNumberFormat != nullptr) {
-        // Fall back to slow path
+    // Check for RBNF (no clone necessary)
+    auto* rbnf = dynamic_cast<const RuleBasedNumberFormat*>(currentNumberFormat);
+    if (rbnf != nullptr) {
+        FieldPosition pos(FieldPosition::DONT_CARE);
+        rbnf->format(value, appendTo, pos);  // 3rd arg is there to speed up processing
+        return;
+    }
+
+    // Fall back to slow path (clone and mutate the NumberFormat)
+    if (currentNumberFormat != nullptr) {
         FieldPosition pos(FieldPosition::DONT_CARE);
         LocalPointer<NumberFormat> nf(dynamic_cast<NumberFormat*>(currentNumberFormat->clone()));
         nf->setMinimumIntegerDigits(minDigits);
diff --git a/icu4c/source/test/intltest/itrbnf.cpp b/icu4c/source/test/intltest/itrbnf.cpp
index e6e9078014..c62715bb85 100644
--- a/icu4c/source/test/intltest/itrbnf.cpp
+++ b/icu4c/source/test/intltest/itrbnf.cpp
@@ -76,6 +76,7 @@ void IntlTestRBNF::runIndexedTest(int32_t index, UBool exec, const char* &name,
         TESTCASE(24, TestLargeNumbers);
         TESTCASE(25, TestCompactDecimalFormatStyle);
         TESTCASE(26, TestParseFailure);
+        TESTCASE(27, TestMinMaxIntegerDigitsIgnored);
 #else
         TESTCASE(0, TestRBNFDisabled);
 #endif
@@ -2300,6 +2301,21 @@ void IntlTestRBNF::TestParseFailure() {
     }
 }
 
+void IntlTestRBNF::TestMinMaxIntegerDigitsIgnored() {
+    IcuTestErrorCode status(*this, "TestMinMaxIntegerDigitsIgnored");
+
+    // NOTE: SimpleDateFormat has an optimization that depends on the fact that min/max integer digits
+    // do not affect RBNF (see SimpleDateFormat#zeroPaddingNumber).
+    RuleBasedNumberFormat rbnf(URBNF_SPELLOUT, "en", status);
+    rbnf.setMinimumIntegerDigits(2);
+    rbnf.setMaximumIntegerDigits(3);
+    UnicodeString result;
+    rbnf.format(3, result.remove(), status);
+    assertEquals("Min integer digits are ignored", u"three", result);
+    rbnf.format(1012, result.remove(), status);
+    assertEquals("Max integer digits are ignored", u"one thousand twelve", result);
+}
+
 void 
 IntlTestRBNF::doTest(RuleBasedNumberFormat* formatter, const char* const testData[][2], UBool testParsing) 
 {
diff --git a/icu4c/source/test/intltest/itrbnf.h b/icu4c/source/test/intltest/itrbnf.h
index e58d321362..c82b50d86f 100644
--- a/icu4c/source/test/intltest/itrbnf.h
+++ b/icu4c/source/test/intltest/itrbnf.h
@@ -148,6 +148,7 @@ class IntlTestRBNF : public IntlTest {
     void TestLargeNumbers();
     void TestCompactDecimalFormatStyle();
     void TestParseFailure();
+    void TestMinMaxIntegerDigitsIgnored();
 
 protected:
   virtual void doTest(RuleBasedNumberFormat* formatter, const char* const testData[][2], UBool testParsing);