From: Markus Scherer <markus.icu@gmail.com>
Date: Tue, 17 Mar 2020 22:31:31 +0000 (-0700)
Subject: ICU-20916 late computation of roundedThreshold to ensure it is up to date
X-Git-Tag: release-67-rc~49
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1b71013da0e6b765bd10ebf1d6717ddf8f380965;p=icu

ICU-20916 late computation of roundedThreshold to ensure it is up to date
---

diff --git a/icu4c/source/common/locdistance.cpp b/icu4c/source/common/locdistance.cpp
index 26d3ff78e5e..18e4d91bce9 100644
--- a/icu4c/source/common/locdistance.cpp
+++ b/icu4c/source/common/locdistance.cpp
@@ -111,11 +111,6 @@ int32_t LocaleDistance::getBestIndexAndDistance(
         const LSR **supportedLSRs, int32_t supportedLSRsLength,
         int32_t shiftedThreshold,
         ULocMatchFavorSubtag favorSubtag, ULocMatchDirection direction) const {
-    // Round up the shifted threshold (if fraction bits are not 0)
-    // for comparison with un-shifted distances until we need fraction bits.
-    // (If we simply shifted non-zero fraction bits away, then we might ignore a language
-    // when it's really still a micro distance below the threshold.)
-    int32_t roundedThreshold = (shiftedThreshold + DISTANCE_FRACTION_MASK) >> DISTANCE_SHIFT;
     BytesTrie iter(trie);
     // Look up the desired language only once for all supported LSRs.
     // Its "distance" is either a match point value of 0, or a non-match negative value.
@@ -155,6 +150,11 @@ int32_t LocaleDistance::getBestIndexAndDistance(
             star = true;
         }
         U_ASSERT(0 <= distance && distance <= 100);
+        // Round up the shifted threshold (if fraction bits are not 0)
+        // for comparison with un-shifted distances until we need fraction bits.
+        // (If we simply shifted non-zero fraction bits away, then we might ignore a language
+        // when it's really still a micro distance below the threshold.)
+        int32_t roundedThreshold = (shiftedThreshold + DISTANCE_FRACTION_MASK) >> DISTANCE_SHIFT;
         // We implement "favor subtag" by reducing the language subtag distance
         // (unscientifically reducing it to a quarter of the normal value),
         // so that the script distance is relatively more important.
@@ -163,7 +163,9 @@ int32_t LocaleDistance::getBestIndexAndDistance(
         if (favorSubtag == ULOCMATCH_FAVOR_SCRIPT) {
             distance >>= 2;
         }
-        if (distance >= roundedThreshold) {
+        // Let distance == roundedThreshold pass until the tie-breaker logic
+        // at the end of the loop.
+        if (distance > roundedThreshold) {
             continue;
         }
 
@@ -181,7 +183,7 @@ int32_t LocaleDistance::getBestIndexAndDistance(
             scriptDistance &= ~DISTANCE_IS_FINAL;
         }
         distance += scriptDistance;
-        if (distance >= roundedThreshold) {
+        if (distance > roundedThreshold) {
             continue;
         }
 
@@ -191,7 +193,7 @@ int32_t LocaleDistance::getBestIndexAndDistance(
             distance += defaultRegionDistance;
         } else {
             int32_t remainingThreshold = roundedThreshold - distance;
-            if (minRegionDistance >= remainingThreshold) {
+            if (minRegionDistance > remainingThreshold) {
                 continue;
             }
 
@@ -319,7 +321,7 @@ int32_t LocaleDistance::getRegionPartitionsDistance(
                     d = getFallbackRegionDistance(iter, startState);
                     star = true;
                 }
-                if (d >= threshold) {
+                if (d > threshold) {
                     return d;
                 } else if (regionDistance < d) {
                     regionDistance = d;
@@ -332,7 +334,7 @@ int32_t LocaleDistance::getRegionPartitionsDistance(
             }
         } else if (!star) {
             int32_t d = getFallbackRegionDistance(iter, startState);
-            if (d >= threshold) {
+            if (d > threshold) {
                 return d;
             } else if (regionDistance < d) {
                 regionDistance = d;
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/impl/locale/LocaleDistance.java b/icu4j/main/classes/core/src/com/ibm/icu/impl/locale/LocaleDistance.java
index 796f4e976ef..fb16814f640 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/impl/locale/LocaleDistance.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/impl/locale/LocaleDistance.java
@@ -244,11 +244,6 @@ public class LocaleDistance {
      */
     public int getBestIndexAndDistance(LSR desired, LSR[] supportedLSRs, int supportedLSRsLength,
             int shiftedThreshold, FavorSubtag favorSubtag, LocaleMatcher.Direction direction) {
-        // Round up the shifted threshold (if fraction bits are not 0)
-        // for comparison with un-shifted distances until we need fraction bits.
-        // (If we simply shifted non-zero fraction bits away, then we might ignore a language
-        // when it's really still a micro distance below the threshold.)
-        int roundedThreshold = (shiftedThreshold + DISTANCE_FRACTION_MASK) >> DISTANCE_SHIFT;
         BytesTrie iter = new BytesTrie(trie);
         // Look up the desired language only once for all supported LSRs.
         // Its "distance" is either a match point value of 0, or a non-match negative value.
@@ -288,6 +283,11 @@ public class LocaleDistance {
                 star = true;
             }
             assert 0 <= distance && distance <= 100;
+            // Round up the shifted threshold (if fraction bits are not 0)
+            // for comparison with un-shifted distances until we need fraction bits.
+            // (If we simply shifted non-zero fraction bits away, then we might ignore a language
+            // when it's really still a micro distance below the threshold.)
+            int roundedThreshold = (shiftedThreshold + DISTANCE_FRACTION_MASK) >> DISTANCE_SHIFT;
             // We implement "favor subtag" by reducing the language subtag distance
             // (unscientifically reducing it to a quarter of the normal value),
             // so that the script distance is relatively more important.
@@ -296,7 +296,9 @@ public class LocaleDistance {
             if (favorSubtag == FavorSubtag.SCRIPT) {
                 distance >>= 2;
             }
-            if (distance >= roundedThreshold) {
+            // Let distance == roundedThreshold pass until the tie-breaker logic
+            // at the end of the loop.
+            if (distance > roundedThreshold) {
                 continue;
             }
 
@@ -314,7 +316,7 @@ public class LocaleDistance {
                 scriptDistance &= ~DISTANCE_IS_FINAL;
             }
             distance += scriptDistance;
-            if (distance >= roundedThreshold) {
+            if (distance > roundedThreshold) {
                 continue;
             }
 
@@ -324,7 +326,7 @@ public class LocaleDistance {
                 distance += defaultRegionDistance;
             } else {
                 int remainingThreshold = roundedThreshold - distance;
-                if (minRegionDistance >= remainingThreshold) {
+                if (minRegionDistance > remainingThreshold) {
                     continue;
                 }
 
@@ -452,7 +454,7 @@ public class LocaleDistance {
                         d = getFallbackRegionDistance(iter, startState);
                         star = true;
                     }
-                    if (d >= threshold) {
+                    if (d > threshold) {
                         return d;
                     } else if (regionDistance < d) {
                         regionDistance = d;
@@ -465,7 +467,7 @@ public class LocaleDistance {
                 }
             } else if (!star) {
                 int d = getFallbackRegionDistance(iter, startState);
-                if (d >= threshold) {
+                if (d > threshold) {
                     return d;
                 } else if (regionDistance < d) {
                     regionDistance = d;