From db3278a71e1a734f9989959d9e65c5ae64c38026 Mon Sep 17 00:00:00 2001
From: Fredrik Roubert <roubert@google.com>
Date: Thu, 20 Aug 2020 23:57:16 +0200
Subject: [PATCH] ICU-21035 Replace backward compatibility ulocimp_getScript()
 overload.

By always calling the dynamic memory allocation implementation directly
instead, the fixed memory buffer boundary gets pushed one step further
towards the edges.
---
 icu4c/source/common/loclikely.cpp |  3 +--
 icu4c/source/common/uloc.cpp      | 31 +++++++++++++++----------------
 icu4c/source/common/ulocimp.h     |  6 +++---
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/icu4c/source/common/loclikely.cpp b/icu4c/source/common/loclikely.cpp
index e87b06edcb4..41a12352bfc 100644
--- a/icu4c/source/common/loclikely.cpp
+++ b/icu4c/source/common/loclikely.cpp
@@ -485,8 +485,7 @@ parseTagString(
         ++position;
     }
 
-    subtagLength = ulocimp_getScript(position, script, *scriptLength, &position);
-    u_terminateChars(script, *scriptLength, subtagLength, err);
+    subtagLength = ulocimp_getScript(position, &position, *err).extract(script, *scriptLength, *err);
 
     if(U_FAILURE(*err)) {
         goto error;
diff --git a/icu4c/source/common/uloc.cpp b/icu4c/source/common/uloc.cpp
index 45fab01917b..5acf312ed38 100644
--- a/icu4c/source/common/uloc.cpp
+++ b/icu4c/source/common/uloc.cpp
@@ -1181,7 +1181,7 @@ ulocimp_getLanguage(const char *localeID,
     return result;
 }
 
-static CharString
+CharString U_EXPORT2
 ulocimp_getScript(const char *localeID,
                   const char **pEnd,
                   UErrorCode &status) {
@@ -1215,14 +1215,6 @@ ulocimp_getScript(const char *localeID,
     return result;
 }
 
-U_CFUNC int32_t
-ulocimp_getScript(const char *localeID,
-                  char *script, int32_t scriptCapacity,
-                  const char **pEnd) {
-    ErrorCode status;
-    return ulocimp_getScript(localeID, pEnd, status).extract(script, scriptCapacity, status);
-}
-
 static CharString
 ulocimp_getCountry(const char *localeID,
                    const char **pEnd,
@@ -1456,7 +1448,10 @@ uloc_openKeywords(const char* localeID,
     if(_isIDSeparator(*tmpLocaleID)) {
         const char *scriptID;
         /* Skip the script if available */
-        ulocimp_getScript(tmpLocaleID+1, NULL, 0, &scriptID);
+        ulocimp_getScript(tmpLocaleID+1, &scriptID, *status);
+        if (U_FAILURE(*status)) {
+            return 0;
+        }
         if(scriptID != tmpLocaleID+1) {
             /* Found optional script */
             tmpLocaleID = scriptID;
@@ -1729,8 +1724,6 @@ uloc_getScript(const char*    localeID,
          int32_t scriptCapacity,
          UErrorCode* err)
 {
-    int32_t i=0;
-
     if(err==NULL || U_FAILURE(*err)) {
         return 0;
     }
@@ -1746,9 +1739,9 @@ uloc_getScript(const char*    localeID,
     }
 
     if(_isIDSeparator(*localeID)) {
-        i=ulocimp_getScript(localeID+1, script, scriptCapacity, NULL);
+        return ulocimp_getScript(localeID+1, NULL, *err).extract(script, scriptCapacity, *err);
     }
-    return u_terminateChars(script, scriptCapacity, i, err);
+    return u_terminateChars(script, scriptCapacity, 0, err);
 }
 
 U_CAPI int32_t  U_EXPORT2
@@ -1776,7 +1769,10 @@ uloc_getCountry(const char* localeID,
     if(_isIDSeparator(*localeID)) {
         const char *scriptID;
         /* Skip the script if available */
-        ulocimp_getScript(localeID+1, NULL, 0, &scriptID);
+        ulocimp_getScript(localeID+1, &scriptID, *err);
+        if (U_FAILURE(*err)) {
+            return 0;
+        }
         if(scriptID != localeID+1) {
             /* Found optional script */
             localeID = scriptID;
@@ -1820,7 +1816,10 @@ uloc_getVariant(const char* localeID,
     if(_isIDSeparator(*tmpLocaleID)) {
         const char *scriptID;
         /* Skip the script if available */
-        ulocimp_getScript(tmpLocaleID+1, NULL, 0, &scriptID);
+        ulocimp_getScript(tmpLocaleID+1, &scriptID, *err);
+        if (U_FAILURE(*err)) {
+            return 0;
+        }
         if(scriptID != tmpLocaleID+1) {
             /* Found optional script */
             tmpLocaleID = scriptID;
diff --git a/icu4c/source/common/ulocimp.h b/icu4c/source/common/ulocimp.h
index cd5a357f82e..279f177f394 100644
--- a/icu4c/source/common/ulocimp.h
+++ b/icu4c/source/common/ulocimp.h
@@ -54,10 +54,10 @@ ulocimp_getLanguage(const char *localeID,
                     const char **pEnd,
                     UErrorCode &status);
 
-U_CFUNC int32_t
+icu::CharString U_EXPORT2
 ulocimp_getScript(const char *localeID,
-                   char *script, int32_t scriptCapacity,
-                   const char **pEnd);
+                  const char **pEnd,
+                  UErrorCode &status);
 
 U_CFUNC int32_t
 ulocimp_getCountry(const char *localeID,