From 930b4d9ab91f406ee9254cbabb55491045eb8338 Mon Sep 17 00:00:00 2001
From: Fredrik Roubert <roubert@google.com>
Date: Tue, 6 Feb 2024 13:35:28 +0100
Subject: [PATCH] ICU-22520 Add convenience wrappers for calling
 ulocimp_getSubtags().

These wrappers that call ulocimp_getSubtags() to get only one particular
subtag and then return that as icu::CharString will be convenient for
replacing code that currently calls the uloc_get*() functions writing
into a fixed size buffer.
---
 icu4c/source/common/uloc.cpp          | 60 +++++++++++++++++++++++++++
 icu4c/source/common/ulocimp.h         | 12 ++++++
 icu4c/source/common/unicode/urename.h |  4 ++
 3 files changed, 76 insertions(+)

diff --git a/icu4c/source/common/uloc.cpp b/icu4c/source/common/uloc.cpp
index c53d345599b..5dff9168bd2 100644
--- a/icu4c/source/common/uloc.cpp
+++ b/icu4c/source/common/uloc.cpp
@@ -1345,6 +1345,66 @@ _getVariant(const char* localeID,
     }
 }
 
+U_EXPORT CharString U_EXPORT2
+ulocimp_getLanguage(const char* localeID, UErrorCode& status) {
+    CharString language;
+    CharStringByteSink sink(&language);
+    ulocimp_getSubtags(
+            localeID,
+            &sink,
+            nullptr,
+            nullptr,
+            nullptr,
+            nullptr,
+            status);
+    return language;
+}
+
+U_EXPORT CharString U_EXPORT2
+ulocimp_getScript(const char* localeID, UErrorCode& status) {
+    CharString script;
+    CharStringByteSink sink(&script);
+    ulocimp_getSubtags(
+            localeID,
+            nullptr,
+            &sink,
+            nullptr,
+            nullptr,
+            nullptr,
+            status);
+    return script;
+}
+
+U_EXPORT CharString U_EXPORT2
+ulocimp_getRegion(const char* localeID, UErrorCode& status) {
+    CharString region;
+    CharStringByteSink sink(&region);
+    ulocimp_getSubtags(
+            localeID,
+            nullptr,
+            nullptr,
+            &sink,
+            nullptr,
+            nullptr,
+            status);
+    return region;
+}
+
+U_EXPORT CharString U_EXPORT2
+ulocimp_getVariant(const char* localeID, UErrorCode& status) {
+    CharString variant;
+    CharStringByteSink sink(&variant);
+    ulocimp_getSubtags(
+            localeID,
+            nullptr,
+            nullptr,
+            nullptr,
+            &sink,
+            nullptr,
+            status);
+    return variant;
+}
+
 U_EXPORT void U_EXPORT2
 ulocimp_getSubtags(
         const char* localeID,
diff --git a/icu4c/source/common/ulocimp.h b/icu4c/source/common/ulocimp.h
index cb0f519df6e..bcfe75d1699 100644
--- a/icu4c/source/common/ulocimp.h
+++ b/icu4c/source/common/ulocimp.h
@@ -79,6 +79,18 @@ ulocimp_getKeywordValue(const char* localeID,
                         icu::ByteSink& sink,
                         UErrorCode* status);
 
+U_EXPORT icu::CharString U_EXPORT2
+ulocimp_getLanguage(const char* localeID, UErrorCode& status);
+
+U_EXPORT icu::CharString U_EXPORT2
+ulocimp_getScript(const char* localeID, UErrorCode& status);
+
+U_EXPORT icu::CharString U_EXPORT2
+ulocimp_getRegion(const char* localeID, UErrorCode& status);
+
+U_EXPORT icu::CharString U_EXPORT2
+ulocimp_getVariant(const char* localeID, UErrorCode& status);
+
 U_EXPORT void U_EXPORT2
 ulocimp_setKeywordValue(const char* keywordName,
                         const char* keywordValue,
diff --git a/icu4c/source/common/unicode/urename.h b/icu4c/source/common/unicode/urename.h
index 35f94988f0e..206ae293cd6 100644
--- a/icu4c/source/common/unicode/urename.h
+++ b/icu4c/source/common/unicode/urename.h
@@ -1195,10 +1195,14 @@
 #define ulocimp_getKeywordValue U_ICU_ENTRY_POINT_RENAME(ulocimp_getKeywordValue)
 #define ulocimp_getKeywords U_ICU_ENTRY_POINT_RENAME(ulocimp_getKeywords)
 #define ulocimp_getKnownCanonicalizedLocaleForTest U_ICU_ENTRY_POINT_RENAME(ulocimp_getKnownCanonicalizedLocaleForTest)
+#define ulocimp_getLanguage U_ICU_ENTRY_POINT_RENAME(ulocimp_getLanguage)
 #define ulocimp_getName U_ICU_ENTRY_POINT_RENAME(ulocimp_getName)
 #define ulocimp_getParent U_ICU_ENTRY_POINT_RENAME(ulocimp_getParent)
+#define ulocimp_getRegion U_ICU_ENTRY_POINT_RENAME(ulocimp_getRegion)
 #define ulocimp_getRegionForSupplementalData U_ICU_ENTRY_POINT_RENAME(ulocimp_getRegionForSupplementalData)
+#define ulocimp_getScript U_ICU_ENTRY_POINT_RENAME(ulocimp_getScript)
 #define ulocimp_getSubtags U_ICU_ENTRY_POINT_RENAME(ulocimp_getSubtags)
+#define ulocimp_getVariant U_ICU_ENTRY_POINT_RENAME(ulocimp_getVariant)
 #define ulocimp_isCanonicalizedLocaleForTest U_ICU_ENTRY_POINT_RENAME(ulocimp_isCanonicalizedLocaleForTest)
 #define ulocimp_minimizeSubtags U_ICU_ENTRY_POINT_RENAME(ulocimp_minimizeSubtags)
 #define ulocimp_setKeywordValue U_ICU_ENTRY_POINT_RENAME(ulocimp_setKeywordValue)