ICU-22520 Make ulocimp_get*() internal to ulocimp_getSubtags().

These functions now no longer have any other callers so they can be made
internal to the compilation unit of ulocimp_getSubtags(), thus bringing
them back to how they originally were intended to be used (and making
the comment above them true once again).

This also makes it possible to remove the temporary icu::CharString
objects that previously were returned to callers and instead write
directly to icu::ByteSink, making the code both simpler and less
wasteful (also that how this was once intended).

icu4c/source/common/uloc.cpp

@@ -1159,17 +1159,19 @@ uloc_getCurrentLanguageID(const char* oldID){
     return oldID;
 }
 /*
- * the internal functions _getLanguage(), _getCountry(), _getVariant()
+ * the internal functions _getLanguage(), _getScript(), _getRegion(), _getVariant()
  * avoid duplicating code to handle the earlier locale ID pieces
  * in the functions for the later ones by
  * setting the *pEnd pointer to where they stopped parsing
  *
  * TODO try to use this in Locale
  */
-CharString U_EXPORT2
-ulocimp_getLanguage(const char *localeID,
-                    const char **pEnd,
-                    UErrorCode &status) {
+static void
+_getLanguage(const char* localeID,
+             ByteSink* sink,
+             const char** pEnd,
+             UErrorCode& status) {
+    U_ASSERT(pEnd != nullptr);
     CharString result;
 
     if (uprv_stricmp(localeID, "root") == 0) {
@@ -1204,23 +1206,23 @@ ulocimp_getLanguage(const char *localeID,
         }
     }
 
-    if(pEnd!=nullptr) {
-        *pEnd=localeID;
+    if (sink != nullptr && !result.isEmpty()) {
+        sink->Append(result.data(), result.length());
     }
 
-    return result;
+    *pEnd = localeID;
 }
 
-CharString U_EXPORT2
-ulocimp_getScript(const char *localeID,
-                  const char **pEnd,
-                  UErrorCode &status) {
+static void
+_getScript(const char* localeID,
+           ByteSink* sink,
+           const char** pEnd,
+           UErrorCode& status) {
+    U_ASSERT(pEnd != nullptr);
     CharString result;
     int32_t idLen = 0;
 
-    if (pEnd != nullptr) {
-        *pEnd = localeID;
-    }
+    *pEnd = localeID;
 
     /* copy the second item as far as possible and count its length */
     while(!_isTerminator(localeID[idLen]) && !_isIDSeparator(localeID[idLen])
@@ -1231,9 +1233,7 @@ ulocimp_getScript(const char *localeID,
     /* If it's exactly 4 characters long, then it's a script and not a country. */
     if (idLen == 4) {
         int32_t i;
-        if (pEnd != nullptr) {
-            *pEnd = localeID+idLen;
-        }
+        *pEnd = localeID + idLen;
         if (idLen >= 1) {
             result.append((char)uprv_toupper(*(localeID++)), status);
         }
@@ -1242,13 +1242,17 @@ ulocimp_getScript(const char *localeID,
         }
     }
 
-    return result;
+    if (sink != nullptr && !result.isEmpty()) {
+        sink->Append(result.data(), result.length());
+    }
 }
 
-CharString U_EXPORT2
-ulocimp_getCountry(const char *localeID,
-                   const char **pEnd,
-                   UErrorCode &status) {
+static void
+_getRegion(const char* localeID,
+           ByteSink* sink,
+           const char** pEnd,
+           UErrorCode& status) {
+    U_ASSERT(pEnd != nullptr);
     CharString result;
     int32_t idLen=0;
 
@@ -1273,11 +1277,11 @@ ulocimp_getCountry(const char *localeID,
         result.clear();
     }
 
-    if(pEnd!=nullptr) {
-        *pEnd=localeID;
+    if (sink != nullptr && !result.isEmpty()) {
+        sink->Append(result.data(), result.length());
     }
 
-    return result;
+    *pEnd = localeID;
 }
 
 /**
@@ -1285,7 +1289,7 @@ ulocimp_getCountry(const char *localeID,
  * are added to 'variant'
  */
 static void
-_getVariant(const char *localeID,
+_getVariant(const char* localeID,
             char prev,
             ByteSink* sink,
             const char** pEnd,
@@ -1396,12 +1400,9 @@ ulocimp_getSubtags(
         localeID = uloc_getDefault();
     }
 
-    {
-        CharString tmp = ulocimp_getLanguage(localeID, &localeID, status);
-        if (U_FAILURE(status)) { return; }
-        U_ASSERT(localeID != nullptr);
-        if (language != nullptr) { language->Append(tmp.data(), tmp.length()); }
-    }
+    _getLanguage(localeID, language, &localeID, status);
+    if (U_FAILURE(status)) { return; }
+    U_ASSERT(localeID != nullptr);
 
     if (pEnd != nullptr) {
         *pEnd = localeID;
@@ -1414,12 +1415,11 @@ ulocimp_getSubtags(
     if (_isIDSeparator(*localeID)) {
         const char* begin = localeID + 1;
         const char* end = nullptr;
-        CharString tmp = ulocimp_getScript(begin, &end, status);
+        _getScript(begin, script, &end, status);
         if (U_FAILURE(status)) { return; }
         U_ASSERT(end != nullptr);
         if (end != begin) {
             localeID = end;
-            if (script != nullptr) { script->Append(tmp.data(), tmp.length()); }
             if (pEnd != nullptr) { *pEnd = localeID; }
         }
     }
@@ -1429,13 +1429,12 @@ ulocimp_getSubtags(
     if (_isIDSeparator(*localeID)) {
         const char* begin = localeID + 1;
         const char* end = nullptr;
-        CharString tmp = ulocimp_getCountry(begin, &end, status);
+        _getRegion(begin, region, &end, status);
         if (U_FAILURE(status)) { return; }
         U_ASSERT(end != nullptr);
         if (end != begin) {
             hasRegion = true;
             localeID = end;
-            if (region != nullptr) { region->Append(tmp.data(), tmp.length()); }
             if (pEnd != nullptr) { *pEnd = localeID; }
         }
     }

icu4c/source/common/ulocimp.h

@@ -58,21 +58,6 @@ ulocimp_getKeywords(const char *localeID,
              UBool valuesToo,
              UErrorCode *status);
 
-icu::CharString U_EXPORT2
-ulocimp_getLanguage(const char *localeID,
-                    const char **pEnd,
-                    UErrorCode &status);
-
-icu::CharString U_EXPORT2
-ulocimp_getScript(const char *localeID,
-                  const char **pEnd,
-                  UErrorCode &status);
-
-icu::CharString U_EXPORT2
-ulocimp_getCountry(const char *localeID,
-                   const char **pEnd,
-                   UErrorCode &status);
-
 U_CAPI void U_EXPORT2
 ulocimp_getName(const char* localeID,
                 icu::ByteSink& sink,

icu4c/source/common/unicode/urename.h

@@ -1192,15 +1192,12 @@
 #define ulocimp_canonicalize U_ICU_ENTRY_POINT_RENAME(ulocimp_canonicalize)
 #define ulocimp_forLanguageTag U_ICU_ENTRY_POINT_RENAME(ulocimp_forLanguageTag)
 #define ulocimp_getBaseName U_ICU_ENTRY_POINT_RENAME(ulocimp_getBaseName)
-#define ulocimp_getCountry U_ICU_ENTRY_POINT_RENAME(ulocimp_getCountry)
 #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_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_isCanonicalizedLocaleForTest U_ICU_ENTRY_POINT_RENAME(ulocimp_isCanonicalizedLocaleForTest)
 #define ulocimp_minimizeSubtags U_ICU_ENTRY_POINT_RENAME(ulocimp_minimizeSubtags)