[PATCH v5 1/1] MdePkg: UefiLib: Add a function to check if a language is supported

["Tom Zhao" <tzhao@solarflare.com>]

Add a function that checks if a target language is in the supported
languages list. Add some calls to this function where appropriate in
UefiLib.c

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Tom Zhao <tzhao@solarflare.com>
---

Notes:
    v3:
    - Add comment about usage for RFC4646 and ISO-639
    v4:
    - Remove reference to CompareISO639Lang
    v5:
    - Change doxygen format to use @retval

 MdePkg/Include/Library/UefiLib.h | 17 ++++++
 MdePkg/Library/UefiLib/UefiLib.c | 60 +++++++++++++-------
 2 files changed, 56 insertions(+), 21 deletions(-)

diff --git a/MdePkg/Include/Library/UefiLib.h
b/MdePkg/Include/Library/UefiLib.h
index 1650f30ddbc6..65e7c90eb94b 100644
--- a/MdePkg/Include/Library/UefiLib.h
+++ b/MdePkg/Include/Library/UefiLib.h
@@ -461,6 +461,23 @@ EfiTestChildHandle (
   IN CONST EFI_GUID         *ProtocolGuid
   );
 +/**
+ * This function checks the supported languages list for a target language,
+ * This only supports RFC 4646 Languages.
+ *
+ * @param      SupportedLanguages  The supported languages
+ * @param      TargetLanguage      The target language
+ *
+ * @retval     EFI_SUCCESS         The target language is supported
+ * @retval     EFI_UNSUPPORTED     The target language is unsupported
+ */
+EFI_STATUS
+EFIAPI
+IsLanguageSupported (
+  IN CONST CHAR8 *SupportedLanguages,
+  IN CONST CHAR8 *TargetLanguage
+  );
+
 /**
   This function looks up a Unicode string in UnicodeStringTable.
 diff --git a/MdePkg/Library/UefiLib/UefiLib.c
b/MdePkg/Library/UefiLib/UefiLib.c
index daa4af762e62..71eba51257f6 100644
--- a/MdePkg/Library/UefiLib/UefiLib.c
+++ b/MdePkg/Library/UefiLib/UefiLib.c
@@ -640,6 +640,36 @@ EfiTestChildHandle (
   return Status;
 }
 +/**
+ * This function checks the supported languages list for a target language,
+ * This only supports RFC 4646 Languages.
+ *
+ * @param      SupportedLanguages  The supported languages
+ * @param      TargetLanguage      The target language
+ *
+ * @retval     EFI_SUCCESS         The target language is supported
+ * @retval     EFI_UNSUPPORTED     The target language is unsupported
+ */
+EFI_STATUS
+EFIAPI
+IsLanguageSupported (
+  IN CONST CHAR8 *SupportedLanguages,
+  IN CONST CHAR8 *TargetLanguage
+  )
+{
+  UINTN Index;
+  while (*SupportedLanguages != 0) {
+    for (Index = 0; SupportedLanguages[Index] != 0 &&
SupportedLanguages[Index] != ';'; Index++);
+    if ((AsciiStrnCmp(SupportedLanguages, TargetLanguage, Index) == 0)
&& (TargetLanguage[Index] == 0)) {
+      return EFI_SUCCESS;
+    }
+    SupportedLanguages += Index;
+    for (; *SupportedLanguages != 0 && *SupportedLanguages == ';';
SupportedLanguages++);
+  }
+
+  return EFI_UNSUPPORTED;
+}
+
 /**
   This function looks up a Unicode string in UnicodeStringTable.
 @@ -800,24 +830,19 @@ LookupUnicodeString2 (
   // Make sure Language is in the set of Supported Languages
   //
   Found = FALSE;
-  while (*SupportedLanguages != 0) {
-    if (Iso639Language) {
+  if (Iso639Language) {
+    while (*SupportedLanguages != 0) {
       if (CompareIso639LanguageCode (Language, SupportedLanguages)) {
         Found = TRUE;
         break;
       }
       SupportedLanguages += 3;
-    } else {
-      for (Index = 0; SupportedLanguages[Index] != 0 &&
SupportedLanguages[Index] != ';'; Index++);
-      if ((AsciiStrnCmp(SupportedLanguages, Language, Index) == 0) &&
(Language[Index] == 0)) {
-        Found = TRUE;
-        break;
-      }
-      SupportedLanguages += Index;
-      for (; *SupportedLanguages != 0 && *SupportedLanguages == ';';
SupportedLanguages++);
     }
+  } else {
+    Found = !IsLanguageSupported(Language, SupportedLanguages);
   }
 +
   //
   // If Language is not a member of SupportedLanguages, then return
EFI_UNSUPPORTED
   //
@@ -1099,24 +1124,17 @@ AddUnicodeString2 (
   // Make sure Language is a member of SupportedLanguages
   //
   Found = FALSE;
-  while (*SupportedLanguages != 0) {
-    if (Iso639Language) {
+  if (Iso639Language) {
+    while (*SupportedLanguages != 0) {
       if (CompareIso639LanguageCode (Language, SupportedLanguages)) {
         Found = TRUE;
         break;
       }
       SupportedLanguages += 3;
-    } else {
-      for (Index = 0; SupportedLanguages[Index] != 0 &&
SupportedLanguages[Index] != ';'; Index++);
-      if (AsciiStrnCmp(SupportedLanguages, Language, Index) == 0) {
-        Found = TRUE;
-        break;
-      }
-      SupportedLanguages += Index;
-      for (; *SupportedLanguages != 0 && *SupportedLanguages == ';';
SupportedLanguages++);
     }
+  } else {
+    Found = !IsLanguageSupported(Language, SupportedLanguages);
   }
-
   //
   // If Language is not a member of SupportedLanguages, then return
EFI_UNSUPPORTED
   //
-- 
2.21.0