CNS // Phase 5: + MD5 check of the CSV data file.

Source/LanguageModelManager.h

@@ -19,6 +19,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (void)loadDataModels;
 + (void)deployZipDataFile:(NSString *)filenameWithoutExtension;
 + (void)loadCNSData;
++ (BOOL)checkIfCNSDataExistAndHashMatched;
 + (void)loadUserPhrases;
 + (void)loadUserPhraseReplacement;
 + (BOOL)checkIfUserLanguageModelFilesExist;

Source/LanguageModelManager.mm

@@ -64,6 +64,23 @@ static void LTLoadLanguageModelFile(NSString *filenameWithoutExtension, vChewing
     glanguageModelCoreCHS.loadCNSData([[self cnsDataPath] UTF8String]);
 }
 
++ (BOOL)checkIfCNSDataExistAndHashMatched
+{
+    if (![self checkIfUserDataFolderExists]) {
+        NSLog(@"User Data Folder N/A.");
+        return NO;
+    }
+    if (![self checkIfFileExist:[self cnsDataPath]]) {
+        NSLog(@"Extracted CNS Data Not Found.");
+        return NO;
+    }
+    if ([AWFileHash md5HashOfFileAtPath:[self cnsDataPath]] != [[NSUserDefaults standardUserDefaults] objectForKey:kMD5HashCNSData]) {
+        NSLog(@"Existing CNS CSV Data fingerprint mismatch, must be tampered since it gets extracted.");
+        return NO;
+    }
+    return YES;
+}
+
 + (void)loadUserPhrases
 {
     glanguageModelCoreCHT.loadUserPhrases([[self userPhrasesDataPath:kBopomofoModeIdentifierCHT] UTF8String], [[self excludedPhrasesDataPath:kBopomofoModeIdentifierCHT] UTF8String]);