Fixed issue 1207

ccmain/tesseractclass.cpp

 ///////////////////////////////////////////////////////////////////////
 // File:        tesseractclass.cpp
-// Description: An instance of Tesseract. For thread safety, *every*
-//              global variable goes in here, directly, or indirectly.
+// Description: The Tesseract class. It holds/owns everything needed
+//              to run Tesseract on a single language, and also a set of
+//              sub-Tesseracts to run sub-languages. For thread safety, *every*
+//              variable that was previously global or static (except for
+//              constant data, and some visual debugging flags) has been moved
+//              in here, directly, or indirectly.
+//              This makes it safe to run multiple Tesseracts in different
+//              threads in parallel, and keeps the different language
+//              instances separate.
+//              Some global functions remain, but they are isolated re-entrant
+//              functions that operate on their arguments. Functions that work
+//              on variable data have been moved to an appropriate class based
+//              mostly on the directory hierarchy. For more information see
+//              slide 6 of "2ArchitectureAndDataStructures" in
+// https://drive.google.com/file/d/0B7l10Bj_LprhbUlIUFlCdGtDYkE/edit?usp=sharing
+//              Some global data and related functions still exist in the
+//              training-related code, but they don't interfere with normal
+//              recognition operation.
 // Author:      Ray Smith
 // Created:     Fri Mar 07 08:17:01 PST 2008
 //
@@ -65,6 +81,9 @@ Tesseract::Tesseract()
                   "Blacklist of chars not to recognize", this->params()),
     STRING_MEMBER(tessedit_char_whitelist, "",
                   "Whitelist of chars to recognize", this->params()),
+    STRING_MEMBER(tessedit_char_unblacklist, "",
+                  "List of chars to override tessedit_char_blacklist",
+                  this->params()),
     BOOL_MEMBER(tessedit_ambigs_training, false,
                 "Perform training for ambiguities", this->params()),
     INT_MEMBER(pageseg_devanagari_split_strategy,
@@ -578,11 +597,13 @@ void Tesseract::ResetDocumentDictionary() {
 void Tesseract::SetBlackAndWhitelist() {
   // Set the white and blacklists (if any)
   unicharset.set_black_and_whitelist(tessedit_char_blacklist.string(),
-                                     tessedit_char_whitelist.string());
+                                     tessedit_char_whitelist.string(),
+                                     tessedit_char_unblacklist.string());
   // Black and white lists should apply to all loaded classifiers.
   for (int i = 0; i < sub_langs_.size(); ++i) {
     sub_langs_[i]->unicharset.set_black_and_whitelist(
-        tessedit_char_blacklist.string(), tessedit_char_whitelist.string());
+        tessedit_char_blacklist.string(), tessedit_char_whitelist.string(),
+        tessedit_char_unblacklist.string());
   }
 }
 

ccmain/tesseractclass.h

 ///////////////////////////////////////////////////////////////////////
 // File:        tesseractclass.h
-// Description: An instance of Tesseract. For thread safety, *every*
+// Description: The Tesseract class. It holds/owns everything needed
+//              to run Tesseract on a single language, and also a set of
+//              sub-Tesseracts to run sub-languages. For thread safety, *every*
 //              global variable goes in here, directly, or indirectly.
+//              This makes it safe to run multiple Tesseracts in different
+//              threads in parallel, and keeps the different language
+//              instances separate.
 // Author:      Ray Smith
 // Created:     Fri Mar 07 08:17:01 PST 2008
 //
@@ -743,6 +748,8 @@ class Tesseract : public Wordrec {
                "Blacklist of chars not to recognize");
   STRING_VAR_H(tessedit_char_whitelist, "",
                "Whitelist of chars to recognize");
+  STRING_VAR_H(tessedit_char_unblacklist, "",
+               "List of chars to override tessedit_char_blacklist");
   BOOL_VAR_H(tessedit_ambigs_training, false,
              "Perform training for ambiguities");
   INT_VAR_H(pageseg_devanagari_split_strategy,

ccutil/unicharset.cpp

@@ -985,8 +985,10 @@ bool UNICHARSET::major_right_to_left() const {
 // Set a whitelist and/or blacklist of characters to recognize.
 // An empty or NULL whitelist enables everything (minus any blacklist).
 // An empty or NULL blacklist disables nothing.
+// An empty or NULL blacklist has no effect.
 void UNICHARSET::set_black_and_whitelist(const char* blacklist,
-                                         const char* whitelist) {
+                                         const char* whitelist,
+                                         const char* unblacklist) {
   bool def_enabled = whitelist == NULL || whitelist[0] == '\0';
   // Set everything to default
   for (int ch = 0; ch < size_used; ++ch)
@@ -1009,6 +1011,15 @@ void UNICHARSET::set_black_and_whitelist(const char* blacklist,
         unichars[encoding[i]].properties.enabled = false;
     }
   }
+  if (unblacklist != NULL && unblacklist[0] != '\0') {
+    // Re-enable the unblacklist.
+    GenericVector<UNICHAR_ID> encoding;
+    encode_string(unblacklist, false, &encoding, NULL, NULL);
+    for (int i = 0; i < encoding.size(); ++i) {
+      if (encoding[i] != INVALID_UNICHAR_ID)
+        unichars[encoding[i]].properties.enabled = true;
+    }
+  }
 }
 
 int UNICHARSET::add_script(const char* script) {

ccutil/unicharset.h

@@ -381,11 +381,14 @@ class UNICHARSET {
   // Set a whitelist and/or blacklist of characters to recognize.
   // An empty or NULL whitelist enables everything (minus any blacklist).
   // An empty or NULL blacklist disables nothing.
+  // An empty or NULL unblacklist has no effect.
   // The blacklist overrides the whitelist.
+  // The unblacklist overrides the blacklist.
   // Each list is a string of utf8 character strings. Boundaries between
   // unicharset units are worked out automatically, and characters not in
   // the unicharset are silently ignored.
-  void set_black_and_whitelist(const char* blacklist, const char* whitelist);
+  void set_black_and_whitelist(const char* blacklist, const char* whitelist,
+                               const char* unblacklist);
 
   // Set the isalpha property of the given unichar to the given value.
   void set_isalpha(UNICHAR_ID unichar_id, bool value) {