diff --git a/poppler/GlobalParams.cc b/poppler/GlobalParams.cc
index ee7bb12..2db88dc 100644
--- a/poppler/GlobalParams.cc
+++ b/poppler/GlobalParams.cc
@@ -548,7 +548,9 @@ Plugin::~Plugin() {
 // parsing
 //------------------------------------------------------------------------
 
-GlobalParams::GlobalParams() {
+GlobalParams::GlobalParams(const char *customPopplerDataDir)
+  : popplerDataDir(customPopplerDataDir)
+{
   UnicodeMap *map;
   int i;
 
@@ -673,8 +675,14 @@ GlobalParams::GlobalParams() {
 void GlobalParams::scanEncodingDirs() {
   GDir *dir;
   GDirEntry *entry;
-
-  dir = new GDir(POPPLER_DATADIR "/nameToUnicode", gTrue);
+  const char *dataRoot = popplerDataDir ? popplerDataDir : POPPLER_DATADIR;
+  
+  // allocate buffer large enough to append "/nameToUnicode"
+  size_t bufSize = strlen(dataRoot) + strlen("/nameToUnicode") + 1;
+  char *dataPathBuffer = new char[bufSize];
+  
+  snprintf(dataPathBuffer, bufSize, "%s/nameToUnicode", dataRoot);
+  dir = new GDir(dataPathBuffer, gTrue);
   while (entry = dir->getNextEntry(), entry != NULL) {
     if (!entry->isDir()) {
       parseNameToUnicode(entry->getFullPath());
@@ -683,27 +691,32 @@ void GlobalParams::scanEncodingDirs() {
   }
   delete dir;
 
-  dir = new GDir(POPPLER_DATADIR "/cidToUnicode", gFalse);
+  snprintf(dataPathBuffer, bufSize, "%s/cidToUnicode", dataRoot);
+  dir = new GDir(dataPathBuffer, gFalse);
   while (entry = dir->getNextEntry(), entry != NULL) {
     addCIDToUnicode(entry->getName(), entry->getFullPath());
     delete entry;
   }
   delete dir;
 
-  dir = new GDir(POPPLER_DATADIR "/unicodeMap", gFalse);
+  snprintf(dataPathBuffer, bufSize, "%s/unicodeMap", dataRoot);
+  dir = new GDir(dataPathBuffer, gFalse);
   while (entry = dir->getNextEntry(), entry != NULL) {
     addUnicodeMap(entry->getName(), entry->getFullPath());
     delete entry;
   }
   delete dir;
 
-  dir = new GDir(POPPLER_DATADIR "/cMap", gFalse);
+  snprintf(dataPathBuffer, bufSize, "%s/cMap", dataRoot);
+  dir = new GDir(dataPathBuffer, gFalse);
   while (entry = dir->getNextEntry(), entry != NULL) {
     addCMapDir(entry->getName(), entry->getFullPath());
     toUnicodeDirs->append(entry->getFullPath()->copy());
     delete entry;
   }
   delete dir;
+  
+  delete dataPathBuffer;
 }
 
 void GlobalParams::parseNameToUnicode(GooString *name) {
diff --git a/poppler/GlobalParams.h b/poppler/GlobalParams.h
index 80c30f5..429e19d 100644
--- a/poppler/GlobalParams.h
+++ b/poppler/GlobalParams.h
@@ -159,7 +159,7 @@ public:
 
   // Initialize the global parameters by attempting to read a config
   // file.
-  GlobalParams();
+  GlobalParams(const char *customPopplerDataDir = NULL);
 
   ~GlobalParams();