diff --git a/core/fpdfapi/font/cpdf_cmap.h b/core/fpdfapi/font/cpdf_cmap.h
index 68ad26c..5526293 100644
--- a/core/fpdfapi/font/cpdf_cmap.h
+++ b/core/fpdfapi/font/cpdf_cmap.h
@@ -66,7 +66,7 @@
 
   void SetVertical(bool vert) { m_bVertical = vert; }
   void SetCodingScheme(CodingScheme scheme) { m_CodingScheme = scheme; }
-  const std::vector<CodeRange>& GetMixedFourByteLeadingRanges() {
+  const std::vector<CodeRange>& GetMixedFourByteLeadingRanges() const {
     return m_MixedFourByteLeadingRanges;
   }
   void AppendMixedFourByteLeadingRanges(const CodeRange& range) {
diff --git a/core/fpdfapi/font/cpdf_cmapparser.cpp b/core/fpdfapi/font/cpdf_cmapparser.cpp
index 5bfe17b..fca1c92 100644
--- a/core/fpdfapi/font/cpdf_cmapparser.cpp
+++ b/core/fpdfapi/font/cpdf_cmapparser.cpp
@@ -109,7 +109,7 @@
     m_Status = 0;
   } else if (m_Status == 7) {
     if (word == "endcodespacerange") {
-      auto code_ranges = m_pCMap->GetMixedFourByteLeadingRanges();
+      const auto& code_ranges = m_pCMap->GetMixedFourByteLeadingRanges();
       size_t nSegs = code_ranges.size();
       if (nSegs == 1) {
         m_pCMap->SetCodingScheme((code_ranges[0].m_CharSize == 2)
@@ -117,7 +117,7 @@
                                      : CPDF_CMap::OneByte);
       } else if (nSegs > 1) {
         m_pCMap->SetCodingScheme(CPDF_CMap::MixedFourBytes);
-        for (auto range : m_PendingRanges)
+        for (const auto& range : m_PendingRanges)
           m_pCMap->AppendMixedFourByteLeadingRanges(range);
         m_PendingRanges.clear();
       }