Fix a problem that JP2 image is not displayed because index color space is used

core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp

Index: core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 79d73518a18c1235fbb62b0b14ae1342cc2c5783..4ed17cdfe521623301f42b5f988dc9c646730cbb 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -505,10 +505,14 @@ DIB_COMP_DATA* CPDF_DIBSource::GetDecodeAndMaskArray(FX_BOOL& bDefaultDecode, FX
     }
     int max_data = (1 << m_bpc) - 1;
     CPDF_Array* pDecode = m_pDict->GetArray(FX_BSTRC("Decode"));
+    FX_DWORD arrSize = pDecode ? pDecode->GetCount() : 0;
+    if (arrSize == 0) {
+        return NULL;
+    }
     if (pDecode) {
         for (FX_DWORD i = 0; i < m_nComponents; i ++) {
-            pCompData[i].m_DecodeMin = pDecode->GetNumber(i * 2);
-            FX_FLOAT max = pDecode->GetNumber(i * 2 + 1);
+            pCompData[i].m_DecodeMin = pDecode->GetNumber((i * 2) % arrSize);
+            FX_FLOAT max = pDecode->GetNumber((i * 2 + 1) % arrSize);
             pCompData[i].m_DecodeStep = (max - pCompData[i].m_DecodeMin) / max_data;
             FX_FLOAT def_value, def_min, def_max;
             m_pColorSpace->GetDefaultValue(i, def_value, def_min, def_max);