Fix an error 'Use-of-uninitialized-value in CPDF_Function::Call'

core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp

Index: core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
index b11254035658ae8c1be4e3688c1dd187806a388e..ae912ac50f827d9b1a16f1fcaf4d3a5c9f13b8d1 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -583,10 +583,10 @@ FX_BOOL CPDF_SampledFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const
                 }
             } else {
                 FX_SAFE_INT32 bitpos2 = blocksize[i];
-                bitpos2 += 1;
-                bitpos2 *= m_nBitsPerSample; 
+                bitpos2 += pos;
                 bitpos2 *= m_nOutputs;
-                bitpos2 += bitpos.ValueOrDie();
+                bitpos2 += j;
+                bitpos2 *= m_nBitsPerSample; 
                 if (!bitpos2.IsValid()) {
                     return FALSE;
                 }