diff --git a/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp b/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
index b3a8515..0e9304a 100644
--- a/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
+++ b/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
@@ -13,22 +13,22 @@
 
 const JBig2ArithCtx::JBig2ArithQe kQeTable[] = {
     // Stupid hack to keep clang-format from reformatting this badly.
-    {0x5601, 1, 1, 1},   {0x3401, 2, 6, 0},   {0x1801, 3, 9, 0},
-    {0x0AC1, 4, 12, 0},  {0x0521, 5, 29, 0},  {0x0221, 38, 33, 0},
-    {0x5601, 7, 6, 1},   {0x5401, 8, 14, 0},  {0x4801, 9, 14, 0},
-    {0x3801, 10, 14, 0}, {0x3001, 11, 17, 0}, {0x2401, 12, 18, 0},
-    {0x1C01, 13, 20, 0}, {0x1601, 29, 21, 0}, {0x5601, 15, 14, 1},
-    {0x5401, 16, 14, 0}, {0x5101, 17, 15, 0}, {0x4801, 18, 16, 0},
-    {0x3801, 19, 17, 0}, {0x3401, 20, 18, 0}, {0x3001, 21, 19, 0},
-    {0x2801, 22, 19, 0}, {0x2401, 23, 20, 0}, {0x2201, 24, 21, 0},
-    {0x1C01, 25, 22, 0}, {0x1801, 26, 23, 0}, {0x1601, 27, 24, 0},
-    {0x1401, 28, 25, 0}, {0x1201, 29, 26, 0}, {0x1101, 30, 27, 0},
-    {0x0AC1, 31, 28, 0}, {0x09C1, 32, 29, 0}, {0x08A1, 33, 30, 0},
-    {0x0521, 34, 31, 0}, {0x0441, 35, 32, 0}, {0x02A1, 36, 33, 0},
-    {0x0221, 37, 34, 0}, {0x0141, 38, 35, 0}, {0x0111, 39, 36, 0},
-    {0x0085, 40, 37, 0}, {0x0049, 41, 38, 0}, {0x0025, 42, 39, 0},
-    {0x0015, 43, 40, 0}, {0x0009, 44, 41, 0}, {0x0005, 45, 42, 0},
-    {0x0001, 45, 43, 0}, {0x5601, 46, 46, 0}};
+    {0x5601, 1, 1, true},    {0x3401, 2, 6, false},   {0x1801, 3, 9, false},
+    {0x0AC1, 4, 12, false},  {0x0521, 5, 29, false},  {0x0221, 38, 33, false},
+    {0x5601, 7, 6, true},    {0x5401, 8, 14, false},  {0x4801, 9, 14, false},
+    {0x3801, 10, 14, false}, {0x3001, 11, 17, false}, {0x2401, 12, 18, false},
+    {0x1C01, 13, 20, false}, {0x1601, 29, 21, false}, {0x5601, 15, 14, true},
+    {0x5401, 16, 14, false}, {0x5101, 17, 15, false}, {0x4801, 18, 16, false},
+    {0x3801, 19, 17, false}, {0x3401, 20, 18, false}, {0x3001, 21, 19, false},
+    {0x2801, 22, 19, false}, {0x2401, 23, 20, false}, {0x2201, 24, 21, false},
+    {0x1C01, 25, 22, false}, {0x1801, 26, 23, false}, {0x1601, 27, 24, false},
+    {0x1401, 28, 25, false}, {0x1201, 29, 26, false}, {0x1101, 30, 27, false},
+    {0x0AC1, 31, 28, false}, {0x09C1, 32, 29, false}, {0x08A1, 33, 30, false},
+    {0x0521, 34, 31, false}, {0x0441, 35, 32, false}, {0x02A1, 36, 33, false},
+    {0x0221, 37, 34, false}, {0x0141, 38, 35, false}, {0x0111, 39, 36, false},
+    {0x0085, 40, 37, false}, {0x0049, 41, 38, false}, {0x0025, 42, 39, false},
+    {0x0015, 43, 40, false}, {0x0009, 44, 41, false}, {0x0005, 45, 42, false},
+    {0x0001, 45, 43, false}, {0x5601, 46, 46, false}};
 
 const unsigned int kDefaultAValue = 0x8000;
 
@@ -37,17 +37,16 @@
 JBig2ArithCtx::JBig2ArithCtx() = default;
 
 int JBig2ArithCtx::DecodeNLPS(const JBig2ArithQe& qe) {
-  // TODO(thestig): |D|, |MPS| and friends probably should be booleans.
-  int D = 1 - m_MPS;
-  if (qe.nSwitch == 1)
-    m_MPS = 1 - m_MPS;
+  bool D = !m_MPS;
+  if (qe.bSwitch)
+    m_MPS = !m_MPS;
   m_I = qe.NLPS;
   return D;
 }
 
 int JBig2ArithCtx::DecodeNMPS(const JBig2ArithQe& qe) {
   m_I = qe.NMPS;
-  return m_MPS;
+  return MPS();
 }
 
 CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream)
diff --git a/core/fxcodec/jbig2/JBig2_ArithDecoder.h b/core/fxcodec/jbig2/JBig2_ArithDecoder.h
index 0a23323..c2fed50 100644
--- a/core/fxcodec/jbig2/JBig2_ArithDecoder.h
+++ b/core/fxcodec/jbig2/JBig2_ArithDecoder.h
@@ -12,6 +12,7 @@
 #include "core/fxcrt/unowned_ptr.h"
 
 class CJBig2_BitStream;
+struct JBig2ArithQe;
 
 class JBig2ArithCtx {
  public:
@@ -19,7 +20,7 @@
     uint16_t Qe;
     uint8_t NMPS;
     uint8_t NLPS;
-    uint8_t nSwitch;
+    bool bSwitch;
   };
 
   JBig2ArithCtx();
@@ -27,11 +28,11 @@
   int DecodeNLPS(const JBig2ArithQe& qe);
   int DecodeNMPS(const JBig2ArithQe& qe);
 
-  unsigned int MPS() const { return m_MPS; }
+  unsigned int MPS() const { return m_MPS ? 1 : 0; }
   unsigned int I() const { return m_I; }
 
  private:
-  unsigned int m_MPS = 0;
+  bool m_MPS = 0;
   unsigned int m_I = 0;
 };