jbig2dec: Work around exponentiation warning from clang.

clang complains like so: jbig2_arith.c:258:17: warning: result of '10 ^ 9' is 3; did you mean '1e9'? [-Wxor-used-as-pow] {0x3801, 10 ^ 9, 14 ^ 9}, But 10 ^ 9 is indeed meant to be xor, not exponentiation. The const values are identical to those in table E.1 in the JBIG2 spec. The workaround is to wrap everything in macros, adding extra parenthesis, which causes the compiler warning not to trip.
ArtifexSoftware · Aug 28, 2023 · fbf863c · fbf863c
1 parent bd26fa7
commit fbf863c
Showing 1 changed file with 50 additions and 47 deletions.
diff --git a/jbig2_arith.c b/jbig2_arith.c
@@ -245,54 +245,57 @@ typedef struct {
     byte lps_xor;               /* lps_xor = index ^ NLPS ^ (SWITCH << 7) */
 } Jbig2ArithQe;
 
+#define MPS(index, nmps) ((index) ^ (nmps))
+#define LPS(index, nlps, swtch) ((index) ^ (nlps) ^ ((swtch) << 7))
+
 static const Jbig2ArithQe jbig2_arith_Qe[MAX_QE_ARRAY_SIZE] = {
-    {0x5601, 1 ^ 0, 1 ^ 0 ^ 0x80},
-    {0x3401, 2 ^ 1, 6 ^ 1},
-    {0x1801, 3 ^ 2, 9 ^ 2},
-    {0x0AC1, 4 ^ 3, 12 ^ 3},
-    {0x0521, 5 ^ 4, 29 ^ 4},
-    {0x0221, 38 ^ 5, 33 ^ 5},
-    {0x5601, 7 ^ 6, 6 ^ 6 ^ 0x80},
-    {0x5401, 8 ^ 7, 14 ^ 7},
-    {0x4801, 9 ^ 8, 14 ^ 8},
-    {0x3801, 10 ^ 9, 14 ^ 9},
-    {0x3001, 11 ^ 10, 17 ^ 10},
-    {0x2401, 12 ^ 11, 18 ^ 11},
-    {0x1C01, 13 ^ 12, 20 ^ 12},
-    {0x1601, 29 ^ 13, 21 ^ 13},
-    {0x5601, 15 ^ 14, 14 ^ 14 ^ 0x80},
-    {0x5401, 16 ^ 15, 14 ^ 15},
-    {0x5101, 17 ^ 16, 15 ^ 16},
-    {0x4801, 18 ^ 17, 16 ^ 17},
-    {0x3801, 19 ^ 18, 17 ^ 18},
-    {0x3401, 20 ^ 19, 18 ^ 19},
-    {0x3001, 21 ^ 20, 19 ^ 20},
-    {0x2801, 22 ^ 21, 19 ^ 21},
-    {0x2401, 23 ^ 22, 20 ^ 22},
-    {0x2201, 24 ^ 23, 21 ^ 23},
-    {0x1C01, 25 ^ 24, 22 ^ 24},
-    {0x1801, 26 ^ 25, 23 ^ 25},
-    {0x1601, 27 ^ 26, 24 ^ 26},
-    {0x1401, 28 ^ 27, 25 ^ 27},
-    {0x1201, 29 ^ 28, 26 ^ 28},
-    {0x1101, 30 ^ 29, 27 ^ 29},
-    {0x0AC1, 31 ^ 30, 28 ^ 30},
-    {0x09C1, 32 ^ 31, 29 ^ 31},
-    {0x08A1, 33 ^ 32, 30 ^ 32},
-    {0x0521, 34 ^ 33, 31 ^ 33},
-    {0x0441, 35 ^ 34, 32 ^ 34},
-    {0x02A1, 36 ^ 35, 33 ^ 35},
-    {0x0221, 37 ^ 36, 34 ^ 36},
-    {0x0141, 38 ^ 37, 35 ^ 37},
-    {0x0111, 39 ^ 38, 36 ^ 38},
-    {0x0085, 40 ^ 39, 37 ^ 39},
-    {0x0049, 41 ^ 40, 38 ^ 40},
-    {0x0025, 42 ^ 41, 39 ^ 41},
-    {0x0015, 43 ^ 42, 40 ^ 42},
-    {0x0009, 44 ^ 43, 41 ^ 43},
-    {0x0005, 45 ^ 44, 42 ^ 44},
-    {0x0001, 45 ^ 45, 43 ^ 45},
-    {0x5601, 46 ^ 46, 46 ^ 46}
+    {0x5601, MPS(0, 1), LPS(0, 1, 1)},
+    {0x3401, MPS(1, 2), LPS(1, 6, 0)},
+    {0x1801, MPS(2, 3), LPS(2, 9, 0)},
+    {0x0AC1, MPS(3, 4), LPS(3, 12, 0)},
+    {0x0521, MPS(4, 5), LPS(4, 29, 0)},
+    {0x0221, MPS(5, 38), LPS(5, 33, 0)},
+    {0x5601, MPS(6, 7), LPS(6, 6, 1)},
+    {0x5401, MPS(7, 8), LPS(7, 14, 0)},
+    {0x4801, MPS(8, 9), LPS(8, 14, 0)},
+    {0x3801, MPS(9, 10), LPS(9, 14, 0)},
+    {0x3001, MPS(10, 11), LPS(10, 17, 0)},
+    {0x2401, MPS(11, 12), LPS(11, 18, 0)},
+    {0x1C01, MPS(12, 13), LPS(12, 20, 0)},
+    {0x1601, MPS(13, 29), LPS(13, 21, 0)},
+    {0x5601, MPS(14, 15), LPS(14, 14, 1)},
+    {0x5401, MPS(15, 16), LPS(15, 14, 0)},
+    {0x5101, MPS(16, 17), LPS(16, 15, 0)},
+    {0x4801, MPS(17, 18), LPS(17, 16, 0)},
+    {0x3801, MPS(18, 19), LPS(18, 17, 0)},
+    {0x3401, MPS(19, 20), LPS(19, 18, 0)},
+    {0x3001, MPS(20, 21), LPS(20, 19, 0)},
+    {0x2801, MPS(21, 22), LPS(21, 19, 0)},
+    {0x2401, MPS(22, 23), LPS(22, 20, 0)},
+    {0x2201, MPS(23, 24), LPS(23, 21, 0)},
+    {0x1C01, MPS(24, 25), LPS(24, 22, 0)},
+    {0x1801, MPS(25, 26), LPS(25, 23, 0)},
+    {0x1601, MPS(26, 27), LPS(26, 24, 0)},
+    {0x1401, MPS(27, 28), LPS(27, 25, 0)},
+    {0x1201, MPS(28, 29), LPS(28, 26, 0)},
+    {0x1101, MPS(29, 30), LPS(29, 27, 0)},
+    {0x0AC1, MPS(30, 31), LPS(30, 28, 0)},
+    {0x09C1, MPS(31, 32), LPS(31, 29, 0)},
+    {0x08A1, MPS(32, 33), LPS(32, 30, 0)},
+    {0x0521, MPS(33, 34), LPS(33, 31, 0)},
+    {0x0441, MPS(34, 35), LPS(34, 32, 0)},
+    {0x02A1, MPS(35, 36), LPS(35, 33, 0)},
+    {0x0221, MPS(36, 37), LPS(36, 34, 0)},
+    {0x0141, MPS(37, 38), LPS(37, 35, 0)},
+    {0x0111, MPS(38, 39), LPS(38, 36, 0)},
+    {0x0085, MPS(39, 40), LPS(39, 37, 0)},
+    {0x0049, MPS(40, 41), LPS(40, 38, 0)},
+    {0x0025, MPS(41, 42), LPS(41, 39, 0)},
+    {0x0015, MPS(42, 43), LPS(42, 40, 0)},
+    {0x0009, MPS(43, 44), LPS(43, 41, 0)},
+    {0x0005, MPS(44, 45), LPS(44, 42, 0)},
+    {0x0001, MPS(45, 45), LPS(45, 43, 0)},
+    {0x5601, MPS(46, 46), LPS(46, 46, 0)}
 };
 
 static int