Replace #defines with C++ constants and inline functions in exor.h (

#656)

* Remove support for `int` sizes other than 32 bits

No viable platform uses anything other than 32 bits for `int`.

* Replace `#define`s with enum constants and inline functions in `exor.h`

This avoids issues with short/common identifiers like `BPI`
and `DIFFERENT` colliding with identifiers used in other projects.

lib/abcesop/eabc/exor.h

@@ -55,38 +55,34 @@ namespace abc::exorcism {
 ///                       MACRO DEFINITIONS                          ///
 ////////////////////////////////////////////////////////////////////////
 
-// the number of bits per integer (can be 16, 32, 64 - tested for 32)
-#define BPI                 32 
-#define BPIMASK             31 
-#define LOGBPI               5
-
-// the maximum number of input variables
-#define MAXVARS           1000
-
-// the number of cubes that are allocated additionally
-#define ADDITIONAL_CUBES    33
-
-// the factor showing how many cube pairs will be allocated
-#define CUBE_PAIR_FACTOR    20
-// the following number of cube pairs are allocated:
-// nCubesAlloc/CUBE_PAIR_FACTOR
-
-#if BPI == 64
-#define DIFFERENT   0x5555555555555555
-#define BIT_COUNT(w)   (BitCount[(w)&0xffff] + BitCount[((w)>>16)&0xffff] + BitCount[((w)>>32)&0xffff] + BitCount[(w)>>48])
-#elif BPI == 32
-#define DIFFERENT   0x55555555
-#define BIT_COUNT(w)   (BitCount[(w)&0xffff] + BitCount[(w)>>16])
-#else
-#define DIFFERENT   0x5555
-#define BIT_COUNT(w)   (BitCount[(w)])
-#endif
-
-
-#define VarWord(element)  ((element)>>LOGBPI)
-#define VarBit(element)   ((element)&BPIMASK)
-
-#define TICKS_TO_SECONDS(time) ((float)(time)/(float)(CLOCKS_PER_SEC))
+enum {
+  // the number of bits per integer
+  BPI = 32,
+  BPIMASK = 31,
+  LOGBPI = 5,
+
+  // the maximum number of input variables
+  MAXVARS = 1000,
+
+  // the number of cubes that are allocated additionally
+  ADDITIONAL_CUBES = 33,
+
+  // the factor showing how many cube pairs will be allocated
+  CUBE_PAIR_FACTOR = 20,
+  // the following number of cube pairs are allocated:
+  // nCubesAlloc/CUBE_PAIR_FACTOR
+
+  DIFFERENT = 0x55555555,
+};
+
+extern unsigned char BitCount[];
+
+static inline int BIT_COUNT(int w) { return BitCount[(w)&0xffff] + BitCount[(w)>>16]; }
+
+static inline int VarWord(int element) { return element>>LOGBPI; }
+static inline int VarBit(int element) { return element&BPIMASK; }
+
+static inline float TICKS_TO_SECONDS(abctime time) { return (float)time/(float)CLOCKS_PER_SEC; }
 
 ////////////////////////////////////////////////////////////////////////
 ///                  CUBE COVER and CUBE typedefs                    ///