algutils.h macros

Some useful macros for algorithms C/C++ (used early in related posts):

#ifndef _ALGUTILS_H_
#define _ALGUTILS_H_

/// Array numbers
#ifndef sizeofarray
#define sizeofarray(ARR) (sizeof(ARR) / sizeof(ARR[0]))
#endif

/// Division with ceil rounding
#define CEILDIV(X,Y) (((X)%(Y))? (1 + ((X)/(Y))) : ((X)/(Y)))

/// min, max, abs
#define MIN(X, Y) ((X)<(Y)?(X):(Y))
#define MAX(X, Y) ((X)>(Y)?(X):(Y))
#define ABS(X) ((X)<0?(-(X)):(X))

/// Swaps two variables via temporary var @a tmp
#define SWAP(x, y, tmp) do { \
    tmp = x; x = y; y = tmp; \
} while (0)

/// Print array @a ARR with length @a LEN by item format @a ELFMT
#define PRINTARRX(ARR, LEN, ELFMT) do { \
    printf("{ "); \
    for (unsigned int i=0; i<(LEN); i++) { \
        printf(ELFMT " ", (ARR)[i]); \
    } \
    printf("}\n"); \
} while (0)

/// Print array @a ARR by item format @a ELFMT
#define PRINTARR(ARR, ELFMT) PRINTARRX(ARR, sizeofarray(ARR), ELFMT)

/// Shift array @a ARR of length @a LEN by @a N positions to right
#define RSHIFT_ARR(ARR, LEN, N) do { \
    register int _rshift_arr_i_; \
    for (_rshift_arr_i_=(N)+(LEN)-1; \
         _rshift_arr_i_>(N)-1; \
         _rshift_arr_i_--) \
    { \
        *((ARR)+_rshift_arr_i_) = *((ARR)+(_rshift_arr_i_-(N))); \
    } \
} while (0)

#endif /* EOF */