/* 
// Some miscellaneous C MACROS
// Apr 05, 1998
// http://www.rdrs.net/document/
//
// Note:
//  for some #define's it may be nessecary to
//  compile with flags; -lm, and include; math.h .
*/

/* compare last z bytes of string x, y */
/* Note: check string length before comparing */
#define strlncmp(x, y, z)   (strcmp(x + strlen(x) - z, y + strlen(y) - z))

/* return digit width */
#define DIGLEN(x)   (x ? (int)(log10((double)(abs(x)))) + 1 : 1)

/* convert R[ed],G[reen],B[lue] values */
#define RGBINT(r,g,b)  (b + 256 * g + 256 * 256 * r)
/* or.. */
#define RGBINT(r,g,b)  ((r << 16) | (g << 8) | b)

/* return absolute value of the difference between its arguments */
#define DIFF(a, b)  ((a) > (b) ? (a) - (b) : (b) - (a))

/* round a floating point value */
#define ROUND(x)        (((x) < 0) ? (int)((x) - 0.5) : (int)((x) + 0.5))

/* octal conversion */
#define octtobin(c)  ((c) - '0')

/* hexadecimal conversion */
#define hextobin(c) ((c) >= 'A' && (c) <= 'F' ? c - 'A' + 10 : (c) >= 'a' && (c) <= 'f' ? c - 'a' + 10 : c - '0')

/* clear the screen */
#define CLRSCRN         "\e[0m\e[2J\e[1;1H"
/* printf("%s", CLRSCRN); */

/* returns true if x is an even digit */
#define EVEN(x)  (((x) & 1) == 0)

/* test if bit number Y in X is set (rightmost bit is bit 0) */
#define BITSET(X, Y)   ((X >> Y) & 0x1)

/* set bit number Y in X to "1" (rightmost bit is bit 0) */
#define SETBIT(X, Y)   X = X | (0x1 << Y)

/* reset bit number Y in X to "0" (rightmost bit is bit 0) */
#define RESETBIT(X, Y)   X = X & (~0 ^ (0x1 << Y))

/* macro to determine how many elements are within array */
/* note: does not matter what type of array ... */
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))

/* define PI */
#define PI   (4.0 * atan(1.0))

/* take square */
#define SQR(x) ((x == 0.0) ? 0.0 : x * x)
/* #define SQUR(X) (X)*(X) */

/* take cube */
#define CUBE(A) (A)*(A)*(A)

/* swap `binary` two values */
#define swap(a, b) a ^= b ^= a ^= b;

/* test if value `x' is an exact power of two */
#define power_two(x) ((x &(x - 1)) == 0)

/* define ctrl */
#define CTRL(c) ((c) & 037)

/* compute the remainder */
#define MOD(x, y) ((x) - ((x) / (y)) * (y))

/* conversion */
#define CENTIMETER_INCH    0.3937 // multiply centimeters by 0.3937
#define CENTIMETER_FEET    0.0328 // multiply centimeters by 0.0328
#define METERS_INCH        39.37  // multiply meters by 39.37
#define METERS_FEET        3.2808 // multiply meters by 3.2808
#define INCH_CENTIMETER    2.54   // multiply inches by 2.54
#define INCH_METER         0.0254 // multiply inches by 0.0254
#define INCH_FEET          12     // divide inches by 12
#define FEET_CENTIMETER    30.48  // multiply feet by 30.48
#define FEET_METER         0.3048 // multiply feet by 0.3048
#define FEET_INCH          12     // multiply feet by 12