ctype.h

一个用于学习的操作系统

#ifndef _CTYPE_H
#define _CTYPE_H

#define _U    0x01    /* upper */
#define _L    0x02    /* lower */
#define _D    0x04    /* digit */
#define _C    0x08    /* cntrl */
#define _P    0x10    /* punct */
#define _S    0x20    /* white space (space/lf/tab) */
#define _X    0x40    /* hex digit */
#define _SP    0x80    /* hard space (0x20) */

extern unsigned char _ctype[];
extern char _ctmp;

#define isalnum(c) ((_ctype+1)[c] & (_U|_L|_D))
#define isalpha(c) ((_ctype+1)[c] & (_U|_L))
#define iscntrl(c) ((_ctype+1)[c] & (_C))
#define isdigit(c) ((_ctype+1)[c] & (_D))
#define isgraph(c) ((_ctype+1)[c] & (_P|_U|_L|_D))
#define islower(c) ((_ctype+1)[c] & (_L))
#define isprint(c) ((_ctype+1)[c] & (_P|_U|_L|_D|_SP))
#define ispunct(c) ((_ctype+1)[c] & (_P))
#define isspace(c) ((_ctype+1)[c] & (_S))
#define isupper(c) ((_ctype+1)[c] & (_U))
#define isxdigit(c) ((_ctype+1)[c] & (_D|_X))

#define isascii(c) (((unsigned) c) <= 0x7f)
#define toascii(c) (((unsigned) c) & 0x7f)

#define tolower(c) (_ctmp = c, isupper(_ctmp) ? _ctmp-('A'-'a') : _ctmp)
#define toupper(c) (_ctmp = c, islower(_ctmp) ? _ctmp-('a'-'A') : _ctmp)

#endif