Return to strtoul.c CVS log

Up to [Research Unix] / researchv10no / cmd / sort

Annotation of researchv10no/cmd/sort/strtoul.c, revision 1.1

1.1     ! root        1: /* Copyright AT&T Bell Laboratories, 1993 */
        !             2: /* Convert string to unsigned long.
        !             3: ** Assumes ASCII properties - contiguity of 0-9, A-Z, a-z,
        !             4: ** digits less than letters, lower case maskable to upper.
        !             5: */
        !             6: #include <ctype.h>
        !             7: #include <errno.h>
        !             8: 
        !             9: #define DIGIT(x)       ((x)<='9'? (x)-'0': TOUPPER(x)+10-'A')
        !            10: #define TOUPPER(x)     ((x) & ~('a'-'A'))
        !            11: #define MBASE  ('z' - 'a' + 1 + 10)
        !            12: #define T_ULONG_MAX    ~(unsigned long)0
        !            13: 
        !            14: unsigned long
        !            15: strtoul(str, nptr, base)
        !            16: char *str;
        !            17: char **nptr;
        !            18: int base;
        !            19: {
        !            20:        register unsigned long val;
        !            21:        register int c;
        !            22:        int xx;
        !            23:        int overflow = 0, neg = 0;
        !            24:        unsigned long   multmax;
        !            25: 
        !            26:        if (nptr)
        !            27:                *nptr = str; /* in case no number is formed */
        !            28:        c = *str;
        !            29:        while (isspace(c))
        !            30:                c = *++str;
        !            31:        switch(c) {
        !            32:        case '-':
        !            33:                neg = 1;
        !            34:        case'+':
        !            35:                c = *++str;
        !            36:        }
        !            37:        if (base == 0)
        !            38:                if (c != '0')
        !            39:                        base = 10;
        !            40:                else if (TOUPPER(str[1]) == 'X')
        !            41:                        base = 16;
        !            42:                else
        !            43:                        base = 8;
        !            44:        if (base < 2 || base > MBASE)
        !            45:                return (0); /* base is invalid -- should be a fatal error */
        !            46:        if (!isalnum(c) || DIGIT(c) >= base)
        !            47:                return (0); /* no number formed */
        !            48:        if (base == 16 && c == '0' && (TOUPPER(str[1]) == 'X') &&
        !            49:                isxdigit(str[2]))
        !            50:                c = *(str += 2); /* skip over leading "0x" or "0X" */
        !            51: 
        !            52:        multmax = T_ULONG_MAX / (unsigned)base;
        !            53:        for (val = DIGIT(c); isalnum(c = *++str) && (xx = DIGIT(c)) < base; )
        !            54:                if (val > multmax || (val = val*base + xx) < xx)
        !            55:                        overflow = 1;
        !            56:        if (nptr)
        !            57:                *nptr = str;
        !            58:        if (overflow) {
        !            59:                errno = ERANGE;
        !            60:                return T_ULONG_MAX;
        !            61:        } else
        !            62:                return neg? -val: val;
        !            63: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.