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Annotation of researchv9/jerq/sgs/optim/strtol.c, revision 1.1

1.1     ! root        1: /*     @(#)strtol.c    2.1     */
        !             2: /*LINTLIBRARY*/
        !             3: #include <ctype.h>
        !             4: #define DIGIT(x)       (isdigit(x) ? (x) - '0' : \
        !             5:                        islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
        !             6: #define MBASE  ('z' - 'a' + 1 + 10)
        !             7: 
        !             8: long
        !             9: strtol(str, ptr, base)
        !            10: register char *str;
        !            11: char **ptr;
        !            12: register int base;
        !            13: {
        !            14:        register long val;
        !            15:        register int c;
        !            16:        int xx, neg = 0;
        !            17: 
        !            18:        if (ptr != (char **)0)
        !            19:                *ptr = str; /* in case no number is formed */
        !            20:        if (base < 0 || base > MBASE)
        !            21:                return (0); /* base is invalid -- should be a fatal error */
        !            22:        if (!isalnum(c = *str)) {
        !            23:                while (isspace(c))
        !            24:                        c = *++str;
        !            25:                switch (c) {
        !            26:                case '-':
        !            27:                        neg++;
        !            28:                case '+': /* fall-through */
        !            29:                        c = *++str;
        !            30:                }
        !            31:        }
        !            32:        if (base == 0)
        !            33:                if (c != '0')
        !            34:                        base = 10;
        !            35:                else if (str[1] == 'x' || str[1] == 'X')
        !            36:                        base = 16;
        !            37:                else
        !            38:                        base = 8;
        !            39:        /*
        !            40:         * for any base > 10, the digits incrementally following
        !            41:         *      9 are assumed to be "abc...z" or "ABC...Z"
        !            42:         */
        !            43:        if (!isalnum(c) || (xx = DIGIT(c)) >= base)
        !            44:                return (0); /* no number formed */
        !            45:        if (base == 16 && c == '0' && isxdigit(str[2]) &&
        !            46:            (str[1] == 'x' || str[1] == 'X'))
        !            47:                c = *(str += 2); /* skip over leading "0x" or "0X" */
        !            48:        for (val = -DIGIT(c); isalnum(c = *++str) && (xx = DIGIT(c)) < base; )
        !            49:                /* accumulate neg avoids surprises near MAXLONG */
        !            50:                val = base * val - xx;
        !            51:        if (ptr != (char **)0)
        !            52:                *ptr = str;
        !            53:        return (neg ? val : -val);
        !            54: }

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