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Annotation of 42BSD/ingres/source/gutil/atoi.c, revision 1.1

1.1     ! root        1: # include      <ingres.h>
        !             2: # include      <sccs.h>
        !             3: 
        !             4: SCCSID(@(#)atoi.c      7.1     2/5/81)
        !             5: 
        !             6: /*
        !             7: **  ASCII CHARACTER STRING TO INTEGER CONVERSION
        !             8: **
        !             9: **     `a' is a pointer to the character string, `i' is a
        !            10: **     pointer to the word which is to contain the result.
        !            11: **     The integer is either 16-bit or 32-bit depending upon
        !            12: **     the natural word length of the machine.
        !            13: **
        !            14: **     The return value of the function is:
        !            15: **             zero:   succesful conversion; `i' contains the integer
        !            16: **             +1:     numeric overflow; `i' is unchanged
        !            17: **             -1:     syntax error; `i' is unchanged
        !            18: **
        !            19: **     A valid string is of the form:
        !            20: **             <space>* [+-] <space>* <digit>* <space>*
        !            21: */
        !            22: 
        !            23: atoi(a, i)
        !            24: register char  *a;
        !            25: int    *i;
        !            26: {
        !            27: # ifdef PDP11
        !            28:        int             sign;           /* flag to indicate the sign */
        !            29:        register int    x;              /* holds the integer being formed */
        !            30:        register char   c;
        !            31: 
        !            32:        sign = 0;
        !            33:        /* skip leading blanks */
        !            34:        while (*a == ' ')
        !            35:                a++;
        !            36:        /* check for sign */
        !            37:        switch (*a)
        !            38:        {
        !            39: 
        !            40:          case '-':
        !            41:                sign = -1;
        !            42: 
        !            43:          case '+':
        !            44:                while (*++a == ' ');
        !            45:        }
        !            46: 
        !            47:        /* at this point everything had better be numeric */
        !            48:        x = 0;
        !            49:        while ((c = *a) <= '9' && c >= '0')
        !            50:        {
        !            51:                if (x > 3276 || (x == 3276 && c > '7'))
        !            52:                        return (1);             /* overflow */
        !            53:                x = x * 10 + c - '0';
        !            54:                a++;
        !            55:        }
        !            56: 
        !            57:        /* eaten all the numerics; better be all blanks */
        !            58:        while (c = *a++)
        !            59:                if(c != ' ')                    /* syntax error */
        !            60:                        return (-1);
        !            61:        *i = sign ? -x : x;
        !            62:        return (0);             /* successful termination */
        !            63: # else
        !            64:        return (atol(a, i));
        !            65: # endif
        !            66: }

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