windows-nt-4.0/private/windbg/lib/strtoli.c

/***
*strtoli.c - Contains C runtimes strtol and strtoul
*
*       Copyright (c) 1989-1993, Microsoft Corporation. All rights reserved.
*       Copyright (c) 1989-1993, Digital Equipment Corporation. All rights reserved.
*
*Purpose:
*       strtoli - convert ascii string to long signed large integer
*       strtouli - convert ascii string to long unsigned large integer
*
*Revision History:
*       04-28-93  MBH   Module created, based on strtol.c
*
*******************************************************************************/


#include <nt.h>
#include <ntrtl.h>
#include <nturtl.h>
#include <ntdbg.h>


#include <windows.h>
#include <shellapi.h>




// #include <cruntime.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <ctype.h>


/***
*strtoli, strtouli(nptr,endptr,ibase) - Convert ascii string to long un/signed
*       large integer.
*
*Purpose:
*       Convert an ascii string to a long 64-bit value.  The base
*       used for the caculations is supplied by the caller.  The base
*       must be in the range 0, 2-36.  If a base of 0 is supplied, the
*       ascii string must be examined to determine the base of the
*       number:
*               (a) First char = '0', second char = 'x' or 'X',
*                   use base 16.
*               (b) First char = '0', use base 8
*               (c) First char in range '1' - '9', use base 10.
*
*       If the 'endptr' value is non-NULL, then strtoli/strtouli places
*       a pointer to the terminating character in this value.
*       See ANSI standard for details
*
*Entry:
*       nptr == NEAR/FAR pointer to the start of string.
*       endptr == NEAR/FAR pointer to the end of the string.
*       ibase == integer base to use for the calculations.
*
*       string format: [whitespace] [sign] [0] [x] [digits/letters]
*
*Exit:
*       Good return:
*               result
*
*       Overflow return:
*               strtoli -- LONG_MAX or LONG_MIN in HighPart
*               strtouli -- ULONG_MAX in HighPart
*               strtoli/strtouli -- errno == ERANGE
*
*       No digits or bad base return:
*               0
*               endptr = nptr*
*
*Exceptions:
*       None.
*******************************************************************************/

/* flag values */
#define FL_UNSIGNED   1       /* strtoul called */
#define FL_NEG        2       /* negative sign found */
#define FL_OVERFLOW   4       /* overflow occured */
#define FL_READDIGIT  8       /* we've read at least one correct digit */

static
LARGE_INTEGER
// MBH - if this is a library, this should be CRTAPI3
_CRTAPI2 strtoxl (
        const char *nptr,
        const char **endptr,
        int ibase,
        int flags
        )
{
        const char *p;
        char c;

        LARGE_INTEGER number;        // being computed
        unsigned long  digval;        // each digit in turn
        LARGE_INTEGER maxval;        // value more than which --> overflow
        LARGE_INTEGER  maxli;         // largest possible large integer
        unsigned long  remainder;     // maxli=maxval/radix + remainder

        p = nptr;                       /* p is our scanning pointer */
        number.QuadPart = 0;
        maxli.QuadPart  = -1;

        c = *p++;                       /* read char */
        while ( isspace((int)(unsigned char)c) )
                c = *p++;               /* skip whitespace */

        if (c == '-') {
                flags |= FL_NEG;        /* remember minus sign */
                c = *p++;
        }
        else if (c == '+')
                c = *p++;               /* skip sign */

        if (ibase < 0 || ibase == 1 || ibase > 36) {
                /* bad base! */
                if (endptr)
                        /* store beginning of string in endptr */
                        *endptr = nptr;
                number.QuadPart = 0;
                return number;
        }
        else if (ibase == 0) {
                /* determine base free-lance, based on first two chars of
                   string */
                if (c != '0')
                        ibase = 10;
                else if (*p == 'x' || *p == 'X')
                        ibase = 16;
                else
                        ibase = 8;
        }

        if (ibase == 16) {
                /* we might have 0x in front of number; remove if there */
                if (c == '0' && (*p == 'x' || *p == 'X')) {
                        ++p;
                        c = *p++;       /* advance past prefix */
                }
        }

        /* if our number exceeds this, we will overflow on multiply */
        maxval.QuadPart = maxli.QuadPart / ibase;
        remainder = (unsigned long)(maxli.QuadPart - maxval.QuadPart);

        for (;;) {      /* exit in middle of loop */
                /* convert c to value */
                if ( isdigit((int)(unsigned char)c) )
                        digval = c - '0';
                else if ( isalpha((int)(unsigned char)c) )
                        digval = toupper(c) - 'A' + 10;
                else
                        break;
                if (digval >= (unsigned)ibase)
                        break;          /* exit loop if bad digit found */

                /* record the fact we have read one digit */
                flags |= FL_READDIGIT;

                /* we now need to compute number = number * base + digval,
                   but we need to know if overflow occured.  This requires
                   a tricky pre-check. */

                if (number.QuadPart <= maxval.QuadPart && digval <= remainder) {
                    //
                    // we won't overflow, go ahead and multiply
                    //
                    number.QuadPart = (number.QuadPart * ibase) + digval;
                } else {
                    //
                    // we would have overflowed -- set the overflow flag
                    //
                    flags |= FL_OVERFLOW;
                }

                c = *p++;               /* read next digit */
        }

        --p;                            /* point to place that stopped scan */

        if (!(flags & FL_READDIGIT)) {
                /* no number there; return 0 and point to beginning of
                   string */
                if (endptr)
                        /* store beginning of string in endptr later on */
                        p = nptr;
                /* return 0 */
                number.QuadPart = 0;
        }
        else if ((flags & FL_OVERFLOW) || (!(flags & FL_UNSIGNED) && (number.QuadPart < 0))) {

                /* overflow occurred or signed overflow occurred */
                errno = ERANGE;
                if (flags & FL_UNSIGNED)
                        number.QuadPart = maxli.QuadPart >> 1;
                else
                        /* set error code, will be negated if necc. */
                        number = maxli;
        }

        if (endptr != NULL)
                /* store pointer to char that stopped the scan */
                *endptr = p;

        if (flags & FL_NEG)
                /* negate result if there was a neg sign */
                number.QuadPart = number.QuadPart * -1;

        return number;                  /* done. */
}

LARGE_INTEGER
// _CRTAPI1
strtoli (
        const char *nptr,
        char **endptr,
        int ibase
        )
{
        return strtoxl(nptr, endptr, ibase, 0);
}

ULARGE_INTEGER
// _CRTAPI1
strtouli (
        const char *nptr,
        char **endptr,
        int ibase
        )
{
        ULARGE_INTEGER uli;
        LARGE_INTEGER li;

        li = strtoxl(nptr, endptr, ibase, FL_UNSIGNED);
        uli.LowPart = li.LowPart;
        uli.HighPart = li.HighPart;
        return uli;
}