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#include <limits.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
long __fastcall__ strtol (const char* nptr, char** endptr, int base)
/* Convert a string to a long int */
{
register const char* S = nptr;
unsigned long Val = 0;
unsigned char Minus = 0;
unsigned char Ovf = 0;
unsigned CvtCount = 0;
unsigned char DigitVal;
unsigned long MaxVal;
unsigned char MaxDigit;
/* Skip white space */
while (isspace (*S)) {
++S;
}
/* Check for leading + or - sign */
switch (*S) {
case '-':
Minus = 1;
/* FALLTHROUGH */
case '+':
++S;
}
/* If base is zero, we may have a 0 or 0x prefix. If base is 16, we may
** have a 0x prefix.
*/
if (base == 0) {
if (*S == '0') {
++S;
if (*S == 'x' || *S == 'X') {
++S;
base = 16;
} else {
base = 8;
}
} else {
base = 10;
}
} else if (base == 16 && *S == '0' && (S[1] == 'x' || S[1] == 'X')) {
S += 2;
}
/* Determine the maximum valid number and (if the number is equal to this
** value) the maximum valid digit.
*/
if (Minus) {
MaxVal = LONG_MIN;
} else {
MaxVal = LONG_MAX;
}
MaxDigit = MaxVal % base;
MaxVal /= base;
/* Convert the number */
while (1) {
/* Convert the digit into a numeric value */
if (isdigit (*S)) {
DigitVal = *S - '0';
} else if (isupper (*S)) {
DigitVal = *S - ('A' - 10);
} else if (islower (*S)) {
DigitVal = *S - ('a' - 10);
} else {
/* Unknown character */
break;
}
/* Don't accept a character that doesn't match base */
if (DigitVal >= base) {
break;
}
/* Don't accept anything that makes the final value invalid */
if (Val > MaxVal || (Val == MaxVal && DigitVal > MaxDigit)) {
Ovf = 1;
}
/* Calculate the next value if digit is not invalid */
if (Ovf == 0) {
Val = (Val * base) + DigitVal;
++CvtCount;
}
/* Next character from input */
++S;
}
/* Store the end pointer. If no conversion was performed, the value of
** nptr is returned in endptr.
*/
if (endptr) {
if (CvtCount > 0) {
*endptr = (char*) S;
} else {
*endptr = (char*) nptr;
}
}
/* Handle overflow */
if (Ovf) {
_seterrno (ERANGE);
if (Minus) {
return LONG_MIN;
} else {
return LONG_MAX;
}
}
/* Return the result */
if (Minus) {
return -(long)Val;
} else {
return Val;
}
}
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