/* 

  * strtoul.c --

  *

  *	Source code for the "strtoul" library procedure.

  *

  * Copyright (c) 1988 The Regents of the University of California.

  * Copyright (c) 1994 Sun Microsystems, Inc.

  *

  * See the file "license.terms" for information on usage and redistribution

  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

  *

  * RCS: @(#) $Id: strtoul.c,v 1.5 2002/02/25 10:36:32 dkf Exp $

  */

 #include "tclInt.h"

 #include "tclPort.h"

 /*

  * The table below is used to convert from ASCII digits to a

  * numerical equivalent.  It maps from '0' through 'z' to integers

  * (100 for non-digit characters).

  */

 static char cvtIn[] = {

     0, 1, 2, 3, 4, 5, 6, 7, 8, 9,		/* '0' - '9' */

     100, 100, 100, 100, 100, 100, 100,		/* punctuation */

     10, 11, 12, 13, 14, 15, 16, 17, 18, 19,	/* 'A' - 'Z' */

     20, 21, 22, 23, 24, 25, 26, 27, 28, 29,

     30, 31, 32, 33, 34, 35,

     100, 100, 100, 100, 100, 100,		/* punctuation */

     10, 11, 12, 13, 14, 15, 16, 17, 18, 19,	/* 'a' - 'z' */

     20, 21, 22, 23, 24, 25, 26, 27, 28, 29,

     30, 31, 32, 33, 34, 35};

 /*

  *----------------------------------------------------------------------

  *

  * strtoul --

  *

  *	Convert an ASCII string into an integer.

  *

  * Results:

  *	The return value is the integer equivalent of string.  If endPtr

  *	is non-NULL, then *endPtr is filled in with the character

  *	after the last one that was part of the integer.  If string

  *	doesn't contain a valid integer value, then zero is returned

  *	and *endPtr is set to string.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 unsigned long int

 strtoul(string, endPtr, base)

     CONST char *string;		/* String of ASCII digits, possibly

 				 * preceded by white space.  For bases

 				 * greater than 10, either lower- or

 				 * upper-case digits may be used.

 				 */

     char **endPtr;		/* Where to store address of terminating

 				 * character, or NULL. */

     int base;			/* Base for conversion.  Must be less

 				 * than 37.  If 0, then the base is chosen

 				 * from the leading characters of string:

 				 * "0x" means hex, "0" means octal, anything

 				 * else means decimal.

 				 */

 {

     register CONST char *p;

     register unsigned long int result = 0;

     register unsigned digit;

     int anyDigits = 0;

     int negative=0;

     int overflow=0;

     /*

      * Skip any leading blanks.

      */

     p = string;

     while (isspace(UCHAR(*p))) {

 	p += 1;

     }

     if (*p == '-') {

         negative = 1;

         p += 1;

     } else {

         if (*p == '+') {

             p += 1;

         }

     }

     /*

      * If no base was provided, pick one from the leading characters

      * of the string.

      */

     if (base == 0)

     {

 	if (*p == '0') {

 	    p += 1;

 	    if ((*p == 'x') || (*p == 'X')) {

 		p += 1;

 		base = 16;

 	    } else {

 		/*

 		 * Must set anyDigits here, otherwise "0" produces a

 		 * "no digits" error.

 		 */

 		anyDigits = 1;

 		base = 8;

 	    }

 	}

 	else base = 10;

     } else if (base == 16) {

 	/*

 	 * Skip a leading "0x" from hex numbers.

 	 */

 	if ((p[0] == '0') && ((p[1] == 'x') || (p[1] == 'X'))) {

 	    p += 2;

 	}

     }

     /*

      * Sorry this code is so messy, but speed seems important.  Do

      * different things for base 8, 10, 16, and other.

      */

     if (base == 8) {

 	unsigned long maxres = ULONG_MAX >> 3;

 	for ( ; ; p += 1) {

 	    digit = *p - '0';

 	    if (digit > 7) {

 		break;

 	    }

 	    if (result > maxres) { overflow = 1; }

 	    result = (result << 3);

 	    if (digit > (ULONG_MAX - result)) { overflow = 1; }

 	    result += digit;

 	    anyDigits = 1;

 	}

     } else if (base == 10) {

 	unsigned long maxres = ULONG_MAX / 10;

 	for ( ; ; p += 1) {

 	    digit = *p - '0';

 	    if (digit > 9) {

 		break;

 	    }

 	    if (result > maxres) { overflow = 1; }

 	    result *= 10;

 	    if (digit > (ULONG_MAX - result)) { overflow = 1; }

 	    result += digit;

 	    anyDigits = 1;

 	}

     } else if (base == 16) {

 	unsigned long maxres = ULONG_MAX >> 4;

 	for ( ; ; p += 1) {

 	    digit = *p - '0';

 	    if (digit > ('z' - '0')) {

 		break;

 	    }

 	    digit = cvtIn[digit];

 	    if (digit > 15) {

 		break;

 	    }

 	    if (result > maxres) { overflow = 1; }

 	    result = (result << 4);

 	    if (digit > (ULONG_MAX - result)) { overflow = 1; }

 	    result += digit;

 	    anyDigits = 1;

 	}

     } else if ( base >= 2 && base <= 36 ) {

 	unsigned long maxres = ULONG_MAX / base;

 	for ( ; ; p += 1) {

 	    digit = *p - '0';

 	    if (digit > ('z' - '0')) {

 		break;

 	    }

 	    digit = cvtIn[digit];

 	    if (digit >= ( (unsigned) base )) {

 		break;

 	    }

 	    if (result > maxres) { overflow = 1; }

 	    result *= base;

 	    if (digit > (ULONG_MAX - result)) { overflow = 1; }

 	    result += digit;

 	    anyDigits = 1;

 	}

     }

     /*

      * See if there were any digits at all.

      */

     if (!anyDigits) {

 	p = string;

     }

     if (endPtr != 0) {

 	/* unsafe, but required by the strtoul prototype */

 	*endPtr = (char *) p;

     }

     if (overflow) {

 	errno = ERANGE;

 	return ULONG_MAX;

     } 

     if (negative) {

 	return -result;

     }

     return result;

 }