/*

 * Very simple implementation of strtoul() for gawk,

 * for old systems.  Descriptive prose from the Linux man page.

 *

 * May 2004

 */

/* #define TEST 1 */

#ifdef TEST

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

#include <string.h>

#include <errno.h>

#include <limits.h>

#define strtoul mystrtoul

#endif

#ifndef ULONG_MAX

#define ULONG_MAX (~ 0UL)

#endif

unsigned long int

strtoul(nptr, endptr, base)

const char *nptr;

char **endptr;

int base;

{

	static char lower[] = "abcdefghijklmnopqrstuvwxyz";

	unsigned long result = 0UL;

	char *nptr_orig = (char *) nptr;

	bool neg = false;

	char *cp, c;

	int val;

	bool sawdigs = false;

	/*

	 * The strtoul() function converts the initial part of the

	 * string in nptr to an unsigned long integer value according

	 * to the given base, which must be between 2 and 36 inclusive,

	 * or be the special value 0.

	 */

	if ((base != 0 && (base < 2 || base > 36)) || nptr == NULL) {

		if (endptr != NULL)

			*endptr = nptr_orig;

		errno = EINVAL;

		return 0;

	}

	/*

	 * The string must [sic] begin with an arbitrary amount of white space

	 * (as determined by isspace(3)) followed by a single optional

	 * `+' or `-' sign.

         */

	while (isspace(*nptr))

		nptr++;

	if (*nptr == '+')

		nptr++;

	else if (*nptr == '-') {

		nptr++;

		neg = true;

	}

       /*

	* If base is zero or 16, the string may then include a `0x' prefix,

	* and the number will be read in base 16; otherwise, a zero base is

	* taken as 10 (decimal) unless the next character is `0', in which

	* case it is taken as 8 (octal).

	*/

       if ((base == 0 || base == 16)

           && nptr[0] == '0'

	   && (nptr[1] == 'x' || nptr[1] == 'X')) {

		base = 16;	/* force it */

		nptr += 2;	/* skip 0x */

	} else if ((base == 0 || base == 8) && nptr[0] == '0') {

		base = 8;

		nptr++;

	} else if (base == 0)

		base = 10;

	/*

	 * The remainder of the string is converted to an unsigned long int

	 * value in the obvious manner, stopping at the first character

	 * which is not a valid digit in the given base. (In bases above 10,

	 * the letter `A' in either upper or lower case represents 10,

	 * `B' represents 11, and so forth, with `Z' representing 35.)

	 */

	for (; *nptr != '\0'; nptr++) {

		c = *nptr;

#if defined(HAVE_LOCALE_H)

		if (base == 10

		    && loc.thousands_sep != NULL

		    && loc.thousands_sep[0] != '\0'

		    && c == loc.thousands_sep[0])

			continue;

#endif

		switch (c) {

		case '0': case '1': case '2':

		case '3': case '4': case '5':

		case '6': case '7': case '8':

		case '9':

			val = c  - '0';

			if (val >= base)  /* even base 2 allowed ... */

				goto out;

			result *= base;

			result += val;

			sawdigs = true;

			break;

		case 'A': case 'B': case 'C': case 'D': case 'E':

		case 'F': case 'G': case 'H': case 'I': case 'J':

		case 'K': case 'L': case 'M': case 'N': case 'O':

		case 'P': case 'Q': case 'R': case 'S': case 'T':

		case 'U': case 'V': case 'W': case 'X': case 'Y':

		case 'Z':

			c += 'a' - 'A';	/* downcase */

			/* fall through */

		case 'a': case 'b': case 'c': case 'd': case 'e':

		case 'f': case 'g': case 'h': case 'i': case 'j':

		case 'k': case 'l': case 'm': case 'n': case 'o':

		case 'p': case 'q': case 'r': case 's': case 't':

		case 'u': case 'v': case 'w': case 'x': case 'y':

		case 'z':

			cp = strchr(lower, c);

			val = cp - lower;

			val += 10;	/* 'a' == 10 */

			if (val >= base)

				goto out;

			result *= base;

			result += val;

			sawdigs = true;

			break;

		default:

			goto out;

		}

	}

out:

	/*

	 * If endptr is not NULL, strtoul() stores the address of the

	 * first invalid character in *endptr. If there were no digits

	 * at all, strtoul() stores the original value of nptr in *endptr

	 * (and returns 0).  In particular, if *nptr is not `\0' but

	 * **endptr is `\0' on return, the entire string is valid.

	 */

	if (endptr != NULL) {

		if (! sawdigs) {

			*endptr = nptr_orig;

			return 0;

		} else

			*endptr = (char *) nptr;

	}

	/*

	 * RETURN VALUE

	 * The strtoul() function returns either the result of the

	 * conversion or, if there was a leading minus sign, the

	 * negation of the result of the conversion, unless the original

	 * (non-negated) value would overflow; in the latter case,

	 * strtoul() returns ULONG_MAX and sets the global variable errno

	 * to ERANGE.

	 */

	/*

	 * ADR: This computation is probably bogus.  If it's a

	 * problem, upgrade to a modern system.

	 */

	if (neg && result == ULONG_MAX) {

		errno = ERANGE;

		return ULONG_MAX;

	} else if (neg)

		result = -result;

	return result;

}

#ifdef TEST

#undef strtoul

int main(void)

{

	char *endptr;

	unsigned long res1, res2;

	res1 = strtoul("0xdeadBeeF", & endptr, 0),

	res2 = mystrtoul("0xdeadBeeF", & endptr, 0),

printf("(real,my)strtoul(\"0xdeadBeeF\", & endptr, 0) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("0101101", & endptr, 2),

	res2 = mystrtoul("0101101", & endptr, 2),

printf("(real,my)strtoul(\"0101101\", & endptr, 2) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("01011012", & endptr, 2),

	res2 = mystrtoul("01011012", & endptr, 2),

printf("(real,my)strtoul(\"01011012\", & endptr, 2) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("  +42a", & endptr, 0),

	res2 = mystrtoul("  +42a", & endptr, 0),

printf("(real,my)strtoul(\"  +42a\", & endptr, 0) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("0377", & endptr, 0),

	res2 = mystrtoul("0377", & endptr, 0),

printf("(real,my)strtoul(\"0377\", & endptr, 0) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("Z", & endptr, 36),

	res2 = mystrtoul("Z", & endptr, 36),

printf("(real,my)strtoul(\"Z\", & endptr, 36) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

	res1 = strtoul("qZ*", & endptr, 36),

	res2 = mystrtoul("qZ*", & endptr, 36),

printf("(real,my)strtoul(\"qZ*\", & endptr, 36) is %lu, %lu *endptr = %d\n",

		res1, res2, *endptr);

}

#endif