strtoul.c

MIPS下的boottloader yamon 的源代码

/************************************************************************
 *
 *  strtoul.c
 *
 *  Note: unsigned long is assumed to equal UINT32.
 *
 *
 * ######################################################################
 *
 * Copyright (c) 1999-2000 MIPS Technologies, Inc. All rights reserved. 
 * 
 * Unpublished rights reserved under the Copyright Laws of the United States of 
 * America. 
 * 
 * This document contains information that is proprietary to MIPS Technologies, 
 * Inc. ("MIPS Technologies"). Any copying, modifying or use of this information 
 * (in whole or in part) which is not expressly permitted in writing by MIPS 
 * Technologies or a contractually-authorized third party is strictly 
 * prohibited. At a minimum, this information is protected under unfair 
 * competition laws and the expression of the information contained herein is 
 * protected under federal copyright laws. Violations thereof may result in 
 * criminal penalties and fines. 
 * MIPS Technologies or any contractually-authorized third party reserves the 
 * right to change the information contained in this document to improve 
 * function, design or otherwise. MIPS Technologies does not assume any 
 * liability arising out of the application or use of this information. Any 
 * license under patent rights or any other intellectual property rights owned 
 * by MIPS Technologies or third parties shall be conveyed by MIPS Technologies 
 * or any contractually-authorized third party in a separate license agreement 
 * between the parties. 
 * The information contained in this document constitutes one or more of the 
 * following: commercial computer software, commercial computer software 
 * documentation or other commercial items. If the user of this information, or 
 * any related documentation of any kind, including related technical data or 
 * manuals, is an agency, department, or other entity of the United States 
 * government ("Government"), the use, duplication, reproduction, release, 
 * modification, disclosure, or transfer of this information, or any related 
 * documentation of any kind, is restricted in accordance with Federal 
 * Acquisition Regulation 12.212 for civilian agencies and Defense Federal 
 * Acquisition Regulation Supplement 227.7202 for military agencies. The use of 
 * this information by the Government is further restricted in accordance with 
 * the terms of the license agreement(s) and/or applicable contract terms and 
 * conditions covering this information from MIPS Technologies or any 
 * contractually-authorized third party. 
 *
 ************************************************************************/

#include <ctype.h>
#include <sysdefs.h>
#include <errno.h>

unsigned long
strtoul(
	const 	char 	*str,
		char 	**endptr,
		int 	base)
{
	const char *s;
	unsigned long acc, cutoff;
	int c;
	int neg, any, cutlim;

	/*
	 * See strtol for comments as to the logic used.
	 */
	s = str;
	do {
		c = (unsigned char) *s++;
	} while (isspace(c));
	if (c == '-') {
		neg = 1;
		c = *s++;
	} else {
		neg = 0;
		if (c == '+')
			c = *s++;
	}
	if ((base == 0 || base == 16) &&
	    c == '0' && (*s == 'x' || *s == 'X')) {
		c = s[1];
		s += 2;
		base = 16;
	}
	if (base == 0)
		base = c == '0' ? 8 : 10;

	cutoff = MAXUINT(sizeof(UINT32)) / (unsigned long)base;
	cutlim = MAXUINT(sizeof(UINT32)) % (unsigned long)base;
	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
		if (isdigit(c))
			c -= '0';
		else if (isalpha(c))
			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
		else
			break;
		if (c >= base)
			break;
		if (any < 0)
			continue;
		if (acc > cutoff || acc == cutoff && c > cutlim) {
			any = -1;
			acc = MAXUINT(sizeof(UINT32));
			errno = ERANGE;
		} else {
			any = 1;
			acc *= (unsigned long)base;
			acc += c;
		}
	}
	if (neg && any > 0)
		acc = -acc;
	if (endptr != 0)
		*endptr = (char *) (any ? s - 1 : (char *) str);
	return (acc);
}