strtoul.c revision 140536
1/* 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#if defined(LIBC_SCCS) && !defined(lint) 35static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93"; 36#endif /* LIBC_SCCS and not lint */ 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: head/lib/libc/stdlib/strtoul.c 140536 2005-01-21 00:42:13Z ache $"); 39 40#include <limits.h> 41#include <ctype.h> 42#include <errno.h> 43#include <stdlib.h> 44 45/* 46 * Convert a string to an unsigned long integer. 47 * 48 * Assumes that the upper and lower case 49 * alphabets and digits are each contiguous. 50 */ 51unsigned long 52strtoul(const char * __restrict nptr, char ** __restrict endptr, int base) 53{ 54 const char *s; 55 unsigned long acc; 56 char c; 57 unsigned long cutoff; 58 int neg, any, cutlim; 59 60 /* 61 * See strtol for comments as to the logic used. 62 */ 63 s = nptr; 64 do { 65 c = *s++; 66 } while (isspace((unsigned char)c)); 67 if (c == '-') { 68 neg = 1; 69 c = *s++; 70 } else { 71 neg = 0; 72 if (c == '+') 73 c = *s++; 74 } 75 if ((base == 0 || base == 16) && 76 c == '0' && (*s == 'x' || *s == 'X') && 77 ((s[1] >= 'a' && s[1] <= 'f') || 78 (s[1] >= 'A' && s[1] <= 'F') || 79 (s[1] >= '0' && s[1] <= '9')) 80 ) { 81 c = s[1]; 82 s += 2; 83 base = 16; 84 } 85 if (base == 0) 86 base = c == '0' ? 8 : 10; 87 acc = any = 0; 88 if (base < 2 || base > 36) 89 goto noconv; 90 91 cutoff = ULONG_MAX / base; 92 cutlim = ULONG_MAX % base; 93 for ( ; ; c = *s++) { 94 if (c >= '0' && c <= '9') 95 c -= '0'; 96 else if (c >= 'A' && c <= 'Z') 97 c -= 'A' - 10; 98 else if (c >= 'a' && c <= 'z') 99 c -= 'a' - 10; 100 else 101 break; 102 if (c >= base) 103 break; 104 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 105 any = -1; 106 else { 107 any = 1; 108 acc *= base; 109 acc += c; 110 } 111 } 112 if (any < 0) { 113 acc = ULONG_MAX; 114 errno = ERANGE; 115 } else if (!any) { 116noconv: 117 errno = EINVAL; 118 } else if (neg) 119 acc = -acc; 120 if (endptr != NULL) 121 *endptr = (char *)(any ? s - 1 : nptr); 122 return (acc); 123} 124