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 * $FreeBSD$ 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <limits.h> 41 #include <ctype.h> 42 #include <errno.h> 43 #include <stdlib.h> 44 45 46 /* 47 * Convert a string to a long integer. 48 * 49 * Assumes that the upper and lower case 50 * alphabets and digits are each contiguous. 51 */ 52 long 53 strtol(nptr, endptr, base) 54 const char *nptr; 55 char **endptr; 56 register int base; 57 { 58 register const char *s; 59 register unsigned long acc; 60 register unsigned char c; 61 register unsigned long cutoff; 62 register int neg, any, cutlim; 63 64 /* 65 * Skip white space and pick up leading +/- sign if any. 66 * If base is 0, allow 0x for hex and 0 for octal, else 67 * assume decimal; if base is already 16, allow 0x. 68 */ 69 s = nptr; 70 do { 71 c = *s++; 72 } while (isspace(c)); 73 if (c == '-') { 74 neg = 1; 75 c = *s++; 76 } else { 77 neg = 0; 78 if (c == '+') 79 c = *s++; 80 } 81 if ((base == 0 || base == 16) && 82 c == '0' && (*s == 'x' || *s == 'X')) { 83 c = s[1]; 84 s += 2; 85 base = 16; 86 } 87 if (base == 0) 88 base = c == '0' ? 8 : 10; 89 acc = any = 0; 90 if (base < 2 || base > 36) 91 goto noconv; 92 93 /* 94 * Compute the cutoff value between legal numbers and illegal 95 * numbers. That is the largest legal value, divided by the 96 * base. An input number that is greater than this value, if 97 * followed by a legal input character, is too big. One that 98 * is equal to this value may be valid or not; the limit 99 * between valid and invalid numbers is then based on the last 100 * digit. For instance, if the range for longs is 101 * [-2147483648..2147483647] and the input base is 10, 102 * cutoff will be set to 214748364 and cutlim to either 103 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 104 * a value > 214748364, or equal but the next digit is > 7 (or 8), 105 * the number is too big, and we will return a range error. 106 * 107 * Set 'any' if any `digits' consumed; make it negative to indicate 108 * overflow. 109 */ 110 cutoff = neg ? -(LONG_MIN + LONG_MAX) + (unsigned long)LONG_MAX 111 : LONG_MAX; 112 cutlim = cutoff % base; 113 cutoff /= base; 114 for ( ; ; c = *s++) { 115 if (!isascii(c)) 116 break; 117 if (isdigit(c)) 118 c -= '0'; 119 else if (isalpha(c)) 120 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 121 else 122 break; 123 if (c >= base) 124 break; 125 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 126 any = -1; 127 else { 128 any = 1; 129 acc *= base; 130 acc += c; 131 } 132 } 133 if (any < 0) { 134 acc = neg ? LONG_MIN : LONG_MAX; 135 errno = ERANGE; 136 } else if (!any) { 137 noconv: 138 errno = EINVAL; 139 } else if (neg) 140 acc = -acc; 141 if (endptr != NULL) 142 *endptr = (char *)(any ? s - 1 : nptr); 143 return (acc); 144 } 145