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) 35 static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #ifndef lint 39 static const char rcsid[] = 40 "$FreeBSD$"; 41 #endif 42 43 #include <limits.h> 44 #include <ctype.h> 45 #include <errno.h> 46 #include <stdlib.h> 47 48 49 /* 50 * Convert a string to a long integer. 51 * 52 * Assumes that the upper and lower case 53 * alphabets and digits are each contiguous. 54 */ 55 long 56 strtol(nptr, endptr, base) 57 const char *nptr; 58 char **endptr; 59 register int base; 60 { 61 register const char *s; 62 register unsigned long acc; 63 register unsigned char c; 64 register unsigned long cutoff; 65 register int neg, any, cutlim; 66 67 /* 68 * Skip white space and pick up leading +/- sign if any. 69 * If base is 0, allow 0x for hex and 0 for octal, else 70 * assume decimal; if base is already 16, allow 0x. 71 */ 72 s = nptr; 73 do { 74 c = *s++; 75 } while (isspace(c)); 76 if (c == '-') { 77 neg = 1; 78 c = *s++; 79 } else { 80 neg = 0; 81 if (c == '+') 82 c = *s++; 83 } 84 if ((base == 0 || base == 16) && 85 c == '0' && (*s == 'x' || *s == 'X')) { 86 c = s[1]; 87 s += 2; 88 base = 16; 89 } 90 if (base == 0) 91 base = c == '0' ? 8 : 10; 92 acc = any = 0; 93 if (base < 2 || base > 36) 94 goto noconv; 95 96 /* 97 * Compute the cutoff value between legal numbers and illegal 98 * numbers. That is the largest legal value, divided by the 99 * base. An input number that is greater than this value, if 100 * followed by a legal input character, is too big. One that 101 * is equal to this value may be valid or not; the limit 102 * between valid and invalid numbers is then based on the last 103 * digit. For instance, if the range for longs is 104 * [-2147483648..2147483647] and the input base is 10, 105 * cutoff will be set to 214748364 and cutlim to either 106 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 107 * a value > 214748364, or equal but the next digit is > 7 (or 8), 108 * the number is too big, and we will return a range error. 109 * 110 * Set 'any' if any `digits' consumed; make it negative to indicate 111 * overflow. 112 */ 113 cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX 114 : LONG_MAX; 115 cutlim = cutoff % base; 116 cutoff /= base; 117 for ( ; ; c = *s++) { 118 if (!isascii(c)) 119 break; 120 if (isdigit(c)) 121 c -= '0'; 122 else if (isalpha(c)) 123 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 124 else 125 break; 126 if (c >= base) 127 break; 128 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 129 any = -1; 130 else { 131 any = 1; 132 acc *= base; 133 acc += c; 134 } 135 } 136 if (any < 0) { 137 acc = neg ? LONG_MIN : LONG_MAX; 138 errno = ERANGE; 139 } else if (!any) { 140 noconv: 141 errno = EINVAL; 142 } else if (neg) 143 acc = -acc; 144 if (endptr != NULL) 145 *endptr = (char *)(any ? s - 1 : nptr); 146 return (acc); 147 } 148