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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <limits.h> 37 #include <ctype.h> 38 #include <errno.h> 39 #include <stdlib.h> 40 41 42 /* 43 * Convert a string to a long integer. 44 * 45 * Assumes that the upper and lower case 46 * alphabets and digits are each contiguous. 47 */ 48 long 49 strtol(const char * __restrict nptr, char ** __restrict endptr, int base) 50 { 51 const char *s; 52 unsigned long acc; 53 char c; 54 unsigned long cutoff; 55 int neg, any, cutlim; 56 57 /* 58 * Skip white space and pick up leading +/- sign if any. 59 * If base is 0, allow 0x for hex and 0 for octal, else 60 * assume decimal; if base is already 16, allow 0x. 61 */ 62 s = nptr; 63 do { 64 c = *s++; 65 } while (isspace((unsigned char)c)); 66 if (c == '-') { 67 neg = 1; 68 c = *s++; 69 } else { 70 neg = 0; 71 if (c == '+') 72 c = *s++; 73 } 74 if ((base == 0 || base == 16) && 75 c == '0' && (*s == 'x' || *s == 'X') && 76 ((s[1] >= '0' && s[1] <= '9') || 77 (s[1] >= 'A' && s[1] <= 'F') || 78 (s[1] >= 'a' && s[1] <= 'f'))) { 79 c = s[1]; 80 s += 2; 81 base = 16; 82 } 83 if (base == 0) 84 base = c == '0' ? 8 : 10; 85 acc = any = 0; 86 if (base < 2 || base > 36) 87 goto noconv; 88 89 /* 90 * Compute the cutoff value between legal numbers and illegal 91 * numbers. That is the largest legal value, divided by the 92 * base. An input number that is greater than this value, if 93 * followed by a legal input character, is too big. One that 94 * is equal to this value may be valid or not; the limit 95 * between valid and invalid numbers is then based on the last 96 * digit. For instance, if the range for longs is 97 * [-2147483648..2147483647] and the input base is 10, 98 * cutoff will be set to 214748364 and cutlim to either 99 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 100 * a value > 214748364, or equal but the next digit is > 7 (or 8), 101 * the number is too big, and we will return a range error. 102 * 103 * Set 'any' if any `digits' consumed; make it negative to indicate 104 * overflow. 105 */ 106 cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX 107 : LONG_MAX; 108 cutlim = cutoff % base; 109 cutoff /= base; 110 for ( ; ; c = *s++) { 111 if (c >= '0' && c <= '9') 112 c -= '0'; 113 else if (c >= 'A' && c <= 'Z') 114 c -= 'A' - 10; 115 else if (c >= 'a' && c <= 'z') 116 c -= 'a' - 10; 117 else 118 break; 119 if (c >= base) 120 break; 121 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 122 any = -1; 123 else { 124 any = 1; 125 acc *= base; 126 acc += c; 127 } 128 } 129 if (any < 0) { 130 acc = neg ? LONG_MIN : LONG_MAX; 131 errno = ERANGE; 132 } else if (!any) { 133 noconv: 134 errno = EINVAL; 135 } else if (neg) 136 acc = -acc; 137 if (endptr != NULL) 138 *endptr = (char *)(any ? s - 1 : nptr); 139 return (acc); 140 } 141