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 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 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(const char * __restrict nptr, char ** __restrict endptr, int base) 54 { 55 const char *s; 56 unsigned long acc; 57 char c; 58 unsigned long cutoff; 59 int neg, any, cutlim; 60 61 /* 62 * Skip white space and pick up leading +/- sign if any. 63 * If base is 0, allow 0x for hex and 0 for octal, else 64 * assume decimal; if base is already 16, allow 0x. 65 */ 66 s = nptr; 67 do { 68 c = *s++; 69 } while (isspace((unsigned char)c)); 70 if (c == '-') { 71 neg = 1; 72 c = *s++; 73 } else { 74 neg = 0; 75 if (c == '+') 76 c = *s++; 77 } 78 if ((base == 0 || base == 16) && 79 c == '0' && (*s == 'x' || *s == 'X')) { 80 c = s[1]; 81 s += 2; 82 base = 16; 83 } 84 if (base == 0) 85 base = c == '0' ? 8 : 10; 86 acc = any = 0; 87 if (base < 2 || base > 36) 88 goto noconv; 89 90 /* 91 * Compute the cutoff value between legal numbers and illegal 92 * numbers. That is the largest legal value, divided by the 93 * base. An input number that is greater than this value, if 94 * followed by a legal input character, is too big. One that 95 * is equal to this value may be valid or not; the limit 96 * between valid and invalid numbers is then based on the last 97 * digit. For instance, if the range for longs is 98 * [-2147483648..2147483647] and the input base is 10, 99 * cutoff will be set to 214748364 and cutlim to either 100 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 101 * a value > 214748364, or equal but the next digit is > 7 (or 8), 102 * the number is too big, and we will return a range error. 103 * 104 * Set 'any' if any `digits' consumed; make it negative to indicate 105 * overflow. 106 */ 107 cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX 108 : LONG_MAX; 109 cutlim = cutoff % base; 110 cutoff /= base; 111 for ( ; ; c = *s++) { 112 if (c >= '0' && c <= '9') 113 c -= '0'; 114 else if (c >= 'A' && c <= 'Z') 115 c -= 'A' - 10; 116 else if (c >= 'a' && c <= 'z') 117 c -= 'a' - 10; 118 else 119 break; 120 if (c >= base) 121 break; 122 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 123 any = -1; 124 else { 125 any = 1; 126 acc *= base; 127 acc += c; 128 } 129 } 130 if (any < 0) { 131 acc = neg ? LONG_MIN : LONG_MAX; 132 errno = ERANGE; 133 } else if (!any) { 134 noconv: 135 errno = EINVAL; 136 } else if (neg) 137 acc = -acc; 138 if (endptr != NULL) 139 *endptr = (char *)(any ? s - 1 : nptr); 140 return (acc); 141 } 142