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