1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 = "from: @(#)strtol.c 5.4 (Berkeley) 2/23/91";*/ 36 static char *rcsid = "$Id: strtol.c,v 1.4 1993/08/26 00:48:14 jtc Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <limits.h> 40 #include <ctype.h> 41 #include <errno.h> 42 #include <stdlib.h> 43 44 45 /* 46 * Convert a string to a long integer. 47 * 48 * Ignores `locale' stuff. Assumes that the upper and lower case 49 * alphabets and digits are each contiguous. 50 */ 51 long 52 strtol(nptr, endptr, base) 53 const char *nptr; 54 char **endptr; 55 register int base; 56 { 57 register const char *s = nptr; 58 register unsigned long acc; 59 register int c; 60 register unsigned long cutoff; 61 register int neg = 0, any, cutlim; 62 63 /* 64 * Skip white space and pick up leading +/- sign if any. 65 * If base is 0, allow 0x for hex and 0 for octal, else 66 * assume decimal; if base is already 16, allow 0x. 67 */ 68 do { 69 c = *s++; 70 } while (isspace(c)); 71 if (c == '-') { 72 neg = 1; 73 c = *s++; 74 } else if (c == '+') 75 c = *s++; 76 if ((base == 0 || base == 16) && 77 c == '0' && (*s == 'x' || *s == 'X')) { 78 c = s[1]; 79 s += 2; 80 base = 16; 81 } 82 if (base == 0) 83 base = c == '0' ? 8 : 10; 84 85 /* 86 * Compute the cutoff value between legal numbers and illegal 87 * numbers. That is the largest legal value, divided by the 88 * base. An input number that is greater than this value, if 89 * followed by a legal input character, is too big. One that 90 * is equal to this value may be valid or not; the limit 91 * between valid and invalid numbers is then based on the last 92 * digit. For instance, if the range for longs is 93 * [-2147483648..2147483647] and the input base is 10, 94 * cutoff will be set to 214748364 and cutlim to either 95 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 96 * a value > 214748364, or equal but the next digit is > 7 (or 8), 97 * the number is too big, and we will return a range error. 98 * 99 * Set any if any `digits' consumed; make it negative to indicate 100 * overflow. 101 */ 102 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 103 cutlim = cutoff % (unsigned long)base; 104 cutoff /= (unsigned long)base; 105 for (acc = 0, any = 0;; c = *s++) { 106 if (isdigit(c)) 107 c -= '0'; 108 else if (isalpha(c)) 109 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 110 else 111 break; 112 if (c >= base) 113 break; 114 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) 115 any = -1; 116 else { 117 any = 1; 118 acc *= base; 119 acc += c; 120 } 121 } 122 if (any < 0) { 123 acc = neg ? LONG_MIN : LONG_MAX; 124 errno = ERANGE; 125 } else if (neg) 126 acc = -acc; 127 if (endptr != 0) 128 *endptr = (char *) (any ? s - 1 : nptr); 129 return (acc); 130 } 131