| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 1 | /* $OpenBSD: strtoul.c,v 1.7 2005/08/08 08:05:37 espie Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 1990 Regents of the University of California. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * 3. Neither the name of the University nor the names of its contributors |
| 15 | * may be used to endorse or promote products derived from this software |
| 16 | * without specific prior written permission. |
| 17 | * |
| 18 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 22 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 23 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 24 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 26 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 27 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 28 | * SUCH DAMAGE. |
| 29 | */ |
| 30 | |
| 31 | #include <ctype.h> |
| 32 | #include <errno.h> |
| 33 | #include <limits.h> |
| 34 | #include <stdlib.h> |
| 35 | |
| 36 | /* |
| 37 | * Convert a string to an unsigned long integer. |
| 38 | * |
| 39 | * Ignores `locale' stuff. Assumes that the upper and lower case |
| 40 | * alphabets and digits are each contiguous. |
| 41 | */ |
| 42 | unsigned long |
| 43 | strtoul(const char *nptr, char **endptr, int base) |
| 44 | { |
| 45 | const char *s; |
| 46 | unsigned long acc, cutoff; |
| 47 | int c; |
| 48 | int neg, any, cutlim; |
| 49 | |
| 50 | /* |
| 51 | * See strtol for comments as to the logic used. |
| 52 | */ |
| 53 | s = nptr; |
| 54 | do { |
| 55 | c = (unsigned char) *s++; |
| 56 | } while (isspace(c)); |
| 57 | if (c == '-') { |
| 58 | neg = 1; |
| 59 | c = *s++; |
| 60 | } else { |
| 61 | neg = 0; |
| 62 | if (c == '+') |
| 63 | c = *s++; |
| 64 | } |
| 65 | if ((base == 0 || base == 16) && |
| 66 | c == '0' && (*s == 'x' || *s == 'X')) { |
| 67 | c = s[1]; |
| 68 | s += 2; |
| 69 | base = 16; |
| 70 | } |
| 71 | if (base == 0) |
| 72 | base = c == '0' ? 8 : 10; |
| 73 | |
| 74 | cutoff = ULONG_MAX / (unsigned long)base; |
| 75 | cutlim = ULONG_MAX % (unsigned long)base; |
| 76 | for (acc = 0, any = 0;; c = (unsigned char) *s++) { |
| 77 | if (isdigit(c)) |
| 78 | c -= '0'; |
| 79 | else if (isalpha(c)) |
| 80 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; |
| 81 | else |
| 82 | break; |
| 83 | if (c >= base) |
| 84 | break; |
| 85 | if (any < 0) |
| 86 | continue; |
| 87 | if (acc > cutoff || (acc == cutoff && c > cutlim)) { |
| 88 | any = -1; |
| 89 | acc = ULONG_MAX; |
| 90 | errno = ERANGE; |
| 91 | } else { |
| 92 | any = 1; |
| 93 | acc *= (unsigned long)base; |
| 94 | acc += c; |
| 95 | } |
| 96 | } |
| 97 | if (neg && any > 0) |
| 98 | acc = -acc; |
| 99 | if (endptr != 0) |
| 100 | *endptr = (char *) (any ? s - 1 : nptr); |
| 101 | return (acc); |
| 102 | } |