root / prex-0.9.0 / usr / lib / libc / stdlib / strtoul.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*
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2 | * Copyright (c) 1990, 1993
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3 | * The Regents of the University of California. All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the University nor the names of its contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | #include <limits.h> |
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31 | #include <ctype.h> |
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32 | #include <errno.h> |
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33 | #include <stdlib.h> |
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34 | |||
35 | /*
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36 | * Convert a string to an unsigned long integer.
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37 | *
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38 | * Ignores `locale' stuff. Assumes that the upper and lower case
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39 | * alphabets and digits are each contiguous.
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40 | */
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41 | unsigned long |
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42 | strtoul(nptr, endptr, base) |
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43 | const char *nptr; |
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44 | char **endptr;
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45 | register int base; |
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46 | { |
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47 | const char *s; |
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48 | unsigned long acc, cutoff; |
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49 | int c;
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50 | int neg, any, cutlim;
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51 | |||
52 | /*
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53 | * See strtol for comments as to the logic used.
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54 | */
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55 | s = nptr; |
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56 | do {
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57 | c = (unsigned char) *s++; |
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58 | } while (isspace(c));
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59 | if (c == '-') { |
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60 | neg = 1;
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61 | c = *s++; |
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62 | } else {
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63 | neg = 0;
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64 | if (c == '+') |
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65 | c = *s++; |
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66 | } |
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67 | if ((base == 0 || base == 16) && |
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68 | c == '0' && (*s == 'x' || *s == 'X')) { |
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69 | c = s[1];
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70 | s += 2;
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71 | base = 16;
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72 | } |
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73 | if (base == 0) |
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74 | base = c == '0' ? 8 : 10; |
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75 | |||
76 | cutoff = ULONG_MAX / (unsigned long)base; |
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77 | cutlim = (int)(ULONG_MAX % (unsigned long)base); |
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78 | for (acc = 0, any = 0;; c = (unsigned char) *s++) { |
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79 | if (isdigit(c))
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80 | c -= '0';
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81 | else if (isalpha(c)) |
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82 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; |
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83 | else
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84 | break;
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85 | if (c >= base)
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86 | break;
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87 | if (any < 0) |
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88 | continue;
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89 | if (acc > cutoff || (acc == cutoff && c > cutlim)) {
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90 | any = -1;
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91 | acc = ULONG_MAX; |
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92 | errno = ERANGE; |
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93 | } else {
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94 | any = 1;
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95 | acc *= (unsigned long)base; |
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96 | acc += c; |
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97 | } |
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98 | } |
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99 | if (neg && any > 0) |
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100 | acc = -acc; |
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101 | if (endptr != 0) |
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102 | /* LINTED interface specification */
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103 | *endptr = (char *)(any ? s - 1 : nptr); |
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104 | return (acc);
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105 | } |