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Rev | Author | Line No. | Line |
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4973 | right-hear | 1 | /* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */ |
2 | #include |
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3 | #include |
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4 | #include |
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5 | #include |
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6 | #include |
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7 | |||
8 | /* |
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9 | * Convert a string to an unsigned long integer. |
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10 | * |
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11 | * Ignores `locale' stuff. Assumes that the upper and lower case |
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12 | * alphabets and digits are each contiguous. |
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13 | */ |
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14 | unsigned long |
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15 | strtoul(const char *nptr, char **endptr, int base) |
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16 | { |
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17 | const char *s = nptr; |
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18 | unsigned long acc; |
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19 | int c; |
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20 | unsigned long cutoff; |
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21 | int neg = 0, any, cutlim; |
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22 | |||
23 | /* |
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24 | * See strtol for comments as to the logic used. |
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25 | */ |
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26 | do { |
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27 | c = *s++; |
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28 | } while (isspace(c)); |
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29 | if (c == '-') |
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30 | { |
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31 | neg = 1; |
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32 | c = *s++; |
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33 | } |
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34 | else if (c == '+') |
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35 | c = *s++; |
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36 | if ((base == 0 || base == 16) && |
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37 | c == '0' && (*s == 'x' || *s == 'X')) |
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38 | { |
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39 | c = s[1]; |
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40 | s += 2; |
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41 | base = 16; |
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42 | } |
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43 | if (base == 0) |
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44 | base = c == '0' ? 8 : 10; |
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45 | cutoff = (unsigned long)ULONG_MAX / (unsigned long)base; |
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46 | cutlim = (unsigned long)ULONG_MAX % (unsigned long)base; |
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47 | for (acc = 0, any = 0;; c = *s++) |
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48 | { |
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49 | if (isdigit(c)) |
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50 | c -= '0'; |
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51 | else if (isalpha(c)) |
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52 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; |
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53 | else |
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54 | break; |
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55 | if (c >= base) |
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56 | break; |
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57 | if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) |
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58 | any = -1; |
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59 | else { |
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60 | any = 1; |
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61 | acc *= base; |
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62 | acc += c; |
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63 | } |
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64 | } |
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65 | if (any < 0) |
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66 | { |
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67 | acc = ULONG_MAX; |
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68 | errno = ERANGE; |
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69 | } |
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70 | else if (neg) |
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71 | acc = -acc; |
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72 | if (endptr != 0) |
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73 | *endptr = any ? unconst(s, char *) - 1 : unconst(nptr, char *); |
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74 | return acc; |
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75 | }>> |