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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 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 | long |
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| 9 | strtol(const char *nptr, char **endptr, int base) |
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| 10 | { |
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| 11 | const char *s = nptr; |
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| 12 | unsigned long acc; |
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| 13 | int c; |
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| 14 | unsigned long cutoff; |
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| 15 | int neg = 0, any, cutlim; |
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| 16 | |||
| 17 | /* |
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| 18 | * Skip white space and pick up leading +/- sign if any. |
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| 19 | * If base is 0, allow 0x for hex and 0 for octal, else |
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| 20 | * assume decimal; if base is already 16, allow 0x. |
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| 21 | */ |
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| 22 | do { |
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| 23 | c = *s++; |
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| 24 | } while (isspace(c)); |
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| 25 | if (c == '-') |
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| 26 | { |
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| 27 | neg = 1; |
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| 28 | c = *s++; |
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| 29 | } |
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| 30 | else if (c == '+') |
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| 31 | c = *s++; |
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| 32 | if ((base == 0 || base == 16) && |
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| 33 | c == '0' && (*s == 'x' || *s == 'X')) |
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| 34 | { |
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| 35 | c = s[1]; |
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| 36 | s += 2; |
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| 37 | base = 16; |
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| 38 | } |
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| 39 | if (base == 0) |
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| 40 | base = c == '0' ? 8 : 10; |
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| 41 | |||
| 42 | /* |
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| 43 | * Compute the cutoff value between legal numbers and illegal |
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| 44 | * numbers. That is the largest legal value, divided by the |
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| 45 | * base. An input number that is greater than this value, if |
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| 46 | * followed by a legal input character, is too big. One that |
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| 47 | * is equal to this value may be valid or not; the limit |
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| 48 | * between valid and invalid numbers is then based on the last |
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| 49 | * digit. For instance, if the range for longs is |
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| 50 | * [-2147483648..2147483647] and the input base is 10, |
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| 51 | * cutoff will be set to 214748364 and cutlim to either |
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| 52 | * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated |
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| 53 | * a value > 214748364, or equal but the next digit is > 7 (or 8), |
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| 54 | * the number is too big, and we will return a range error. |
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| 55 | * |
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| 56 | * Set any if any `digits' consumed; make it negative to indicate |
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| 57 | * overflow. |
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| 58 | */ |
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| 59 | cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; |
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| 60 | cutlim = cutoff % (unsigned long)base; |
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| 61 | cutoff /= (unsigned long)base; |
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| 62 | for (acc = 0, any = 0;; c = *s++) |
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| 63 | { |
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| 64 | if (isdigit(c)) |
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| 65 | c -= '0'; |
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| 66 | else if (isalpha(c)) |
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| 67 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; |
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| 68 | else |
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| 69 | break; |
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| 70 | if (c >= base) |
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| 71 | break; |
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| 72 | if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) |
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| 73 | any = -1; |
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| 74 | else |
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| 75 | { |
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| 76 | any = 1; |
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| 77 | acc *= base; |
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| 78 | acc += c; |
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| 79 | } |
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| 80 | } |
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| 81 | if (any < 0) |
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| 82 | { |
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| 83 | acc = neg ? LONG_MIN : LONG_MAX; |
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| 84 | errno = ERANGE; |
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| 85 | } |
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| 86 | else if (neg) |
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| 87 | acc = -acc; |
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| 88 | if (endptr != 0) |
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| 89 | *endptr = any ? unconst(s, char *) - 1 : unconst(nptr, char *); |
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| 90 | return acc; |
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| 91 | } |