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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 | |||
| 6 | static long double powten[] = |
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| 7 | { |
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| 8 | 1e1L, 1e2L, 1e4L, 1e8L, 1e16L, 1e32L, 1e64L, 1e128L, 1e256L, |
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| 9 | 1e512L, 1e1024L, 1e2048L, 1e4096L |
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| 10 | }; |
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| 11 | |||
| 12 | long double |
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| 13 | _strtold(const char *s, char **sret) |
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| 14 | { |
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| 15 | long double r; /* result */ |
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| 16 | int e, ne; /* exponent */ |
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| 17 | int sign; /* +- 1.0 */ |
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| 18 | int esign; |
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| 19 | int flags=0; |
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| 20 | int l2powm1; |
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| 21 | |||
| 22 | r = 0.0L; |
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| 23 | sign = 1; |
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| 24 | e = ne = 0; |
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| 25 | esign = 1; |
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| 26 | |||
| 27 | while(*s && isspace(*s)) |
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| 28 | s++; |
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| 29 | |||
| 30 | if (*s == '+') |
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| 31 | s++; |
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| 32 | else if (*s == '-') |
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| 33 | { |
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| 34 | sign = -1; |
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| 35 | s++; |
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| 36 | } |
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| 37 | |||
| 38 | while ((*s >= '0') && (*s <= '9')) |
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| 39 | { |
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| 40 | flags |= 1; |
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| 41 | r *= 10.0L; |
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| 42 | r += *s - '0'; |
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| 43 | s++; |
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| 44 | } |
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| 45 | |||
| 46 | if (*s == '.') |
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| 47 | { |
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| 48 | s++; |
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| 49 | while ((*s >= '0') && (*s <= '9')) |
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| 50 | { |
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| 51 | flags |= 2; |
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| 52 | r *= 10.0L; |
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| 53 | r += *s - '0'; |
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| 54 | s++; |
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| 55 | ne++; |
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| 56 | } |
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| 57 | } |
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| 58 | if (flags == 0) |
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| 59 | { |
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| 60 | if (sret) |
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| 61 | *sret = unconst(s, char *); |
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| 62 | return 0.0L; |
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| 63 | } |
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| 64 | |||
| 65 | if ((*s == 'e') || (*s == 'E')) |
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| 66 | { |
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| 67 | s++; |
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| 68 | if (*s == '+') |
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| 69 | s++; |
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| 70 | else if (*s == '-') |
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| 71 | { |
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| 72 | s++; |
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| 73 | esign = -1; |
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| 74 | } |
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| 75 | while ((*s >= '0') && (*s <= '9')) |
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| 76 | { |
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| 77 | e *= 10; |
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| 78 | e += *s - '0'; |
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| 79 | s++; |
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| 80 | } |
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| 81 | } |
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| 82 | if (esign < 0) |
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| 83 | { |
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| 84 | esign = -esign; |
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| 85 | e = -e; |
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| 86 | } |
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| 87 | e = e - ne; |
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| 88 | if (e < -4096) |
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| 89 | { |
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| 90 | /* possibly subnormal number, 10^e would overflow */ |
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| 91 | r *= 1.0e-2048L; |
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| 92 | e += 2048; |
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| 93 | } |
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| 94 | if (e < 0) |
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| 95 | { |
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| 96 | e = -e; |
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| 97 | esign = -esign; |
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| 98 | } |
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| 99 | if (e >= 8192) |
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| 100 | e = 8191; |
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| 101 | if (e) |
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| 102 | { |
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| 103 | long double d = 1.0L; |
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| 104 | l2powm1 = 0; |
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| 105 | while (e) |
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| 106 | { |
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| 107 | if (e & 1) |
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| 108 | d *= powten[l2powm1]; |
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| 109 | e >>= 1; |
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| 110 | l2powm1++; |
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| 111 | } |
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| 112 | if (esign > 0) |
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| 113 | r *= d; |
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| 114 | else |
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| 115 | r /= d; |
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| 116 | } |
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| 117 | if (sret) |
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| 118 | *sret = unconst(s, char *); |
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| 119 | return r * sign; |
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| 120 | } |