| 1 | // Copyright 2010 the V8 project authors. All rights reserved. |
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| 2 | // Redistribution and use in source and binary forms, with or without |
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| 3 | // modification, are permitted provided that the following conditions are |
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| 4 | // met: |
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| 5 | // |
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| 6 | // * Redistributions of source code must retain the above copyright |
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| 7 | // notice, this list of conditions and the following disclaimer. |
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| 8 | // * Redistributions in binary form must reproduce the above |
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| 9 | // copyright notice, this list of conditions and the following |
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| 10 | // disclaimer in the documentation and/or other materials provided |
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| 11 | // with the distribution. |
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| 12 | // * Neither the name of Google Inc. nor the names of its |
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| 13 | // contributors may be used to endorse or promote products derived |
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| 14 | // from this software without specific prior written permission. |
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| 15 | // |
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| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | |
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| 28 | #ifndef DOUBLE_CONVERSION_CACHED_POWERS_H_ |
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| 29 | #define DOUBLE_CONVERSION_CACHED_POWERS_H_ |
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| 30 | |
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| 31 | #include <double-conversion/diy-fp.h> |
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| 32 | |
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| 33 | namespace double_conversion { |
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| 34 | |
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| 35 | class PowersOfTenCache { |
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| 36 | public: |
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| 37 | |
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| 38 | // Not all powers of ten are cached. The decimal exponent of two neighboring |
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| 39 | // cached numbers will differ by kDecimalExponentDistance. |
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| 40 | static const int kDecimalExponentDistance; |
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| 41 | |
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| 42 | static const int kMinDecimalExponent; |
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| 43 | static const int kMaxDecimalExponent; |
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| 44 | |
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| 45 | // Returns a cached power-of-ten with a binary exponent in the range |
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| 46 | // [min_exponent; max_exponent] (boundaries included). |
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| 47 | static void GetCachedPowerForBinaryExponentRange(int min_exponent, |
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| 48 | int max_exponent, |
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| 49 | DiyFp* power, |
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| 50 | int* decimal_exponent); |
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| 51 | |
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| 52 | // Returns a cached power of ten x ~= 10^k such that |
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| 53 | // k <= decimal_exponent < k + kCachedPowersDecimalDistance. |
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| 54 | // The given decimal_exponent must satisfy |
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| 55 | // kMinDecimalExponent <= requested_exponent, and |
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| 56 | // requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance. |
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| 57 | static void GetCachedPowerForDecimalExponent(int requested_exponent, |
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| 58 | DiyFp* power, |
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| 59 | int* found_exponent); |
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| 60 | }; |
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| 61 | |
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| 62 | } // namespace double_conversion |
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| 63 | |
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| 64 | #endif // DOUBLE_CONVERSION_CACHED_POWERS_H_ |
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| 65 | |
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