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Diffstat (limited to 'mfbt/double-conversion/cached-powers.h')
-rw-r--r-- | mfbt/double-conversion/cached-powers.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/mfbt/double-conversion/cached-powers.h b/mfbt/double-conversion/cached-powers.h new file mode 100644 index 000000000..61a50614c --- /dev/null +++ b/mfbt/double-conversion/cached-powers.h @@ -0,0 +1,64 @@ +// Copyright 2010 the V8 project authors. All rights reserved. +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following +// disclaimer in the documentation and/or other materials provided +// with the distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived +// from this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#ifndef DOUBLE_CONVERSION_CACHED_POWERS_H_ +#define DOUBLE_CONVERSION_CACHED_POWERS_H_ + +#include "diy-fp.h" + +namespace double_conversion { + +class PowersOfTenCache { + public: + + // Not all powers of ten are cached. The decimal exponent of two neighboring + // cached numbers will differ by kDecimalExponentDistance. + static const int kDecimalExponentDistance; + + static const int kMinDecimalExponent; + static const int kMaxDecimalExponent; + + // Returns a cached power-of-ten with a binary exponent in the range + // [min_exponent; max_exponent] (boundaries included). + static void GetCachedPowerForBinaryExponentRange(int min_exponent, + int max_exponent, + DiyFp* power, + int* decimal_exponent); + + // Returns a cached power of ten x ~= 10^k such that + // k <= decimal_exponent < k + kCachedPowersDecimalDistance. + // The given decimal_exponent must satisfy + // kMinDecimalExponent <= requested_exponent, and + // requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance. + static void GetCachedPowerForDecimalExponent(int requested_exponent, + DiyFp* power, + int* found_exponent); +}; + +} // namespace double_conversion + +#endif // DOUBLE_CONVERSION_CACHED_POWERS_H_ |