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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
commit | 46651ce6fe013220ed397add242004d764fc0153 (patch) | |
tree | 6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/common/ryu_common.h | |
parent | Initial commit. (diff) | |
download | postgresql-14-upstream.tar.xz postgresql-14-upstream.zip |
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/common/ryu_common.h')
-rw-r--r-- | src/common/ryu_common.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/src/common/ryu_common.h b/src/common/ryu_common.h new file mode 100644 index 0000000..34b1e36 --- /dev/null +++ b/src/common/ryu_common.h @@ -0,0 +1,133 @@ +/*--------------------------------------------------------------------------- + * + * Common routines for Ryu floating-point output. + * + * Portions Copyright (c) 2018-2021, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/common/ryu_common.h + * + * This is a modification of code taken from github.com/ulfjack/ryu under the + * terms of the Boost license (not the Apache license). The original copyright + * notice follows: + * + * Copyright 2018 Ulf Adams + * + * The contents of this file may be used under the terms of the Apache + * License, Version 2.0. + * + * (See accompanying file LICENSE-Apache or copy at + * http://www.apache.org/licenses/LICENSE-2.0) + * + * Alternatively, the contents of this file may be used under the terms of the + * Boost Software License, Version 1.0. + * + * (See accompanying file LICENSE-Boost or copy at + * https://www.boost.org/LICENSE_1_0.txt) + * + * Unless required by applicable law or agreed to in writing, this software is + * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. + * + *--------------------------------------------------------------------------- + */ +#ifndef RYU_COMMON_H +#define RYU_COMMON_H + +/* + * Upstream Ryu's output is always the shortest possible. But we adjust that + * slightly to improve portability: we avoid outputting the exact midpoint + * value between two representable floats, since that relies on the reader + * getting the round-to-even rule correct, which seems to be the common + * failure mode. + * + * Defining this to 1 would restore the upstream behavior. + */ +#define STRICTLY_SHORTEST 0 + +#if SIZEOF_SIZE_T < 8 +#define RYU_32_BIT_PLATFORM +#endif + +/* Returns e == 0 ? 1 : ceil(log_2(5^e)). */ +static inline uint32 +pow5bits(const int32 e) +{ + /* + * This approximation works up to the point that the multiplication + * overflows at e = 3529. + * + * If the multiplication were done in 64 bits, it would fail at 5^4004 + * which is just greater than 2^9297. + */ + Assert(e >= 0); + Assert(e <= 3528); + return ((((uint32) e) * 1217359) >> 19) + 1; +} + +/* Returns floor(log_10(2^e)). */ +static inline int32 +log10Pow2(const int32 e) +{ + /* + * The first value this approximation fails for is 2^1651 which is just + * greater than 10^297. + */ + Assert(e >= 0); + Assert(e <= 1650); + return (int32) ((((uint32) e) * 78913) >> 18); +} + +/* Returns floor(log_10(5^e)). */ +static inline int32 +log10Pow5(const int32 e) +{ + /* + * The first value this approximation fails for is 5^2621 which is just + * greater than 10^1832. + */ + Assert(e >= 0); + Assert(e <= 2620); + return (int32) ((((uint32) e) * 732923) >> 20); +} + +static inline int +copy_special_str(char *const result, const bool sign, const bool exponent, const bool mantissa) +{ + if (mantissa) + { + memcpy(result, "NaN", 3); + return 3; + } + if (sign) + { + result[0] = '-'; + } + if (exponent) + { + memcpy(result + sign, "Infinity", 8); + return sign + 8; + } + result[sign] = '0'; + return sign + 1; +} + +static inline uint32 +float_to_bits(const float f) +{ + uint32 bits = 0; + + memcpy(&bits, &f, sizeof(float)); + return bits; +} + +static inline uint64 +double_to_bits(const double d) +{ + uint64 bits = 0; + + memcpy(&bits, &d, sizeof(double)); + return bits; +} + +#endif /* RYU_COMMON_H */ |