From a175314c3e5827eb193872241446f2f8f5c9d33c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 20:07:14 +0200 Subject: Adding upstream version 1:10.5.12. Signed-off-by: Daniel Baumann --- storage/tokudb/tokudb_math.h | 147 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) create mode 100644 storage/tokudb/tokudb_math.h (limited to 'storage/tokudb/tokudb_math.h') diff --git a/storage/tokudb/tokudb_math.h b/storage/tokudb/tokudb_math.h new file mode 100644 index 00000000..99cebd5b --- /dev/null +++ b/storage/tokudb/tokudb_math.h @@ -0,0 +1,147 @@ +/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4: +#ident "$Id$" +/*====== +This file is part of TokuDB + + +Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved. + + TokuDBis is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License, version 2, + as published by the Free Software Foundation. + + TokuDB is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with TokuDB. If not, see . + +======= */ + +#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved." + +#if !defined(_TOKUDB_MATH_H) +#define _TOKUDB_MATH_H + +namespace tokudb { + +// Add and subtract ints with overflow detection. +// Overflow detection adapted from "Hackers Delight", Henry S. Warren + +// Return a bit mask for bits 0 .. length_bits-1 +TOKUDB_UNUSED(static uint64_t uint_mask(uint length_bits)); +static uint64_t uint_mask(uint length_bits) { + return length_bits == 64 ? ~0ULL : (1ULL< x; // check for overflow + return s; +} + +// Return the highest int with a given number of bits +TOKUDB_UNUSED(static int64_t int_high_endpoint(uint length_bits)); +static int64_t int_high_endpoint(uint length_bits) { + return (1ULL<<(length_bits-1))-1; +} + +// Return the lowest int with a given number of bits +TOKUDB_UNUSED(static int64_t int_low_endpoint(uint length_bits)); +static int64_t int_low_endpoint(uint length_bits) { + int64_t mask = uint_mask(length_bits); + return (1ULL<<(length_bits-1)) | ~mask; +} + +// Sign extend to 64 bits an int with a given number of bits +TOKUDB_UNUSED(static int64_t int_sign_extend(int64_t n, uint length_bits)); +static int64_t int_sign_extend(int64_t n, uint length_bits) { + if (n & (1ULL<<(length_bits-1))) + n |= ~uint_mask(length_bits); + return n; +} + +// Add two signed ints with max maximum value. +// If there is an overflow then set the sum to the max or the min of the int range, +// depending on the sign bit. +// Sign extend to 64 bits. +// Return the sum and the overflow. +TOKUDB_UNUSED(static int64_t int_add( + int64_t x, + int64_t y, + uint length_bits, + bool* over)); +static int64_t int_add(int64_t x, int64_t y, uint length_bits, bool *over) { + int64_t mask = uint_mask(length_bits); + int64_t n = (x + y) & mask; + *over = (((n ^ x) & (n ^ y)) >> (length_bits-1)) & 1; // check for overflow + if (n & (1LL<<(length_bits-1))) + n |= ~mask; // sign extend + return n; +} + +// Subtract two signed ints. +// If there is an overflow then set the sum to the max or the min of the int range, +// depending on the sign bit. +// Sign extend to 64 bits. +// Return the sum and the overflow. +TOKUDB_UNUSED(static int64_t int_sub( + int64_t x, + int64_t y, + uint length_bits, + bool* over)); +static int64_t int_sub(int64_t x, int64_t y, uint length_bits, bool *over) { + int64_t mask = uint_mask(length_bits); + int64_t n = (x - y) & mask; + *over = (((x ^ y) & (n ^ x)) >> (length_bits-1)) & 1; // check for overflow + if (n & (1LL<<(length_bits-1))) + n |= ~mask; // sign extend + return n; +} + +} // namespace tokudb + +#endif -- cgit v1.2.3