Tor
0.4.7.0-alpha-dev
lib
intmath
addsub.c
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/* Copyright (c) 2003-2004, Roger Dingledine
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* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
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* Copyright (c) 2007-2021, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file addsub.c
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*
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* \brief Helpers for addition and subtraction.
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*
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* Currently limited to non-wrapping (saturating) addition.
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**/
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#include "
lib/intmath/addsub.h
"
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#include "
lib/cc/compat_compiler.h
"
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/* Helper: safely add two uint32_t's, capping at UINT32_MAX rather
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* than overflow */
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uint32_t
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tor_add_u32_nowrap(uint32_t a, uint32_t b)
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{
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/* a+b > UINT32_MAX check, without overflow */
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if
(PREDICT_UNLIKELY(a > UINT32_MAX - b)) {
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return
UINT32_MAX;
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}
else
{
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return
a+b;
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}
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}
addsub.h
Header for addsub.c.
compat_compiler.h
Utility macros to handle different features and behavior in different compilers.
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