/*
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* Copyright (C) 2015 Southern Storm Software, Pty Ltd.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef CRYPTO_BIGNUMBERUTIL_h
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#define CRYPTO_BIGNUMBERUTIL_h
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#include <inttypes.h>
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#include <stddef.h>
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// Define exactly one of these to 1 to set the size of the basic limb type.
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#if defined(__AVR__) || defined(ESP8266)
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// 16-bit limbs seem to give the best performance on 8-bit AVR micros.
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// They also seem to give better performance on ESP8266 as well.
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#define BIGNUMBER_LIMB_8BIT 0
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#define BIGNUMBER_LIMB_16BIT 1
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#define BIGNUMBER_LIMB_32BIT 0
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#define BIGNUMBER_LIMB_64BIT 0
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#elif defined(__GNUC__) && __WORDSIZE == 64
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// 64-bit system with 128-bit double limbs.
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#define BIGNUMBER_LIMB_8BIT 0
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#define BIGNUMBER_LIMB_16BIT 0
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#define BIGNUMBER_LIMB_32BIT 0
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#define BIGNUMBER_LIMB_64BIT 1
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#else
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// On all other platforms, assume 32-bit is best.
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#define BIGNUMBER_LIMB_8BIT 0
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#define BIGNUMBER_LIMB_16BIT 0
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#define BIGNUMBER_LIMB_32BIT 1
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#define BIGNUMBER_LIMB_64BIT 0
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#endif
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// Define the limb types to use on this platform.
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#if BIGNUMBER_LIMB_8BIT
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typedef uint8_t limb_t;
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typedef int8_t slimb_t;
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typedef uint16_t dlimb_t;
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#elif BIGNUMBER_LIMB_16BIT
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typedef uint16_t limb_t;
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typedef int16_t slimb_t;
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typedef uint32_t dlimb_t;
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#elif BIGNUMBER_LIMB_32BIT
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typedef uint32_t limb_t;
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typedef int32_t slimb_t;
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typedef uint64_t dlimb_t;
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#elif BIGNUMBER_LIMB_64BIT
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typedef uint64_t limb_t;
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typedef int64_t slimb_t;
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typedef unsigned __int128 dlimb_t;
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#else
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#error "limb_t must be 8, 16, 32, or 64 bits in size"
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#endif
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class BigNumberUtil
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{
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public:
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static void unpackLE(limb_t *limbs, size_t count,
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const uint8_t *bytes, size_t len);
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static void unpackBE(limb_t *limbs, size_t count,
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const uint8_t *bytes, size_t len);
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static void packLE(uint8_t *bytes, size_t len,
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const limb_t *limbs, size_t count);
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static void packBE(uint8_t *bytes, size_t len,
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const limb_t *limbs, size_t count);
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static limb_t add(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static limb_t sub(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static void mul(limb_t *result, const limb_t *x, size_t xcount,
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const limb_t *y, size_t ycount);
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static void reduceQuick(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static limb_t add_P(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static limb_t sub_P(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static void mul_P(limb_t *result, const limb_t *x, size_t xcount,
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const limb_t *y, size_t ycount);
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static void reduceQuick_P(limb_t *result, const limb_t *x,
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const limb_t *y, size_t size);
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static limb_t isZero(const limb_t *x, size_t size);
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private:
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// Constructor and destructor are private - cannot instantiate this class.
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BigNumberUtil() {}
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~BigNumberUtil() {}
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};
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#endif
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