rust-secp256k1-unsafe-fast/secp256k1-sys/depend/secp256k1/src/ecmult.h

51 lines
2.5 KiB
C

/***********************************************************************
* Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
***********************************************************************/
#ifndef SECP256K1_ECMULT_H
#define SECP256K1_ECMULT_H
#include "group.h"
#include "scalar.h"
#include "scratch.h"
/* Noone will ever need more than a window size of 24. The code might
* be correct for larger values of ECMULT_WINDOW_SIZE but this is not
* tested.
*
* The following limitations are known, and there are probably more:
* If WINDOW_G > 27 and size_t has 32 bits, then the code is incorrect
* because the size of the memory object that we allocate (in bytes)
* will not fit in a size_t.
* If WINDOW_G > 31 and int has 32 bits, then the code is incorrect
* because certain expressions will overflow.
*/
#if ECMULT_WINDOW_SIZE < 2 || ECMULT_WINDOW_SIZE > 24
# error Set ECMULT_WINDOW_SIZE to an integer in range [2..24].
#endif
/** The number of entries a table with precomputed multiples needs to have. */
#define ECMULT_TABLE_SIZE(w) (1L << ((w)-2))
/** Double multiply: R = na*A + ng*G */
static void rustsecp256k1_v0_6_1_ecmult(rustsecp256k1_v0_6_1_gej *r, const rustsecp256k1_v0_6_1_gej *a, const rustsecp256k1_v0_6_1_scalar *na, const rustsecp256k1_v0_6_1_scalar *ng);
typedef int (rustsecp256k1_v0_6_1_ecmult_multi_callback)(rustsecp256k1_v0_6_1_scalar *sc, rustsecp256k1_v0_6_1_ge *pt, size_t idx, void *data);
/**
* Multi-multiply: R = inp_g_sc * G + sum_i ni * Ai.
* Chooses the right algorithm for a given number of points and scratch space
* size. Resets and overwrites the given scratch space. If the points do not
* fit in the scratch space the algorithm is repeatedly run with batches of
* points. If no scratch space is given then a simple algorithm is used that
* simply multiplies the points with the corresponding scalars and adds them up.
* Returns: 1 on success (including when inp_g_sc is NULL and n is 0)
* 0 if there is not enough scratch space for a single point or
* callback returns 0
*/
static int rustsecp256k1_v0_6_1_ecmult_multi_var(const rustsecp256k1_v0_6_1_callback* error_callback, rustsecp256k1_v0_6_1_scratch *scratch, rustsecp256k1_v0_6_1_gej *r, const rustsecp256k1_v0_6_1_scalar *inp_g_sc, rustsecp256k1_v0_6_1_ecmult_multi_callback cb, void *cbdata, size_t n);
#endif /* SECP256K1_ECMULT_H */