src/num.h

   1 /**********************************************************************
   2  * Copyright (c) 2013, 2014 Pieter Wuille                             *
   3  * Distributed under the MIT software license, see the accompanying   *
   4  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
   5  **********************************************************************/
   6
   7 #ifndef SECP256K1_NUM_H
   8 #define SECP256K1_NUM_H
   9
  10 #ifndef USE_NUM_NONE
  11
  12 #if defined HAVE_CONFIG_H
  13 #include "libsecp256k1-config.h"
  14 #endif
  15
  16 #if defined(USE_NUM_GMP)
  17 #include "num_gmp.h"
  18 #else
  19 #error "Please select num implementation"
  20 #endif
  21
  22 /** Copy a number. */
  23 static void secp256k1_num_copy(secp256k1_num *r, const secp256k1_num *a);
  24
  25 /** Convert a number's absolute value to a binary big-endian string.
  26  *  There must be enough place. */
  27 static void secp256k1_num_get_bin(unsigned char *r, unsigned int rlen, const secp256k1_num *a);
  28
  29 /** Set a number to the value of a binary big-endian string. */
  30 static void secp256k1_num_set_bin(secp256k1_num *r, const unsigned char *a, unsigned int alen);
  31
  32 /** Compute a modular inverse. The input must be less than the modulus. */
  33 static void secp256k1_num_mod_inverse(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *m);
  34
  35 /** Compute the jacobi symbol (a|b). b must be positive and odd. */
  36 static int secp256k1_num_jacobi(const secp256k1_num *a, const secp256k1_num *b);
  37
  38 /** Compare the absolute value of two numbers. */
  39 static int secp256k1_num_cmp(const secp256k1_num *a, const secp256k1_num *b);
  40
  41 /** Test whether two number are equal (including sign). */
  42 static int secp256k1_num_eq(const secp256k1_num *a, const secp256k1_num *b);
  43
  44 /** Add two (signed) numbers. */
  45 static void secp256k1_num_add(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b);
  46
  47 /** Subtract two (signed) numbers. */
  48 static void secp256k1_num_sub(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b);
  49
  50 /** Multiply two (signed) numbers. */
  51 static void secp256k1_num_mul(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b);
  52
  53 /** Replace a number by its remainder modulo m. M's sign is ignored. The result is a number between 0 and m-1,
  54     even if r was negative. */
  55 static void secp256k1_num_mod(secp256k1_num *r, const secp256k1_num *m);
  56
  57 /** Right-shift the passed number by bits bits. */
  58 static void secp256k1_num_shift(secp256k1_num *r, int bits);
  59
  60 /** Check whether a number is zero. */
  61 static int secp256k1_num_is_zero(const secp256k1_num *a);
  62
  63 /** Check whether a number is one. */
  64 static int secp256k1_num_is_one(const secp256k1_num *a);
  65
  66 /** Check whether a number is strictly negative. */
  67 static int secp256k1_num_is_neg(const secp256k1_num *a);
  68
  69 /** Change a number's sign. */
  70 static void secp256k1_num_negate(secp256k1_num *r);
  71
  72 #endif
  73
  74 #endif /* SECP256K1_NUM_H */