bigint_impl.h

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/*
 *  Copyright(C) 2006 Cameron Rich
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation; either version 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  This library 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef BIGINT_IMPL_HEADER
#define BIGINT_IMPL_HEADER

/* Maintain a number of precomputed variables when doing reduction */
#define BIGINT_M_OFFSET     0    /**< Normal modulo offset. */
#ifdef CONFIG_BIGINT_CRT
#define BIGINT_P_OFFSET     1    /**< p modulo offset. */
#define BIGINT_Q_OFFSET     2    /**< q module offset. */
#define BIGINT_NUM_MODS     3    /**< The number of modulus constants used. */
#else
#define BIGINT_NUM_MODS     1    
#endif

/* Architecture specific functions for big ints */
#ifdef WIN32
#define COMP_RADIX          4294967296i64         
#define COMP_BIG_MSB        0x8000000000000000i64 
#else
#define COMP_RADIX          4294967296ULL         /**< Max component + 1 */
#define COMP_BIG_MSB        0x8000000000000000ULL /**< (Max dbl comp + 1)/ 2 */
#endif
#define COMP_BIT_SIZE       32  /**< Number of bits in a component. */
#define COMP_BYTE_SIZE      4   /**< Number of bytes in a component. */
#define COMP_NUM_NIBBLES    8   /**< Used For diagnostics only. */

typedef uint32_t comp;          /**< A single precision component. */
typedef uint64_t long_comp;     /**< A double precision component. */
typedef int64_t slong_comp;     /**< A signed double precision component. */

/**
 * @struct  _bigint
 * @brief A big integer basic object
 */
struct _bigint
{
    struct _bigint* next;       /**< The next bigint in the cache. */
    short size;                 /**< The number of components in this bigint. */
    short max_comps;            /**< The heapsize allocated for this bigint */
    int refs;                   /**< An internal reference count. */
    comp* comps;                /**< A ptr to the actual component data */
};

typedef struct _bigint bigint;  /**< An alias for _bigint */

/**
 * Maintains the state of the cache, and a number of variables used in 
 * reduction.
 */
typedef struct /**< A big integer "session" context. */
{
    bigint *active_list;                    /**< Bigints currently used. */
    bigint *free_list;                      /**< Bigints not used. */
    bigint *bi_radix;                       /**< The radix used. */
    bigint *bi_mod[BIGINT_NUM_MODS];        /**< modulus */

#if defined(CONFIG_BIGINT_MONTGOMERY)
    bigint *bi_RR_mod_m[BIGINT_NUM_MODS];   /**< R^2 mod m */
    bigint *bi_R_mod_m[BIGINT_NUM_MODS];    /**< R mod m */
    comp N0_dash[BIGINT_NUM_MODS];
#elif defined(CONFIG_BIGINT_BARRETT)
    bigint *bi_mu[BIGINT_NUM_MODS];         /**< Storage for mu */
#endif
    bigint *bi_normalised_mod[BIGINT_NUM_MODS]; /**< Normalised mod storage. */
    bigint **g;                 /**< Used by sliding-window. */
    int window;                 /**< The size of the sliding window */
    int active_count;           /**< Number of active bigints. */
    int free_count;             /**< Number of free bigints. */

#ifdef CONFIG_BIGINT_MONTGOMERY
    uint8_t use_classical;      /**< Use classical reduction. */
#endif
    uint8_t mod_offset;         /**< The mod offset we are using */
} BI_CTX;

#ifndef WIN32
#define max(a,b) ((a)>(b)?(a):(b))  /**< Find the maximum of 2 numbers. */
#define min(a,b) ((a)<(b)?(a):(b))  /**< Find the minimum of 2 numbers. */
#endif

#define PERMANENT           0x7FFF55AA  /**< A magic number for permanents. */

#define V1      v->comps[v->size-1]                 /**< v1 for division */
#define V2      v->comps[v->size-2]                 /**< v2 for division */
#define U(j)    tmp_u->comps[tmp_u->size-j-1]       /**< uj for division */
#define Q(j)    quotient->comps[quotient->size-j-1] /**< qj for division */

#endif