/* *  IV uniqueness detection method, as designed by Stanislaw Pusep: * *  Each IV byte is stored in corresponding "level". We have 3 levels with *  IV[2] as root index (level 0), IV[1] and IV[2] as level 2 and level 1 *  indices respectively. Space required to allocate all data is at maximum *  2^24/8 (2 MB) and space required by filled index structures is 257 KB. */#include <stdlib.h>#define IV_NOTHERE  0#define IV_PRESENT  1/* select byte within which desired bit is located */#define BITWISE_OFFT(x)         (x >> 3)/* mask to extract desired bit */#define BITWISE_MASK(x)         (1 << (x & 7))/* allocate root structure */unsigned char **uniqueiv_init( void ){    int i;    /* allocate root bucket (level 0) as vector of pointers */        unsigned char **uiv_root = (unsigned char **)        malloc( 256 * sizeof( unsigned char * ) );        if( uiv_root == NULL )        return( NULL );    /* setup initial state as empty */    for( i = 0; i < 256; ++i )        uiv_root[i] = NULL;    return( uiv_root );}/* update records with new IV */int uniqueiv_mark( unsigned char **uiv_root, unsigned char IV[3] ){    unsigned char **uiv_lvl1;    unsigned char  *uiv_lvl2;    short i;    if( uiv_root == NULL )        return( 0 );    /* select bucket from level 1 */    uiv_lvl1 = (unsigned char **) uiv_root[IV[2]];    /* create if it doesn't exists */    if( uiv_lvl1 == NULL )    {        /* allocate level 2 bucket being a vector of bits */        uiv_lvl1 = (unsigned char **) malloc( 256 * sizeof( unsigned char * ) );        if( uiv_lvl1 == NULL )            return( 1 );        /* setup initial state as empty */        for( i = 0; i < 256; i++ )            uiv_lvl1[i] = NULL;        /* link to parent bucket */        uiv_root[IV[2]] = (unsigned char *) uiv_lvl1;    }    /* select bucket from level 2 */    uiv_lvl2 = (unsigned char *) uiv_lvl1[IV[1]];    /* create if it doesn't exists */    if( uiv_lvl2 == NULL )    {        /* allocate level 2 bucket as a vector of pointers */        uiv_lvl2 = (unsigned char *) malloc( 32 * sizeof( unsigned char ) );        if( uiv_lvl1 == NULL )            return( 1 );        /* setup initial state as empty */        for( i = 0; i < 32; i++ )            uiv_lvl2[i] = 0;        /* link to parent bucket */        uiv_lvl1[IV[1]] = uiv_lvl2;    }    /* place single bit into level 2 bucket */    uiv_lvl2[BITWISE_OFFT( IV[0] )] |= BITWISE_MASK( IV[0] );            return( 0 );}/* check if already seen IV */int uniqueiv_check( unsigned char **uiv_root, unsigned char IV[3] ){    unsigned char **uiv_lvl1;    unsigned char  *uiv_lvl2;            if( uiv_root == NULL )        return( IV_NOTHERE );    /* select bucket from level 1 */    uiv_lvl1 = (unsigned char **) uiv_root[IV[2]];    /* stop here if not even allocated */    if( uiv_lvl1 == NULL )        return( IV_NOTHERE );    /* select bucket from level 2 */    uiv_lvl2 = (unsigned char *) uiv_lvl1[IV[1]];    /* stop here if not even allocated */    if( uiv_lvl2 == NULL )        return( IV_NOTHERE );    /* check single bit from level 2 bucket */    if( ( uiv_lvl2[ BITWISE_OFFT( IV[0] ) ]                  & BITWISE_MASK( IV[0] ) ) == 0 )        return( IV_NOTHERE );    else        return( IV_PRESENT );}/* unallocate everything */void uniqueiv_wipe( unsigned char **uiv_root ){    int i, j;    unsigned char **uiv_lvl1;    unsigned char  *uiv_lvl2;            if( uiv_root == NULL )        return;    /* recursively wipe out allocated buckets */    for( i = 0; i < 256; ++i )    {        uiv_lvl1 = (unsigned char **) uiv_root[i];        if( uiv_lvl1 != NULL )        {            for( j = 0; j < 256; ++j )            {                uiv_lvl2 = (unsigned char *) uiv_lvl1[j];                if( uiv_lvl2 != NULL )                    free( uiv_lvl2 );            }            free( uiv_lvl1 );        }    }    free( uiv_root );    return;}