void bignum_init_base_convert(size_t size, int base) {
bignum multiplier;
bignum_init(&multiplier);
bignum_from_int(&multiplier, 1);
mul_lut = malloc(size * sizeof(bignum));
mul_lut_size = size;
for (int i = 0; i < size; ++i) {
bignum_init(&mul_lut[i]);
bignum_copy(&mul_lut[i], &multiplier);
bignum_mul_int(&multiplier, base);
}
bignum_free(&multiplier);
bignum sum;
bignum_init(&sum);
for (int i = 0; i < SUMSZ; ++i) {
for (int j = 0; j < 256; ++j) {
int m = i*8;
bignum_from_int(&sum, 0);
for (uint8_t mask = 1; mask != 0; mask <<= 1) {
if (j & mask) {
bignum_add(&sum, &mul_lut[m]);
}
++m;
}
bignum_init(&sum_lut[i][j]);
bignum_copy(&sum_lut[i][j], &sum);
}
}
bignum_free(&sum);
}
/**
* NAME: regular_mult
* INPUT: MATRIX* m1, MATRIX* m2, MATRIX* res
* USAGE: Multiplies m1 and m2 naively and stores the result in res.
*
* NOTES: pointers for m1, m2, m3 must all be malloced before using this function.
*/
void regular_mult(MATRIX* m1, MATRIX* m2, MATRIX* res)
{
// Checks to see whether m1 and m2 can be multiplied.
if (m1->numCols != m2->numRows)
{
printf("Error: Matrices cannot be multiplied");
return;
}
// Define numRows and numCols of res
int rowSize = m1->numRows;
int colSize = m2->numCols;
// Fill in matrix information
res->numRows = rowSize;
res->numCols = colSize;
// Allocate memory for the rows of the matrix.
res->matrix = (BIGNUM**) malloc(rowSize * sizeof(BIGNUM*));
for(int i = 0; i < rowSize; i++)
{
// Allocate memory for each entry in the matrix.
res->matrix[i] = (BIGNUM*) malloc(colSize * sizeof(BIGNUM));
// Go across the columns of m2
for (int j=0; j< colSize; j++)
{
// Initialize a temporary bignum to store a sum.
BIGNUM* sum = malloc(sizeof(BIGNUM));
bignum_from_int(0,sum);
// Go down the rows of m1 and across the columns of m2.
// Naive multiplication is performed here.
for (int k = 0; k < m1->numCols; k++)
{
// Initialize a temporary bignum to store the result of multiplication.
BIGNUM* multRes = malloc(sizeof(BIGNUM));
bignum_from_int(0,multRes);
mult_bignums(&m1->matrix[i][k], &m2->matrix[k][j], multRes);
// Initialize a temporary bignum for addition.
BIGNUM* addRes = malloc(sizeof(BIGNUM));
bignum_from_int(0,addRes);
add_bignums(multRes, sum, addRes);
// Store the addition and free varibles.
*sum = *addRes;
free(multRes);
free(addRes);
}
// Store the sum into the matrix and free temp bignum.
res->matrix[i][j] = *sum;
free(sum);
}
}
}
/*
Examples:
82000 (base 3) = 11011111001 =
1*3**0 + 0*3**1 + 0*3**2 + 1*3**3 +3**4 +3**5 +3**6 +3**7 +0*3**8 +3**9 +3**10
82000 (base 5) = 10111000 =
0*5**0 + 0*5**1 + 0*5**2 + 1*5**3 + 1*5**4 + 1*5**5 + 0*5**6 + 1*5**7
*/
void bignum_from_string_binary(bignum *n, char const* s, size_t base) {
char const *end_of_s = s + strlen(s) - 1;
bignum_from_int(n, 0);
bignum multiplier;
bignum_init(&multiplier);
bignum_from_int(&multiplier, 1);
while (end_of_s != s) {
assert((*end_of_s == '1') || (*end_of_s == '0'));
if (*end_of_s == '1') {
bignum_add(n, &multiplier);
}
bignum_mul_int(&multiplier, base);
--end_of_s;
}
bignum_add(n, &multiplier);
bignum_free(&multiplier);
}
// remainder is optional
void bignum_div_mod(bignum *a, bignum *b, bignum *remainder) {
int i = a->size;
unsigned int temp = 0;
int bb = bignum_to_int(b);
while (i > 0) {
--i;
temp <<= 8;
temp |= a->data[i];
a->data[i] = temp / bb;
temp -= a->data[i] * bb;
}
if (remainder) {
bignum_from_int(remainder, temp);
}
while (a->size > 0 && a->data[a->size - 1] == 0) {
--a->size;
}
if (a->size == 0) {
a->size = 1;
}
}
