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POLY: add null-ptr tolerant fmpz_cmp_si_n() function

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hasufell 2014-06-02 22:02:53 +02:00
parent 6199ab2505
commit 2eb7af07dc
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GPG Key ID: 220CD1C5BDEED020
2 changed files with 32 additions and 4 deletions
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25
src/poly.c
View File

@ -89,6 +89,23 @@ poly_mod2_to_modq(const fmpz_poly_t a,
/*------------------------------------------------------------------------*/ /*------------------------------------------------------------------------*/
int
fmpz_cmp_si_n(const fmpz_t f, slong g)
{
fmpz_t f_cmp;
fmpz_init(f_cmp);
if (f)
fmpz_set(f_cmp, f);
else
fmpz_set_si(f_cmp, 0);
return fmpz_cmp_si(f_cmp, g);
}
/*------------------------------------------------------------------------*/
void void
poly_new(fmpz_poly_t new_poly, poly_new(fmpz_poly_t new_poly,
int const * const c, int const * const c,
@ -252,8 +269,8 @@ poly_starmultiply(const fmpz_poly_t a,
a_tmp_coeff_i = fmpz_poly_get_coeff_ptr(a_tmp, i); a_tmp_coeff_i = fmpz_poly_get_coeff_ptr(a_tmp, i);
b_coeff_j = fmpz_poly_get_coeff_ptr(b, j); b_coeff_j = fmpz_poly_get_coeff_ptr(b, j);
if (a_tmp_coeff_i && fmpz_cmp_si(a_tmp_coeff_i, 0) && if (fmpz_cmp_si_n(a_tmp_coeff_i, 0) &&
b_coeff_j && fmpz_cmp_si(b_coeff_j, 0)) { fmpz_cmp_si_n(b_coeff_j, 0)) {
fmpz_t fmpz_tmp; fmpz_t fmpz_tmp;
fmpz_init(fmpz_tmp); fmpz_init(fmpz_tmp);
@ -350,7 +367,7 @@ poly_inverse_poly_q(const fmpz_poly_t a,
k = k % ctx->N; k = k % ctx->N;
b_last = fmpz_poly_get_coeff_ptr(b, ctx->N); b_last = fmpz_poly_get_coeff_ptr(b, ctx->N);
if (b_last && fmpz_cmp_si(b_last, 0)) if (fmpz_cmp_si_n(b_last, 0))
goto _cleanup; goto _cleanup;
/* Fq(x) = x^(N-k) * b(x) */ /* Fq(x) = x^(N-k) * b(x) */
@ -498,7 +515,7 @@ poly_inverse_poly_p(const fmpz_poly_t a,
k = k % ctx->N; k = k % ctx->N;
b_last = fmpz_poly_get_coeff_ptr(b, ctx->N); b_last = fmpz_poly_get_coeff_ptr(b, ctx->N);
if (b_last && fmpz_cmp_si(b_last, 0)) if (fmpz_cmp_si_n(b_last, 0))
goto cleanup; goto cleanup;
/* Fp(x) = x^(N-k) * b(x) */ /* Fp(x) = x^(N-k) * b(x) */

11
src/poly.h
View File

@ -39,6 +39,17 @@
#include <fmpz_poly.h> #include <fmpz_poly.h>
/**
* The same as fmpz_cmp_si except that it
* will interpret f as a 0-coefficient if it is a NULL pointer.
*
* @param poly the polynom we want to compare
* @param n the coefficient we want to compare
* @return negative value if f < g, positiv evalue if g < f, otherwise 0
*/
int
fmpz_cmp_si_n(const fmpz_t f, slong g);
/** /**
* Initializes and builds a polynomial with the * Initializes and builds a polynomial with the
* coefficient values of c[] of size len within NTRU * coefficient values of c[] of size len within NTRU