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mruby-bigint (mpz_xor): simplify the code

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2024-07-27 17:14:12 +09:00
parent b573a8430f
commit 2247e4f355
1 changed files with 21 additions and 50 deletions
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mrbgems/mruby-bigint/core/bigint.c
+21 -50
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@@ -961,60 +961,31 @@ mpz_xor(mrb_state *mrb, mpz_t *z, mpz_t *x, mpz_t *y) /* not the most efficient
}
mrb_assert(x->sz > 0 || y->sz > 0);
z->sn = x->sn > 0 && y->sn > 0 ? 1 : -1;
if (x->sn == 0) {
mpz_set(mrb, z, y);
return;
}
if (y->sn == 0) {
mpz_set(mrb, z, x);
return;
}
mrb_assert(x->sz > 0 || y->sz > 0);
mpz_t xx, yy;
if (x->sn < 0) {
mpz_init_set(mrb, &xx, x);
x = &xx;
mpz_2comp(mrb, x);
}
if (y->sn < 0) {
mpz_init_set(mrb, &yy, y);
y = &yy;
mpz_2comp(mrb, y);
}
size_t max_sz = (x->sz > y->sz) ? x->sz : y->sz;
mpz_realloc(mrb, z, max_sz);
z->sn = (x->sn == y->sn) ? 1 : -1;
uint32_t *ds1, *ds2, *zds;
size_t l1, l2;
short sign;
char c1 = 1, c2 = 1, c3 = 1;
for (size_t i = 0; i < max_sz; i++) {
uint32_t xv = (i < x->sz) ? x->p[i] : 0;
uint32_t yv = (i < y->sz) ? y->p[i] : 0;
if (x->sz > y->sz) {
l1 = y->sz;
l2 = x->sz;
ds1 = y->p;
ds2 = x->p;
sign = y->sn;
if (x->sn < 0) make_2comp(xv, c1);
if (y->sn < 0) make_2comp(yv, c2);
uint32_t zv = xv ^ yv;
if (z->sn < 0) make_2comp(zv, c3);
z->p[i] = zv;
}
else {
l1 = x->sz;
l2 = y->sz;
ds1 = x->p;
ds2 = y->p;
sign =x->sn;
}
mpz_realloc(mrb, z, l2);
zds = z->p;
size_t i;
for (i=0; i<l1; i++) {
zds[i] = ds1[i] ^ ds2[i];
}
for (; i<l2; i++) {
zds[i] = sign>0?ds2[i]:~ds2[i];
}
if (z->sn < 0) mpz_2comp(mrb, z);
size_t sz = imax(x->sz, y->sz);
mpz_realloc(mrb, z, sz);
for (size_t i=0; i < sz; i++)
z->p[i] = dg(x,i) ^ dg(y,i);
if ((x->sn <= 0 && y->sn > 0) || (x->sn > 0 && y->sn <=0))
z->sn = (-1);
else
z->sn = 1;
if (uzero_p(z))
z->sn = 0;
}
static void