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mruby-bigint: revert mpz_add refactoring due to memory leak

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Revert previous refactoring of `mpz_add` as `mpz_init_auto` was causing
a memory leak when called on an already initialized `mpz_t`. The old
implementation has been restored to fix this issue.

Co-authored-by: Gemini <gemini@google.com>
This commit is contained in:
Yukihiro "Matz" Matsumoto
2025-07-29 09:06:07 +09:00
parent 5797d5ef48
commit e6d1564ccb
1 changed files with 28 additions and 60 deletions
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mrbgems/mruby-bigint/core/bigint.c
+28 -60
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@@ -413,79 +413,45 @@ zero(mpz_t *x)
static void
mpz_add(mpz_ctx_t *ctx, mpz_t *zz, mpz_t *x, mpz_t *y)
{
/* Handle aliasing: if result parameter is same as input, copy input first */
mpz_t x_copy, y_copy;
mpz_t *x_ptr = x, *y_ptr = y;
if (zz == x) {
mpz_init_set(ctx, &x_copy, x);
x_ptr = &x_copy;
if (zero_p(x)) {
mpz_set(ctx, zz, y);
return;
}
if (zz == y) {
mpz_init_set(ctx, &y_copy, y);
y_ptr = &y_copy;
if (zero_p(y)) {
mpz_set(ctx, zz, x);
return;
}
mpz_t z;
size_t estimated_size = ((x->sz > y->sz) ? x->sz : y->sz) + 1;
mpz_init(ctx, &z);
mpz_realloc(ctx, &z, estimated_size);
size_t estimated_size = ((x_ptr->sz > y_ptr->sz) ? x_ptr->sz : y_ptr->sz) + 1;
/* Use new simplified API - heap allocation for result */
mpz_init_auto(ctx, zz, estimated_size);
if (zero_p(x_ptr)) {
/* Copy y to zz */
for (size_t i = 0; i < y_ptr->sz && i < zz->sz; i++) {
zz->p[i] = y_ptr->p[i];
}
zz->sz = (y_ptr->sz < zz->sz) ? y_ptr->sz : zz->sz;
zz->sn = y_ptr->sn;
goto cleanup;
if (x->sn > 0 && y->sn > 0) {
uadd(&z, x, y);
z.sn = 1;
}
if (zero_p(y_ptr)) {
/* Copy x to zz */
for (size_t i = 0; i < x_ptr->sz && i < zz->sz; i++) {
zz->p[i] = x_ptr->p[i];
}
zz->sz = (x_ptr->sz < zz->sz) ? x_ptr->sz : zz->sz;
zz->sn = x_ptr->sn;
goto cleanup;
}
if (x_ptr->sn > 0 && y_ptr->sn > 0) {
/* Both positive */
uadd(zz, x_ptr, y_ptr);
zz->sn = 1;
}
else if (x_ptr->sn < 0 && y_ptr->sn < 0) {
/* Both negative */
uadd(zz, x_ptr, y_ptr);
zz->sn = -1;
else if (x->sn < 0 && y->sn < 0) {
uadd(&z, x, y);
z.sn = -1;
}
else {
/* Signs differ */
int mg = ucmp(x_ptr, y_ptr);
int mg;
if (mg == 0) {
zero(zz);
/* signs differ */
if ((mg = ucmp(x,y)) == 0) {
zero(&z);
}
else if (mg > 0) { /* abs(y) < abs(x) */
usub(zz, x_ptr, y_ptr);
zz->sn = (x_ptr->sn > 0 && y_ptr->sn < 0) ? 1 : (-1);
usub(&z, x, y);
z.sn = (x->sn > 0 && y->sn < 0) ? 1 : (-1);
}
else { /* abs(y) > abs(x) */
usub(zz, y_ptr, x_ptr);
zz->sn = (x_ptr->sn < 0 && y_ptr->sn > 0) ? 1 : (-1);
usub(&z, y, x);
z.sn = (x->sn < 0 && y->sn > 0) ? 1 : (-1);
}
}
trim(zz);
cleanup:
/* Clean up temporary copies if they were created */
if (zz == x) {
mpz_clear(ctx, &x_copy);
}
if (zz == y) {
mpz_clear(ctx, &y_copy);
}
trim(&z);
mpz_move(ctx, zz, &z);
}
/* x += n */
@@ -2527,6 +2493,7 @@ mrb_bint_add_n(mrb_state *mrb, mrb_value x, mrb_value y)
}
y = mrb_as_bint(mrb, y);
bint_as_mpz(RBIGINT(y), &b);
mpz_init(&ctx, &z);
mpz_add(&ctx, &z, &a, &b);
struct RBigint *v = bint_new(mrb, &z);
return mrb_obj_value(v);
@@ -2572,6 +2539,7 @@ mrb_bint_sub_n(mrb_state *mrb, mrb_value x, mrb_value y)
}
y = mrb_as_bint(mrb, y);
bint_as_mpz(RBIGINT(y), &b);
mpz_init(&ctx, &z);
mpz_sub(&ctx, &z, &a, &b);
struct RBigint *v = bint_new(mrb, &z);
return mrb_obj_value(v);