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scratch: add stack frame support

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This commit is contained in:
Andrew Poelstra
2018-03-20 13:21:33 +00:00
parent 9bc2e26502
commit 6fe50439ae
8 changed files with 92 additions and 76 deletions
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61
src/scratch_impl.h
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@@ -15,16 +15,10 @@
* TODO: Determine this at configure time. */
#define ALIGNMENT 16
static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t init_size, size_t max_size) {
static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t max_size) {
secp256k1_scratch* ret = (secp256k1_scratch*)checked_malloc(error_callback, sizeof(*ret));
if (ret != NULL) {
ret->data = checked_malloc(error_callback, init_size);
if (ret->data == NULL) {
free (ret);
return NULL;
}
ret->offset = 0;
ret->init_size = init_size;
memset(ret, 0, sizeof(*ret));
ret->max_size = max_size;
ret->error_callback = error_callback;
}
@@ -33,45 +27,60 @@ static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* err
static void secp256k1_scratch_destroy(secp256k1_scratch* scratch) {
if (scratch != NULL) {
free(scratch->data);
VERIFY_CHECK(scratch->frame == 0);
free(scratch);
}
}
static size_t secp256k1_scratch_max_allocation(const secp256k1_scratch* scratch, size_t objects) {
if (scratch->max_size <= objects * ALIGNMENT) {
size_t i = 0;
size_t allocated = 0;
for (i = 0; i < scratch->frame; i++) {
allocated += scratch->frame_size[i];
}
if (scratch->max_size - allocated <= objects * ALIGNMENT) {
return 0;
}
return scratch->max_size - objects * ALIGNMENT;
return scratch->max_size - allocated - objects * ALIGNMENT;
}
static int secp256k1_scratch_resize(secp256k1_scratch* scratch, size_t n, size_t objects) {
n += objects * ALIGNMENT;
if (n > scratch->init_size && n <= scratch->max_size) {
void *tmp = checked_realloc(scratch->error_callback, scratch->data, n);
if (tmp == NULL) {
static int secp256k1_scratch_allocate_frame(secp256k1_scratch* scratch, size_t n, size_t objects) {
VERIFY_CHECK(scratch->frame < SECP256K1_SCRATCH_MAX_FRAMES);
if (n <= secp256k1_scratch_max_allocation(scratch, objects)) {
n += objects * ALIGNMENT;
scratch->data[scratch->frame] = checked_malloc(scratch->error_callback, n);
if (scratch->data[scratch->frame] == NULL) {
return 0;
}
scratch->init_size = n;
scratch->data = tmp;
scratch->frame_size[scratch->frame] = n;
scratch->offset[scratch->frame] = 0;
scratch->frame++;
return 1;
} else {
return 0;
}
return n <= scratch->max_size;
}
static void secp256k1_scratch_deallocate_frame(secp256k1_scratch* scratch) {
VERIFY_CHECK(scratch->frame > 0);
scratch->frame -= 1;
free(scratch->data[scratch->frame]);
}
static void *secp256k1_scratch_alloc(secp256k1_scratch* scratch, size_t size) {
void *ret;
size_t frame = scratch->frame - 1;
size = ((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT;
if (size + scratch->offset > scratch->init_size) {
if (scratch->frame == 0 || size + scratch->offset[frame] > scratch->frame_size[frame]) {
return NULL;
}
ret = (void *) ((unsigned char *) scratch->data + scratch->offset);
ret = (void *) ((unsigned char *) scratch->data[frame] + scratch->offset[frame]);
memset(ret, 0, size);
scratch->offset += size;
scratch->offset[frame] += size;
return ret;
}
static void secp256k1_scratch_reset(secp256k1_scratch* scratch) {
scratch->offset = 0;
}
#endif