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scratch: replace frames with "checkpoint" system

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This commit is contained in:
Andrew Poelstra
2019-05-25 14:15:38 +00:00
parent 7623cf2b97
commit 98836b11f0
4 changed files with 101 additions and 83 deletions
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63
src/scratch_impl.h
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@@ -25,7 +25,7 @@ static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* err
static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback, secp256k1_scratch* scratch) {
if (scratch != NULL) {
VERIFY_CHECK(scratch->frame == 0);
VERIFY_CHECK(scratch->alloc_size == 0); /* all checkpoints should be applied */
if (memcmp(scratch->magic, "scratch", 8) != 0) {
secp256k1_callback_call(error_callback, "invalid scratch space");
return;
@@ -35,58 +35,39 @@ static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback,
}
}
static size_t secp256k1_scratch_max_allocation(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch, size_t objects) {
size_t i = 0;
size_t allocated = 0;
static size_t secp256k1_scratch_checkpoint(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch) {
if (memcmp(scratch->magic, "scratch", 8) != 0) {
secp256k1_callback_call(error_callback, "invalid scratch space");
return 0;
}
for (i = 0; i < scratch->frame; i++) {
allocated += scratch->frame_size[i];
}
if (scratch->max_size - allocated <= objects * (ALIGNMENT - 1)) {
return 0;
}
return scratch->max_size - allocated - objects * (ALIGNMENT - 1);
return scratch->alloc_size;
}
static int secp256k1_scratch_allocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t n, size_t objects) {
VERIFY_CHECK(scratch->frame < SECP256K1_SCRATCH_MAX_FRAMES);
if (memcmp(scratch->magic, "scratch", 8) != 0) {
secp256k1_callback_call(error_callback, "invalid scratch space");
return 0;
}
if (n <= secp256k1_scratch_max_allocation(error_callback, scratch, objects)) {
n += objects * (ALIGNMENT - 1);
scratch->current_frame = scratch->data;
scratch->data = (void *) ((char *) scratch->data + n);
scratch->frame_size[scratch->frame] = n;
scratch->offset[scratch->frame] = 0;
scratch->frame++;
return 1;
} else {
return 0;
}
}
static void secp256k1_scratch_deallocate_frame(const secp256k1_callback* error_callback, secp256k1_scratch* scratch) {
static void secp256k1_scratch_apply_checkpoint(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t checkpoint) {
if (memcmp(scratch->magic, "scratch", 8) != 0) {
secp256k1_callback_call(error_callback, "invalid scratch space");
return;
}
if (checkpoint > scratch->alloc_size) {
secp256k1_callback_call(error_callback, "invalid checkpoint");
return;
}
scratch->alloc_size = checkpoint;
}
VERIFY_CHECK(scratch->frame > 0);
scratch->frame--;
scratch->data = (void *) ((char *) scratch->data - scratch->frame_size[scratch->frame]);
static size_t secp256k1_scratch_max_allocation(const secp256k1_callback* error_callback, const secp256k1_scratch* scratch, size_t objects) {
if (memcmp(scratch->magic, "scratch", 8) != 0) {
secp256k1_callback_call(error_callback, "invalid scratch space");
return 0;
}
if (scratch->max_size - scratch->alloc_size <= objects * (ALIGNMENT - 1)) {
return 0;
}
return scratch->max_size - scratch->alloc_size - objects * (ALIGNMENT - 1);
}
static void *secp256k1_scratch_alloc(const secp256k1_callback* error_callback, secp256k1_scratch* scratch, size_t size) {
void *ret;
size_t frame = scratch->frame - 1;
size = ROUND_TO_ALIGN(size);
if (memcmp(scratch->magic, "scratch", 8) != 0) {
@@ -94,12 +75,12 @@ static void *secp256k1_scratch_alloc(const secp256k1_callback* error_callback, s
return NULL;
}
if (scratch->frame == 0 || size + scratch->offset[frame] > scratch->frame_size[frame]) {
if (size > scratch->max_size - scratch->alloc_size) {
return NULL;
}
ret = (void *) ((char *) scratch->current_frame + scratch->offset[frame]);
ret = (void *) ((char *) scratch->data + scratch->alloc_size);
memset(ret, 0, size);
scratch->offset[frame] += size;
scratch->alloc_size += size;
return ret;
}