diff options
Diffstat (limited to 'src/secp256k1/src/scratch_impl.h')
-rw-r--r-- | src/secp256k1/src/scratch_impl.h | 92 |
1 files changed, 47 insertions, 45 deletions
diff --git a/src/secp256k1/src/scratch_impl.h b/src/secp256k1/src/scratch_impl.h index abed713b21..4cee700001 100644 --- a/src/secp256k1/src/scratch_impl.h +++ b/src/secp256k1/src/scratch_impl.h @@ -7,78 +7,80 @@ #ifndef _SECP256K1_SCRATCH_IMPL_H_ #define _SECP256K1_SCRATCH_IMPL_H_ +#include "util.h" #include "scratch.h" -/* Using 16 bytes alignment because common architectures never have alignment - * requirements above 8 for any of the types we care about. In addition we - * leave some room because currently we don't care about a few bytes. - * TODO: Determine this at configure time. */ -#define ALIGNMENT 16 - -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)); +static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t size) { + const size_t base_alloc = ((sizeof(secp256k1_scratch) + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT; + void *alloc = checked_malloc(error_callback, base_alloc + size); + secp256k1_scratch* ret = (secp256k1_scratch *)alloc; if (ret != NULL) { memset(ret, 0, sizeof(*ret)); - ret->max_size = max_size; - ret->error_callback = error_callback; + memcpy(ret->magic, "scratch", 8); + ret->data = (void *) ((char *) alloc + base_alloc); + ret->max_size = size; } return ret; } -static void secp256k1_scratch_destroy(secp256k1_scratch* scratch) { +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; + } + memset(scratch->magic, 0, sizeof(scratch->magic)); free(scratch); } } -static size_t secp256k1_scratch_max_allocation(const secp256k1_scratch* scratch, size_t objects) { - 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) { +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; } - return scratch->max_size - allocated - objects * ALIGNMENT; + return scratch->alloc_size; } -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->frame_size[scratch->frame] = n; - scratch->offset[scratch->frame] = 0; - scratch->frame++; - return 1; - } else { - return 0; +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; } -static void secp256k1_scratch_deallocate_frame(secp256k1_scratch* scratch) { - VERIFY_CHECK(scratch->frame > 0); - scratch->frame -= 1; - free(scratch->data[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(secp256k1_scratch* scratch, size_t size) { +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 = ((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT; + size = ROUND_TO_ALIGN(size); + + if (memcmp(scratch->magic, "scratch", 8) != 0) { + secp256k1_callback_call(error_callback, "invalid scratch space"); + 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 *) ((unsigned char *) scratch->data[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; } |