rust-secp256k1-unsafe-fast/secp256k1-sys/depend/secp256k1/src/scratch_impl.h

75 lines
2.8 KiB
C

/***********************************************************************
* Copyright (c) 2017 Andrew Poelstra *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
***********************************************************************/
#ifndef SECP256K1_SCRATCH_IMPL_H
#define SECP256K1_SCRATCH_IMPL_H
#include "util.h"
#include "scratch.h"
static size_t rustsecp256k1_v0_5_0_scratch_checkpoint(const rustsecp256k1_v0_5_0_callback* error_callback, const rustsecp256k1_v0_5_0_scratch* scratch) {
if (rustsecp256k1_v0_5_0_memcmp_var(scratch->magic, "scratch", 8) != 0) {
rustsecp256k1_v0_5_0_callback_call(error_callback, "invalid scratch space");
return 0;
}
return scratch->alloc_size;
}
static void rustsecp256k1_v0_5_0_scratch_apply_checkpoint(const rustsecp256k1_v0_5_0_callback* error_callback, rustsecp256k1_v0_5_0_scratch* scratch, size_t checkpoint) {
if (rustsecp256k1_v0_5_0_memcmp_var(scratch->magic, "scratch", 8) != 0) {
rustsecp256k1_v0_5_0_callback_call(error_callback, "invalid scratch space");
return;
}
if (checkpoint > scratch->alloc_size) {
rustsecp256k1_v0_5_0_callback_call(error_callback, "invalid checkpoint");
return;
}
scratch->alloc_size = checkpoint;
}
static size_t rustsecp256k1_v0_5_0_scratch_max_allocation(const rustsecp256k1_v0_5_0_callback* error_callback, const rustsecp256k1_v0_5_0_scratch* scratch, size_t objects) {
if (rustsecp256k1_v0_5_0_memcmp_var(scratch->magic, "scratch", 8) != 0) {
rustsecp256k1_v0_5_0_callback_call(error_callback, "invalid scratch space");
return 0;
}
/* Ensure that multiplication will not wrap around */
if (ALIGNMENT > 1 && objects > SIZE_MAX/(ALIGNMENT - 1)) {
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 *rustsecp256k1_v0_5_0_scratch_alloc(const rustsecp256k1_v0_5_0_callback* error_callback, rustsecp256k1_v0_5_0_scratch* scratch, size_t size) {
void *ret;
size_t rounded_size;
rounded_size = ROUND_TO_ALIGN(size);
/* Check that rounding did not wrap around */
if (rounded_size < size) {
return NULL;
}
size = rounded_size;
if (rustsecp256k1_v0_5_0_memcmp_var(scratch->magic, "scratch", 8) != 0) {
rustsecp256k1_v0_5_0_callback_call(error_callback, "invalid scratch space");
return NULL;
}
if (size > scratch->max_size - scratch->alloc_size) {
return NULL;
}
ret = (void *) ((char *) scratch->data + scratch->alloc_size);
memset(ret, 0, size);
scratch->alloc_size += size;
return ret;
}
#endif