78 lines
2.6 KiB
C
78 lines
2.6 KiB
C
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/**********************************************************************
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* Copyright (c) 2017 Andrew Poelstra *
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* Distributed under the MIT software license, see the accompanying *
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* file COPYING or http://www.opensource.org/licenses/mit-license.php.*
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**********************************************************************/
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#ifndef _SECP256K1_SCRATCH_IMPL_H_
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#define _SECP256K1_SCRATCH_IMPL_H_
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#include "scratch.h"
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/* Using 16 bytes alignment because common architectures never have alignment
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* requirements above 8 for any of the types we care about. In addition we
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* leave some room because currently we don't care about a few bytes.
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* TODO: Determine this at configure time. */
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#define ALIGNMENT 16
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static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t init_size, size_t max_size) {
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secp256k1_scratch* ret = (secp256k1_scratch*)checked_malloc(error_callback, sizeof(*ret));
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if (ret != NULL) {
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ret->data = checked_malloc(error_callback, init_size);
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if (ret->data == NULL) {
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free (ret);
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return NULL;
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}
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ret->offset = 0;
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ret->init_size = init_size;
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ret->max_size = max_size;
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ret->error_callback = error_callback;
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}
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return ret;
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}
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static void secp256k1_scratch_destroy(secp256k1_scratch* scratch) {
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if (scratch != NULL) {
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free(scratch->data);
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free(scratch);
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}
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}
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static size_t secp256k1_scratch_max_allocation(const secp256k1_scratch* scratch, size_t objects) {
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if (scratch->max_size <= objects * ALIGNMENT) {
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return 0;
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}
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return scratch->max_size - objects * ALIGNMENT;
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}
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static int secp256k1_scratch_resize(secp256k1_scratch* scratch, size_t n, size_t objects) {
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n += objects * ALIGNMENT;
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if (n > scratch->init_size && n <= scratch->max_size) {
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void *tmp = checked_realloc(scratch->error_callback, scratch->data, n);
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if (tmp == NULL) {
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return 0;
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}
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scratch->init_size = n;
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scratch->data = tmp;
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}
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return n <= scratch->max_size;
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}
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static void *secp256k1_scratch_alloc(secp256k1_scratch* scratch, size_t size) {
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void *ret;
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size = ((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT;
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if (size + scratch->offset > scratch->init_size) {
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return NULL;
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}
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ret = (void *) ((unsigned char *) scratch->data + scratch->offset);
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memset(ret, 0, size);
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scratch->offset += size;
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return ret;
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}
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static void secp256k1_scratch_reset(secp256k1_scratch* scratch) {
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scratch->offset = 0;
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}
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#endif
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