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libsecp256k1/src/secp256k1.c  view on Meta::CPAN

secp256k1_context* secp256k1_context_create(unsigned int flags) {
    size_t const prealloc_size = secp256k1_context_preallocated_size(flags);
    secp256k1_context* ctx = (secp256k1_context*)checked_malloc(&default_error_callback, prealloc_size);
    if (EXPECT(secp256k1_context_preallocated_create(ctx, flags) == NULL, 0)) {
        free(ctx);
        return NULL;
    }

    return ctx;
}

secp256k1_context* secp256k1_context_preallocated_clone(const secp256k1_context* ctx, void* prealloc) {
    secp256k1_context* ret;
    VERIFY_CHECK(ctx != NULL);
    ARG_CHECK(prealloc != NULL);
    ARG_CHECK(secp256k1_context_is_proper(ctx));

    ret = (secp256k1_context*)prealloc;
    *ret = *ctx;
    return ret;
}

secp256k1_context* secp256k1_context_clone(const secp256k1_context* ctx) {
    secp256k1_context* ret;
    size_t prealloc_size;

    VERIFY_CHECK(ctx != NULL);
    ARG_CHECK(secp256k1_context_is_proper(ctx));

    prealloc_size = secp256k1_context_preallocated_clone_size(ctx);
    ret = (secp256k1_context*)checked_malloc(&ctx->error_callback, prealloc_size);
    ret = secp256k1_context_preallocated_clone(ctx, ret);
    return ret;
}

void secp256k1_context_preallocated_destroy(secp256k1_context* ctx) {
    ARG_CHECK_VOID(ctx == NULL || secp256k1_context_is_proper(ctx));

    /* Defined as noop */
    if (ctx == NULL) {
        return;
    }

    secp256k1_ecmult_gen_context_clear(&ctx->ecmult_gen_ctx);
}

void secp256k1_context_destroy(secp256k1_context* ctx) {
    ARG_CHECK_VOID(ctx == NULL || secp256k1_context_is_proper(ctx));

    /* Defined as noop */
    if (ctx == NULL) {
        return;
    }

    secp256k1_context_preallocated_destroy(ctx);
    free(ctx);
}

void secp256k1_context_set_illegal_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) {
    /* We compare pointers instead of checking secp256k1_context_is_proper() here
       because setting callbacks is allowed on *copies* of the static context:
       it's harmless and makes testing easier. */
    ARG_CHECK_VOID(ctx != secp256k1_context_static);
    if (fun == NULL) {
        fun = secp256k1_default_illegal_callback_fn;
    }
    ctx->illegal_callback.fn = fun;
    ctx->illegal_callback.data = data;
}

void secp256k1_context_set_error_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) {
    /* We compare pointers instead of checking secp256k1_context_is_proper() here
       because setting callbacks is allowed on *copies* of the static context:
       it's harmless and makes testing easier. */
    ARG_CHECK_VOID(ctx != secp256k1_context_static);
    if (fun == NULL) {
        fun = secp256k1_default_error_callback_fn;
    }
    ctx->error_callback.fn = fun;
    ctx->error_callback.data = data;
}

static secp256k1_scratch_space* secp256k1_scratch_space_create(const secp256k1_context* ctx, size_t max_size) {
    VERIFY_CHECK(ctx != NULL);
    return secp256k1_scratch_create(&ctx->error_callback, max_size);
}

static void secp256k1_scratch_space_destroy(const secp256k1_context *ctx, secp256k1_scratch_space* scratch) {
    VERIFY_CHECK(ctx != NULL);
    secp256k1_scratch_destroy(&ctx->error_callback, scratch);
}

/* Mark memory as no-longer-secret for the purpose of analysing constant-time behaviour
 *  of the software.
 */
static SECP256K1_INLINE void secp256k1_declassify(const secp256k1_context* ctx, const void *p, size_t len) {
    if (EXPECT(ctx->declassify, 0)) SECP256K1_CHECKMEM_DEFINE(p, len);
}

static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) {
    secp256k1_ge_from_bytes(ge, pubkey->data);
    ARG_CHECK(!secp256k1_fe_is_zero(&ge->x));
    return 1;
}

static void secp256k1_pubkey_save(secp256k1_pubkey* pubkey, secp256k1_ge* ge) {
    secp256k1_ge_to_bytes(pubkey->data, ge);
}

int secp256k1_ec_pubkey_parse(const secp256k1_context* ctx, secp256k1_pubkey* pubkey, const unsigned char *input, size_t inputlen) {
    secp256k1_ge Q;

    VERIFY_CHECK(ctx != NULL);
    ARG_CHECK(pubkey != NULL);
    memset(pubkey, 0, sizeof(*pubkey));
    ARG_CHECK(input != NULL);
    if (!secp256k1_eckey_pubkey_parse(&Q, input, inputlen)) {
        return 0;
    }
    if (!secp256k1_ge_is_in_correct_subgroup(&Q)) {
        return 0;
    }
    secp256k1_pubkey_save(pubkey, &Q);
    secp256k1_ge_clear(&Q);
    return 1;
}

int secp256k1_ec_pubkey_serialize(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_pubkey* pubkey, unsigned int flags) {
    secp256k1_ge Q;
    size_t len;
    int ret = 0;

    VERIFY_CHECK(ctx != NULL);