SHA256_MB_CTX
void sha256_multi_block(SHA256_MB_CTX *, const HASH_DESC *, int);
unsigned char storage[sizeof(SHA256_MB_CTX) + 32];
SHA256_MB_CTX *ctx;
ctx = (SHA256_MB_CTX *)(storage + 32 - ((size_t)storage % 32));
void sha256_multi_block(SHA256_MB_CTX *, const HASH_DESC *, int);
unsigned char storage[sizeof(SHA256_MB_CTX) + 32];
SHA256_MB_CTX *mctx;
mctx = (SHA256_MB_CTX *)(storage + 32 - ((size_t)storage % 32)); /* align */