chromium/third_party/boringssl/src/crypto/fipsmodule/digest/md32_common.h

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#ifndef OPENSSL_HEADER_DIGEST_MD32_COMMON_H
#define OPENSSL_HEADER_DIGEST_MD32_COMMON_H

#include <openssl/base.h>

#include <assert.h>

#include "../../internal.h"

#if defined(__cplusplus)
extern "C" {
#endif


// This is a generic 32-bit "collector" for message digest algorithms. It
// collects input character stream into chunks of 32-bit values and invokes the
// block function that performs the actual hash calculations.
//
// To make use of this mechanism, the hash context should be defined with the
// following parameters.
//
//     typedef struct <name>_state_st {
//       uint32_t h[<chaining length> / sizeof(uint32_t)];
//       uint32_t Nl, Nh;
//       uint8_t data[<block size>];
//       unsigned num;
//       ...
//     } <NAME>_CTX;
//
// <chaining length> is the output length of the hash in bytes, before
// any truncation (e.g. 64 for SHA-224 and SHA-256, 128 for SHA-384 and
// SHA-512).
//
// |h| is the hash state and is updated by a function of type
// |crypto_md32_block_func|. |data| is the partial unprocessed block and has
// |num| bytes. |Nl| and |Nh| maintain the number of bits processed so far.

// A crypto_md32_block_func should incorporate |num_blocks| of input from |data|
// into |state|. It is assumed the caller has sized |state| and |data| for the
// hash function.
crypto_md32_block_func;

// crypto_md32_update adds |len| bytes from |in| to the digest. |data| must be a
// buffer of length |block_size| with the first |*num| bytes containing a
// partial block. This function combines the partial block with |in| and
// incorporates any complete blocks into the digest state |h|. It then updates
// |data| and |*num| with the new partial block and updates |*Nh| and |*Nl| with
// the data consumed.
static inline void crypto_md32_update(crypto_md32_block_func block_func,
                                      uint32_t *h, uint8_t *data,
                                      size_t block_size, unsigned *num,
                                      uint32_t *Nh, uint32_t *Nl,
                                      const uint8_t *in, size_t len) { … }

// crypto_md32_final incorporates the partial block and trailing length into the
// digest state |h|. The trailing length is encoded in little-endian if
// |is_big_endian| is zero and big-endian otherwise. |data| must be a buffer of
// length |block_size| with the first |*num| bytes containing a partial block.
// |Nh| and |Nl| contain the total number of bits processed. On return, this
// function clears the partial block in |data| and
// |*num|.
//
// This function does not serialize |h| into a final digest. This is the
// responsibility of the caller.
static inline void crypto_md32_final(crypto_md32_block_func block_func,
                                     uint32_t *h, uint8_t *data,
                                     size_t block_size, unsigned *num,
                                     uint32_t Nh, uint32_t Nl,
                                     int is_big_endian) { … }


#if defined(__cplusplus)
}  // extern C
#endif

#endif  // OPENSSL_HEADER_DIGEST_MD32_COMMON_H