text: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.] */
  
  #ifndef OPENSSL_HEADER_DIGEST_H
  #define OPENSSL_HEADER_DIGEST_H
  
  #include <openssl/base.h>
  
  #if defined(__cplusplus)
  extern "C" {
  #endif
  
  
  // Digest functions.
  //
  // An EVP_MD abstracts the details of a specific hash function allowing code to
  // deal with the concept of a "hash function" without needing to know exactly
  // which hash function it is.
  
  
  // Hash algorithms.
  //
  // The following functions return |EVP_MD| objects that implement the named hash
  // function.
  
  OPENSSL_EXPORT const EVP_MD *EVP_md4(void);
  OPENSSL_EXPORT const EVP_MD *EVP_md5(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha1(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha224(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha256(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha384(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha512(void);
  OPENSSL_EXPORT const EVP_MD *EVP_sha512_256(void);
  OPENSSL_EXPORT const EVP_MD *EVP_blake2b256(void);
  
  // EVP_md5_sha1 is a TLS-specific |EVP_MD| which computes the concatenation of
  // MD5 and SHA-1, as used in TLS 1.1 and below.
  OPENSSL_EXPORT const EVP_MD *EVP_md5_sha1(void);
  
  // EVP_get_digestbynid returns an |EVP_MD| for the given NID, or NULL if no
  // such digest is known.
  OPENSSL_EXPORT const EVP_MD *EVP_get_digestbynid(int nid);
  
  // EVP_get_digestbyobj returns an |EVP_MD| for the given |ASN1_OBJECT|, or NULL
  // if no such digest is known.
  OPENSSL_EXPORT const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *obj);
  
  
  // Digest contexts.
  //
  // An EVP_MD_CTX represents the state of a specific digest operation in
  // progress.
  
  // EVP_MD_CTX_init initialises an, already allocated, |EVP_MD_CTX|. This is the
  // same as setting the structure to zero.
  OPENSSL_EXPORT void EVP_MD_CTX_init(EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_new allocates and initialises a fresh |EVP_MD_CTX| and returns
  // it, or NULL on allocation failure. The caller must use |EVP_MD_CTX_free| to
  // release the resulting object.
  OPENSSL_EXPORT EVP_MD_CTX *EVP_MD_CTX_new(void);
  
  // EVP_MD_CTX_cleanup frees any resources owned by |ctx| and resets it to a
  // freshly initialised state. It does not free |ctx| itself. It returns one.
  OPENSSL_EXPORT int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_free calls |EVP_MD_CTX_cleanup| and then frees |ctx| itself.
  OPENSSL_EXPORT void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_copy_ex sets |out|, which must already be initialised, to be a
  // copy of |in|. It returns one on success and zero on allocation failure.
  OPENSSL_EXPORT int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
  
  // EVP_MD_CTX_reset calls |EVP_MD_CTX_cleanup| followed by |EVP_MD_CTX_init|. It
  // returns one.
  OPENSSL_EXPORT int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
  
  
  // Digest operations.
  
  // EVP_DigestInit_ex configures |ctx|, which must already have been
  // initialised, for a fresh hashing operation using |type|. It returns one on
  // success and zero on allocation failure.
  OPENSSL_EXPORT int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type,
                                       ENGINE *engine);
  
  // EVP_DigestInit acts like |EVP_DigestInit_ex| except that |ctx| is
  // initialised before use.
  OPENSSL_EXPORT int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
  
  // EVP_DigestUpdate hashes |len| bytes from |data| into the hashing operation
  // in |ctx|. It returns one.
  OPENSSL_EXPORT int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *data,
                                      size_t len);
  
  // EVP_MAX_MD_SIZE is the largest digest size supported, in bytes.
  // Functions that output a digest generally require the buffer have
  // at least this much space.
  #define EVP_MAX_MD_SIZE 64  // SHA-512 is the longest so far.
  
  // EVP_MAX_MD_BLOCK_SIZE is the largest digest block size supported, in
  // bytes.
  #define EVP_MAX_MD_BLOCK_SIZE 128  // SHA-512 is the longest so far.
  
  // EVP_DigestFinal_ex finishes the digest in |ctx| and writes the output to
  // |md_out|. |EVP_MD_CTX_size| bytes are written, which is at most
  // |EVP_MAX_MD_SIZE|. If |out_size| is not NULL then |*out_size| is set to the
  // number of bytes written. It returns one. After this call, the hash cannot be
  // updated or finished again until |EVP_DigestInit_ex| is called to start
  // another hashing operation.
  OPENSSL_EXPORT int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, uint8_t *md_out,
                                        unsigned int *out_size);
  
  // EVP_DigestFinal acts like |EVP_DigestFinal_ex| except that
  // |EVP_MD_CTX_cleanup| is called on |ctx| before returning.
  OPENSSL_EXPORT int EVP_DigestFinal(EVP_MD_CTX *ctx, uint8_t *md_out,
                                     unsigned int *out_size);
  
  // EVP_Digest performs a complete hashing operation in one call. It hashes |len|
  // bytes from |data| and writes the digest to |md_out|. |EVP_MD_CTX_size| bytes
  // are written, which is at most |EVP_MAX_MD_SIZE|. If |out_size| is not NULL
  // then |*out_size| is set to the number of bytes written. It returns one on
  // success and zero otherwise.
  OPENSSL_EXPORT int EVP_Digest(const void *data, size_t len, uint8_t *md_out,
                                unsigned int *md_out_size, const EVP_MD *type,
                                ENGINE *impl);
  
  
  // Digest function accessors.
  //
  // These functions allow code to learn details about an abstract hash
  // function.
  
  // EVP_MD_type returns a NID identifying |md|. (For example, |NID_sha256|.)
  OPENSSL_EXPORT int EVP_MD_type(const EVP_MD *md);
  
  // EVP_MD_flags returns the flags for |md|, which is a set of |EVP_MD_FLAG_*|
  // values, ORed together.
  OPENSSL_EXPORT uint32_t EVP_MD_flags(const EVP_MD *md);
  
  // EVP_MD_size returns the digest size of |md|, in bytes.
  OPENSSL_EXPORT size_t EVP_MD_size(const EVP_MD *md);
  
  // EVP_MD_block_size returns the native block-size of |md|, in bytes.
  OPENSSL_EXPORT size_t EVP_MD_block_size(const EVP_MD *md);
  
  // EVP_MD_FLAG_PKEY_DIGEST indicates that the digest function is used with a
  // specific public key in order to verify signatures. (For example,
  // EVP_dss1.)
  #define EVP_MD_FLAG_PKEY_DIGEST 1
  
  // EVP_MD_FLAG_DIGALGID_ABSENT indicates that the parameter type in an X.509
  // DigestAlgorithmIdentifier representing this digest function should be
  // undefined rather than NULL.
  #define EVP_MD_FLAG_DIGALGID_ABSENT 2
  
  // EVP_MD_FLAG_XOF indicates that the digest is an extensible-output function
  // (XOF). This flag is defined for compatibility and will never be set in any
  // |EVP_MD| in BoringSSL.
  #define EVP_MD_FLAG_XOF 4
  
  
  // Digest operation accessors.
  
  // EVP_MD_CTX_md returns the underlying digest function, or NULL if one has not
  // been set.
  OPENSSL_EXPORT const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_size returns the digest size of |ctx|, in bytes. It
  // will crash if a digest hasn't been set on |ctx|.
  OPENSSL_EXPORT size_t EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_block_size returns the block size of the digest function used by
  // |ctx|, in bytes. It will crash if a digest hasn't been set on |ctx|.
  OPENSSL_EXPORT size_t EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
  
  // EVP_MD_CTX_type returns a NID describing the digest function used by |ctx|.
  // (For example, |NID_sha256|.) It will crash if a digest hasn't been set on
  // |ctx|.
  OPENSSL_EXPORT int EVP_MD_CTX_type(const EVP_MD_CTX *ctx);
  
  
  // ASN.1 functions.
  //
  // These functions allow code to parse and serialize AlgorithmIdentifiers for
  // hash functions.
  
  // EVP_parse_digest_algorithm parses an AlgorithmIdentifier structure containing
  // a hash function OID (for example, 2.16.840.1.101.3.4.2.1 is SHA-256) and
  // advances |cbs|. The parameters field may either be omitted or a NULL. It
  // returns the digest function or NULL on error.
  OPENSSL_EXPORT const EVP_MD *EVP_parse_digest_algorithm(CBS *cbs);
  
  // EVP_marshal_digest_algorithm marshals |md| as an AlgorithmIdentifier
  // structure and appends the result to |cbb|. It returns one on success and zero
  // on error.
  OPENSSL_EXPORT int EVP_marshal_digest_algorithm(CBB *cbb, const EVP_MD *md);
  
  
  // Deprecated functions.
  
  // EVP_MD_CTX_copy sets |out|, which must /not/ be initialised, to be a copy of
  // |in|. It returns one on success and zero on error.
  OPENSSL_EXPORT int EVP_MD_CTX_copy(EVP_MD_CTX *out, const EVP_MD_CTX *in);
  
  // EVP_add_digest does nothing and returns one. It exists only for
  // compatibility with OpenSSL.
  OPENSSL_EXPORT int EVP_add_digest(const EVP_MD *digest);
  
  // EVP_get_digestbyname returns an |EVP_MD| given a human readable name in
  // |name|, or NULL if the name is unknown.
  OPENSSL_EXPORT const EVP_MD *EVP_get_digestbyname(const char *);
  
  // EVP_dss1 returns the value of EVP_sha1(). This was provided by OpenSSL to
  // specifiy the original DSA signatures, which were fixed to use SHA-1. Note,
  // however, that attempting to sign or verify DSA signatures with the EVP
  // interface will always fail.
  OPENSSL_EXPORT const EVP_MD *EVP_dss1(void);
  
  // EVP_MD_CTX_create calls |EVP_MD_CTX_new|.
  OPENSSL_EXPORT EVP_MD_CTX *EVP_MD_CTX_create(void);
  
  // EVP_MD_CTX_destroy calls |EVP_MD_CTX_free|.
  OPENSSL_EXPORT void EVP_MD_CTX_destroy(EVP_MD_CTX *ctx);
  
  // EVP_DigestFinalXOF returns zero and adds an error to the error queue.
  // BoringSSL does not support any XOF digests.
  OPENSSL_EXPORT int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, uint8_t *out,
                                        size_t len);
  
  // EVP_MD_meth_get_flags calls |EVP_MD_flags|.
  OPENSSL_EXPORT uint32_t EVP_MD_meth_get_flags(const EVP_MD *md);
  
  // EVP_MD_CTX_set_flags does nothing.
  OPENSSL_EXPORT void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
  
  // EVP_MD_CTX_FLAG_NON_FIPS_ALLOW is meaningless. In OpenSSL it permits non-FIPS
  // algorithms in FIPS mode. But BoringSSL FIPS mode doesn't prohibit algorithms
  // (it's up the the caller to use the FIPS module in a fashion compliant with
  // their needs). Thus this exists only to allow code to compile.
  #define EVP_MD_CTX_FLAG_NON_FIPS_ALLOW 0
  
  
  struct evp_md_pctx_ops;
  
  struct env_md_ctx_st {
    // digest is the underlying digest function, or NULL if not set.
    const EVP_MD *digest;
    // md_data points to a block of memory that contains the hash-specific
    // context.
    void *md_data;
  
    // pctx is an opaque (at this layer) pointer to additional context that
    // EVP_PKEY functions may store in this object.
    EVP_PKEY_CTX *pctx;
  
    // pctx_ops, if not NULL, points to a vtable that contains functions to
    // manipulate |pctx|.
    const struct evp_md_pctx_ops *pctx_ops;
  } /* EVP_MD_CTX */;
  
  
  #if defined(__cplusplus)
  }  // extern C
  
  #if !defined(BORINGSSL_NO_CXX)
  extern "C++" {
  
  BSSL_NAMESPACE_BEGIN
  
  BORINGSSL_MAKE_DELETER(EVP_MD_CTX, EVP_MD_CTX_free)
  
  using ScopedEVP_MD_CTX =
      internal::StackAllocated<EVP_MD_CTX, int, EVP_MD_CTX_init,
                               EVP_MD_CTX_cleanup>;
  
  BSSL_NAMESPACE_END
  
  }  // extern C++
  #endif
  
  #endif
  
  #define DIGEST_R_INPUT_NOT_INITIALIZED 100
  #define DIGEST_R_DECODE_ERROR 101
  #define DIGEST_R_UNKNOWN_HASH 102
  
  #endif  // OPENSSL_HEADER_DIGEST_H
  