/*
* Copyright (C) 2012 Martin Storsjo
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifndef AVUTIL_HMAC_H
#define AVUTIL_HMAC_H

#include <stdint.h>

/**
* @defgroup lavu_hmac HMAC
* @ingroup lavu_crypto
* @{
*/

enum AVHMACType {
AV_HMAC_MD5,
AV_HMAC_SHA1,
AV_HMAC_SHA224 = 10,
AV_HMAC_SHA256,
AV_HMAC_SHA384,
AV_HMAC_SHA512,
};

typedef struct AVHMAC AVHMAC;

/**
* Allocate an AVHMAC context.
* @param type The hash function used for the HMAC.
*/
AVHMAC *av_hmac_alloc(enum AVHMACType type);

/**
* Free an AVHMAC context.
* @param ctx The context to free, may be NULL
*/
void av_hmac_free(AVHMAC *ctx);

/**
* Initialize an AVHMAC context with an authentication key.
* @param ctx The HMAC context
* @param key The authentication key
* @param keylen The length of the key, in bytes
*/
void av_hmac_init(AVHMAC *ctx, const uint8_t *key, unsigned int keylen);

/**
* Hash data with the HMAC.
* @param ctx The HMAC context
* @param data The data to hash
* @param len The length of the data, in bytes
*/
void av_hmac_update(AVHMAC *ctx, const uint8_t *data, unsigned int len);

/**
* Finish hashing and output the HMAC digest.
* @param ctx The HMAC context
* @param out The output buffer to write the digest into
* @param outlen The length of the out buffer, in bytes
* @return The number of bytes written to out, or a negative error code.
*/
int av_hmac_final(AVHMAC *ctx, uint8_t *out, unsigned int outlen);

/**
* Hash an array of data with a key.
* @param ctx The HMAC context
* @param data The data to hash
* @param len The length of the data, in bytes
* @param key The authentication key
* @param keylen The length of the key, in bytes
* @param out The output buffer to write the digest into
* @param outlen The length of the out buffer, in bytes
* @return The number of bytes written to out, or a negative error code.
*/
int av_hmac_calc(AVHMAC *ctx, const uint8_t *data, unsigned int len,
const uint8_t *key, unsigned int keylen,
uint8_t *out, unsigned int outlen);

/**
* @}
*/

#endif /* AVUTIL_HMAC_H */