/**
 * \file sha2.h
 */
#ifndef POLARSSL_SHA2_H
#define POLARSSL_SHA2_H

/**
 * \brief          SHA-256 context structure
 */
typedef struct
{
    unsigned long total[2];     /*!< number of bytes processed  */
    unsigned long state[8];     /*!< intermediate digest state  */
    unsigned char buffer[64];   /*!< data block being processed */

    unsigned char ipad[64];     /*!< HMAC: inner padding        */
    unsigned char opad[64];     /*!< HMAC: outer padding        */
    int is224;                  /*!< 0 => SHA-256, else SHA-224 */
}
sha2_context;

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          SHA-256 context setup
 *
 * \param ctx      context to be initialized
 * \param is224    0 = use SHA256, 1 = use SHA224
 */
void sha2_starts( sha2_context *ctx, int is224 );

/**
 * \brief          SHA-256 process buffer
 *
 * \param ctx      SHA-256 context
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 */
void sha2_update( sha2_context *ctx, unsigned char *input, int ilen );

/**
 * \brief          SHA-256 final digest
 *
 * \param ctx      SHA-256 context
 * \param output   SHA-224/256 checksum result
 */
void sha2_finish( sha2_context *ctx, unsigned char output[32] );

/**
 * \brief          Output = SHA-256( input buffer )
 *
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 * \param output   SHA-224/256 checksum result
 * \param is224    0 = use SHA256, 1 = use SHA224
 */
void sha2( unsigned char *input, int ilen,
           unsigned char output[32], int is224 );

/**
 * \brief          Output = SHA-256( file contents )
 *
 * \param path     input file name
 * \param output   SHA-224/256 checksum result
 * \param is224    0 = use SHA256, 1 = use SHA224
 *
 * \return         0 if successful, 1 if fopen failed,
 *                 or 2 if fread failed
 */
int sha2_file( char *path, unsigned char output[32], int is224 );

/**
 * \brief          SHA-256 HMAC context setup
 *
 * \param ctx      HMAC context to be initialized
 * \param key      HMAC secret key
 * \param keylen   length of the HMAC key
 * \param is224    0 = use SHA256, 1 = use SHA224
 */
void sha2_hmac_starts( sha2_context *ctx, unsigned char *key, int keylen,
                       int is224 );

/**
 * \brief          SHA-256 HMAC process buffer
 *
 * \param ctx      HMAC context
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 */
void sha2_hmac_update( sha2_context *ctx, unsigned char *input, int ilen );

/**
 * \brief          SHA-256 HMAC final digest
 *
 * \param ctx      HMAC context
 * \param output   SHA-224/256 HMAC checksum result
 */
void sha2_hmac_finish( sha2_context *ctx, unsigned char output[32] );

/**
 * \brief          Output = HMAC-SHA-256( hmac key, input buffer )
 *
 * \param key      HMAC secret key
 * \param keylen   length of the HMAC key
 * \param input    buffer holding the  data
 * \param ilen     length of the input data
 * \param output   HMAC-SHA-224/256 result
 * \param is224    0 = use SHA256, 1 = use SHA224
 */
void sha2_hmac( unsigned char *key, int keylen,
                unsigned char *input, int ilen,
                unsigned char output[32], int is224 );

/**
 * \brief          Checkup routine
 *
 * \return         0 if successful, or 1 if the test failed
 */
int sha2_self_test( int verbose );

#ifdef __cplusplus
}
#endif

#endif /* sha2.h */