#ifndef _SHA256_H
  #define _SHA256_H
  
  #define SHA256_SUM_LEN	32

  /* Reset watchdog each time we process this many bytes */
  #define CHUNKSZ_SHA256	(64 * 1024)

  typedef struct {
  	uint32_t total[2];
  	uint32_t state[8];
  	uint8_t buffer[64];
  } sha256_context;
  
  void sha256_starts(sha256_context * ctx);

  void sha256_update(sha256_context *ctx, const uint8_t *input, uint32_t length);

  void sha256_finish(sha256_context * ctx, uint8_t digest[SHA256_SUM_LEN]);

  void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
  		unsigned char *output, unsigned int chunk_sz);

  #endif /* _SHA256_H */