/**************************** usha.c ****************************/
/******************** See RFC 4634 for details ******************/
/*
 *  Description:
 *     This file implements a unified interface to the SHA algorithms.
 */

#include "sha.h"

/*
 *  USHAReset
 *
 *  Description:
 *      This function will initialize the SHA Context in preparation
 *      for computing a new SHA message digest.
 *
 *  Parameters:
 *      context: [in/out]
 *          The context to reset.
 *      whichSha: [in]
 *          Selects which SHA reset to call
 *
 *  Returns:
 *      sha Error Code.
 *
 */
int
USHAReset (USHAContext * ctx, enum SHAversion whichSha)
{
  if (ctx)
    {
      ctx->whichSha = whichSha;
      switch (whichSha)
	{
	case SHA1:
	  return SHA1Reset ((SHA1Context *) & ctx->ctx);
	case SHA224:
	  return SHA224Reset ((SHA224Context *) & ctx->ctx);
	case SHA256:
	  return SHA256Reset ((SHA256Context *) & ctx->ctx);
	case SHA384:
	  return SHA384Reset ((SHA384Context *) & ctx->ctx);
	case SHA512:
	  return SHA512Reset ((SHA512Context *) & ctx->ctx);
	default:
	  return shaBadParam;
	}
    }
  else
    {
      return shaNull;
    }
}

/*
 *  USHAInput
 *
 *  Description:
 *      This function accepts an array of octets as the next portion
 *      of the message.
 *
 *  Parameters:
 *      context: [in/out]
 *          The SHA context to update
 *      message_array: [in]
 *          An array of characters representing the next portion of
 *          the message.
 *      length: [in]
 *          The length of the message in message_array
 *
 *  Returns:
 *      sha Error Code.
 *
 */
int
USHAInput (USHAContext * ctx, const uint8_t * bytes, unsigned int bytecount)
{
  if (ctx)
    {
      switch (ctx->whichSha)
	{
	case SHA1:
	  return SHA1Input ((SHA1Context *) & ctx->ctx, bytes, bytecount);
	case SHA224:
	  return SHA224Input ((SHA224Context *) & ctx->ctx, bytes, bytecount);
	case SHA256:
	  return SHA256Input ((SHA256Context *) & ctx->ctx, bytes, bytecount);
	case SHA384:
	  return SHA384Input ((SHA384Context *) & ctx->ctx, bytes, bytecount);
	case SHA512:
	  return SHA512Input ((SHA512Context *) & ctx->ctx, bytes, bytecount);
	default:
	  return shaBadParam;
	}
    }
  else
    {
      return shaNull;
    }
}

/*
 * USHAFinalBits
 *
 * Description:
 *   This function will add in any final bits of the message.
 *
 * Parameters:
 *   context: [in/out]
 *     The SHA context to update
 *   message_bits: [in]
 *     The final bits of the message, in the upper portion of the
 *     byte. (Use 0b###00000 instead of 0b00000### to input the
 *     three bits ###.)
 *   length: [in]
 *     The number of bits in message_bits, between 1 and 7.
 *
 * Returns:
 *   sha Error Code.
 */
int
USHAFinalBits (USHAContext * ctx, const uint8_t bits, unsigned int bitcount)
{
  if (ctx)
    {
      switch (ctx->whichSha)
	{
	case SHA1:
	  return SHA1FinalBits ((SHA1Context *) & ctx->ctx, bits, bitcount);
	case SHA224:
	  return SHA224FinalBits ((SHA224Context *) & ctx->ctx, bits,
				  bitcount);
	case SHA256:
	  return SHA256FinalBits ((SHA256Context *) & ctx->ctx, bits,
				  bitcount);
	case SHA384:
	  return SHA384FinalBits ((SHA384Context *) & ctx->ctx, bits,
				  bitcount);
	case SHA512:
	  return SHA512FinalBits ((SHA512Context *) & ctx->ctx, bits,
				  bitcount);
	default:
	  return shaBadParam;
	}
    }
  else
    {
      return shaNull;
    }
}

/*
 * USHAResult
 *
 * Description:
 *   This function will return the 160-bit message digest into the
 *   Message_Digest array provided by the caller.
 *   NOTE: The first octet of hash is stored in the 0th element,
 *      the last octet of hash in the 19th element.
 *
 * Parameters:
 *   context: [in/out]
 *     The context to use to calculate the SHA-1 hash.
 *   Message_Digest: [out]
 *     Where the digest is returned.
 *
 * Returns:
 *   sha Error Code.
 *
 */
int
USHAResult (USHAContext * ctx, uint8_t Message_Digest[USHAMaxHashSize])
{
  if (ctx)
    {
      switch (ctx->whichSha)
	{
	case SHA1:
	  return SHA1Result ((SHA1Context *) & ctx->ctx, Message_Digest);
	case SHA224:
	  return SHA224Result ((SHA224Context *) & ctx->ctx, Message_Digest);
	case SHA256:
	  return SHA256Result ((SHA256Context *) & ctx->ctx, Message_Digest);
	case SHA384:
	  return SHA384Result ((SHA384Context *) & ctx->ctx, Message_Digest);
	case SHA512:
	  return SHA512Result ((SHA512Context *) & ctx->ctx, Message_Digest);
	default:
	  return shaBadParam;
	}
    }
  else
    {
      return shaNull;
    }
}

/*
 * USHABlockSize
 *
 * Description:
 *   This function will return the blocksize for the given SHA
 *   algorithm.
 *
 * Parameters:
 *   whichSha:
 *     which SHA algorithm to query
 *
 * Returns:
 *   block size
 *
 */
int
USHABlockSize (enum SHAversion whichSha)
{
  switch (whichSha)
    {
    case SHA1:
      return SHA1_Message_Block_Size;
    case SHA224:
      return SHA224_Message_Block_Size;
    case SHA256:
      return SHA256_Message_Block_Size;
    case SHA384:
      return SHA384_Message_Block_Size;
    default:
    case SHA512:
      return SHA512_Message_Block_Size;
    }
}

/*
 * USHAHashSize
 *
 * Description:
 *   This function will return the hashsize for the given SHA
 *   algorithm.
 *
 * Parameters:
 *   whichSha:
 *     which SHA algorithm to query
 *
 * Returns:
 *   hash size
 *
 */
int
USHAHashSize (enum SHAversion whichSha)
{
  switch (whichSha)
    {
    case SHA1:
      return SHA1HashSize;
    case SHA224:
      return SHA224HashSize;
    case SHA256:
      return SHA256HashSize;
    case SHA384:
      return SHA384HashSize;
    default:
    case SHA512:
      return SHA512HashSize;
    }
}

/*
 * USHAHashSizeBits
 *
 * Description:
 *   This function will return the hashsize for the given SHA
 *   algorithm, expressed in bits.
 *
 * Parameters:
 *   whichSha:
 *     which SHA algorithm to query
 *
 * Returns:
 *   hash size in bits
 *
 */
int
USHAHashSizeBits (enum SHAversion whichSha)
{
  switch (whichSha)
    {
    case SHA1:
      return SHA1HashSizeBits;
    case SHA224:
      return SHA224HashSizeBits;
    case SHA256:
      return SHA256HashSizeBits;
    case SHA384:
      return SHA384HashSizeBits;
    default:
    case SHA512:
      return SHA512HashSizeBits;
    }
}