/* See LICENSE file for copyright and license details. */
#include "common.h"


/**
 * Round constants, SHA-256, should keep the 32 most significant bits of 64 first constants
 */
static const uint64_t ROUND_CONSTANTS[] = {
	0x428A2F98D728AE22ULL, 0x7137449123EF65CDULL, 0xB5C0FBCFEC4D3B2FULL, 0xE9B5DBA58189DBBCULL,
	0x3956C25BF348B538ULL, 0x59F111F1B605D019ULL, 0x923F82A4AF194F9BULL, 0xAB1C5ED5DA6D8118ULL,
	0xD807AA98A3030242ULL, 0x12835B0145706FBEULL, 0x243185BE4EE4B28CULL, 0x550C7DC3D5FFB4E2ULL,
	0x72BE5D74F27B896FULL, 0x80DEB1FE3B1696B1ULL, 0x9BDC06A725C71235ULL, 0xC19BF174CF692694ULL,
	0xE49B69C19EF14AD2ULL, 0xEFBE4786384F25E3ULL, 0x0FC19DC68B8CD5B5ULL, 0x240CA1CC77AC9C65ULL,
	0x2DE92C6F592B0275ULL, 0x4A7484AA6EA6E483ULL, 0x5CB0A9DCBD41FBD4ULL, 0x76F988DA831153B5ULL,
	0x983E5152EE66DFABULL, 0xA831C66D2DB43210ULL, 0xB00327C898FB213FULL, 0xBF597FC7BEEF0EE4ULL,
	0xC6E00BF33DA88FC2ULL, 0xD5A79147930AA725ULL, 0x06CA6351E003826FULL, 0x142929670A0E6E70ULL,
	0x27B70A8546D22FFCULL, 0x2E1B21385C26C926ULL, 0x4D2C6DFC5AC42AEDULL, 0x53380D139D95B3DFULL,
	0x650A73548BAF63DEULL, 0x766A0ABB3C77B2A8ULL, 0x81C2C92E47EDAEE6ULL, 0x92722C851482353BULL,
	0xA2BFE8A14CF10364ULL, 0xA81A664BBC423001ULL, 0xC24B8B70D0F89791ULL, 0xC76C51A30654BE30ULL,
	0xD192E819D6EF5218ULL, 0xD69906245565A910ULL, 0xF40E35855771202AULL, 0x106AA07032BBD1B8ULL,
	0x19A4C116B8D2D0C8ULL, 0x1E376C085141AB53ULL, 0x2748774CDF8EEB99ULL, 0x34B0BCB5E19B48A8ULL,
	0x391C0CB3C5C95A63ULL, 0x4ED8AA4AE3418ACBULL, 0x5B9CCA4F7763E373ULL, 0x682E6FF3D6B2B8A3ULL,
	0x748F82EE5DEFB2FCULL, 0x78A5636F43172F60ULL, 0x84C87814A1F0AB72ULL, 0x8CC702081A6439ECULL,
	0x90BEFFFA23631E28ULL, 0xA4506CEBDE82BDE9ULL, 0xBEF9A3F7B2C67915ULL, 0xC67178F2E372532BULL,
	0xCA273ECEEA26619CULL, 0xD186B8C721C0C207ULL, 0xEADA7DD6CDE0EB1EULL, 0xF57D4F7FEE6ED178ULL,
	0x06F067AA72176FBAULL, 0x0A637DC5A2C898A6ULL, 0x113F9804BEF90DAEULL, 0x1B710B35131C471BULL,
	0x28DB77F523047D84ULL, 0x32CAAB7B40C72493ULL, 0x3C9EBE0A15C9BEBCULL, 0x431D67C49C100D4CULL,
	0x4CC5D4BECB3E42B6ULL, 0x597F299CFC657E2AULL, 0x5FCB6FAB3AD6FAECULL, 0x6C44198C4A475817ULL
};


/**
 * Initial state for SHA224
 */
static const uint32_t H_224[] = {
	0xC1059ED8UL, 0x367CD507UL, 0x3070DD17UL, 0xF70E5939UL,
	0xFFC00B31UL, 0x68581511UL, 0x64F98FA7UL, 0xBEFA4FA4UL
};

/**
 * Initial state for SHA256
 */
static const uint32_t H_256[] = {
	0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
	0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL
};

/**
 * Initial state for SHA384
 */
static const uint64_t H_384[] = {
	0xCBBB9D5DC1059ED8ULL, 0x629A292A367CD507ULL, 0x9159015A3070DD17ULL, 0x152FECD8F70E5939ULL,
	0x67332667FFC00B31ULL, 0x8EB44A8768581511ULL, 0xDB0C2E0D64F98FA7ULL, 0x47B5481DBEFA4FA4ULL
};

/**
 * Initial state for SHA512
 */
static const uint64_t H_512[] = {
	0x6A09E667F3BCC908ULL, 0xBB67AE8584CAA73BULL, 0x3C6EF372FE94F82BULL, 0xA54FF53A5F1D36F1ULL,
	0x510E527FADE682D1ULL, 0x9B05688C2B3E6C1FULL, 0x1F83D9ABFB41BD6BULL, 0x5BE0CD19137E2179ULL
};

/**
 * Initial state for SHA512/224
 */
static const uint64_t H_512_224[] = {
	0x8C3D37C819544DA2ULL, 0x73E1996689DCD4D6ULL, 0x1DFAB7AE32FF9C82ULL, 0x679DD514582F9FCFULL,
	0x0F6D2B697BD44DA8ULL, 0x77E36F7304C48942ULL, 0x3F9D85A86A1D36C8ULL, 0x1112E6AD91D692A1ULL
};

/**
 * Initial state for SHA512/256
 */
static const uint64_t H_512_256[] = {
	0x22312194FC2BF72CULL, 0x9F555FA3C84C64C2ULL, 0x2393B86B6F53B151ULL, 0x963877195940EABDULL,
	0x96283EE2A88EFFE3ULL, 0xBE5E1E2553863992ULL, 0x2B0199FC2C85B8AAULL, 0x0EB72DDC81C52CA2ULL
};


/**
 * Initialise a state
 * 
 * @parma   state      The state that should be initialised
 * @parma   algorithm  The hashing algorithm
 * @return             Zero on success, -1 on error
 */
int
libsha2_init(struct libsha2_state *restrict state, enum libsha2_algorithm algorithm)
{
	size_t i;

	memset(state, 0, sizeof(*state));
	state->message_size = 0;
	state->algorithm = algorithm;

	/* Set initial hash values. */
	switch (algorithm) {
	case LIBSHA2_224:     memcpy(state->h.b32, H_224,     sizeof(H_224));     break;
	case LIBSHA2_256:     memcpy(state->h.b32, H_256,     sizeof(H_256));     break;
	case LIBSHA2_384:     memcpy(state->h.b64, H_384,     sizeof(H_384));     break;
	case LIBSHA2_512:     memcpy(state->h.b64, H_512,     sizeof(H_512));     break;
	case LIBSHA2_512_224: memcpy(state->h.b64, H_512_224, sizeof(H_512_224)); break;
	case LIBSHA2_512_256: memcpy(state->h.b64, H_512_256, sizeof(H_512_256)); break;
	default:
		return errno = EINVAL, -1;
	}

	/* Set round constants, and chunk size. */
	switch (algorithm) {
	case LIBSHA2_224:
	case LIBSHA2_256:
		for (i = 0; i < 64; i++)
			state->k.b32[i] = (uint32_t)(ROUND_CONSTANTS[i] >> 32);
		state->chunk_size = 64;
		break;

	default:
		memcpy(state->k.b64, ROUND_CONSTANTS, sizeof(ROUND_CONSTANTS));
		state->chunk_size = 128;
		break;
	}
  
	return 0;
}