/*
 *  Copyright 2014-2023 The GmSSL Project. All Rights Reserved.
 *
 *  Licensed under the Apache License, Version 2.0 (the License); you may
 *  not use this file except in compliance with the License.
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 */


#include <string.h>
#include <gmssl/sm3.h>
#include <gmssl/error.h>


#define GETU32(ptr) \
	((uint32_t)(ptr)[0] << 24 | \
	 (uint32_t)(ptr)[1] << 16 | \
	 (uint32_t)(ptr)[2] <<  8 | \
	 (uint32_t)(ptr)[3])

#define PUTU32(ptr,a) \
	((ptr)[0] = (uint8_t)((a) >> 24), \
	 (ptr)[1] = (uint8_t)((a) >> 16), \
	 (ptr)[2] = (uint8_t)((a) >>  8), \
	 (ptr)[3] = (uint8_t)(a))

#define ROTL(x,n)  (((x)<<(n)) | ((x)>>(32-(n))))

#define P0(x) ((x) ^ ROTL((x), 9) ^ ROTL((x),17))
#define P1(x) ((x) ^ ROTL((x),15) ^ ROTL((x),23))

#define FF00(x,y,z)  ((x) ^ (y) ^ (z))
#define FF16(x,y,z)  (((x)&(y)) | ((x)&(z)) | ((y)&(z)))
#define GG00(x,y,z)  ((x) ^ (y) ^ (z))
#define GG16(x,y,z)  ((((y)^(z)) & (x)) ^ (z))


static uint32_t K[64] = {
	0x79cc4519U, 0xf3988a32U, 0xe7311465U, 0xce6228cbU,
	0x9cc45197U, 0x3988a32fU, 0x7311465eU, 0xe6228cbcU,
	0xcc451979U, 0x988a32f3U, 0x311465e7U, 0x6228cbceU,
	0xc451979cU, 0x88a32f39U, 0x11465e73U, 0x228cbce6U,
	0x9d8a7a87U, 0x3b14f50fU, 0x7629ea1eU, 0xec53d43cU,
	0xd8a7a879U, 0xb14f50f3U, 0x629ea1e7U, 0xc53d43ceU,
	0x8a7a879dU, 0x14f50f3bU, 0x29ea1e76U, 0x53d43cecU,
	0xa7a879d8U, 0x4f50f3b1U, 0x9ea1e762U, 0x3d43cec5U,
	0x7a879d8aU, 0xf50f3b14U, 0xea1e7629U, 0xd43cec53U,
	0xa879d8a7U, 0x50f3b14fU, 0xa1e7629eU, 0x43cec53dU,
	0x879d8a7aU, 0x0f3b14f5U, 0x1e7629eaU, 0x3cec53d4U,
	0x79d8a7a8U, 0xf3b14f50U, 0xe7629ea1U, 0xcec53d43U,
	0x9d8a7a87U, 0x3b14f50fU, 0x7629ea1eU, 0xec53d43cU,
	0xd8a7a879U, 0xb14f50f3U, 0x629ea1e7U, 0xc53d43ceU,
	0x8a7a879dU, 0x14f50f3bU, 0x29ea1e76U, 0x53d43cecU,
	0xa7a879d8U, 0x4f50f3b1U, 0x9ea1e762U, 0x3d43cec5U,
};

void sm3_compress_blocks(uint32_t digest[8], const uint8_t *data, size_t blocks)
{
	uint32_t A;
	uint32_t B;
	uint32_t C;
	uint32_t D;
	uint32_t E;
	uint32_t F;
	uint32_t G;
	uint32_t H;
	uint32_t W[68];
	uint32_t SS1, SS2, TT1, TT2;
	int j;

	while (blocks--) {

		A = digest[0];
		B = digest[1];
		C = digest[2];
		D = digest[3];
		E = digest[4];
		F = digest[5];
		G = digest[6];
		H = digest[7];

		for (j = 0; j < 16; j++) {
			W[j] = GETU32(data + j*4);
		}

		for (; j < 68; j++) {
			W[j] = P1(W[j - 16] ^ W[j - 9] ^ ROTL(W[j - 3], 15))
				^ ROTL(W[j - 13], 7) ^ W[j - 6];
		}

		for (j = 0; j < 16; j++) {
			SS1 = ROTL((ROTL(A, 12) + E + K[j]), 7);
			SS2 = SS1 ^ ROTL(A, 12);
			TT1 = FF00(A, B, C) + D + SS2 + (W[j] ^ W[j + 4]);
			TT2 = GG00(E, F, G) + H + SS1 + W[j];
			D = C;
			C = ROTL(B, 9);
			B = A;
			A = TT1;
			H = G;
			G = ROTL(F, 19);
			F = E;
			E = P0(TT2);
		}

		for (; j < 64; j++) {
			SS1 = ROTL((ROTL(A, 12) + E + K[j]), 7);
			SS2 = SS1 ^ ROTL(A, 12);
			TT1 = FF16(A, B, C) + D + SS2 + (W[j] ^ W[j + 4]);
			TT2 = GG16(E, F, G) + H + SS1 + W[j];
			D = C;
			C = ROTL(B, 9);
			B = A;
			A = TT1;
			H = G;
			G = ROTL(F, 19);
			F = E;
			E = P0(TT2);
		}

		digest[0] ^= A;
		digest[1] ^= B;
		digest[2] ^= C;
		digest[3] ^= D;
		digest[4] ^= E;
		digest[5] ^= F;
		digest[6] ^= G;
		digest[7] ^= H;

		data += 64;
	}
}

void sm3_init(SM3_CTX *ctx)
{
	memset(ctx, 0, sizeof(*ctx));
	ctx->digest[0] = 0x7380166F;
	ctx->digest[1] = 0x4914B2B9;
	ctx->digest[2] = 0x172442D7;
	ctx->digest[3] = 0xDA8A0600;
	ctx->digest[4] = 0xA96F30BC;
	ctx->digest[5] = 0x163138AA;
	ctx->digest[6] = 0xE38DEE4D;
	ctx->digest[7] = 0xB0FB0E4E;
}

void sm3_update(SM3_CTX *ctx, const uint8_t *data, size_t data_len)
{
	size_t blocks;

	ctx->num &= 0x3f;
	if (ctx->num) {
		size_t left = SM3_BLOCK_SIZE - ctx->num;
		if (data_len < left) {
			memcpy(ctx->block + ctx->num, data, data_len);
			ctx->num += data_len;
			return;
		} else {
			memcpy(ctx->block + ctx->num, data, left);
			sm3_compress_blocks(ctx->digest, ctx->block, 1);
			ctx->nblocks++;
			data += left;
			data_len -= left;
		}
	}

	blocks = data_len / SM3_BLOCK_SIZE;
	if (blocks) {
		sm3_compress_blocks(ctx->digest, data, blocks);
		ctx->nblocks += blocks;
		data += SM3_BLOCK_SIZE * blocks;
		data_len -= SM3_BLOCK_SIZE * blocks;
	}

	ctx->num = data_len;
	if (data_len) {
		memcpy(ctx->block, data, data_len);
	}
}

void sm3_finish(SM3_CTX *ctx, uint8_t *digest)
{
	int i;

	ctx->num &= 0x3f;
	ctx->block[ctx->num] = 0x80;

	if (ctx->num <= SM3_BLOCK_SIZE - 9) {
		memset(ctx->block + ctx->num + 1, 0, SM3_BLOCK_SIZE - ctx->num - 9);
	} else {
		memset(ctx->block + ctx->num + 1, 0, SM3_BLOCK_SIZE - ctx->num - 1);
		sm3_compress_blocks(ctx->digest, ctx->block, 1);
		memset(ctx->block, 0, SM3_BLOCK_SIZE - 8);
	}

	PUTU32(ctx->block + 56, ctx->nblocks >> 23);
	PUTU32(ctx->block + 60, (ctx->nblocks << 9) + (ctx->num << 3));
	sm3_compress_blocks(ctx->digest, ctx->block, 1);

	for (i = 0; i < 8; i++) {
		PUTU32(digest + i*4, ctx->digest[i]);
	}
}

/*
void sm3_digest(const uint8_t *msg, size_t msglen,
	uint8_t dgst[SM3_DIGEST_SIZE])
{
	SM3_CTX ctx;
	sm3_init(&ctx);
	sm3_update(&ctx, msg, msglen);
	sm3_finish(&ctx, dgst);
	memset(&ctx, 0, sizeof(ctx));
}
*/