#include "git-compat-util.h"
#include "./sha256.h"

#undef RND
#undef BLKSIZE

#define BLKSIZE blk_SHA256_BLKSIZE

void blk_SHA256_Init(blk_SHA256_CTX *ctx)
{
        ctx->offset = 0;
        ctx->size = 0;
        ctx->state[0] = 0x6a09e667ul;
        ctx->state[1] = 0xbb67ae85ul;
        ctx->state[2] = 0x3c6ef372ul;
        ctx->state[3] = 0xa54ff53aul;
        ctx->state[4] = 0x510e527ful;
        ctx->state[5] = 0x9b05688cul;
        ctx->state[6] = 0x1f83d9abul;
        ctx->state[7] = 0x5be0cd19ul;
}

static inline uint32_t ror(uint32_t x, unsigned n)
{
        return (x >> n) | (x << (32 - n));
}

static inline uint32_t ch(uint32_t x, uint32_t y, uint32_t z)
{
        return z ^ (x & (y ^ z));
}

static inline uint32_t maj(uint32_t x, uint32_t y, uint32_t z)
{
        return ((x | y) & z) | (x & y);
}

static inline uint32_t sigma0(uint32_t x)
{
        return ror(x, 2) ^ ror(x, 13) ^ ror(x, 22);
}

static inline uint32_t sigma1(uint32_t x)
{
        return ror(x, 6) ^ ror(x, 11) ^ ror(x, 25);
}

static inline uint32_t gamma0(uint32_t x)
{
        return ror(x, 7) ^ ror(x, 18) ^ (x >> 3);
}

static inline uint32_t gamma1(uint32_t x)
{
        return ror(x, 17) ^ ror(x, 19) ^ (x >> 10);
}

static void blk_SHA256_Transform(blk_SHA256_CTX *ctx, const unsigned char *buf)
{

        uint32_t S[8], W[64], t0, t1;
        int i;

        /* copy state into S */
        for (i = 0; i < 8; i++)
                S[i] = ctx->state[i];

        /* copy the state into 512-bits into W[0..15] */
        for (i = 0; i < 16; i++, buf += sizeof(uint32_t))
                W[i] = get_be32(buf);

        /* fill W[16..63] */
        for (i = 16; i < 64; i++)
                W[i] = gamma1(W[i - 2]) + W[i - 7] + gamma0(W[i - 15]) + W[i - 16];

#define RND(a,b,c,d,e,f,g,h,i,ki)                    \
        t0 = h + sigma1(e) + ch(e, f, g) + ki + W[i];   \
        t1 = sigma0(a) + maj(a, b, c);                  \
        d += t0;                                        \
        h  = t0 + t1;

        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],0,0x428a2f98);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],1,0x71374491);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],2,0xb5c0fbcf);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],3,0xe9b5dba5);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],4,0x3956c25b);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],5,0x59f111f1);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],6,0x923f82a4);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],7,0xab1c5ed5);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],8,0xd807aa98);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],9,0x12835b01);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],10,0x243185be);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],11,0x550c7dc3);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],12,0x72be5d74);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],13,0x80deb1fe);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],14,0x9bdc06a7);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],15,0xc19bf174);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],16,0xe49b69c1);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],17,0xefbe4786);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],18,0x0fc19dc6);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],19,0x240ca1cc);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],20,0x2de92c6f);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],21,0x4a7484aa);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],22,0x5cb0a9dc);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],23,0x76f988da);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],24,0x983e5152);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],25,0xa831c66d);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],26,0xb00327c8);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],27,0xbf597fc7);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],28,0xc6e00bf3);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],29,0xd5a79147);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],30,0x06ca6351);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],31,0x14292967);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],32,0x27b70a85);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],33,0x2e1b2138);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],34,0x4d2c6dfc);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],35,0x53380d13);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],36,0x650a7354);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],37,0x766a0abb);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],38,0x81c2c92e);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],39,0x92722c85);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],40,0xa2bfe8a1);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],41,0xa81a664b);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],42,0xc24b8b70);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],43,0xc76c51a3);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],44,0xd192e819);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],45,0xd6990624);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],46,0xf40e3585);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],47,0x106aa070);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],48,0x19a4c116);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],49,0x1e376c08);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],50,0x2748774c);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],51,0x34b0bcb5);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],52,0x391c0cb3);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],53,0x4ed8aa4a);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],54,0x5b9cca4f);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],55,0x682e6ff3);
        RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],56,0x748f82ee);
        RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],57,0x78a5636f);
        RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],58,0x84c87814);
        RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],59,0x8cc70208);
        RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],60,0x90befffa);
        RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],61,0xa4506ceb);
        RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],62,0xbef9a3f7);
        RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],63,0xc67178f2);

        for (i = 0; i < 8; i++)
                ctx->state[i] += S[i];
}

void blk_SHA256_Update(blk_SHA256_CTX *ctx, const void *data, size_t len)
{
        unsigned int len_buf = ctx->size & 63;

        ctx->size += len;

        /* Read the data into buf and process blocks as they get full */
        if (len_buf) {
                unsigned int left = 64 - len_buf;
                if (len < left)
                        left = len;
                memcpy(len_buf + ctx->buf, data, left);
                len_buf = (len_buf + left) & 63;
                len -= left;
                data = ((const char *)data + left);
                if (len_buf)
                        return;
                blk_SHA256_Transform(ctx, ctx->buf);
        }
        while (len >= 64) {
                blk_SHA256_Transform(ctx, data);
                data = ((const char *)data + 64);
                len -= 64;
        }
        if (len)
                memcpy(ctx->buf, data, len);
}

void blk_SHA256_Final(unsigned char *digest, blk_SHA256_CTX *ctx)
{
        static const unsigned char pad[64] = { 0x80 };
        unsigned int padlen[2];
        int i;

        /* Pad with a binary 1 (ie 0x80), then zeroes, then length */
        padlen[0] = htonl((uint32_t)(ctx->size >> 29));
        padlen[1] = htonl((uint32_t)(ctx->size << 3));

        i = ctx->size & 63;
        blk_SHA256_Update(ctx, pad, 1 + (63 & (55 - i)));
        blk_SHA256_Update(ctx, padlen, 8);

        /* copy output */
        for (i = 0; i < 8; i++, digest += sizeof(uint32_t))
                put_be32(digest, ctx->state[i]);
}