/*
 * The blake256_* and blake224_* functions are largely copied from
 * blake256_light.c and blake224_light.c from the BLAKE website:
 *
 *     http://131002.net/blake/
 *
 * The hmac_* functions implement HMAC-BLAKE-256 and HMAC-BLAKE-224.
 * HMAC is specified by RFC 2104.
 */

#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include "c_blake256.h"

#define U8TO32(p) \
    (((uint32_t)((p)[0]) << 24) | ((uint32_t)((p)[1]) << 16) |    \
     ((uint32_t)((p)[2]) <<  8) | ((uint32_t)((p)[3])      ))
#define U32TO8(p, v) \
    (p)[0] = (uint8_t)((v) >> 24); (p)[1] = (uint8_t)((v) >> 16); \
    (p)[2] = (uint8_t)((v) >>  8); (p)[3] = (uint8_t)((v)      );

const uint8_t sigma[][16] = {
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15},
    {14,10, 4, 8, 9,15,13, 6, 1,12, 0, 2,11, 7, 5, 3},
    {11, 8,12, 0, 5, 2,15,13,10,14, 3, 6, 7, 1, 9, 4},
    { 7, 9, 3, 1,13,12,11,14, 2, 6, 5,10, 4, 0,15, 8},
    { 9, 0, 5, 7, 2, 4,10,15,14, 1,11,12, 6, 8, 3,13},
    { 2,12, 6,10, 0,11, 8, 3, 4,13, 7, 5,15,14, 1, 9},
    {12, 5, 1,15,14,13, 4,10, 0, 7, 6, 3, 9, 2, 8,11},
    {13,11, 7,14,12, 1, 3, 9, 5, 0,15, 4, 8, 6, 2,10},
    { 6,15,14, 9,11, 3, 0, 8,12, 2,13, 7, 1, 4,10, 5},
    {10, 2, 8, 4, 7, 6, 1, 5,15,11, 9,14, 3,12,13, 0},
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15},
    {14,10, 4, 8, 9,15,13, 6, 1,12, 0, 2,11, 7, 5, 3},
    {11, 8,12, 0, 5, 2,15,13,10,14, 3, 6, 7, 1, 9, 4},
    { 7, 9, 3, 1,13,12,11,14, 2, 6, 5,10, 4, 0,15, 8}
};

const uint32_t cst[16] = {
    0x243F6A88, 0x85A308D3, 0x13198A2E, 0x03707344,
    0xA4093822, 0x299F31D0, 0x082EFA98, 0xEC4E6C89,
    0x452821E6, 0x38D01377, 0xBE5466CF, 0x34E90C6C,
    0xC0AC29B7, 0xC97C50DD, 0x3F84D5B5, 0xB5470917
};

static const uint8_t padding[] = {
    0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};


void blake256_compress(state *S, const uint8_t *block) {
    uint32_t v[16], m[16], i;

#define ROT(x,n) (((x)<<(32-n))|((x)>>(n)))
#define G(a,b,c,d,e)                                      \
    v[a] += (m[sigma[i][e]] ^ cst[sigma[i][e+1]]) + v[b]; \
    v[d] = ROT(v[d] ^ v[a],16);                           \
    v[c] += v[d];                                         \
    v[b] = ROT(v[b] ^ v[c],12);                           \
    v[a] += (m[sigma[i][e+1]] ^ cst[sigma[i][e]])+v[b];   \
    v[d] = ROT(v[d] ^ v[a], 8);                           \
    v[c] += v[d];                                         \
    v[b] = ROT(v[b] ^ v[c], 7);

    for (i = 0; i < 16; ++i) m[i] = U8TO32(block + i * 4);
    for (i = 0; i < 8;  ++i) v[i] = S->h[i];
    v[ 8] = S->s[0] ^ 0x243F6A88;
    v[ 9] = S->s[1] ^ 0x85A308D3;
    v[10] = S->s[2] ^ 0x13198A2E;
    v[11] = S->s[3] ^ 0x03707344;
    v[12] = 0xA4093822;
    v[13] = 0x299F31D0;
    v[14] = 0x082EFA98;
    v[15] = 0xEC4E6C89;

    if (S->nullt == 0) {
        v[12] ^= S->t[0];
        v[13] ^= S->t[0];
        v[14] ^= S->t[1];
        v[15] ^= S->t[1];
    }

    for (i = 0; i < 14; ++i) {
        G(0, 4,  8, 12,  0);
        G(1, 5,  9, 13,  2);
        G(2, 6, 10, 14,  4);
        G(3, 7, 11, 15,  6);
        G(3, 4,  9, 14, 14);
        G(2, 7,  8, 13, 12);
        G(0, 5, 10, 15,  8);
        G(1, 6, 11, 12, 10);
    }

    for (i = 0; i < 16; ++i) S->h[i % 8] ^= v[i];
    for (i = 0; i < 8;  ++i) S->h[i] ^= S->s[i % 4];
}

void blake256_init(state *S) {
    S->h[0] = 0x6A09E667;
    S->h[1] = 0xBB67AE85;
    S->h[2] = 0x3C6EF372;
    S->h[3] = 0xA54FF53A;
    S->h[4] = 0x510E527F;
    S->h[5] = 0x9B05688C;
    S->h[6] = 0x1F83D9AB;
    S->h[7] = 0x5BE0CD19;
    S->t[0] = S->t[1] = S->buflen = S->nullt = 0;
    S->s[0] = S->s[1] = S->s[2] = S->s[3] = 0;
}

void blake224_init(state *S) {
    S->h[0] = 0xC1059ED8;
    S->h[1] = 0x367CD507;
    S->h[2] = 0x3070DD17;
    S->h[3] = 0xF70E5939;
    S->h[4] = 0xFFC00B31;
    S->h[5] = 0x68581511;
    S->h[6] = 0x64F98FA7;
    S->h[7] = 0xBEFA4FA4;
    S->t[0] = S->t[1] = S->buflen = S->nullt = 0;
    S->s[0] = S->s[1] = S->s[2] = S->s[3] = 0;
}

// datalen = number of bits
void blake256_update(state *S, const uint8_t *data, uint64_t datalen) {
    int left = S->buflen >> 3;
    int fill = 64 - left;

    if (left && (((datalen >> 3) & 0x3F) >= (unsigned) fill)) {
        memcpy((void *) (S->buf + left), (void *) data, fill);
        S->t[0] += 512;
        if (S->t[0] == 0) S->t[1]++;
        blake256_compress(S, S->buf);
        data += fill;
        datalen -= (fill << 3);
        left = 0;
    }

    while (datalen >= 512) {
        S->t[0] += 512;
        if (S->t[0] == 0) S->t[1]++;
        blake256_compress(S, data);
        data += 64;
        datalen -= 512;
    }

    if (datalen > 0) {
        memcpy((void *) (S->buf + left), (void *) data, datalen >> 3);
        S->buflen = (left << 3) + (int) datalen;
    } else {
        S->buflen = 0;
    }
}

// datalen = number of bits
void blake224_update(state *S, const uint8_t *data, uint64_t datalen) {
    blake256_update(S, data, datalen);
}

void blake256_final_h(state *S, uint8_t *digest, uint8_t pa, uint8_t pb) {
    uint8_t msglen[8];
    uint32_t lo = S->t[0] + S->buflen, hi = S->t[1];
    if (lo < (unsigned) S->buflen) hi++;
    U32TO8(msglen + 0, hi);
    U32TO8(msglen + 4, lo);

    if (S->buflen == 440) { /* one padding byte */
        S->t[0] -= 8;
        blake256_update(S, &pa, 8);
    } else {
        if (S->buflen < 440) { /* enough space to fill the block  */
            if (S->buflen == 0) S->nullt = 1;
            S->t[0] -= 440 - S->buflen;
            blake256_update(S, padding, 440 - S->buflen);
        } else { /* need 2 compressions */
            S->t[0] -= 512 - S->buflen;
            blake256_update(S, padding, 512 - S->buflen);
            S->t[0] -= 440;
            blake256_update(S, padding + 1, 440);
            S->nullt = 1;
        }
        blake256_update(S, &pb, 8);
        S->t[0] -= 8;
    }
    S->t[0] -= 64;
    blake256_update(S, msglen, 64);

    U32TO8(digest +  0, S->h[0]);
    U32TO8(digest +  4, S->h[1]);
    U32TO8(digest +  8, S->h[2]);
    U32TO8(digest + 12, S->h[3]);
    U32TO8(digest + 16, S->h[4]);
    U32TO8(digest + 20, S->h[5]);
    U32TO8(digest + 24, S->h[6]);
    U32TO8(digest + 28, S->h[7]);
}

void blake256_final(state *S, uint8_t *digest) {
    blake256_final_h(S, digest, 0x81, 0x01);
}

void blake224_final(state *S, uint8_t *digest) {
    blake256_final_h(S, digest, 0x80, 0x00);
}

// inlen = number of bytes
void blake256_hash(uint8_t *out, const uint8_t *in, uint64_t inlen) {
    state S;
    blake256_init(&S);
    blake256_update(&S, in, inlen * 8);
    blake256_final(&S, out);
}

// inlen = number of bytes
void blake224_hash(uint8_t *out, const uint8_t *in, uint64_t inlen) {
    state S;
    blake224_init(&S);
    blake224_update(&S, in, inlen * 8);
    blake224_final(&S, out);
}

// keylen = number of bytes
void hmac_blake256_init(hmac_state *S, const uint8_t *_key, uint64_t keylen) {
    const uint8_t *key = _key;
    uint8_t keyhash[32];
    uint8_t pad[64];
    uint64_t i;

    if (keylen > 64) {
        blake256_hash(keyhash, key, keylen);
        key = keyhash;
        keylen = 32;
    }

    blake256_init(&S->inner);
    memset(pad, 0x36, 64);
    for (i = 0; i < keylen; ++i) {
        pad[i] ^= key[i];
    }
    blake256_update(&S->inner, pad, 512);

    blake256_init(&S->outer);
    memset(pad, 0x5c, 64);
    for (i = 0; i < keylen; ++i) {
        pad[i] ^= key[i];
    }
    blake256_update(&S->outer, pad, 512);

    memset(keyhash, 0, 32);
}

// keylen = number of bytes
void hmac_blake224_init(hmac_state *S, const uint8_t *_key, uint64_t keylen) {
    const uint8_t *key = _key;
    uint8_t keyhash[32];
    uint8_t pad[64];
    uint64_t i;

    if (keylen > 64) {
        blake256_hash(keyhash, key, keylen);
        key = keyhash;
        keylen = 28;
    }

    blake224_init(&S->inner);
    memset(pad, 0x36, 64);
    for (i = 0; i < keylen; ++i) {
        pad[i] ^= key[i];
    }
    blake224_update(&S->inner, pad, 512);

    blake224_init(&S->outer);
    memset(pad, 0x5c, 64);
    for (i = 0; i < keylen; ++i) {
        pad[i] ^= key[i];
    }
    blake224_update(&S->outer, pad, 512);

    memset(keyhash, 0, 32);
}

// datalen = number of bits
void hmac_blake256_update(hmac_state *S, const uint8_t *data, uint64_t datalen) {
  // update the inner state
  blake256_update(&S->inner, data, datalen);
}

// datalen = number of bits
void hmac_blake224_update(hmac_state *S, const uint8_t *data, uint64_t datalen) {
  // update the inner state
  blake224_update(&S->inner, data, datalen);
}

void hmac_blake256_final(hmac_state *S, uint8_t *digest) {
    uint8_t ihash[32];
    blake256_final(&S->inner, ihash);
    blake256_update(&S->outer, ihash, 256);
    blake256_final(&S->outer, digest);
    memset(ihash, 0, 32);
}

void hmac_blake224_final(hmac_state *S, uint8_t *digest) {
    uint8_t ihash[32];
    blake224_final(&S->inner, ihash);
    blake224_update(&S->outer, ihash, 224);
    blake224_final(&S->outer, digest);
    memset(ihash, 0, 32);
}

// keylen = number of bytes; inlen = number of bytes
void hmac_blake256_hash(uint8_t *out, const uint8_t *key, uint64_t keylen, const uint8_t *in, uint64_t inlen) {
    hmac_state S;
    hmac_blake256_init(&S, key, keylen);
    hmac_blake256_update(&S, in, inlen * 8);
    hmac_blake256_final(&S, out);
}

// keylen = number of bytes; inlen = number of bytes
void hmac_blake224_hash(uint8_t *out, const uint8_t *key, uint64_t keylen, const uint8_t *in, uint64_t inlen) {
    hmac_state S;
    hmac_blake224_init(&S, key, keylen);
    hmac_blake224_update(&S, in, inlen * 8);
    hmac_blake224_final(&S, out);
}
