/*

 * Copyright (C) 2007 Michael Niedermayer <michaelni@gmx.at>

 * Copyright (C) 2009 Konstantin Shishkov

 * based on public domain SHA-1 code by Steve Reid <steve@edmweb.com>

 * and on BSD-licensed SHA-2 code by Aaron D. Gifford

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <string.h>

#include "config.h"

#include "attributes.h"

#include "bswap.h"

#include "error.h"

#include "sha.h"

#include "intreadwrite.h"

#include "mem.h"

/** hash context */

typedef struct AVSHA {

    uint8_t  digest_len;  ///< digest length in 32-bit words

    uint64_t count;       ///< number of bytes in buffer

    uint8_t  buffer[64];  ///< 512-bit buffer of input values used in hash updating

    uint32_t state[8];    ///< current hash value

    /** function used to update hash for 512-bit input block */

    void     (*transform)(uint32_t *state, const uint8_t buffer[64]);

} AVSHA;

const int av_sha_size = sizeof(AVSHA);

struct AVSHA *av_sha_alloc(void)

{

    return av_mallocz(sizeof(struct AVSHA));

}

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */

#define blk0(i) (block[i] = AV_RB32(buffer + 4 * (i)))

#define blk(i)  (block[i] = rol(block[(i)-3] ^ block[(i)-8] ^ block[(i)-14] ^ block[(i)-16], 1))

#define R0(v,w,x,y,z,i) z += (((w)&((x)^(y)))^(y))       + blk0(i) + 0x5A827999 + rol(v, 5); w = rol(w, 30);

#define R1(v,w,x,y,z,i) z += (((w)&((x)^(y)))^(y))       + blk (i) + 0x5A827999 + rol(v, 5); w = rol(w, 30);

#define R2(v,w,x,y,z,i) z += ( (w)^(x)       ^(y))       + blk (i) + 0x6ED9EBA1 + rol(v, 5); w = rol(w, 30);

#define R3(v,w,x,y,z,i) z += ((((w)|(x))&(y))|((w)&(x))) + blk (i) + 0x8F1BBCDC + rol(v, 5); w = rol(w, 30);

#define R4(v,w,x,y,z,i) z += ( (w)^(x)       ^(y))       + blk (i) + 0xCA62C1D6 + rol(v, 5); w = rol(w, 30);

/* Hash a single 512-bit block. This is the core of the algorithm. */

static void sha1_transform(uint32_t state[5], const uint8_t buffer[64])

{

    uint32_t block[80];

    unsigned int i, a, b, c, d, e;

    a = state[0];

    b = state[1];

    c = state[2];

    d = state[3];

    e = state[4];

#if CONFIG_SMALL

    for (i = 0; i < 80; i++) {

        int t;

        if (i < 16)

            t = AV_RB32(buffer + 4 * i);

        else

            t = rol(block[i-3] ^ block[i-8] ^ block[i-14] ^ block[i-16], 1);

        block[i] = t;

        t += e + rol(a, 5);

        if (i < 40) {

            if (i < 20)

                t += ((b&(c^d))^d)     + 0x5A827999;

            else

                t += ( b^c     ^d)     + 0x6ED9EBA1;

        } else {

            if (i < 60)

                t += (((b|c)&d)|(b&c)) + 0x8F1BBCDC;

            else

                t += ( b^c     ^d)     + 0xCA62C1D6;

        }

        e = d;

        d = c;

        c = rol(b, 30);

        b = a;

        a = t;

    }

#else

#define R1_0 \

    R0(a, b, c, d, e, 0 + i); \

    R0(e, a, b, c, d, 1 + i); \

    R0(d, e, a, b, c, 2 + i); \

    R0(c, d, e, a, b, 3 + i); \

    R0(b, c, d, e, a, 4 + i); \

    i += 5

    i = 0;

    R1_0; R1_0; R1_0;

    R0(a, b, c, d, e, 15);

    R1(e, a, b, c, d, 16);

    R1(d, e, a, b, c, 17);

    R1(c, d, e, a, b, 18);

    R1(b, c, d, e, a, 19);

#define R1_20 \

    R2(a, b, c, d, e, 0 + i); \

    R2(e, a, b, c, d, 1 + i); \

    R2(d, e, a, b, c, 2 + i); \

    R2(c, d, e, a, b, 3 + i); \

    R2(b, c, d, e, a, 4 + i); \

    i += 5

    i = 20;

    R1_20; R1_20; R1_20; R1_20;

#define R1_40 \

    R3(a, b, c, d, e, 0 + i); \

    R3(e, a, b, c, d, 1 + i); \

    R3(d, e, a, b, c, 2 + i); \

    R3(c, d, e, a, b, 3 + i); \

    R3(b, c, d, e, a, 4 + i); \

    i += 5

    R1_40; R1_40; R1_40; R1_40;

#define R1_60 \

    R4(a, b, c, d, e, 0 + i); \

    R4(e, a, b, c, d, 1 + i); \

    R4(d, e, a, b, c, 2 + i); \

    R4(c, d, e, a, b, 3 + i); \

    R4(b, c, d, e, a, 4 + i); \

    i += 5

    R1_60; R1_60; R1_60; R1_60;

#endif

    state[0] += a;

    state[1] += b;

    state[2] += c;

    state[3] += d;

    state[4] += e;

}

static const uint32_t K256[64] = {

    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,

    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,

    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,

    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,

    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,

    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,

    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,

    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,

    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,

    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,

    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,

    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,

    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,

    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,

    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,

    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2

};

#define Ch(x,y,z)   (((x) & ((y) ^ (z))) ^ (z))

#define Maj(z,y,x)  ((((x) | (y)) & (z)) | ((x) & (y)))

#define Sigma0_256(x)   (rol((x), 30) ^ rol((x), 19) ^ rol((x), 10))

#define Sigma1_256(x)   (rol((x), 26) ^ rol((x), 21) ^ rol((x),  7))

#define sigma0_256(x)   (rol((x), 25) ^ rol((x), 14) ^ ((x) >> 3))

#define sigma1_256(x)   (rol((x), 15) ^ rol((x), 13) ^ ((x) >> 10))

#undef blk

#define blk(i)  (block[i] = block[i - 16] + sigma0_256(block[i - 15]) + \

                            sigma1_256(block[i - 2]) + block[i - 7])

#define ROUND256(a,b,c,d,e,f,g,h)   \

    T1 += (h) + Sigma1_256(e) + Ch((e), (f), (g)) + K256[i]; \

    (d) += T1; \

    (h) = T1 + Sigma0_256(a) + Maj((a), (b), (c)); \

    i++

#define ROUND256_0_TO_15(a,b,c,d,e,f,g,h)   \

    T1 = blk0(i); \

    ROUND256(a,b,c,d,e,f,g,h)

#define ROUND256_16_TO_63(a,b,c,d,e,f,g,h)   \

    T1 = blk(i); \

    ROUND256(a,b,c,d,e,f,g,h)

static void sha256_transform(uint32_t *state, const uint8_t buffer[64])

{

    unsigned int i, a, b, c, d, e, f, g, h;

    uint32_t block[64];

    uint32_t T1;

    a = state[0];

    b = state[1];

    c = state[2];

    d = state[3];

    e = state[4];

    f = state[5];

    g = state[6];

    h = state[7];

#if CONFIG_SMALL

    for (i = 0; i < 64; i++) {

        uint32_t T2;

        if (i < 16)

            T1 = blk0(i);

        else

            T1 = blk(i);

        T1 += h + Sigma1_256(e) + Ch(e, f, g) + K256[i];

        T2 = Sigma0_256(a) + Maj(a, b, c);

        h = g;

        g = f;

        f = e;

        e = d + T1;

        d = c;

        c = b;

        b = a;

        a = T1 + T2;

    }

#else

    i = 0;

#define R256_0 \

    ROUND256_0_TO_15(a, b, c, d, e, f, g, h); \

    ROUND256_0_TO_15(h, a, b, c, d, e, f, g); \

    ROUND256_0_TO_15(g, h, a, b, c, d, e, f); \

    ROUND256_0_TO_15(f, g, h, a, b, c, d, e); \

    ROUND256_0_TO_15(e, f, g, h, a, b, c, d); \

    ROUND256_0_TO_15(d, e, f, g, h, a, b, c); \

    ROUND256_0_TO_15(c, d, e, f, g, h, a, b); \

    ROUND256_0_TO_15(b, c, d, e, f, g, h, a)

    R256_0; R256_0;

#define R256_16 \

    ROUND256_16_TO_63(a, b, c, d, e, f, g, h); \

    ROUND256_16_TO_63(h, a, b, c, d, e, f, g); \

    ROUND256_16_TO_63(g, h, a, b, c, d, e, f); \

    ROUND256_16_TO_63(f, g, h, a, b, c, d, e); \

    ROUND256_16_TO_63(e, f, g, h, a, b, c, d); \

    ROUND256_16_TO_63(d, e, f, g, h, a, b, c); \

    ROUND256_16_TO_63(c, d, e, f, g, h, a, b); \

    ROUND256_16_TO_63(b, c, d, e, f, g, h, a)

    R256_16; R256_16; R256_16;

    R256_16; R256_16; R256_16;

#endif

    state[0] += a;

    state[1] += b;

    state[2] += c;

    state[3] += d;

    state[4] += e;

    state[5] += f;

    state[6] += g;

    state[7] += h;

}

av_cold int av_sha_init(AVSHA *ctx, int bits)

{

    ctx->digest_len = bits >> 5;

    switch (bits) {

    case 160: // SHA-1

        ctx->state[0] = 0x67452301;

        ctx->state[1] = 0xEFCDAB89;

        ctx->state[2] = 0x98BADCFE;

        ctx->state[3] = 0x10325476;

        ctx->state[4] = 0xC3D2E1F0;

        ctx->transform = sha1_transform;

        break;

    case 224: // SHA-224

        ctx->state[0] = 0xC1059ED8;

        ctx->state[1] = 0x367CD507;

        ctx->state[2] = 0x3070DD17;

        ctx->state[3] = 0xF70E5939;

        ctx->state[4] = 0xFFC00B31;

        ctx->state[5] = 0x68581511;

        ctx->state[6] = 0x64F98FA7;

        ctx->state[7] = 0xBEFA4FA4;

        ctx->transform = sha256_transform;

        break;

    case 256: // SHA-256

        ctx->state[0] = 0x6A09E667;

        ctx->state[1] = 0xBB67AE85;

        ctx->state[2] = 0x3C6EF372;

        ctx->state[3] = 0xA54FF53A;

        ctx->state[4] = 0x510E527F;

        ctx->state[5] = 0x9B05688C;

        ctx->state[6] = 0x1F83D9AB;

        ctx->state[7] = 0x5BE0CD19;

        ctx->transform = sha256_transform;

        break;

    default:

        return AVERROR(EINVAL);

    }

    ctx->count = 0;

    return 0;

}

void av_sha_update(struct AVSHA *ctx, const uint8_t *data, size_t len)

{

    unsigned int j;

    size_t i;

    j = ctx->count & 63;

    ctx->count += len;

#if CONFIG_SMALL

    for (i = 0; i < len; i++) {

        ctx->buffer[j++] = data[i];

        if (64 == j) {

            ctx->transform(ctx->state, ctx->buffer);

            j = 0;

        }

    }

#else

    if (len >= 64 - j) {

        const uint8_t *end;

        memcpy(&ctx->buffer[j], data, (i = 64 - j));

        ctx->transform(ctx->state, ctx->buffer);

        data += i;

        len  -= i;

        end   = data + (len & ~63);

        len   = len % 64;

        for (; data < end; data += 64)

            ctx->transform(ctx->state, data);

        j = 0;

    }

    memcpy(&ctx->buffer[j], data, len);

#endif

}

void av_sha_final(AVSHA* ctx, uint8_t *digest)

{

    int i;

    uint64_t finalcount = av_be2ne64(ctx->count << 3);

    av_sha_update(ctx, "\200", 1);

    while ((ctx->count & 63) != 56)

        av_sha_update(ctx, "", 1);

    av_sha_update(ctx, (uint8_t *)&finalcount, 8); /* Should cause a transform() */

    for (i = 0; i < ctx->digest_len; i++)

        AV_WB32(digest + i*4, ctx->state[i]);

}