/*

 * Copyright (C) Maxim Dounin

 * Copyright (C) NGINX, Inc.

 *

 * An internal SHA1 implementation.

 */

#include <nxt_main.h>

#include <nxt_sha1.h>

static const u_char *nxt_sha1_body(nxt_sha1_t *ctx, const u_char *data,

    size_t size);

void

nxt_sha1_init(nxt_sha1_t *ctx)

{

    ctx->a = 0x67452301;

    ctx->b = 0xefcdab89;

    ctx->c = 0x98badcfe;

    ctx->d = 0x10325476;

    ctx->e = 0xc3d2e1f0;

    ctx->bytes = 0;

}

void

nxt_sha1_update(nxt_sha1_t *ctx, const void *data, size_t size)

{

    size_t  used, free;

    used = (size_t) (ctx->bytes & 0x3f);

    ctx->bytes += size;

    if (used) {

        free = 64 - used;

        if (size < free) {

            memcpy(&ctx->buffer[used], data, size);

            return;

        }

        memcpy(&ctx->buffer[used], data, free);

        data = (u_char *) data + free;

        size -= free;

        (void) nxt_sha1_body(ctx, ctx->buffer, 64);

    }

    if (size >= 64) {

        data = nxt_sha1_body(ctx, data, size & ~(size_t) 0x3f);

        size &= 0x3f;

    }

    memcpy(ctx->buffer, data, size);

}

void

nxt_sha1_final(u_char result[20], nxt_sha1_t *ctx)

{

    size_t  used, free;

    used = (size_t) (ctx->bytes & 0x3f);

    ctx->buffer[used++] = 0x80;

    free = 64 - used;

    if (free < 8) {

        nxt_memzero(&ctx->buffer[used], free);

        (void) nxt_sha1_body(ctx, ctx->buffer, 64);

        used = 0;

        free = 64;

    }

    nxt_memzero(&ctx->buffer[used], free - 8);

    ctx->bytes <<= 3;

    ctx->buffer[56] = (u_char) (ctx->bytes >> 56);

    ctx->buffer[57] = (u_char) (ctx->bytes >> 48);

    ctx->buffer[58] = (u_char) (ctx->bytes >> 40);

    ctx->buffer[59] = (u_char) (ctx->bytes >> 32);

    ctx->buffer[60] = (u_char) (ctx->bytes >> 24);

    ctx->buffer[61] = (u_char) (ctx->bytes >> 16);

    ctx->buffer[62] = (u_char) (ctx->bytes >> 8);

    ctx->buffer[63] = (u_char)  ctx->bytes;

    (void) nxt_sha1_body(ctx, ctx->buffer, 64);

    result[0]  = (u_char) (ctx->a >> 24);

    result[1]  = (u_char) (ctx->a >> 16);

    result[2]  = (u_char) (ctx->a >> 8);

    result[3]  = (u_char)  ctx->a;

    result[4]  = (u_char) (ctx->b >> 24);

    result[5]  = (u_char) (ctx->b >> 16);

    result[6]  = (u_char) (ctx->b >> 8);

    result[7]  = (u_char)  ctx->b;

    result[8]  = (u_char) (ctx->c >> 24);

    result[9]  = (u_char) (ctx->c >> 16);

    result[10] = (u_char) (ctx->c >> 8);

    result[11] = (u_char)  ctx->c;

    result[12] = (u_char) (ctx->d >> 24);

    result[13] = (u_char) (ctx->d >> 16);

    result[14] = (u_char) (ctx->d >> 8);

    result[15] = (u_char)  ctx->d;

    result[16] = (u_char) (ctx->e >> 24);

    result[17] = (u_char) (ctx->e >> 16);

    result[18] = (u_char) (ctx->e >> 8);

    result[19] = (u_char)  ctx->e;

    nxt_memzero(ctx, sizeof(*ctx));

}

/*

 * Helper functions.

 */

#define ROTATE(bits, word)  (((word) << (bits)) | ((word) >> (32 - (bits))))

#define F1(b, c, d)  (((b) & (c)) | ((~(b)) & (d)))

#define F2(b, c, d)  ((b) ^ (c) ^ (d))

#define F3(b, c, d)  (((b) & (c)) | ((b) & (d)) | ((c) & (d)))

#define STEP(f, a, b, c, d, e, w, t)                                          \

    temp = ROTATE(5, (a)) + f((b), (c), (d)) + (e) + (w) + (t);               \

    (e) = (d);                                                                \

    (d) = (c);                                                                \

    (c) = ROTATE(30, (b));                                                    \

    (b) = (a);                                                                \

    (a) = temp;

/*

 * GET() reads 4 input bytes in big-endian byte order and returns

 * them as uint32_t.

 */

#define GET(n)                                                                \

    (  ((uint32_t) p[n * 4 + 3])                                              \

     | ((uint32_t) p[n * 4 + 2] << 8)                                         \

     | ((uint32_t) p[n * 4 + 1] << 16)                                        \

     | ((uint32_t) p[n * 4]     << 24))

/*

 * This processes one or more 64-byte data blocks, but does not update

 * the bit counters.  There are no alignment requirements.

 */

static const u_char *

nxt_sha1_body(nxt_sha1_t *ctx, const u_char *data, size_t size)

{

    uint32_t       a, b, c, d, e, temp;

    uint32_t       saved_a, saved_b, saved_c, saved_d, saved_e;

    uint32_t       words[80];

    nxt_uint_t     i;

    const u_char  *p;

    p = data;

    a = ctx->a;

    b = ctx->b;

    c = ctx->c;

    d = ctx->d;

    e = ctx->e;

    do {

        saved_a = a;

        saved_b = b;

        saved_c = c;

        saved_d = d;

        saved_e = e;

        /* Load data block into the words array */

        for (i = 0; i < 16; i++) {

            words[i] = GET(i);

        }

        for (i = 16; i < 80; i++) {

            words[i] = ROTATE(1, words[i - 3]

                                 ^ words[i - 8]

                                 ^ words[i - 14]

                                 ^ words[i - 16]);

        }

        /* Transformations */

        STEP(F1, a, b, c, d, e, words[0],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[1],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[2],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[3],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[4],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[5],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[6],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[7],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[8],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[9],  0x5a827999);

        STEP(F1, a, b, c, d, e, words[10], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[11], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[12], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[13], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[14], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[15], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[16], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[17], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[18], 0x5a827999);

        STEP(F1, a, b, c, d, e, words[19], 0x5a827999);

        STEP(F2, a, b, c, d, e, words[20], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[21], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[22], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[23], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[24], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[25], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[26], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[27], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[28], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[29], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[30], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[31], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[32], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[33], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[34], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[35], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[36], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[37], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[38], 0x6ed9eba1);

        STEP(F2, a, b, c, d, e, words[39], 0x6ed9eba1);

        STEP(F3, a, b, c, d, e, words[40], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[41], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[42], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[43], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[44], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[45], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[46], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[47], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[48], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[49], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[50], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[51], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[52], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[53], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[54], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[55], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[56], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[57], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[58], 0x8f1bbcdc);

        STEP(F3, a, b, c, d, e, words[59], 0x8f1bbcdc);

        STEP(F2, a, b, c, d, e, words[60], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[61], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[62], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[63], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[64], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[65], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[66], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[67], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[68], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[69], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[70], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[71], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[72], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[73], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[74], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[75], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[76], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[77], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[78], 0xca62c1d6);

        STEP(F2, a, b, c, d, e, words[79], 0xca62c1d6);

        a += saved_a;

        b += saved_b;

        c += saved_c;

        d += saved_d;

        e += saved_e;

        p += 64;

    } while (size -= 64);

    ctx->a = a;

    ctx->b = b;

    ctx->c = c;

    ctx->d = d;

    ctx->e = e;

    return p;

}