/*

 * An internal implementation, based on Alexander Peslyak's

 * public domain implementation:

 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5

 */

#include <njs_unix.h>

#include <njs_types.h>

#include <njs_clang.h>

#include <njs_str.h>

#include "njs_hash.h"

static const u_char *njs_md5_body(njs_hash_t *ctx, const u_char *data,

    size_t size);

void

njs_md5_init(njs_hash_t *ctx)

{

    ctx->a = 0x67452301;

    ctx->b = 0xefcdab89;

    ctx->c = 0x98badcfe;

    ctx->d = 0x10325476;

    ctx->bytes = 0;

}

void

njs_md5_update(njs_hash_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) njs_md5_body(ctx, ctx->buffer, 64);

    }

    if (size >= 64) {

        data = njs_md5_body(ctx, data, size & ~(size_t) 0x3f);

        size &= 0x3f;

    }

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

}

void

njs_md5_final(u_char result[32], njs_hash_t *ctx)

{

    size_t  used, free;

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

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

    free = 64 - used;

    if (free < 8) {

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

        (void) njs_md5_body(ctx, ctx->buffer, 64);

        used = 0;

        free = 64;

    }

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

    ctx->bytes <<= 3;

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

    ctx->buffer[57] = (u_char) (ctx->bytes >> 8);

    ctx->buffer[58] = (u_char) (ctx->bytes >> 16);

    ctx->buffer[59] = (u_char) (ctx->bytes >> 24);

    ctx->buffer[60] = (u_char) (ctx->bytes >> 32);

    ctx->buffer[61] = (u_char) (ctx->bytes >> 40);

    ctx->buffer[62] = (u_char) (ctx->bytes >> 48);

    ctx->buffer[63] = (u_char) (ctx->bytes >> 56);

    (void) njs_md5_body(ctx, ctx->buffer, 64);

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

    result[1]  = (u_char) (ctx->a >> 8);

    result[2]  = (u_char) (ctx->a >> 16);

    result[3]  = (u_char) (ctx->a >> 24);

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

    result[5]  = (u_char) (ctx->b >> 8);

    result[6]  = (u_char) (ctx->b >> 16);

    result[7]  = (u_char) (ctx->b >> 24);

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

    result[9]  = (u_char) (ctx->c >> 8);

    result[10] = (u_char) (ctx->c >> 16);

    result[11] = (u_char) (ctx->c >> 24);

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

    result[13] = (u_char) (ctx->d >> 8);

    result[14] = (u_char) (ctx->d >> 16);

    result[15] = (u_char) (ctx->d >> 24);

    njs_explicit_memzero(ctx, sizeof(*ctx));

}

/*

 * The basic MD5 functions.

 *

 * F and G are optimized compared to their RFC 1321 definitions for

 * architectures that lack an AND-NOT instruction, just like in

 * Colin Plumb's implementation.

 */

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

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

#define H(x, y, z)  ((x) ^ (y) ^ (z))

#define I(x, y, z)  ((y) ^ ((x) | ~(z)))

/*

 * The MD5 transformation for all four rounds.

 */

#define STEP(f, a, b, c, d, x, t, s)                                          \

    (a) += f((b), (c), (d)) + (x) + (t);                                      \

    (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s))));                \

    (a) += (b)

/*

 * SET() reads 4 input bytes in little-endian byte order and stores them

 * in a properly aligned word in host byte order.

 */

#define SET(n)                                                                \

    (block[n] =                                                               \

     (   (uint32_t) p[n * 4]                                                  \

      | ((uint32_t) p[n * 4 + 1] << 8)                                        \

      | ((uint32_t) p[n * 4 + 2] << 16)                                       \

      | ((uint32_t) p[n * 4 + 3] << 24)))                                     \

#define GET(n)      block[n]

/*

 * 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 *

njs_md5_body(njs_hash_t *ctx, const u_char *data, size_t size)

{

    uint32_t       a, b, c, d;

    uint32_t       saved_a, saved_b, saved_c, saved_d;

    const u_char   *p;

    uint32_t       block[16];

    p = data;

    a = ctx->a;

    b = ctx->b;

    c = ctx->c;

    d = ctx->d;

    do {

        saved_a = a;

        saved_b = b;

        saved_c = c;

        saved_d = d;

        /* Round 1 */

        STEP(F, a, b, c, d, SET(0),  0xd76aa478, 7);

        STEP(F, d, a, b, c, SET(1),  0xe8c7b756, 12);

        STEP(F, c, d, a, b, SET(2),  0x242070db, 17);

        STEP(F, b, c, d, a, SET(3),  0xc1bdceee, 22);

        STEP(F, a, b, c, d, SET(4),  0xf57c0faf, 7);

        STEP(F, d, a, b, c, SET(5),  0x4787c62a, 12);

        STEP(F, c, d, a, b, SET(6),  0xa8304613, 17);

        STEP(F, b, c, d, a, SET(7),  0xfd469501, 22);

        STEP(F, a, b, c, d, SET(8),  0x698098d8, 7);

        STEP(F, d, a, b, c, SET(9),  0x8b44f7af, 12);

        STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17);

        STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22);

        STEP(F, a, b, c, d, SET(12), 0x6b901122, 7);

        STEP(F, d, a, b, c, SET(13), 0xfd987193, 12);

        STEP(F, c, d, a, b, SET(14), 0xa679438e, 17);

        STEP(F, b, c, d, a, SET(15), 0x49b40821, 22);

        /* Round 2 */

        STEP(G, a, b, c, d, GET(1),  0xf61e2562, 5);

        STEP(G, d, a, b, c, GET(6),  0xc040b340, 9);

        STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14);

        STEP(G, b, c, d, a, GET(0),  0xe9b6c7aa, 20);

        STEP(G, a, b, c, d, GET(5),  0xd62f105d, 5);

        STEP(G, d, a, b, c, GET(10), 0x02441453, 9);

        STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14);

        STEP(G, b, c, d, a, GET(4),  0xe7d3fbc8, 20);

        STEP(G, a, b, c, d, GET(9),  0x21e1cde6, 5);

        STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9);

        STEP(G, c, d, a, b, GET(3),  0xf4d50d87, 14);

        STEP(G, b, c, d, a, GET(8),  0x455a14ed, 20);

        STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5);

        STEP(G, d, a, b, c, GET(2),  0xfcefa3f8, 9);

        STEP(G, c, d, a, b, GET(7),  0x676f02d9, 14);

        STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20);

        /* Round 3 */

        STEP(H, a, b, c, d, GET(5),  0xfffa3942, 4);

        STEP(H, d, a, b, c, GET(8),  0x8771f681, 11);

        STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16);

        STEP(H, b, c, d, a, GET(14), 0xfde5380c, 23);

        STEP(H, a, b, c, d, GET(1),  0xa4beea44, 4);

        STEP(H, d, a, b, c, GET(4),  0x4bdecfa9, 11);

        STEP(H, c, d, a, b, GET(7),  0xf6bb4b60, 16);

        STEP(H, b, c, d, a, GET(10), 0xbebfbc70, 23);

        STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4);

        STEP(H, d, a, b, c, GET(0),  0xeaa127fa, 11);

        STEP(H, c, d, a, b, GET(3),  0xd4ef3085, 16);

        STEP(H, b, c, d, a, GET(6),  0x04881d05, 23);

        STEP(H, a, b, c, d, GET(9),  0xd9d4d039, 4);

        STEP(H, d, a, b, c, GET(12), 0xe6db99e5, 11);

        STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16);

        STEP(H, b, c, d, a, GET(2),  0xc4ac5665, 23);

        /* Round 4 */

        STEP(I, a, b, c, d, GET(0),  0xf4292244, 6);

        STEP(I, d, a, b, c, GET(7),  0x432aff97, 10);

        STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15);

        STEP(I, b, c, d, a, GET(5),  0xfc93a039, 21);

        STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6);

        STEP(I, d, a, b, c, GET(3),  0x8f0ccc92, 10);

        STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15);

        STEP(I, b, c, d, a, GET(1),  0x85845dd1, 21);

        STEP(I, a, b, c, d, GET(8),  0x6fa87e4f, 6);

        STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10);

        STEP(I, c, d, a, b, GET(6),  0xa3014314, 15);

        STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21);

        STEP(I, a, b, c, d, GET(4),  0xf7537e82, 6);

        STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10);

        STEP(I, c, d, a, b, GET(2),  0x2ad7d2bb, 15);

        STEP(I, b, c, d, a, GET(9),  0xeb86d391, 21);

        a += saved_a;

        b += saved_b;

        c += saved_c;

        d += saved_d;

        p += 64;

    } while (size -= 64);

    ctx->a = a;

    ctx->b = b;

    ctx->c = c;

    ctx->d = d;

    return p;

}