/*
 * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
 * MD5 Message-Digest Algorithm (RFC 1321).
 *
 * Homepage:
 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5
 *
 * Author:
 * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
 *
 * This software was written by Alexander Peslyak in 2001.  No copyright is
 * claimed, and the software is hereby placed in the public domain.
 * In case this attempt to disclaim copyright and place the software in the
 * public domain is deemed null and void, then the software is
 * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
 * general public under the following terms:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted.
 *
 * There's ABSOLUTELY NO WARRANTY, express or implied.
 *
 * (This is a heavily cut-down "BSD license".)
 *
 * This differs from Colin Plumb's older public domain implementation in that
 * no exactly 32-bit integer data type is required (any 32-bit or wider
 * unsigned integer data type will do), there's no compile-time endianness
 * configuration, and the function prototypes match OpenSSL's.  No code from
 * Colin Plumb's implementation has been reused; this comment merely compares
 * the properties of the two independent implementations.
 *
 * The primary goals of this implementation are portability and ease of use.
 * It is meant to be fast, but not as fast as possible.  Some known
 * optimizations are not included to reduce source code size and avoid
 * compile-time configuration.
 */

#include "co/hash/md5.h"

#ifdef _MSC_VER
#pragma warning (disable:4244)
#endif

/*
 * 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 H2(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.
 *
 * The check for little-endian architectures that tolerate unaligned
 * memory accesses is just an optimization.  Nothing will break if it
 * doesn't work.
 */
#if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
#  define SET(n) \
    (*(uint32*) &ptr[(n) * 4])
#  define GET(n) \
    SET(n)
#else
#  define SET(n) \
    (ctx->block[(n)] = \
    (uint32)ptr[(n) * 4] | \
    ((uint32)ptr[(n) * 4 + 1] << 8) | \
    ((uint32)ptr[(n) * 4 + 2] << 16) | \
    ((uint32)ptr[(n) * 4 + 3] << 24))
#  define GET(n) \
    (ctx->block[(n)])
#endif

/*
 * This processes one or more 64-byte data blocks, but does NOT update
 * the bit counters.  There are no alignment requirements.
 */
static const void* body(md5_ctx_t* ctx, const void* data, size_t size) {
    const uint8* ptr;
    uint32 a, b, c, d;
    uint32 saved_a, saved_b, saved_c, saved_d;

    ptr = (const uint8*) 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(H2, d, a, b, c, GET(8), 0x8771f681, 11)
        STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
        STEP(H2, b, c, d, a, GET(14), 0xfde5380c, 23)
        STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
        STEP(H2, d, a, b, c, GET(4), 0x4bdecfa9, 11)
        STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
        STEP(H2, b, c, d, a, GET(10), 0xbebfbc70, 23)
        STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
        STEP(H2, d, a, b, c, GET(0), 0xeaa127fa, 11)
        STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
        STEP(H2, b, c, d, a, GET(6), 0x04881d05, 23)
        STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
        STEP(H2, d, a, b, c, GET(12), 0xe6db99e5, 11)
        STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
        STEP(H2, 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;
        ptr += 64;
    } while (size -= 64);

    ctx->a = a;
    ctx->b = b;
    ctx->c = c;
    ctx->d = d;
    return ptr;
}

#undef F
#undef G
#undef H
#undef H2
#undef I
#undef STEP
#undef SET
#undef GET

void md5_init(md5_ctx_t* ctx) {
    ctx->a = 0x67452301;
    ctx->b = 0xefcdab89;
    ctx->c = 0x98badcfe;
    ctx->d = 0x10325476;
    ctx->lo = 0;
    ctx->hi = 0;
}

void md5_update(md5_ctx_t* ctx, const void* data, size_t size) {
    uint32 saved_lo;
    size_t used, available;

    saved_lo = ctx->lo;
    if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo) {
        ++ctx->hi;
    }
    ctx->hi += (uint32) (size >> 29);

    used = saved_lo & 0x3f;

    if (used) {
        available = 64 - used;

        if (size < available) {
            memcpy(&ctx->buffer[used], data, size);
            return;
        }

        memcpy(&ctx->buffer[used], data, available);
        data = (const uint8*) data + available;
        size -= available;
        body(ctx, ctx->buffer, 64);
    }

    if (size >= 64) {
        data = body(ctx, data, size & ~(size_t)0x3f);
        size &= 0x3f;
    }

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

void md5_final(md5_ctx_t* ctx, uint8 res[16]) {
    size_t used, available;

    used = ctx->lo & 0x3f;
    ctx->buffer[used++] = 0x80;

    available = 64 - used;

    if (available < 8) {
        memset(&ctx->buffer[used], 0, available);
        body(ctx, ctx->buffer, 64);
        used = 0;
        available = 64;
    }

    memset(&ctx->buffer[used], 0, available - 8);

    ctx->lo <<= 3;
    ctx->buffer[56] = ctx->lo;
    ctx->buffer[57] = ctx->lo >> 8;
    ctx->buffer[58] = ctx->lo >> 16;
    ctx->buffer[59] = ctx->lo >> 24;
    ctx->buffer[60] = ctx->hi;
    ctx->buffer[61] = ctx->hi >> 8;
    ctx->buffer[62] = ctx->hi >> 16;
    ctx->buffer[63] = ctx->hi >> 24;

    body(ctx, ctx->buffer, 64);

    res[0] = ctx->a;
    res[1] = ctx->a >> 8;
    res[2] = ctx->a >> 16;
    res[3] = ctx->a >> 24;
    res[4] = ctx->b;
    res[5] = ctx->b >> 8;
    res[6] = ctx->b >> 16;
    res[7] = ctx->b >> 24;
    res[8] = ctx->c;
    res[9] = ctx->c >> 8;
    res[10] = ctx->c >> 16;
    res[11] = ctx->c >> 24;
    res[12] = ctx->d;
    res[13] = ctx->d >> 8;
    res[14] = ctx->d >> 16;
    res[15] = ctx->d >> 24;

    memset(ctx, 0, sizeof(*ctx));
}

void md5sum(const void* s, size_t n, char res[32]) {
    uint8 buf[16];
    md5digest(s, n, (char*)buf);

    char* x = res;
    for (int i = 0; i < 16; i += 4) {
        #define hex_tb "0123456789abcdef"
        x[0] = hex_tb[buf[i] >> 4];
        x[1] = hex_tb[buf[i] & 0x0f];
        x[2] = hex_tb[buf[i + 1] >> 4];
        x[3] = hex_tb[buf[i + 1] & 0x0f];
        x[4] = hex_tb[buf[i + 2] >> 4];
        x[5] = hex_tb[buf[i + 2] & 0x0f];
        x[6] = hex_tb[buf[i + 3] >> 4];
        x[7] = hex_tb[buf[i + 3] & 0x0f];
        x += 8;
        #undef hex_tb
    }
}
