#include <string.h>
#include "encrypt_md5.h"

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static unsigned char PADDING[64] = {
    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
};

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

#define FF(a, b, c, d, x, s, ac) {   (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac);   (a) = ROTATE_LEFT ((a), (s));   (a) += (b);   }
#define GG(a, b, c, d, x, s, ac) {   (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac);   (a) = ROTATE_LEFT ((a), (s));   (a) += (b);   }
#define HH(a, b, c, d, x, s, ac) {   (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac);   (a) = ROTATE_LEFT ((a), (s));   (a) += (b);   }
#define II(a, b, c, d, x, s, ac) {   (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac);   (a) = ROTATE_LEFT ((a), (s));   (a) += (b); }


static void md5_encode(unsigned char *output, UINT4 *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
    {
        output[j] = (unsigned char)(input[i] & 0xff);
        output[j + 1] = (unsigned char)((input[i] >> 8) & 0xff);
        output[j + 2] = (unsigned char)((input[i] >> 16) & 0xff);
        output[j + 3] = (unsigned char)((input[i] >> 24) & 0xff);
    }
}

static void md5_decode(UINT4 *output, unsigned char *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4) output[i] = ((UINT4)input[j]) | (((UINT4)input[j + 1]) << 8) |
            (((UINT4)input[j + 2]) << 16) | (((UINT4)input[j + 3]) << 24);
}

static void md5_transform(UINT4 state[4], unsigned char block[64])
{
    UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
    md5_decode(x, block, 64);
    FF(a, b, c, d, x[0], S11, 0xd76aa478);
    FF(d, a, b, c, x[1], S12, 0xe8c7b756);
    FF(c, d, a, b, x[2], S13, 0x242070db);
    FF(b, c, d, a, x[3], S14, 0xc1bdceee);
    FF(a, b, c, d, x[4], S11, 0xf57c0faf);
    FF(d, a, b, c, x[5], S12, 0x4787c62a);
    FF(c, d, a, b, x[6], S13, 0xa8304613);
    FF(b, c, d, a, x[7], S14, 0xfd469501);
    FF(a, b, c, d, x[8], S11, 0x698098d8);
    FF(d, a, b, c, x[9], S12, 0x8b44f7af);
    FF(c, d, a, b, x[10], S13, 0xffff5bb1);
    FF(b, c, d, a, x[11], S14, 0x895cd7be);
    FF(a, b, c, d, x[12], S11, 0x6b901122);
    FF(d, a, b, c, x[13], S12, 0xfd987193);
    FF(c, d, a, b, x[14], S13, 0xa679438e);
    FF(b, c, d, a, x[15], S14, 0x49b40821);
    GG(a, b, c, d, x[1], S21, 0xf61e2562);
    GG(d, a, b, c, x[6], S22, 0xc040b340);
    GG(c, d, a, b, x[11], S23, 0x265e5a51);
    GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);
    GG(a, b, c, d, x[5], S21, 0xd62f105d);
    GG(d, a, b, c, x[10], S22,   0x2441453);
    GG(c, d, a, b, x[15], S23, 0xd8a1e681);
    GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);
    GG(a, b, c, d, x[9], S21, 0x21e1cde6);
    GG(d, a, b, c, x[14], S22, 0xc33707d6);
    GG(c, d, a, b, x[3], S23, 0xf4d50d87);
    GG(b, c, d, a, x[8], S24, 0x455a14ed);
    GG(a, b, c, d, x[13], S21, 0xa9e3e905);
    GG(d, a, b, c, x[2], S22, 0xfcefa3f8);
    GG(c, d, a, b, x[7], S23, 0x676f02d9);
    GG(b, c, d, a, x[12], S24, 0x8d2a4c8a);
    HH(a, b, c, d, x[5], S31, 0xfffa3942);
    HH(d, a, b, c, x[8], S32, 0x8771f681);
    HH(c, d, a, b, x[11], S33, 0x6d9d6122);
    HH(b, c, d, a, x[14], S34, 0xfde5380c);
    HH(a, b, c, d, x[1], S31, 0xa4beea44);
    HH(d, a, b, c, x[4], S32, 0x4bdecfa9);
    HH(c, d, a, b, x[7], S33, 0xf6bb4b60);
    HH(b, c, d, a, x[10], S34, 0xbebfbc70);
    HH(a, b, c, d, x[13], S31, 0x289b7ec6);
    HH(d, a, b, c, x[0], S32, 0xeaa127fa);
    HH(c, d, a, b, x[3], S33, 0xd4ef3085);
    HH(b, c, d, a, x[6], S34,   0x4881d05);
    HH(a, b, c, d, x[9], S31, 0xd9d4d039);
    HH(d, a, b, c, x[12], S32, 0xe6db99e5);
    HH(c, d, a, b, x[15], S33, 0x1fa27cf8);
    HH(b, c, d, a, x[2], S34, 0xc4ac5665);
    II(a, b, c, d, x[0], S41, 0xf4292244);
    II(d, a, b, c, x[7], S42, 0x432aff97);
    II(c, d, a, b, x[14], S43, 0xab9423a7);
    II(b, c, d, a, x[5], S44, 0xfc93a039);
    II(a, b, c, d, x[12], S41, 0x655b59c3);
    II(d, a, b, c, x[3], S42, 0x8f0ccc92);
    II(c, d, a, b, x[10], S43, 0xffeff47d);
    II(b, c, d, a, x[1], S44, 0x85845dd1);
    II(a, b, c, d, x[8], S41, 0x6fa87e4f);
    II(d, a, b, c, x[15], S42, 0xfe2ce6e0);
    II(c, d, a, b, x[6], S43, 0xa3014314);
    II(b, c, d, a, x[13], S44, 0x4e0811a1);
    II(a, b, c, d, x[4], S41, 0xf7537e82);
    II(d, a, b, c, x[11], S42, 0xbd3af235);
    II(c, d, a, b, x[2], S43, 0x2ad7d2bb);
    II(b, c, d, a, x[9], S44, 0xeb86d391);
    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;
    memset((POINTER)x, 0, sizeof(x));
}

void md5_init(MD5_CTX *context)
{
    context->count[0] = context->count[1] = 0;
    context->state[0] = 0x67452301;
    context->state[1] = 0xefcdab89;
    context->state[2] = 0x98badcfe;
    context->state[3] = 0x10325476;
}

void md5_update(MD5_CTX *context, unsigned char *input, unsigned int inputLen)
{
    unsigned int i, index, partLen;

    index = (unsigned int)((context->count[0] >> 3) & 0x3F);
    if ((context->count[0] += ((UINT4)inputLen << 3))
        < ((UINT4)inputLen << 3)) context->count[1]++;
    context->count[1] += ((UINT4)inputLen >> 29);

    partLen = 64 - index;

    if (inputLen >= partLen)
    {
        memcpy((POINTER)&context->buffer[index], (POINTER)input, partLen);
        md5_transform(context->state, context->buffer);

        for (i = partLen; i + 63 < inputLen; i += 64) md5_transform(context->state, &input[i]);
        index = 0;
    } else i = 0;

    memcpy((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen - i);
}

void md5_final(unsigned char digest[16], MD5_CTX *context)
{
    unsigned char bits[8];
    unsigned int index, padLen;

    md5_encode(bits, context->count, 8);
    index = (unsigned int)((context->count[0] >> 3) & 0x3f);
    padLen = (index < 56) ? (56 - index) : (120 - index);
    md5_update(context, PADDING, padLen);
    md5_update(context, bits, 8);
    md5_encode(digest, context->state, 16);
    memset((POINTER)context, 0, sizeof(*context));
}

void md5_digest(char *pszInput, unsigned long nInputSize, char *pszOutPut)
{
    MD5_CTX context;

    md5_init(&context);
    md5_update(&context, (unsigned char *)pszInput, nInputSize);
    md5_final((unsigned char *)pszOutPut, &context);
}