/* Copyright (c) 2021 Xie Meiyi(xiemeiyi@hust.edu.cn) and OceanBase and/or its affiliates. All rights reserved.
miniob is licensed under Mulan PSL v2.
You can use this software according to the terms and conditions of the Mulan PSL v2.
You may obtain a copy of Mulan PSL v2 at:
         http://license.coscl.org.cn/MulanPSL2
THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
See the Mulan PSL v2 for more details. */

//
// Created by Longda on 2010
//

#include "common/math/md5.h"
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
namespace common {

#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 void MD5Transform(UINT4[4], unsigned char[64]);
static void Encode(unsigned char *, UINT4 *, unsigned int);
static void Decode(UINT4 *, unsigned char *, unsigned int);
static void MD5_memcpy(POINTER, POINTER, unsigned int);
static void MD5_memset(POINTER, int, unsigned int);

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};

/*
 * F, G, H and I are basic MD5 functions.
 */
#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)))

/*
 * ROTATE_LEFT rotates x left n bits.
 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

/*
 * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4. Rotation is
 * separate from addition to prevent recomputation.
 */
#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);                                  \
  }

/*
 * MD5 initialization. Begins an MD5 operation, writing a new context.
 */
void MD5Init(MD5_CTX *context)
{
  context->count[0] = context->count[1] = 0;
  /*
   * Load magic initialization constants.
   */
  context->state[0] = 0x67452301;
  context->state[1] = 0xefcdab89;
  context->state[2] = 0x98badcfe;
  context->state[3] = 0x10325476;
}

/*
 * MD5 block update operation. Continues an MD5 message-digest operation,
 * processing another message block, and updating the context.
 */
void MD5Update(MD5_CTX *context, unsigned char *input, unsigned int inputLen)
{
  unsigned int i, index, partLen;

  /* Compute number of bytes mod 64 */
  index = (unsigned int)((context->count[0] >> 3) & 0x3F);

  /* update number of bits */
  if ((context->count[0] += ((UINT4)inputLen << 3)) < ((UINT4)inputLen << 3))
    context->count[1]++;
  context->count[1] += ((UINT4)inputLen >> 29);

  partLen = 64 - index;

  /*
   * Transform as many times as possible.
   */
  if (inputLen >= partLen) {
    MD5_memcpy((POINTER)&context->buffer[index], (POINTER)input, partLen);
    MD5Transform(context->state, context->buffer);

    for (i = partLen; i + 63 < inputLen; i += 64)
      MD5Transform(context->state, &input[i]);

    index = 0;
  } else
    i = 0;

  /* Buffer remaining input */
  MD5_memcpy((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen - i);
}

/*
 * MD5 finalization. Ends an MD5 message-digest operation, writing the the
 * message digest and zeroizing the context.
 */
void MD5Final(unsigned char digest[16], MD5_CTX *context)
{
  unsigned char bits[8];
  unsigned int index, padLen;

  /* Save number of bits */
  Encode(bits, context->count, 8);

  /*
   * Pad out to 56 mod 64.
   */
  index = (unsigned int)((context->count[0] >> 3) & 0x3f);
  padLen = (index < 56) ? (56 - index) : (120 - index);
  MD5Update(context, PADDING, padLen);

  /* Append length (before padding) */
  MD5Update(context, bits, 8);
  /* Store state in digest */
  Encode(digest, context->state, 16);

  /*
   * Zeroize sensitive information.
   */
  MD5_memset((POINTER)context, 0, sizeof(*context));
}

/*
 * MD5 basic transformation. Transforms state based on block.
 */
static void MD5Transform(UINT4 state[4], unsigned char block[64])
{
  UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

  Decode(x, block, 64);

  /* Round 1 */
  FF(a, b, c, d, x[0], S11, 0xd76aa478);  /* 1 */
  FF(d, a, b, c, x[1], S12, 0xe8c7b756);  /* 2 */
  FF(c, d, a, b, x[2], S13, 0x242070db);  /* 3 */
  FF(b, c, d, a, x[3], S14, 0xc1bdceee);  /* 4 */
  FF(a, b, c, d, x[4], S11, 0xf57c0faf);  /* 5 */
  FF(d, a, b, c, x[5], S12, 0x4787c62a);  /* 6 */
  FF(c, d, a, b, x[6], S13, 0xa8304613);  /* 7 */
  FF(b, c, d, a, x[7], S14, 0xfd469501);  /* 8 */
  FF(a, b, c, d, x[8], S11, 0x698098d8);  /* 9 */
  FF(d, a, b, c, x[9], S12, 0x8b44f7af);  /* 10 */
  FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
  FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
  FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
  FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
  FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
  FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

  /* Round 2 */
  GG(a, b, c, d, x[1], S21, 0xf61e2562);  /* 17 */
  GG(d, a, b, c, x[6], S22, 0xc040b340);  /* 18 */
  GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
  GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);  /* 20 */
  GG(a, b, c, d, x[5], S21, 0xd62f105d);  /* 21 */
  GG(d, a, b, c, x[10], S22, 0x2441453);  /* 22 */
  GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
  GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);  /* 24 */
  GG(a, b, c, d, x[9], S21, 0x21e1cde6);  /* 25 */
  GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
  GG(c, d, a, b, x[3], S23, 0xf4d50d87);  /* 27 */
  GG(b, c, d, a, x[8], S24, 0x455a14ed);  /* 28 */
  GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
  GG(d, a, b, c, x[2], S22, 0xfcefa3f8);  /* 30 */
  GG(c, d, a, b, x[7], S23, 0x676f02d9);  /* 31 */
  GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

  /* Round 3 */
  HH(a, b, c, d, x[5], S31, 0xfffa3942);  /* 33 */
  HH(d, a, b, c, x[8], S32, 0x8771f681);  /* 34 */
  HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
  HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
  HH(a, b, c, d, x[1], S31, 0xa4beea44);  /* 37 */
  HH(d, a, b, c, x[4], S32, 0x4bdecfa9);  /* 38 */
  HH(c, d, a, b, x[7], S33, 0xf6bb4b60);  /* 39 */
  HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
  HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
  HH(d, a, b, c, x[0], S32, 0xeaa127fa);  /* 42 */
  HH(c, d, a, b, x[3], S33, 0xd4ef3085);  /* 43 */
  HH(b, c, d, a, x[6], S34, 0x4881d05);   /* 44 */
  HH(a, b, c, d, x[9], S31, 0xd9d4d039);  /* 45 */
  HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  HH(b, c, d, a, x[2], S34, 0xc4ac5665);  /* 48 */

  /* Round 4 */
  II(a, b, c, d, x[0], S41, 0xf4292244);  /* 49 */
  II(d, a, b, c, x[7], S42, 0x432aff97);  /* 50 */
  II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  II(b, c, d, a, x[5], S44, 0xfc93a039);  /* 52 */
  II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  II(d, a, b, c, x[3], S42, 0x8f0ccc92);  /* 54 */
  II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  II(b, c, d, a, x[1], S44, 0x85845dd1);  /* 56 */
  II(a, b, c, d, x[8], S41, 0x6fa87e4f);  /* 57 */
  II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  II(c, d, a, b, x[6], S43, 0xa3014314);  /* 59 */
  II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  II(a, b, c, d, x[4], S41, 0xf7537e82);  /* 61 */
  II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  II(c, d, a, b, x[2], S43, 0x2ad7d2bb);  /* 63 */
  II(b, c, d, a, x[9], S44, 0xeb86d391);  /* 64 */

  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;

  /*
   * Zeroize sensitive information.
   *
   */
  MD5_memset((POINTER)x, 0, sizeof(x));
}

/*
 * Encodes input (UINT4) into output (unsigned char). Assumes len is a
 * multiple of 4.
 */
static void 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);
  }
}

/*
 * Decodes input (unsigned char) into output (UINT4). Assumes len is a
 * multiple of 4.
 */
static void 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);
}

/*
 * Note: Replace "for loop" with standard memcpy if possible.
 */

static void MD5_memcpy(POINTER output, POINTER input, unsigned int len)
{
  unsigned int i;

  for (i = 0; i < len; i++)
    output[i] = input[i];
}

/*
 * Note: Replace "for loop" with standard memset if possible.
 */
static void MD5_memset(POINTER output, int value, unsigned int len)
{
  unsigned int i;

  for (i = 0; i < len; i++)
    ((char *)output)[i] = (char)value;
}

/*
 * Digests a string
 */
int MD5String(char *string, unsigned char digest[16])
{
  MD5_CTX context;
  unsigned int len = strlen(string);

  MD5Init(&context);
  MD5Update(&context, (unsigned char *)string, len);
  MD5Final(digest, &context);
  return 0;
}

int MD5Buffer(char *buffer, unsigned int len, unsigned char digest[16])
{
  MD5_CTX context;

  MD5Init(&context);
  MD5Update(&context, (unsigned char *)buffer, len);
  MD5Final(digest, &context);
  return 0;
}

int MD5File(char *filename, unsigned char digest[16])
{
  FILE *file;
  MD5_CTX context;
  int len;
  unsigned char buffer[1024];

  if ((file = fopen(filename, "rb")) == NULL)
    return -1;
  else {
    MD5Init(&context);
    while ((len = fread(buffer, 1, 1024, file)) > 0) {
      MD5Update(&context, buffer, len);
    }
    MD5Final(digest, &context);

    fclose(file);
  }
  return 0;
}

}  // namespace common