text: ﻿/**
   * 文件名: md5.c
   * 目标: 计算文件的md5值
   */
  
  #include <stdio.h>
  #include <string.h>
  
  #include "tool.h"
  #include "__md5.h"
  
  struct MD5_CTX {
      unsigned int count[2];
      unsigned int state[4];
      unsigned char buffer[64];
  };
  
  static void MD5Transform(unsigned int state[4],unsigned char block[64]);
  static void MD5Encode(unsigned char *output,const unsigned int *input,unsigned int len);
  static void MD5Decode(unsigned int *output,const unsigned char *input,unsigned int len);
  
  unsigned char PADDING[] = {
                  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
          };
  
  MD5_CTX *MD5Init(void) {
      MD5_CTX *context = calloc(1, sizeof(MD5_CTX));
      context->count[0] = 0;
      context->count[1] = 0;
      context->state[0] = 0x67452301;
      context->state[1] = 0xEFCDAB89;
      context->state[2] = 0x98BADCFE;
      context->state[3] = 0x10325476;
      return context;
  }
  
  void MD5Update(MD5_CTX *context, unsigned char *input, unsigned int input_len) {
      unsigned int i;
      unsigned int index;
      unsigned int part_len;
  
      index = (context->count[0] >> (unsigned)3) & (unsigned)0x3F;
      part_len = 64 - index;
      context->count[0] += input_len << (unsigned)3;
  
      if(context->count[0] < (input_len << (unsigned)3))
          context->count[1]++;
      context->count[1] += input_len >> (unsigned)29;
  
      if(input_len >= part_len) {
          memcpy(&context->buffer[index], input, part_len);
          MD5Transform(context->state, context->buffer);
  
          for(i = part_len; i + 64 <= input_len; i+=64)
              MD5Transform(context->state, &input[i]);
  
          index = 0;
      }
      else
          i = 0;
      memcpy(&context->buffer[index], &input[i], input_len - i);
  }
  
  void MD5Final(MD5_CTX *context, unsigned char digest[16]) {
      unsigned int index;
      unsigned int pad_len;
      unsigned char bits[8];
  
      index = (context->count[0] >> (unsigned)3) & (unsigned)0x3F;
      pad_len = (index < 56) ? (56 - index) : (120 - index);
      MD5Encode(bits, context->count, 8);
      MD5Update(context, PADDING, pad_len);
      MD5Update(context, bits, 8);
      MD5Encode(digest, context->state, 16);
      free(context);
  }
  
  static void MD5Encode(unsigned char *output,const unsigned int *input, unsigned int len) {
      unsigned int i = 0;
      unsigned int j = 0;
  
      while(j < len)
      {
          output[j] = input[i] & (unsigned)0xFF;
          output[j+1] = (input[i] >> (unsigned)8) & (unsigned)0xFF;
          output[j+2] = (input[i] >> (unsigned)16) & (unsigned)0xFF;
          output[j+3] = (input[i] >> (unsigned)24) & (unsigned)0xFF;
          i++;
          j += 4;
      }
  }
  
  static void MD5Decode(unsigned int *output, const unsigned char *input, unsigned int len) {
      for (unsigned int i=0, j=0; j < len; i++, j+=4) {
          output[i] = (input[j]) |
                      (input[j+1] << (unsigned)8) |
                      (input[j+2] << (unsigned)16) |
                      (input[j+3] << (unsigned)24);
      }
  }
  
  static void MD5Transform(unsigned int state[4], unsigned char block[64]) {
      unsigned int a = state[0];
      unsigned int b = state[1];
      unsigned int c = state[2];
      unsigned int d = state[3];
      unsigned int x[64];
  
      MD5Decode(x,block,64);
  
      FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
      FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
      FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
      FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
      FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
      FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
      FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
      FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
      FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
      FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
      FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
      FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
      FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
      FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
      FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
      FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
  
      /* Round 2 */
      GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
      GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
      GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
      GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
      GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
      GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */
      GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
      GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
      GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
      GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
      GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
      GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
      GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
      GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
      GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
      GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
  
      /* Round 3 */
      HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
      HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
      HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
      HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
      HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
      HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
      HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
      HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
      HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
      HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
      HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
      HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */
      HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
      HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
      HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
      HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */
  
      /* Round 4 */
      II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
      II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
      II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
      II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
      II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
      II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
      II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
      II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
      II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
      II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
      II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
      II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
      II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
      II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
      II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
      II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */
      state[0] += a;
      state[1] += b;
      state[2] += c;
      state[3] += d;
  }
  
  
  char *getFileMd5(char *path) {
      FILE *fd;
  
      unsigned long ret;
      unsigned char data[READ_DATA_SIZE];
      unsigned char md5_value[MD5_SIZE];
  
      if ((fd = fileOpen(path, "rb")) == NULL)
          return NULL;
  
      char *md5str = calloc(MD5_STRING, sizeof(char));
      MD5_CTX *md5 = MD5Init();
      while (1) {
          ret = fread(data, 1, READ_DATA_SIZE, fd);
          MD5Update(md5, data, ret);
          if (ret < READ_DATA_SIZE)
              break;
      }
  
      fileClose(fd);
      MD5Final(md5, md5_value);
  
      for(int i = 0; i < MD5_SIZE; i++)
          snprintf(md5str + i * 2, 2 + 1, "%02x", md5_value[i]);
  
      return md5str;
  }