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C++ 递归遍历文件并计算MD5的实例代码
来源：jb51　　时间：2021/7/19 9:04:38　　对本文有异议

递归遍历文件夹，对比文件md5

首先，需要引用 md5 的相关代码，参考这篇文章，防止链接内容被删除，这里再记录一次：

md5.h

  1.   #ifndef MD5_H
  2.     #define MD5_H
  3.  
  4.     #include <string>
  5.     #include <fstream>
  6.  
  7.     /* Type define */
  8.     typedef unsigned char byte;
  9.     typedef unsigned int uint32;
  10.  
  11.     using std::string;
  12.     using std::ifstream;
  13.  
  14.     /* MD5 declaration. */
  15.     class MD5 {
  16.     public:
  17.     MD5();
  18.     MD5(const void* input, size_t length);
  19.     MD5(const string& str);
  20.     MD5(ifstream& in);
  21.     void update(const void* input, size_t length);
  22.     void update(const string& str);
  23.     void update(ifstream& in);
  24.     const byte* digest();
  25.     string toString();
  26.     void reset();
  27.  
  28.     private:
  29.     void update(const byte* input, size_t length);
  30.     void final();
  31.     void transform(const byte block[64]);
  32.     void encode(const uint32* input, byte* output, size_t length);
  33.     void decode(const byte* input, uint32* output, size_t length);
  34.     string bytesToHexString(const byte* input, size_t length);
  35.  
  36.     /* class uncopyable */
  37.     MD5(const MD5&);
  38.     MD5& operator=(const MD5&);
  39.  
  40.     private:
  41.     uint32 _state[4]; /* state (ABCD) */
  42.     uint32 _count[2]; /* number of bits, modulo 2^64 (low-order word first) */
  43.     byte _buffer[64]; /* input buffer */
  44.     byte _digest[16]; /* message digest */
  45.     bool _finished;   /* calculate finished ? */
  46.  
  47.     static const byte PADDING[64]; /* padding for calculate */
  48.     static const char HEX[16];
  49.     enum { BUFFER_SIZE = 1024 };
  50.     };
  51.  
  52.     #endif /*MD5_H*/

md5.cpp

  1.    #include "md5.h"
  2.  
  3.     using namespace std;
  4.  
  5.     /* Constants for MD5Transform routine. */
  6.     #define S11 7
  7.     #define S12 12
  8.     #define S13 17
  9.     #define S14 22
  10.     #define S21 5
  11.     #define S22 9
  12.     #define S23 14
  13.     #define S24 20
  14.     #define S31 4
  15.     #define S32 11
  16.     #define S33 16
  17.     #define S34 23
  18.     #define S41 6
  19.     #define S42 10
  20.     #define S43 15
  21.     #define S44 21
  22.  
  23.  
  24.     /* F, G, H and I are basic MD5 functions.
  25.     */
  26.     #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
  27.     #define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
  28.     #define H(x, y, z) ((x) ^ (y) ^ (z))
  29.     #define I(x, y, z) ((y) ^ ((x) | (~z)))
  30.  
  31.     /* ROTATE_LEFT rotates x left n bits.
  32.     */
  33.     #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
  34.  
  35.     /* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
  36.     Rotation is separate from addition to prevent recomputation.
  37.     */
  38.     #define FF(a, b, c, d, x, s, ac) {     (a) += F ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b);     }
  39.     #define GG(a, b, c, d, x, s, ac) {     (a) += G ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b);     }
  40.     #define HH(a, b, c, d, x, s, ac) {     (a) += H ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b);     }
  41.     #define II(a, b, c, d, x, s, ac) {     (a) += I ((b), (c), (d)) + (x) + ac;     (a) = ROTATE_LEFT ((a), (s));     (a) += (b);     }
  42.  
  43.  
  44.     const byte MD5::PADDING[64] = { 0x80 };
  45.     const char MD5::HEX[16] = {
  46.     ‘0‘, ‘1‘, ‘2‘, ‘3‘,
  47.     ‘4‘, ‘5‘, ‘6‘, ‘7‘,
  48.     ‘8‘, ‘9‘, ‘a‘, ‘b‘,
  49.     ‘c‘, ‘d‘, ‘e‘, ‘f‘
  50.     };
  51.  
  52.  
  53.     /* Default construct. */
  54.     MD5::MD5() {
  55.     reset();
  56.     }
  57.  
  58.     /* Construct a MD5 object with a input buffer. */
  59.     MD5::MD5(const void* input, size_t length) {
  60.     reset();
  61.     update(input, length);
  62.     }
  63.  
  64.     /* Construct a MD5 object with a string. */
  65.     MD5::MD5(const string& str) {
  66.     reset();
  67.     update(str);
  68.     }
  69.  
  70.     /* Construct a MD5 object with a file. */
  71.     MD5::MD5(ifstream& in) {
  72.     reset();
  73.     update(in);
  74.     }
  75.  
  76.     /* Return the message-digest */
  77.     const byte* MD5::digest() {
  78.  
  79.     if (!_finished) {
  80.        _finished = true;
  81.        final();
  82.     }
  83.     return _digest;
  84.     }
  85.  
  86.     /* Reset the calculate state */
  87.     void MD5::reset() {
  88.  
  89.     _finished = false;
  90.     /* reset number of bits. */
  91.     _count[0] = _count[1] = 0;
  92.     /* Load magic initialization constants. */
  93.     _state[0] = 0x67452301;
  94.     _state[1] = 0xefcdab89;
  95.     _state[2] = 0x98badcfe;
  96.     _state[3] = 0x10325476;
  97.     }
  98.  
  99.     /* Updating the context with a input buffer. */
  100.     void MD5::update(const void* input, size_t length) {
  101.     update((const byte*)input, length);
  102.     }
  103.  
  104.     /* Updating the context with a string. */
  105.     void MD5::update(const string& str) {
  106.     update((const byte*)str.c_str(), str.length());
  107.     }
  108.  
  109.     /* Updating the context with a file. */
  110.     void MD5::update(ifstream& in) {
  111.  
  112.     if (!in) {
  113.        return;
  114.     }
  115.  
  116.     std::streamsize length;
  117.     char buffer[BUFFER_SIZE];
  118.     while (!in.eof()) {
  119.        in.read(buffer, BUFFER_SIZE);
  120.        length = in.gcount();
  121.        if (length > 0) {
  122.         update(buffer, length);
  123.        }
  124.     }
  125.     in.close();
  126.     }
  127.  
  128.     /* MD5 block update operation. Continues an MD5 message-digest
  129.     operation, processing another message block, and updating the
  130.     context.
  131.     */
  132.     void MD5::update(const byte* input, size_t length) {
  133.  
  134.     uint32 i, index, partLen;
  135.  
  136.     _finished = false;
  137.  
  138.     /* Compute number of bytes mod 64 */
  139.     index = (uint32)((_count[0] >> 3) & 0x3f);
  140.  
  141.     /* update number of bits */
  142.     if ((_count[0] += ((uint32)length << 3)) < ((uint32)length << 3)) {
  143.        ++_count[1];
  144.     }
  145.     _count[1] += ((uint32)length >> 29);
  146.  
  147.     partLen = 64 - index;
  148.  
  149.     /* transform as many times as possible. */
  150.     if (length >= partLen) {
  151.  
  152.        memcpy(&_buffer[index], input, partLen);
  153.        transform(_buffer);
  154.  
  155.        for (i = partLen; i + 63 < length; i += 64) {
  156.         transform(&input[i]);
  157.        }
  158.        index = 0;
  159.  
  160.     } else {
  161.        i = 0;
  162.     }
  163.  
  164.     /* Buffer remaining input */
  165.     memcpy(&_buffer[index], &input[i], length - i);
  166.     }
  167.  
  168.     /* MD5 finalization. Ends an MD5 message-_digest operation, writing the
  169.     the message _digest and zeroizing the context.
  170.     */
  171.     void MD5::final() {
  172.  
  173.     byte bits[8];
  174.     uint32 oldState[4];
  175.     uint32 oldCount[2];
  176.     uint32 index, padLen;
  177.  
  178.     /* Save current state and count. */
  179.     memcpy(oldState, _state, 16);
  180.     memcpy(oldCount, _count, 8);
  181.  
  182.     /* Save number of bits */
  183.     encode(_count, bits, 8);
  184.  
  185.     /* Pad out to 56 mod 64. */
  186.     index = (uint32)((_count[0] >> 3) & 0x3f);
  187.     padLen = (index < 56) ? (56 - index) : (120 - index);
  188.     update(PADDING, padLen);
  189.  
  190.     /* Append length (before padding) */
  191.     update(bits, 8);
  192.  
  193.     /* Store state in digest */
  194.     encode(_state, _digest, 16);
  195.  
  196.     /* Restore current state and count. */
  197.     memcpy(_state, oldState, 16);
  198.     memcpy(_count, oldCount, 8);
  199.     }
  200.  
  201.     /* MD5 basic transformation. Transforms _state based on block. */
  202.     void MD5::transform(const byte block[64]) {
  203.  
  204.     uint32 a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];
  205.  
  206.     decode(block, x, 64);
  207.  
  208.     /* Round 1 */
  209.     FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
  210.     FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
  211.     FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
  212.     FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
  213.     FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
  214.     FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
  215.     FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
  216.     FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
  217.     FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
  218.     FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
  219.     FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
  220.     FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
  221.     FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
  222.     FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
  223.     FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
  224.     FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
  225.  
  226.     /* Round 2 */
  227.     GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
  228.     GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
  229.     GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
  230.     GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
  231.     GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
  232.     GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
  233.     GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
  234.     GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
  235.     GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
  236.     GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
  237.     GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
  238.     GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
  239.     GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
  240.     GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
  241.     GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
  242.     GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
  243.  
  244.     /* Round 3 */
  245.     HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
  246.     HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
  247.     HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
  248.     HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
  249.     HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
  250.     HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
  251.     HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
  252.     HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
  253.     HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
  254.     HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
  255.     HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
  256.     HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
  257.     HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
  258.     HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  259.     HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  260.     HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
  261.  
  262.     /* Round 4 */
  263.     II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
  264.     II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
  265.     II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  266.     II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
  267.     II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  268.     II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
  269.     II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  270.     II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
  271.     II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
  272.     II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  273.     II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
  274.     II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  275.     II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
  276.     II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  277.     II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
  278.     II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
  279.  
  280.     _state[0] += a;
  281.     _state[1] += b;
  282.     _state[2] += c;
  283.     _state[3] += d;
  284.     }
  285.  
  286.     /* Encodes input (ulong) into output (byte). Assumes length is
  287.     a multiple of 4.
  288.     */
  289.     void MD5::encode(const uint32* input, byte* output, size_t length) {
  290.  
  291.     for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
  292.        output[j]= (byte)(input[i] & 0xff);
  293.        output[j + 1] = (byte)((input[i] >> 8) & 0xff);
  294.        output[j + 2] = (byte)((input[i] >> 16) & 0xff);
  295.        output[j + 3] = (byte)((input[i] >> 24) & 0xff);
  296.     }
  297.     }
  298.  
  299.     /* Decodes input (byte) into output (ulong). Assumes length is
  300.     a multiple of 4.
  301.     */
  302.     void MD5::decode(const byte* input, uint32* output, size_t length) {
  303.  
  304.     for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
  305.        output[i] = ((uint32)input[j]) | (((uint32)input[j + 1]) << 8) |
  306.        (((uint32)input[j + 2]) << 16) | (((uint32)input[j + 3]) << 24);
  307.     }
  308.     }
  309.  
  310.     /* Convert byte array to hex string. */
  311.     string MD5::bytesToHexString(const byte* input, size_t length) {
  312.  
  313.     string str;
  314.     str.reserve(length << 1);
  315.     for (size_t i = 0; i < length; ++i) {
  316.        int t = input[i];
  317.        int a = t / 16;
  318.        int b = t % 16;
  319.        str.append(1, HEX[a]);
  320.        str.append(1, HEX[b]);
  321.     }
  322.     return str;
  323.     }
  324.  
  325.     /* Convert digest to string value */
  326.     string MD5::toString() {
  327.     return bytesToHexString(digest(), 16);
  328.     }

调用例子:

  1.    #include "md5.h"
  2.     #include <iostream>
  3.  
  4.     using namespace std;
  5.  
  6.     void PrintMD5(const string& str, MD5& md5) {
  7.           cout << "MD5("" << str << "") = " << md5.toString() << endl;
  8.     }
  9.  
  10.     int main() {
  11.  
  12.          MD5 md5;
  13.          md5.update("");
  14.          PrintMD5("", md5);
  15.  
  16.          md5.update("a");
  17.          PrintMD5("a", md5);
  18.  
  19.          md5.update("bc");
  20.          PrintMD5("abc", md5);
  21.  
  22.          md5.update("defghijklmnopqrstuvwxyz");
  23.          PrintMD5("abcdefghijklmnopqrstuvwxyz", md5);
  24.  
  25.          md5.reset();
  26.          md5.update("message digest");
  27.          PrintMD5("message digest", md5);
  28.  
  29.          md5.reset();
  30.          md5.update(ifstream("D:\\test.txt"));
  31.          PrintMD5("D:\\test.txt", md5);
  32.  
  33.         return 0;
  34.     }

配置好了以后开始写我们的递归遍历函数：

  1. /*	遍历目录下所有文件,对比 md5
  2. 	path：文件夹路径（末尾不要有‘\‘）
  3. 	format：要筛选的文件后缀名
  4. 	str_md5：md5 字符串
  5. 	isFound：是否匹配到与 str_md5 相等的 md5 值
  6. */ 
  7. void findAllFile_MD5(const char * path,const char * format,string str_md5,BOOL &isFound)
  8. {
  9. 	// 路径末尾追加 ‘\*.*‘
  10.     char newpath[200];
  11.     strcpy(newpath, path);
  12.     strcat(newpath, "\\*.*");
  13.     
  14.    // 找到目录下的第一个文件 #include <io.h>
  15. 	_finddata_t findData;
  16. 	/*	文件信息结构体
  17. 		struct _finddata_t{
  18.              unsigned attrib;			// 文件属性
  19.              time_t time_create;		// 创建时的时间戳
  20.              time_t time_access;		// 最后一次被访问时的时间戳
  21.              time_t time_write;			// 最后一次被修改时的时间戳
  22.              _fsize_t size;				// 文件字节大小
  23.              char name[_MAX_FNAME];		// 文件名
  24.         };
  25. 	*/
  26. 	long handle = _findfirst(newpath, &findData);
  27. 	if (handle == -1){return;}     
  28.      
  29. 	// 遍历文件和文件夹
  30.     while (_findnext(handle, &findData) == 0){
  31.         // 文件夹
  32. 		if (findData.attrib & _A_SUBDIR){
  33. 			// 文件夹名不能有敏感字符 ‘.‘、‘..‘
  34. 			if (strcmp(findData.name, ".") == 0 || strcmp(findData.name, "..") == 0){continue;}
  35.                 
  36. 			// 进入这个文件夹继续遍历
  37.             strcpy(newpath, path);
  38.             strcat(newpath, "\\");
  39.             strcat(newpath, findData.name);
  40.             findAllFile_MD5(newpath,format,str_md5,isFound);
  41. 		}
  42. 		// 文件
  43.         else{
  44. 			// 判断是不是指定后缀的文件
  45.             if(strstr( findData.name,format)){    
  46.                 // 输出（用来测试）
  47. 				//cout << "findData.size = " << findData.size << endl;
  48. 				//cout << "findData.name = " << findData.name << endl;
  49. 				//cout << "path = " << path << endl;
  50. 				
  51. 				// 取文件全路径
  52. 				string str_fullPath = path;
  53. 				str_fullPath+="\\"; str_fullPath+=findData.name;
  54.  
  55. 				// 取文件 md5,判断是否匹配特征
  56. 				MD5 md5;
  57. 				md5.reset();
  58. 				md5.update(ifstream(str_fullPath));
  59. 				if(md5.toString() == str_md5){isFound = TRUE;}
  60.             }
  61.         }
  62.     }
  63.  
  64. 	// 关闭搜索句柄
  65.     _findclose(handle);    
  66. }

调用例子（遍历%temp% 下的文件）

  1. 	// 获取 %temp% 目录
  2. 	TCHAR lpTempPathBuffer[MAX_PATH];
  3. 	GetTempPath(MAX_PATH,lpTempPathBuffer);
  4.  
  5. 	// 删除末尾 ‘\‘
  6. 	string str_tempPath = lpTempPathBuffer;
  7. 	str_tempPath = str_tempPath.substr(0,str_tempPath.length()-1);
  8.  
  9. 	// 遍历目录下所有 exe 文件,匹配 MD5
  10. 	BOOL isFound = FALSE;
  11. 	findAllFile_MD5(stringToCharP(str_tempPath),".exe","52f5ce92c6f72c7e193b560bf4e76330",isFound);
  12. 	if(isFound){cout << "找到了！" << endl;;}

知识点扩展：

C++计算MD5

  1. #include "md5.h"
  2.  
  3. using namespace std;
  4.  
  5. /* Constants for MD5Transform routine. */
  6. #define S11 7
  7. #define S12 12
  8. #define S13 17
  9. #define S14 22
  10. #define S21 5
  11. #define S22 9
  12. #define S23 14
  13. #define S24 20
  14. #define S31 4
  15. #define S32 11
  16. #define S33 16
  17. #define S34 23
  18. #define S41 6
  19. #define S42 10
  20. #define S43 15
  21. #define S44 21
  22.  
  23.  
  24. /* F, G, H and I are basic MD5 functions.
  25. */
  26. #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
  27. #define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
  28. #define H(x, y, z) ((x) ^ (y) ^ (z))
  29. #define I(x, y, z) ((y) ^ ((x) | (~z)))
  30.  
  31. /* ROTATE_LEFT rotates x left n bits.
  32. */
  33. #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
  34.  
  35. /* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
  36. Rotation is separate from addition to prevent recomputation.
  37. */
  38. #define FF(a, b, c, d, x, s, ac) { (a) += F ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
  39. #define GG(a, b, c, d, x, s, ac) { (a) += G ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
  40. #define HH(a, b, c, d, x, s, ac) { (a) += H ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
  41. #define II(a, b, c, d, x, s, ac) { (a) += I ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }
  42.  
  43.  
  44. const byte MD5::PADDING[64] = { 0x80 };
  45. const char MD5::HEX[16] = {
  46. '0', '1', '2', '3',
  47. '4', '5', '6', '7',
  48. '8', '9', 'a', 'b',
  49. 'c', 'd', 'e', 'f'
  50. };
  51.  
  52.  
  53. /* Default construct. */
  54. MD5::MD5() {
  55.     reset();
  56. }
  57.  
  58. /* Construct a MD5 object with a input buffer. */
  59. MD5::MD5(const void* input, size_t length) {
  60.     reset();
  61.     update(input, length);
  62. }
  63.  
  64. /* Construct a MD5 object with a string. */
  65. MD5::MD5(const string& str) {
  66.     reset();
  67.     update(str);
  68. }
  69.  
  70. /* Construct a MD5 object with a file. */
  71. MD5::MD5(ifstream& in) {
  72.     reset();
  73.     update(in);
  74. }
  75.  
  76. /* Return the message-digest */
  77. const byte* MD5::digest() {
  78.  
  79.     if (!_finished) {
  80.         _finished = true;
  81.         final();
  82.     }
  83.     return _digest;
  84. }
  85.  
  86. /* Reset the calculate state */
  87. void MD5::reset() {
  88.  
  89.     _finished = false;
  90.     /* reset number of bits. */
  91.     _count[0] = _count[1] = 0;
  92.     /* Load magic initialization constants. */
  93.     _state[0] = 0x67452301;
  94.     _state[1] = 0xefcdab89;
  95.     _state[2] = 0x98badcfe;
  96.     _state[3] = 0x10325476;
  97. }
  98.  
  99. /* Updating the context with a input buffer. */
  100. void MD5::update(const void* input, size_t length) {
  101.     update((const byte*)input, length);
  102. }
  103.  
  104. /* Updating the context with a string. */
  105. void MD5::update(const string& str) {
  106.     update((const byte*)str.c_str(), str.length());
  107. }
  108.  
  109. /* Updating the context with a file. */
  110. void MD5::update(ifstream& in) {
  111.  
  112.     if (!in) {
  113.         return;
  114.     }
  115.  
  116.     std::streamsize length;
  117.     char buffer[BUFFER_SIZE];
  118.     while (!in.eof()) {
  119.         in.read(buffer, BUFFER_SIZE);
  120.         length = in.gcount();
  121.         if (length > 0) {
  122.             update(buffer, length);
  123.         }
  124.     }
  125.     in.close();
  126. }
  127.  
  128. /* MD5 block update operation. Continues an MD5 message-digest
  129. operation, processing another message block, and updating the
  130. context.
  131. */
  132. void MD5::update(const byte* input, size_t length) {
  133.  
  134.     uint32 i, index, partLen;
  135.  
  136.     _finished = false;
  137.  
  138.     /* Compute number of bytes mod 64 */
  139.     index = (uint32)((_count[0] >> 3) & 0x3f);
  140.  
  141.     /* update number of bits */
  142.     if ((_count[0] += ((uint32)length << 3)) < ((uint32)length << 3)) {
  143.         ++_count[1];
  144.     }
  145.     _count[1] += ((uint32)length >> 29);
  146.  
  147.     partLen = 64 - index;
  148.  
  149.     /* transform as many times as possible. */
  150.     if (length >= partLen) {
  151.  
  152.         memcpy(&_buffer[index], input, partLen);
  153.         transform(_buffer);
  154.  
  155.         for (i = partLen; i + 63 < length; i += 64) {
  156.             transform(&input[i]);
  157.         }
  158.         index = 0;
  159.  
  160.     }
  161.     else {
  162.         i = 0;
  163.     }
  164.  
  165.     /* Buffer remaining input */
  166.     memcpy(&_buffer[index], &input[i], length - i);
  167. }
  168.  
  169. /* MD5 finalization. Ends an MD5 message-_digest operation, writing the
  170. the message _digest and zeroizing the context.
  171. */
  172. void MD5::final() {
  173.  
  174.     byte bits[8];
  175.     uint32 oldState[4];
  176.     uint32 oldCount[2];
  177.     uint32 index, padLen;
  178.  
  179.     /* Save current state and count. */
  180.     memcpy(oldState, _state, 16);
  181.     memcpy(oldCount, _count, 8);
  182.  
  183.     /* Save number of bits */
  184.     encode(_count, bits, 8);
  185.  
  186.     /* Pad out to 56 mod 64. */
  187.     index = (uint32)((_count[0] >> 3) & 0x3f);
  188.     padLen = (index < 56) ? (56 - index) : (120 - index);
  189.     update(PADDING, padLen);
  190.  
  191.     /* Append length (before padding) */
  192.     update(bits, 8);
  193.  
  194.     /* Store state in digest */
  195.     encode(_state, _digest, 16);
  196.  
  197.     /* Restore current state and count. */
  198.     memcpy(_state, oldState, 16);
  199.     memcpy(_count, oldCount, 8);
  200. }
  201.  
  202. /* MD5 basic transformation. Transforms _state based on block. */
  203. void MD5::transform(const byte block[64]) {
  204.  
  205.     uint32 a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];
  206.  
  207.     decode(block, x, 64);
  208.  
  209.     /* Round 1 */
  210.     FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
  211.     FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
  212.     FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
  213.     FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
  214.     FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
  215.     FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
  216.     FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
  217.     FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
  218.     FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
  219.     FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
  220.     FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
  221.     FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
  222.     FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
  223.     FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
  224.     FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
  225.     FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
  226.  
  227.     /* Round 2 */
  228.     GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
  229.     GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
  230.     GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
  231.     GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
  232.     GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
  233.     GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
  234.     GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
  235.     GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
  236.     GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
  237.     GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
  238.     GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
  239.     GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
  240.     GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
  241.     GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
  242.     GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
  243.     GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
  244.  
  245.     /* Round 3 */
  246.     HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
  247.     HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
  248.     HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
  249.     HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
  250.     HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
  251.     HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
  252.     HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
  253.     HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
  254.     HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
  255.     HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
  256.     HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
  257.     HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
  258.     HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
  259.     HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  260.     HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  261.     HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */
  262.  
  263.     /* Round 4 */
  264.     II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
  265.     II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
  266.     II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  267.     II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
  268.     II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  269.     II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
  270.     II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  271.     II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
  272.     II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
  273.     II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  274.     II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
  275.     II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  276.     II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
  277.     II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  278.     II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
  279.     II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */
  280.  
  281.     _state[0] += a;
  282.     _state[1] += b;
  283.     _state[2] += c;
  284.     _state[3] += d;
  285. }
  286.  
  287. /* Encodes input (ulong) into output (byte). Assumes length is
  288. a multiple of 4.
  289. */
  290. void MD5::encode(const uint32* input, byte* output, size_t length) {
  291.  
  292.     for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
  293.         output[j] = (byte)(input[i] & 0xff);
  294.         output[j + 1] = (byte)((input[i] >> 8) & 0xff);
  295.         output[j + 2] = (byte)((input[i] >> 16) & 0xff);
  296.         output[j + 3] = (byte)((input[i] >> 24) & 0xff);
  297.     }
  298. }
  299.  
  300. /* Decodes input (byte) into output (ulong). Assumes length is
  301. a multiple of 4.
  302. */
  303. void MD5::decode(const byte* input, uint32* output, size_t length) {
  304.  
  305.     for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
  306.         output[i] = ((uint32)input[j]) | (((uint32)input[j + 1]) << 8) |
  307.             (((uint32)input[j + 2]) << 16) | (((uint32)input[j + 3]) << 24);
  308.     }
  309. }
  310.  
  311. /* Convert byte array to hex string. */
  312. string MD5::bytesToHexString(const byte* input, size_t length) {
  313.  
  314.     string str;
  315.     str.reserve(length << 1);
  316.     for (size_t i = 0; i < length; ++i) {
  317.         int t = input[i];
  318.         int a = t / 16;
  319.         int b = t % 16;
  320.         str.append(1, HEX[a]);
  321.         str.append(1, HEX[b]);
  322.     }
  323.     return str;
  324. }
  325.  
  326. /* Convert digest to string value */
  327. string MD5::toString() {
  328.     return bytesToHexString(digest(), 16);
  329. }

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