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C++实现MD5,兼容C++17

C++实现MD5,兼容C++17

作者: 李铁满 | 来源:发表于2022-06-07 15:57 被阅读0次

    h文件:

    #pragma once
    #ifndef MY_MD5_H
    #define MY_MD5_H
    
    #include <string>
    #include <fstream>
    #include <cstring>
    
    /* Type define */
    typedef unsigned char byte;
    typedef unsigned int uint32;
    
    using std::string;
    using std::ifstream;
    
    /* MD5 declaration. */
    class MD5 {
    public:
        MD5();
        MD5(const void* input, size_t length);
        MD5(const string& str);
        MD5(ifstream& in);
        void update(const void* input, size_t length);
        void update(const string& str);
        void update(ifstream& in);
        const byte* digest();
        string toString();
        void reset();
    
    private:
        void update(const byte* input, size_t length);
        void final();
        void transform(const byte block[64]);
        void encode(const uint32* input, byte* output, size_t length);
        void decode(const byte* input, uint32* output, size_t length);
        string bytesToHexString(const byte* input, size_t length);
    
        /* class uncopyable */
        MD5(const MD5&);
        MD5& operator=(const MD5&);
    
    private:
        uint32 _state[4];   /* state (ABCD) */
        uint32 _count[2];   /* number of bits, modulo 2^64 (low-order word first) */
        byte _buffer[64];   /* input buffer */
        byte _digest[16];   /* message digest */
        bool _finished;     /* calculate finished ? */
    
        static const byte PADDING[64];  /* padding for calculate */
        static const char HEX[16];
        enum { BUFFER_SIZE = 1024 };
    };
    
    #endif /*MY_MD5_H*/
    
    

    cpp文件:

    #include "myMD5.h"
    
    using namespace std;
    
    /* Constants for MD5Transform routine. */
    #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
    
    
    /* 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) + ac; \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
    }
    #define GG(a, b, c, d, x, s, ac) { \
        (a) += G ((b), (c), (d)) + (x) + ac; \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
    }
    #define HH(a, b, c, d, x, s, ac) { \
        (a) += H ((b), (c), (d)) + (x) + ac; \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
    }
    #define II(a, b, c, d, x, s, ac) { \
        (a) += I ((b), (c), (d)) + (x) + ac; \
        (a) = ROTATE_LEFT ((a), (s)); \
        (a) += (b); \
    }
    
    
    const ::byte MD5::PADDING[64] = { 0x80 };
    const char MD5::HEX[16] = {
        '0', '1', '2', '3',
        '4', '5', '6', '7',
        '8', '9', 'a', 'b',
        'c', 'd', 'e', 'f'
    };
    
    
    /* Default construct. */
    MD5::MD5() {
        reset();
    }
    
    /* Construct a MD5 object with a input buffer. */
    MD5::MD5(const void* input, size_t length) {
        reset();
        update(input, length);
    }
    
    /* Construct a MD5 object with a string. */
    MD5::MD5(const string& str) {
        reset();
        update(str);
    }
    
    /* Construct a MD5 object with a file. */
    MD5::MD5(ifstream& in) {
        reset();
        update(in);
    }
    
    /* Return the message-digest */
    const ::byte* MD5::digest() {
    
        if (!_finished) {
            _finished = true;
            final();
        }
        return _digest;
    }
    
    /* Reset the calculate state */
    void MD5::reset() {
    
        _finished = false;
        /* reset number of bits. */
        _count[0] = _count[1] = 0;
        /* Load magic initialization constants. */
        _state[0] = 0x67452301;
        _state[1] = 0xefcdab89;
        _state[2] = 0x98badcfe;
        _state[3] = 0x10325476;
    }
    
    /* Updating the context with a input buffer. */
    void MD5::update(const void* input, size_t length) {
        update((const ::byte*)input, length);
    }
    
    /* Updating the context with a string. */
    void MD5::update(const string& str) {
        update((const ::byte*)str.c_str(), str.length());
    }
    
    /* Updating the context with a file. */
    void MD5::update(ifstream& in) {
    
        if (!in) {
            return;
        }
    
        std::streamsize length;
        char buffer[BUFFER_SIZE];
        while (!in.eof()) {
            in.read(buffer, BUFFER_SIZE);
            length = in.gcount();
            if (length > 0) {
                update(buffer, length);
            }
        }
        in.close();
    }
    
    /* MD5 block update operation. Continues an MD5 message-digest
    operation, processing another message block, and updating the
    context.
    */
    void MD5::update(const ::byte* input, size_t length) {
    
        uint32 i, index, partLen;
    
        _finished = false;
    
        /* Compute number of bytes mod 64 */
        index = (uint32)((_count[0] >> 3) & 0x3f);
    
        /* update number of bits */
        if ((_count[0] += ((uint32)length << 3)) < ((uint32)length << 3)) {
            ++_count[1];
        }
        _count[1] += ((uint32)length >> 29);
    
        partLen = 64 - index;
    
        /* transform as many times as possible. */
        if (length >= partLen) {
    
            memcpy(&_buffer[index], input, partLen);
            transform(_buffer);
    
            for (i = partLen; i + 63 < length; i += 64) {
                transform(&input[i]);
            }
            index = 0;
    
        }
        else {
            i = 0;
        }
    
        /* Buffer remaining input */
        memcpy(&_buffer[index], &input[i], length - i);
    }
    
    /* MD5 finalization. Ends an MD5 message-_digest operation, writing the
    the message _digest and zeroizing the context.
    */
    void MD5::final() {
    
        ::byte bits[8];
        uint32 oldState[4];
        uint32 oldCount[2];
        uint32 index, padLen;
    
        /* Save current state and count. */
        memcpy(oldState, _state, 16);
        memcpy(oldCount, _count, 8);
    
        /* Save number of bits */
        encode(_count, bits, 8);
    
        /* Pad out to 56 mod 64. */
        index = (uint32)((_count[0] >> 3) & 0x3f);
        padLen = (index < 56) ? (56 - index) : (120 - index);
        update(PADDING, padLen);
    
        /* Append length (before padding) */
        update(bits, 8);
    
        /* Store state in digest */
        encode(_state, _digest, 16);
    
        /* Restore current state and count. */
        memcpy(_state, oldState, 16);
        memcpy(_count, oldCount, 8);
    }
    
    /* MD5 basic transformation. Transforms _state based on block. */
    void MD5::transform(const ::byte block[64]) {
    
        uint32 a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];
    
        decode(block, x, 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;
    }
    
    /* Encodes input (ulong) into output (byte). Assumes length is
    a multiple of 4.
    */
    void MD5::encode(const uint32* input, ::byte* output, size_t length) {
    
        for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
            output[j] = (::byte)(input[i] & 0xff);
            output[j + 1] = (::byte)((input[i] >> 8) & 0xff);
            output[j + 2] = (::byte)((input[i] >> 16) & 0xff);
            output[j + 3] = (::byte)((input[i] >> 24) & 0xff);
        }
    }
    
    /* Decodes input (byte) into output (ulong). Assumes length is
    a multiple of 4.
    */
    void MD5::decode(const byte* input, uint32* output, size_t length) {
    
        for (size_t i = 0, j = 0; j < length; ++i, j += 4) {
            output[i] = ((uint32)input[j]) | (((uint32)input[j + 1]) << 8) |
                (((uint32)input[j + 2]) << 16) | (((uint32)input[j + 3]) << 24);
        }
    }
    
    /* Convert byte array to hex string. */
    string MD5::bytesToHexString(const ::byte* input, size_t length) {
    
        string str;
        str.reserve(length << 1);
        for (size_t i = 0; i < length; ++i) {
            int t = input[i];
            int a = t / 16;
            int b = t % 16;
            str.append(1, HEX[a]);
            str.append(1, HEX[b]);
        }
        return str;
    }
    
    /* Convert digest to string value */
    string MD5::toString() {
        return bytesToHexString(digest(), 16);
    }
    
    
    

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