tea.cpp

#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <fstream>
#include <cstddef>
#include <vector>
#include <map>
#include <stdint.h>
#include "SString.h"
#include <stdarg.h>
using namespace std;



    void encodeXtea(unsigned int* v, unsigned int* w, unsigned int* k) {
        register unsigned int v0=v[0], v1=v[1], i, sum=0;
        register unsigned int delta=0x9E3779B9;
        for(i=0; i<32; i++) {
           v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
            sum += delta;
            v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
        }
        w[0]=v0; w[1]=v1;
    }

    void decodeXtea(unsigned int* v, unsigned int* w, unsigned int* k) {
        register unsigned int v0=v[0], v1=v[1], i, sum=0xC6EF3720;
        register unsigned int delta=0x9E3779B9;
        for(i=0; i<32; i++) {
            v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
            sum -= delta;
            v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
        }
        w[0]=v0; w[1]=v1;
    }

    void TeaEncode ( const SString& str, const SString& key, SString* out )
    {
        unsigned int v[2];
        unsigned int w[2];
        unsigned int k[4];
        unsigned int keybuffer [ 4 ];

        // Clear buffers
        memset ( v, 0, sizeof(v) );
        memset ( w, 0, sizeof(w) );
        memset ( k, 0, sizeof(k) );
        memset ( keybuffer, 0, sizeof(keybuffer) );
        out->clear ();

        // Process the key
        int len = key.length ();
        if ( len > 16 )
            len = 16;
        memcpy ( keybuffer, key.c_str(), len );
        for ( int i = 0; i < 4; ++i )
            k[i] = keybuffer[i];

        // Copy the input string to a buffer of size multiple of 4
        int strbuflen = str.length ();
        if ( strbuflen == 0 )
            return;
        if ( (strbuflen % 4) > 0 )
            strbuflen += 4 - (strbuflen % 4);
        unsigned char* strbuf = new unsigned char [ strbuflen ];
        memset ( strbuf, 0, strbuflen );
        memcpy ( strbuf, str.c_str(), str.length() );

        // Encode it!
        v[1] = 0;
        for ( int i = 0; i < strbuflen; i += 4 )
        {
            v[0] = *(unsigned int*)&strbuf[i];

            encodeXtea ( &v[0], &w[0], &k[0] );
            out->append ( (char*)&w[0], 4 );

            v[1] = w[1];
        }
        out->append ( (char*)&v[1], 4 );

        delete [] strbuf;
    }

    void TeaDecode ( const SString& str, const SString& key, SString* out )
    {
        unsigned int v[2];
        unsigned int w[2];
        unsigned int k[4];
        unsigned int keybuffer [ 4 ];

        // Clear buffers
        memset ( v, 0, sizeof(v) );
        memset ( w, 0, sizeof(w) );
        memset ( k, 0, sizeof(k) );
        memset ( keybuffer, 0, sizeof(keybuffer) );
        out->clear ();

        // Count the number of passes that we need
        int numBlocks = str.length() / 4;
        int numPasses = numBlocks - 1;

        if ( numPasses <= 0 )
            return;

        // Process the key
        int len = key.length ();
        if ( len > 16 )
            len = 16;
        memcpy ( keybuffer, key.c_str(), len );
        for ( int i = 0; i < 4; ++i )
            k[i] = keybuffer[i];

        // Create a temporary buffer to store the result
        unsigned char* buffer = new unsigned char [ numPasses * 4 + 4 ];
        memset ( buffer, 0, numPasses * 4 + 4 );

        // Decode it!
        const char* p = str.c_str();
        v[1] = *(unsigned int*)&p[numPasses * 4];
        for ( int i = 0; i < numPasses; ++i )
        {
            v[0] = *(unsigned int*)&p[(numPasses-i-1)*4];
            decodeXtea ( &v[0], &w[0], &k[0] );
            *(unsigned int*)&buffer[(numPasses-i-1)*4] = w[0];
            v[1] = w[1];
        }

        out->assign ( (char *)buffer, numPasses*4 );
        delete [] buffer;
    }

int main ()
{

}