#include <iostream>
#include "iconvlite.h"

using namespace std;

typedef struct ConvLetter {
    unsigned char    win1251;
    int             unicode;
} Letter;

static Letter g_letters[] = {
    {0x82, 0x201A}, // SINGLE LOW-9 QUOTATION MARK
    {0x83, 0x0453}, // CYRILLIC SMALL LETTER GJE
    {0x84, 0x201E}, // DOUBLE LOW-9 QUOTATION MARK
    {0x85, 0x2026}, // HORIZONTAL ELLIPSIS
    {0x86, 0x2020}, // DAGGER
    {0x87, 0x2021}, // DOUBLE DAGGER
    {0x88, 0x20AC}, // EURO SIGN
    {0x89, 0x2030}, // PER MILLE SIGN
    {0x8A, 0x0409}, // CYRILLIC CAPITAL LETTER LJE
    {0x8B, 0x2039}, // SINGLE LEFT-POINTING ANGLE QUOTATION MARK
    {0x8C, 0x040A}, // CYRILLIC CAPITAL LETTER NJE
    {0x8D, 0x040C}, // CYRILLIC CAPITAL LETTER KJE
    {0x8E, 0x040B}, // CYRILLIC CAPITAL LETTER TSHE
    {0x8F, 0x040F}, // CYRILLIC CAPITAL LETTER DZHE
    {0x90, 0x0452}, // CYRILLIC SMALL LETTER DJE
    {0x91, 0x2018}, // LEFT SINGLE QUOTATION MARK
    {0x92, 0x2019}, // RIGHT SINGLE QUOTATION MARK
    {0x93, 0x201C}, // LEFT DOUBLE QUOTATION MARK
    {0x94, 0x201D}, // RIGHT DOUBLE QUOTATION MARK
    {0x95, 0x2022}, // BULLET
    {0x96, 0x2013}, // EN DASH
    {0x97, 0x2014}, // EM DASH
    {0x99, 0x2122}, // TRADE MARK SIGN
    {0x9A, 0x0459}, // CYRILLIC SMALL LETTER LJE
    {0x9B, 0x203A}, // SINGLE RIGHT-POINTING ANGLE QUOTATION MARK
    {0x9C, 0x045A}, // CYRILLIC SMALL LETTER NJE
    {0x9D, 0x045C}, // CYRILLIC SMALL LETTER KJE
    {0x9E, 0x045B}, // CYRILLIC SMALL LETTER TSHE
    {0x9F, 0x045F}, // CYRILLIC SMALL LETTER DZHE
    {0xA0, 0x00A0}, // NO-BREAK SPACE
    {0xA1, 0x040E}, // CYRILLIC CAPITAL LETTER SHORT U
    {0xA2, 0x045E}, // CYRILLIC SMALL LETTER SHORT U
    {0xA3, 0x0408}, // CYRILLIC CAPITAL LETTER JE
    {0xA4, 0x00A4}, // CURRENCY SIGN
    {0xA5, 0x0490}, // CYRILLIC CAPITAL LETTER GHE WITH UPTURN
    {0xA6, 0x00A6}, // BROKEN BAR
    {0xA7, 0x00A7}, // SECTION SIGN
    {0xA8, 0x0401}, // CYRILLIC CAPITAL LETTER IO
    {0xA9, 0x00A9}, // COPYRIGHT SIGN
    {0xAA, 0x0404}, // CYRILLIC CAPITAL LETTER UKRAINIAN IE
    {0xAB, 0x00AB}, // LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
    {0xAC, 0x00AC}, // NOT SIGN
    {0xAD, 0x00AD}, // SOFT HYPHEN
    {0xAE, 0x00AE}, // REGISTERED SIGN
    {0xAF, 0x0407}, // CYRILLIC CAPITAL LETTER YI
    {0xB0, 0x00B0}, // DEGREE SIGN
    {0xB1, 0x00B1}, // PLUS-MINUS SIGN
    {0xB2, 0x0406}, // CYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I
    {0xB3, 0x0456}, // CYRILLIC SMALL LETTER BYELORUSSIAN-UKRAINIAN I
    {0xB4, 0x0491}, // CYRILLIC SMALL LETTER GHE WITH UPTURN
    {0xB5, 0x00B5}, // MICRO SIGN
    {0xB6, 0x00B6}, // PILCROW SIGN
    {0xB7, 0x00B7}, // MIDDLE DOT
    {0xB8, 0x0451}, // CYRILLIC SMALL LETTER IO
    {0xB9, 0x2116}, // NUMERO SIGN
    {0xBA, 0x0454}, // CYRILLIC SMALL LETTER UKRAINIAN IE
    {0xBB, 0x00BB}, // RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
    {0xBC, 0x0458}, // CYRILLIC SMALL LETTER JE
    {0xBD, 0x0405}, // CYRILLIC CAPITAL LETTER DZE
    {0xBE, 0x0455}, // CYRILLIC SMALL LETTER DZE
    {0xBF, 0x0457} // CYRILLIC SMALL LETTER YI
};

static void cp1251_to_utf8(char *out, const char *in, size_t len) {
    static const int table[128] = {
        0x82D0,0x83D0,0x9A80E2,0x93D1,0x9E80E2,0xA680E2,0xA080E2,0xA180E2,
        0xAC82E2,0xB080E2,0x89D0,0xB980E2,0x8AD0,0x8CD0,0x8BD0,0x8FD0,
        0x92D1,0x9880E2,0x9980E2,0x9C80E2,0x9D80E2,0xA280E2,0x9380E2,0x9480E2,
        0,0xA284E2,0x99D1,0xBA80E2,0x9AD1,0x9CD1,0x9BD1,0x9FD1,
        0xA0C2,0x8ED0,0x9ED1,0x88D0,0xA4C2,0x90D2,0xA6C2,0xA7C2,
        0x81D0,0xA9C2,0x84D0,0xABC2,0xACC2,0xADC2,0xAEC2,0x87D0,
        0xB0C2,0xB1C2,0x86D0,0x96D1,0x91D2,0xB5C2,0xB6C2,0xB7C2,
        0x91D1,0x9684E2,0x94D1,0xBBC2,0x98D1,0x85D0,0x95D1,0x97D1,
        0x90D0,0x91D0,0x92D0,0x93D0,0x94D0,0x95D0,0x96D0,0x97D0,
        0x98D0,0x99D0,0x9AD0,0x9BD0,0x9CD0,0x9DD0,0x9ED0,0x9FD0,
        0xA0D0,0xA1D0,0xA2D0,0xA3D0,0xA4D0,0xA5D0,0xA6D0,0xA7D0,
        0xA8D0,0xA9D0,0xAAD0,0xABD0,0xACD0,0xADD0,0xAED0,0xAFD0,
        0xB0D0,0xB1D0,0xB2D0,0xB3D0,0xB4D0,0xB5D0,0xB6D0,0xB7D0,
        0xB8D0,0xB9D0,0xBAD0,0xBBD0,0xBCD0,0xBDD0,0xBED0,0xBFD0,
        0x80D1,0x81D1,0x82D1,0x83D1,0x84D1,0x85D1,0x86D1,0x87D1,
        0x88D1,0x89D1,0x8AD1,0x8BD1,0x8CD1,0x8DD1,0x8ED1,0x8FD1
    };
    while (*in) {
        if (*in & 0x80) {
            int v = table[(int)(0x7f & *in++)];
            if (!v)
                continue;
            *out++ = (char)v;
            *out++ = (char)(v >> 8);
            if (v >>= 16)
                *out++ = (char)v;
        } else {
            *out++ = *in++;
        }
    }
    *out = 0;
}

static int utf8_to_cp1251(const char* utf8, char* windows1251, size_t n) {
    int i = 0;
    int j = 0;
    for(; i < (int)n && utf8[i] != 0; ++i) {
        char prefix = utf8[i];
        char suffix = utf8[i+1];
        if ((prefix & 0x80) == 0) {
            windows1251[j] = (char)prefix;
            ++j;
        } else if ((~prefix) & 0x20) {
            int first5bit = prefix & 0x1F;
            first5bit <<= 6;
            int sec6bit = suffix & 0x3F;
            int unicode_char = first5bit + sec6bit;

            if ( unicode_char >= 0x410 && unicode_char <= 0x44F ) {
                windows1251[j] = (char)(unicode_char - 0x350);
            } else if (unicode_char >= 0x80 && unicode_char <= 0xFF) {
                windows1251[j] = (char)(unicode_char);
            } else if (unicode_char >= 0x402 && unicode_char <= 0x403) {
                windows1251[j] = (char)(unicode_char - 0x382);
            } else {
                int count = sizeof(g_letters) / sizeof(Letter);
                for (int k = 0; k < count; ++k) {
                    if (unicode_char == g_letters[k].unicode) {
                        windows1251[j] = g_letters[k].win1251;
                        goto NEXT_LETTER;
                    }
                }
                // can't convert this char
                return 0;
            }
NEXT_LETTER:
            ++i;
            ++j;
        } else {
            // can't convert this chars
            return 0;
        }
    }
    windows1251[j] = 0;
    return 1;
}

string utf2cp(string s) {
    size_t len = s.size();
    char* output = new char[len+1];
    utf8_to_cp1251(s.c_str(), output, len);
    string ns(output);
    delete[] output;
    return ns;
}

string cp2utf(string s) {
    size_t len = s.size();
    char* output = new char[len*3+1];
    cp1251_to_utf8(output, s.c_str(), len);
    string ns(output);
    delete[] output;
    return ns;
}