2012-01-08 199 views
1

我在從存儲文件讀取序列化對象時遇到問題。 (請參閱下面的代碼)。C++:自定義對象序列化/反序列化失敗

序列化過程「有效」(雖然可能寫得很差),並且因爲無法知道用戶是否傳遞了std :: ios :: binary標誌或者沒有選擇不使用格式化用whitespace輸出。 (這也節省內存爲大量像素數據的潛在對我並沒有失去。)

我第一次嘗試看起來一樣的樣品,但int小號是unsigned char s的意圖位壓縮的下半部分和上半部分放入char s中,然後重新組裝它們。

目前我可以讀取所有的數據到一個文件中,但是當我試圖讀取第一片非校驗和數據,要麼返回0(與char S中的嘗試的情況下)或垃圾的(在的情況下與int S上的嘗試)

連載:

std::ostream& operator<<(std::ostream& os, const Sprite& data) { 
    int dF = data._dimensions.first; 
    int dS = data._dimensions.second; 

    int cF = data._center.first; 
    int cS = data._center.second; 

    int fF = data._frameDimensions.first; 
    int fS = data._frameDimensions.second; 

    double sF = data._scaleDimensions.first; 
    double sS = data._scaleDimensions.second; 


    std::string name(*data._file); 
    name.shrink_to_fit(); 
    os << 'S' << 'P' << 'R' << (name.length() + 1) << name.c_str() << dF << dS << cF << cS << fF << fS << sF << sS; 
    for(int x = 0; x < data._dimensions.first; ++x) { 
     for(int y = 0; y < data._dimensions.second; ++y) { 
      int color = getpixel(data._image, x, y); 
      os << static_cast<unsigned char>(getr(color)) << static_cast<unsigned char>(getg(color)) << static_cast<unsigned char>(getb(color)); 
     } 
    } 
    int tint = data._tint; 
    os << static_cast<unsigned char>(getr(tint)) << static_cast<unsigned char>(getg(tint)) << static_cast<unsigned char>(getb(tint)); 
    os << data._tintIntensity << data._alpha; 
    return os; 
} 

反序列化:

std::istream& operator>>(std::istream& is, Sprite& data) { 
    char checksum[3]; 
    is >> checksum[0] >> checksum[1] >> checksum[2]; 
    if(checksum[0] != 'S' || checksum[1] != 'P' || checksum[2] != 'R') { 
     is.setstate(std::ios::failbit); 
     return is; 
    } 
    int name_length; 
    is >> name_length; 

    std::string name(name_length, '\0'); 

    for(int i = 0; i <= name_length; ++i) { 
     char current_char = '\0'; 
     is >> current_char; 
     name[i] = current_char; 
    } 

    int upper = 0; 
    int lower = 0; 
    is >> upper; 
    is >> lower; 
    data._dimensions.first = (upper << 8) | lower; 

    upper = 0; 
    lower = 0; 
    is >> upper >> lower; 
    data._dimensions.second = ((upper << 8) | lower); 

    upper = 0; 
    lower = 0; 
    is >> upper >> lower; 
    data._center.first = ((upper << 8) | lower); 

    upper = 0; 
    lower = 0; 
    is >> upper >> lower; 
    data._center.second = ((upper << 8) | lower); 

    upper = 0; 
    lower = 0; 
    is >> upper >> lower; 
    data._frameDimensions.first = ((upper << 8) | lower); 

    upper = 0; 
    lower = 0; 
    is >> upper >> lower; 
    data._frameDimensions.second = ((upper << 8) | lower); 

    double f = 0.0; 
    double s = 0.0; 
    is >> f >> s; 
    data._scaleDimensions.first = f; 
    data._scaleDimensions.second = s; 

    destroy_bitmap(data._image); 
    data._image = NULL; 
    data._image = create_bitmap(data._dimensions.first, data._dimensions.second); 
    for(int x = 0; x < data._dimensions.first; ++x) { 
     for(int y = 0; y < data._dimensions.second; ++y) { 
      unsigned char r = 0; 
      unsigned char g = 0; 
      unsigned char b = 0; 
      is >> r >> g >> b; 
      int color = ((r << 16) | (g << 8) | b); //0xRRGGBB 
      putpixel(data._image, x, y, color); 
     } 
    } 
    unsigned char rtint = 0; 
    unsigned char gtint = 0; 
    unsigned char btint = 0; 
    is >> rtint >> gtint >> btint; 
    data._tint = ((rtint << 16) | (gtint << 8) | btint); //0xRRGGBB 

    is >> data._tintIntensity; 
    is >> data._alpha; 
    return is; 
} 
+1

什麼具有格式標誌'std :: ios_base :: binary'做與不做格式化I/O?該標誌只是決定如何處理行結束符:當以非二進制模式寫入'\ n'時,它可能被替換(例如通過CR/LF),而在二進制模式下它不會被替換。類似地,當讀取結束行序列被非二進制模式中的單個'\ n'替換或以二進制模式保持原樣時。爲防止用戶使用或不使用此標誌打開,您應該使用格式化的I/O! – 2012-01-08 23:40:01

+0

查看代碼:在不插入空格的情況下編寫多個值將導致'std :: istream'讀取一個較大的值而不是多個較小的值。可能這個大值會導致溢出錯誤,從而導致數據流進入不良狀態。這就是你的問題開始的地方...... – 2012-01-08 23:42:33

+0

@DietmarKühl:做出答案並且我會接受它。 :d – Casey 2012-01-09 03:04:02

回答

0

不應deserial化是這樣的:

int upper = 0; 
int lower = 0; 
is >> upper; 
is >> lower; 
data._dimensions.first = upper; 
data._dimensions.second = lower; 

和中心相似,frameDimensions

-1

我會用bitfileds。之後請不要忘記添加#pragma pack(1)#pragma pack()。由於計算機只能處理字節,因此必須確保您的位域是8的倍數。此外,位的打包依賴於編譯器/機器,所以您的閱讀器應該使用相同的編譯器進行編譯。 然後只是使用例如:

somefilestream.write(&some_bitfield_struct, sizeof(some_bitfield_struct));