C语言 为什么我的代码 seg 在尝试从 bmp 文件中提取 RGB 组件时出错

Question

我正在尝试从 bmp 文件中提取 RGB 组件，但是当它到达Data[i][j].Blue时我遇到了 seg 错误。我尝试打印出三种颜色的十六进制，它打印出来很好，但随后它打印出所有 RGB 组件都0xFF，然后在它变成蓝色时出现错误。我得到的任何帮助都非常感谢。

int inputColors(char *filename, struct INFOHEADER *InfoHeader, struct PIXEL **Data){
    int i = 0, j = 0;
    FILE *inputFile;
    printf("The height of the picture is %dn", InfoHeader->Height);
    printf("The width of the picture is %dn", InfoHeader->Width);
    if((inputFile = fopen(filename, "r")) == NULL){
            printf("Unable to open .bmp filen");
            exit(1);
    }
    //Mallocing enough space for the 2D structures of pixels (colors)
    Data = (struct PIXEL **)malloc(InfoHeader->Width * sizeof(struct PIXEL *));
    for(i = 0; i < InfoHeader->Height; i++){
            Data[i] = (struct PIXEL *)malloc(InfoHeader->Height * InfoHeader->Width * sizeof(struct PIXEL));
    }
    //This goes until after we are down with the header
    fseek(inputFile, 54, SEEK_SET);
    //Inputing the data into the malloced struct
    i = 0;
    for(i = 0; i < InfoHeader->Height; i++){
            for(j = 0; j < InfoHeader->Width; j++){
                    Data[i][j].Red = getc(inputFile);
            //      printf("The Red componet is %Xn", Data[i][j].Red);
                    Data[i][j].Green = getc(inputFile);
            //      printf("The green componet is %Xn", Data[i][j].Green);
                    Data[i][j].Blue = getc(inputFile);
            //      printf("The blue componet is %Xn", Data[i][j].Blue);
            }
    }
    fclose(inputFile);
return 0;
}

Answer 1

对于初学者来说，你的第一个malloc使用

。

InfoHeader->Width * sizeof(struct PIXEL *)

但是，在迭代数组时，您可以使用 InfoHeader->Height。 由于这种不匹配，如果 InfoHeader->Width 小于 InfoHeader->Height，则它不会分配足够的内存来执行迭代，并且会出错。

Answer 2

Data = (struct PIXEL **)malloc(InfoHeader->Width * sizeof(struct PIXEL *));
//                                         ^^^^^
for(i = 0; i < InfoHeader->Height; i++){
//                         ^^^^^^
        Data[i] = (struct PIXEL *)malloc(InfoHeader->Height * InfoHeader->Width * sizeof(struct PIXEL));
}