Parse/Read Bitmap file in C

Question

I\'m trying to make a program to read data from a bitmap file (.bmp, Windows file format, 8bit). Right now I\'m stuck on reading the headers before the image data.

I

Answer 1

Yup I forgot to pack the structs. This fixes things. Oops:

typedef struct __attribute__((__packed__)) {                                                                                                                                                                                                                             
    unsigned char fileMarker1;                                                                                                                                                                                              
    unsigned char fileMarker2;                                                                                                                                                                                               
    unsigned int   bfSize;                                                                                                                                                                                                                   
    uint16_t unused1;                                                                                                                                                                                                                        
    uint16_t unused2;                                                                                                                                                                                                                        
    unsigned int   imageDataOffset;                                                                                                                                                            
} FILEHEADER;                                                                                                                                                                                                                                

typedef struct __attribute__((__packed__)) {                                                                                                                                                                                                                             
    unsigned int   biSize;                                                                                                                                                                                                                   
    int            width;                                                                                                                                                                
    int            height;                                                                                                                                                                     
    uint16_t planes;                                                                                                                                                                                                                         
    uint16_t bitPix;                                                                                                                                                                                                                         
    unsigned int   biCompression;                                                                                                                                                                                                            
    unsigned int   biSizeImage;                                                                                                                                                                                                              
    int            biXPelsPerMeter;                                                                                                                                                                                                          
    int            biYPelsPerMeter;                                                                                                                                                                                                          
    unsigned int   biClrUsed;                                                                                                                                                                                                                
    unsigned int   biClrImportant;                                                                                                                                                                                                           
} INFOHEADER;                                                                                                                                                                                                                                

typedef struct __attribute__((__packed__)) {                                                                                                                                                                                                                             
    unsigned char  b;                                                                                                                                                                                                                        
    unsigned char  g;                                                                                                                                                                                                                        
    unsigned char  r;                                                                                                                                                                                                                        
} IMAGE;