binery file read error

[sagar474]

bindery file read error

I wrote the following code to read bmp file and write it to new bmp file
that is, to create a duplicate the bmp file.

but the created bmp file is not in correct format

when opened shows an error "this is not valid bmp file"

#include<stdio.h>
#include<stdlib.h>
int main()
{
struct BITMAPFILEHEADER{
   unsigned short type;
   unsigned long size;
   unsigned short reserved1;
   unsigned short reserved2;
   unsigned long offsetbits;
};



struct BITMAPINFOHEADER{
   unsigned long size;
   unsigned long width;
   unsigned long height;
   unsigned short planes;
   unsigned short bitcount;
   unsigned long compression;
   unsigned long sizeimage;
   long xpelspermeter;
   long ypelspermeter;
   unsigned long colorsused;
   unsigned long colorsimportant;
};



struct SINGLE_PIXEL{
   unsigned char blue;
   unsigned char green;
   unsigned char red;
};

int i=0;
int S=0;
struct BITMAPFILEHEADER source_head;
struct BITMAPINFOHEADER source_info;
struct SINGLE_PIXEL source_pix;

struct head dist_head;
struct BITMAPINFOHEADER dist_info;
struct SINGLE_PIXEL dist_pix;


FILE *fp;
FILE *Dfp;

fp=fopen("rajni.bmp","rb");
Dfp=fopen("rajni2.bmp","wb");

fread(&source_head,sizeof(struct head),1,fp);
fread(&source_info,sizeof(struct BITMAPINFOHEADER),1,fp);

fwrite(&source_head,sizeof(struct head),1,Dfp);
fwrite(&source_info,sizeof(struct BITMAPINFOHEADER),1,Dfp);

S=source_info.width*source_info.height;

for(i=1;i<=S;i++)
{
fread(&source_pix,sizeof(struct SINGLE_PIXEL),1,fp);
fwrite(&source_pix,sizeof(struct SINGLE_PIXEL),1,Dfp);
}
fclose(fp);
fclose(Dfp);
return 0;
}

 

[kalyanasv]

Your header file format seems to out of place. There is no better place: Wiki.
That having said I do believe the bmp was 14 byte initial header which doesn't match with yours. Then there is a DIB header.. which is variant.

 

[sagar474]

I figured out the problem
this is only a data type misuse.
I used int for declaring i and S which. S stores the number of pixels to read or write. and i increments till it reaches to s.
the size of s depends on height and width of the image. my image is 400x300 hence the space that is allocated previously is insufficient.
and i changed it to unsigned long int. my stupidity is I used a signed integer where it is no question about sign while representing number of pixels.

thank you