How to mount a BMP header (Bitmap) in C

Hello.

I am wanting to mount a BMP in C language. I only get the image data, data size, width, height, bpp.

I managed to mount the following BMP header structure:

struct BMPHeader
{
    uint16 signature;           // 0-1   magic chars 'BM'
    uint32 fileSize;            // 2-5   uint32 filesize (not reliable)
    uint32 filler1;             // 6-9   uint32 0
    uint32 bitmapOffset;        // 10-13 uint32 bitmapOffset
    uint32 infoSize;            // 14-17 uint32 info size
    int32 width;                // 18-21 int32  width
    int32 height;               // 22-25 int32  height
    uint16 nPlanes;             // 26-27 uint16 nplanes
    uint16 bpp;                 // 28-29 uint16 bits per pixel
    uint32 compression;         // 30-33 uint32 compression flag
    uint32 imageSize;           // 34-37 uint32 image size in bytes
    int32 biXPelsPerMeter;      // 38-41 int32  biXPelsPerMeter
    int32 biYPelsPerMeter;      // 32-45 int32  biYPelsPerMeter
    uint32 colorsUsed;          // 46-49 uint32 colors used
    uint32 importantColorCount; // 50-53 uint32 important color count
};

As mentioned above, much of the header information I receive from an application in java, except these:

int32 biXPelsPerMeter;      // 38-41 int32  biXPelsPerMeter
int32 biYPelsPerMeter;      // 32-45 int32  biYPelsPerMeter

Can anyone tell if these two variables come from the calculation of the variables I received? I didn't quite understand what they represent...

Thank you right now.