Determining if a file is a Dicom file

[martinrame]

Hi, I need to read a directory and determine if a file is Dicom, what is the fastest way to do this.

Currently I'm using DcmFileFormat to open each file, but this is too slow in some cases.

Thanks in advance.

[omarelgazzar]

In the dcmtk tool dcmftest, you can find a code in the main function that checks whether a DICOM file uses DICOM part 10. It checks the meta header of the file for the File Preamble and for the DICOM prefix ("DICM") so you don't need to load the file using DcmFileFormat.

[martinrame]

Thanks omarelgazzar, here's the function with a slight modification:

Code: Select all

  bool fileIsDicom(char * fname)
  {
    bool ok = false;
    FILE* f = NULL;

    f = fopen(fname, "rb");
    if (f == 0) {
        ok = false;
    } else {
        char signature[4];
        if ((fseek(f, DCM_PreambleLen, SEEK_SET) < 0) ||
            (fread(signature, 1, DCM_MagicLen, f) != DCM_MagicLen)) {
            ok = false;
        } else if (strncmp(signature, DCM_Magic, DCM_MagicLen) != 0) {
            ok = false;
        } else {
            /* looks ok */
            ok = true; 
        }
        fclose(f);
    }
    return ok;
  }