If you will only be supporting a handful of the popular image formats, then you can simply read the first few bytes of the file to determine the type based on the Magic Number Examples from the link provided: GIF image files have the ASCII code for “GIF89a” (47 49 46 38 39 61) or … Read more
Yes. They are different file formats (and their file extensions). Wikipedia entries for each of the formats will give you quite a bit of information: JPEG (or JPG, for the file extension; Joint Photographic Experts Group) PNG (Portable Network Graphics) BMP (Bitmap) GIF (Graphics Interchange Format) TIFF (or TIF, for the file extension; Tagged Image … Read more
The CSV “standard” (such as it is) does not dictate how comments should be handled, no, it’s up to the application to establish a convention and stick with it.
Delphi 2009 comes with built in support for JPEG, BMP, GIF and PNG. For earlier versions of Delphi you may need to find third party implementations for PNG and GIF, but in Delphi 2009 you simply add the Jpeg, pngimage and GIFImg units to your uses clause. If the file has an extension you can … Read more
In times like these, the official HTTP specification is always helpful. From RFC 2616 7.2.1 (my emphasis added): Any HTTP/1.1 message containing an entity-body SHOULD include a Content-Type header field defining the media type of that body. If and only if the media type is not given by a Content-Type field, the recipient MAY attempt … Read more
If a file contains only the decimal bytes 9–13, 32–126, it’s probably a pure ASCII text file. Otherwise, it’s not. However, it may still be text in another encoding. If, in addition to the above bytes, the file contains only the decimal bytes 128–255, it’s probably a text file in an 8-bit or variable-length ASCII-based … Read more
Here are some tips that come to mind: From my experience, interactive scripting languages (I use Python) can be a great help. You can write a simple framework to deal with binary streams and some simple algorithms. Then you can write scripts that will take your binary and check various things. For example: Do some … Read more
Safe Encoding Constructors Getting Java to properly notify you of encoding errors is tricky. You must use the most verbose and, alas, the least used of the four alternate contructors for each of InputStreamReader and OutputStreamWriter to receive a proper exception on an encoding glitch. For file I/O, always make sure to always use as … Read more