CODEWITHSUNDEEP
image-processingtiff
noste99
noste99

Reputation: 385

Reading TIFF files

I need to read and interpret a binary file containing a TIFF image. I know there exist readers for doing this but I want to go the hard way. I found the TIFF format description and need to parse the binary file in small chunks. Assume I was able to read in memory the complete binary file. This means that I have a variable containing one long list of bytes. I know via the format definition what the meaning is of the different groups of n bytes.

How can one define character variables with different lengths (sometimes 2, sometimes 3, sometimes 4 etc.) so that the variable address points to the right position in the image variable array?

With other words, assume my image is loaded into an array Image containing all bytes of the file. The first 2 bytes I want to load in a string with length 2 bytes so that I can just link the address pointer to the first position in the Image array and automatically the first 2 bytes are associated with the first character string. A second string of 4 bytes would have another meaning and so I make the address for the second string of 4 bytes point to the 3rd position of the Image array.

Is this feasible in C++? I remember that this was a normal way of working for dynamical memory allocation in Fortran 77 in a simulation code I analysed a long time ago.

Thanks in advance for the hints!

Regards,

Stefan

Upvotes: 1

Views: 2218

Answers (1)

BitBank
BitBank

Reputation: 8715

The C++ language is easily capable of processing TIFF files from a byte array. The idea you have in mind is basically correct, but there a few problems with it. C strings are zero-terminated and the strings which appear in TIFF files are not necessarily zero terminated since their length is specified explicitly. It really is simpler to create a dedicated data structure to hold the TIFF-specific data fields and then parse the binary data into the structure. Your method will immediately run into trouble with the Motorola/Intel byte issue if your machine has the opposite endian-ness.

Upvotes: 2

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