Some images available on a royalty-free compilation CD Some images available as a poster History This program is a simple generic binary to ascii file converter.
There are various datatypes which may be read, the simplest is characters where no byte swapping is required. The next simplest is an unsigned short integer represented by 2 bytes. While this approach can be used for unsigned shorts, ints, and longs and can be easily modified for signed versions of the same, it is rather difficult for real numbers floats and double precision numbers.
Fortunately the standard IEEE numerical format is used almost exclusively now days so that the bytes making up the particular number can be swapped around appropriately in memory. This does assume that the size of the particular numerical type is the same length on both machines, the machine that wrote the file and the machine reading the file.
The usual standards are short integers are 2 bytes, long integers are 4 bytes, floats are 4 bytes and doubles are 8 bytes. In summary, to read 2 byte integers signed or unsigned one reads the 2 bytes as normal, eg: It turns out that for long integers, floats and doubles the requirements is to reverse the bytes as they appear in memory.
See the source below for more details. Source code Some routines illustrating the methods required to do the byte swapping for various numerical types. Strategies for developers There are three basic strategies for software developers when choosing how to create endian independent data files and associated software.
Decide that the file format will be one particular endian. In this case software running on machines of the same endian does nothing special, software running on other machines byte swap everything on reading and writing.
This is common for file formats and software designed with an implicit endian assumption which get ported at a future date to other machines. Store in the file the endian-ness of the file. The software writes the binary file in the natural endian of the underlying hardware but pays attention to the endian-ness when reading binary files.
Both endian files need to be handled, the software has knowledge of its own endian-ness so it can do the right thing. The poorer cousin of the last approaches is not to store the endian-ness and for software to always write in its natural endian.
This leads to two possible file types and the user is expected to know which endian a file is and chooses the appropriate one when specifying which file to read. This is obviously the least attractive approach. Reason Each time the FORTRAN write is issued a "record" is written, the record consists of a 4 byte header, then the data, then a trailer that matches the header.
The 4 byte header and trailer consist of the number of bytes that will be written in the data section. So the following write 60 nx,ny,nz gets written on the disk as follows where nx,ny,nz are each 4 bytes, the other numbers below are 2 byte integers written in decimal 0 12 nx ny nz 0 12 The total length written is 20 bytes.
The discussion here does not address the transfer of binary files between machines with a different endian. In that case after a short, int, float, double is read the bytes must be rearranged.
Fortunately this is relatively straightforward with these macros.Understanding the nature of file formats and escape characters has been an itch of mine.
I recently found a few useful explanations that inspired me to write my understanding of binary files.. How computers represent data.
Everything is bits and bytes, 1’s and 0’s to the computer. This program was designed to convert scientific data in a quick and easy way (so you can view them in Excel for instance), it's in no way meant to replace a program reading directly the binary files which will always be much faster.
In this simple example we write and then read two objects to a file in ASCII mode, and then do the exact same thing in binary mode, which results in file sizes of: Bytes (ASCII) Vs.
33 Bytes (Binary). In this simple example we write and then read two objects to a file in ASCII mode, and then do the exact same thing in binary mode, which results in file sizes of: Bytes (ASCII) Vs.
33 Bytes (Binary). Package binary import "encoding/binary" Overview Index Examples. Read reads structured binary data from r into data.
Data must be a pointer to a fixed-size value or a slice of fixed-size values. Write writes the binary representation of data into w. Data must be a fixed-size value or a slice of fixed-size values, or a pointer to such. I'm trying to write code to read a binary file into a buffer, then write the buffer to another file.
I have the following code, but the buffer only stores a couple of ASCII characters from the first line in .