rust-hexdump: hexdump command written in Rust! 🦀

"display file contents in hexadecimal, decimal, octal, or ascii" - linux manpage

Usage

To run, provide the filepath and any options that you would like! Only a primitive set of options from hexdump are are provided, in particular:

-n, --length length
    Interpret only length bytes of input.
-x, --two-bytes-hex
    Two-byte hexadecimal display. Display the input offset in
    hexadecimal, followed by eight space-separated, four-column,
    zero-filled, two-byte quantities of input data, in
    hexadecimal, per line.
-d, --two-bytes-decimal
    Two-byte decimal display. Display the input offset in
    hexadecimal, followed by eight space-separated, five-column,
    zero-filled, two-byte units of input data, in unsigned
    decimal, per line.
-o, --two-bytes-octal
    Two-byte octal display. Display the input offset in
    hexadecimal, followed by eight space-separated, six-column,
    zero-filled, two-byte quantities of input data, in octal, per
    line.
-b, --one-byte-octal
    One-byte octal display. Display the input offset in
    hexadecimal, followed by sixteen space-separated,
    three-column, zero-filled bytes of input data, in octal, per
    line.
-c, --one-byte-char
    One-byte character display. Display the input offset in
    hexadecimal, followed by sixteen space-separated,
    three-column, space-filled characters of input data per line.

Example Usage:

❯ cargo run -- -n 42 -f examples/html.txt
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.07s
     Running `target/debug/rust-hexdump -n 42 -f html.txt`
0000000 6f59 2075 6163 276e 2074 6170 7372 2065
0000010 585b 485d 4d54 204c 6977 6874 7220 6765
0000020 7865 202e 6542 6163 7375
000002a

Implementation Notes

Some cool functionality that I wanted to feature in this implementation was the fact that you could print the hexadecimal, decimal, octal, or ascii representations of the file's bytes simultaneously, and in a specific noted order. For example:

❯ hexdump -b -x -c -n 32 examples/html.txt
0000000 131 157 165 040 143 141 156 047 164 040 160 141 162 163 145 040
0000000    6f59    2075    6163    276e    2074    6170    7372    2065
0000000   Y   o   u       c   a   n   '   t       p   a   r   s   e
0000010 133 130 135 110 124 115 114 040 167 151 164 150 040 162 145 147
0000010    585b    485d    4d54    204c    6977    6874    7220    6765
0000010   [   X   ]   H   T   M   L       w   i   t   h       r   e   g
0000020

At this point in time, I realized that I didn't have a way to retain the order of the options given with clap, so I ended up additionally using the Rust standard library to fetch and handle certain option flags while retaining their order, like -b, manually. The clap Args struct remains as to at least verify the syntax of the arguments passed into the CLI tool--it parses flags like -b but doesn't actually do anything with them. My implementation handles the above case by creating an iterator struct for each of the option flags given, namely ones like -b -x -c, and storing them in an array. Each of the iterators in my array is called in order to print each representation. A "fun" thing to note is that the same option flag can be used multiple times, for example -b -b, in which the octal representation would be doubly printed. Though all two-byte printing styles have practically the same semantics, for example TwoByteHexadecimal and TwoByteDecimal, and could be kept within one unified TwoByte struct, I chose to divide them into their own structs as to avoid an O(1) check within TwoByte's next() function when determining which numeric formatting to use. I based the output formatting from what I saw on my Macbook, so the output may differ from the actual hexdump command depending on the machine you're running it on.

Credits

The functionality of this tool is meant to mimic hexdump. Hence, many of the options and their explanations are taken directly from the manpage. In addition, examples/html.txt is a copy-paste of this notorious StackOverflow post and examples/bee_movie.txt is a copy-paste the "Bee Movie (2007)" script. All credits go to the original authors of these works.