Hi Everyone!
I am new to Elixir. I followed ElixirSchool and Elixir course at Pragmatic Studio. I also developed some toy Phoenix application. I mean I am familiar with the syntax (except the typespecs).
Right now i’m following The little Elixir & OTP Guidebook by @bentanweihao
The following code is really confusing. The writer has tried to explain it, but I didn’t get it, even if I am familiar with the Elixir syntax.
defmodule ID3Parser do
def parse(file_name) do
case File.read(file_name) do
{:ok, mp3} ->
mp3_byte_size = byte_size(mp3) - 128
# from here
<< _ :: binary-size(mp3_byte_size), id3_tag :: binary >> = mp3
<< "TAG", title :: binary-size(30),
artist :: binary-size(30),
album :: binary-size(30),
year :: binary-size(4),
_rest :: binary >> = id3_tag
# up to here
IO.puts "#{artist} - #{title} (#{album}, #{year})"
_ ->
IO.puts "Couldn't open #{file_name}"
end
end
end
I have marked the points with comment. The code which is confusing.
Would someone explain it in more detail?
Also when I ran the program on a sample mp3 file, it didn’t give me the result as
Some Artist - Some Song (Some Album, 2020)
:ok
but as
Some Artist^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@ - Some Song^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@ (Some Album^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@, 2020)
:ok
(The sample file I had didn’t have metadata, so I added the metadata (title, artist, album and year) through VLC).
Thank you!
