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Added a rating function to tag2 #60

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c655629
Added a rating function to tag2
dkniffin Jul 31, 2015
fa78fc0
Fixed a bug with undefined ratings
dkniffin Jul 31, 2015
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106 changes: 77 additions & 29 deletions lib/mp3info/id3v2.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@ class ID3v2Error < StandardError ; end
# It works like a hash, where key represents the tag name as 3 or 4 upper case letters
# (respectively related to 2.2 and 2.3+ tag) and value represented as array or raw value.
# Written version is always 2.3.
class ID3v2 < DelegateClass(Hash)
class ID3v2 < DelegateClass(Hash)

TAGS = {
"AENC" => "Audio encryption",
"APIC" => "Attached picture",
Expand Down Expand Up @@ -168,17 +168,17 @@ class ID3v2 < DelegateClass(Hash)

# In Ruby 2.1.0 (and possibly others), DelegateClass breaks Kernel methods.
include Kernel

# this is the position in the file where the tag really ends
attr_reader :io_position

# :+lang+: for writing comments
#
# [DEPRECATION] :+encoding+: one of the string of +TEXT_ENCODINGS+,
# [DEPRECATION] :+encoding+: one of the string of +TEXT_ENCODINGS+,
# use of :encoding parameter is DEPRECATED. In ruby 1.8, use utf-8 encoded strings for tags.
# In ruby >= 1.9, strings are automatically transcoded from their originaloriginal encoding.
attr_reader :options

# possible options are described above ('options' attribute)
# you can access this object like an hash, with [] and []= methods
# special cases are ["disc_number"] and ["disc_total"] mirroring TPOS attribute
Expand Down Expand Up @@ -208,7 +208,7 @@ def parsed?
def changed?
@hash_orig != @hash
end

# full version of this tag (like "2.3.0") or nil
# if tag was not correctly read
def version
Expand Down Expand Up @@ -237,14 +237,14 @@ def to_inspect_hash
end

### ID3V2::add_picture
### Takes an image string as input and writes it with header.
### Takes an image string as input and writes it with header.
### Mime type is automatically guessed by default.
### It is possible but not necessary to include:
### :pic_type => 0 - 14 (see http://id3.org/id3v2.3.0#Attached_picture)
### :mime => 'gif'
### :mime => 'gif'
### :description => "Image description"
def add_picture(data, opts = {})
options = {
options = {
:pic_type => 0,
:mime => nil,
:description => "image"
Expand Down Expand Up @@ -282,15 +282,15 @@ def pictures
apic_images.each_index do |index|
pic = apic_images[index]
next if !pic.is_a?(String) or pic == ""
pic.force_encoding 'BINARY'
pic.force_encoding 'BINARY'
picture = []
jpg = Regexp.new("jpg|JPG|jpeg|JPEG".force_encoding("BINARY"),
Regexp::FIXEDENCODING )
png = Regexp.new("png|PNG".force_encoding("BINARY"),
Regexp::FIXEDENCODING )
header = pic.unpack('a120').first.force_encoding "BINARY"
mime_pos = 0

# safest way to correctly extract jpg and png is finding mime
if header.match jpg
mime = "jpg"
Expand Down Expand Up @@ -325,18 +325,18 @@ def pictures

if mime == "jpg"
# inspect jpg image header (first 10 chars) for "\xFF\x00" (expect "\xFF")
trailing_null_byte = Regexp.new("(\377)(\000)".force_encoding('BINARY'),
trailing_null_byte = Regexp.new("(\377)(\000)".force_encoding('BINARY'),
Regexp::FIXEDENCODING)
if (data =~ trailing_null_byte) < 10
data.gsub!(trailing_null_byte, "\xff".force_encoding('BINARY'))
end
end

desc = "%02i_#{desc[0,25]}" % (index + 1)

filename = desc.match("#{mime}$") ? desc : "#{desc}.#{mime}"
filename.gsub!('/','')

picture[0] = filename
picture[1] = data
result << picture
Expand All @@ -347,12 +347,27 @@ def pictures
def inspect
self.to_inspect_hash
end

def remove_pictures
self["APIC"] = ""
self["PIC"] = ""
end

### Parses the POPM field, and returns a Float, or nil, given the rating scheme
def rating(scheme=:mm)
rating_raw = split_popm(self["POPM"])[1]
return "ERROR: Invalid rating" if ! (rating_raw.nil? || rating_raw.integer?)
case scheme
when :mm # MediaMonkey
mm_rating(rating_raw)
when :wmp # Windows Media Player
wmp_rating(rating_raw)
else
puts "ERROR: Unknown rating scheme"
return nil
end
end

### gets id3v2 tag information from io object (must support #seek() method)
def from_io(io)
@io = io
Expand All @@ -363,7 +378,7 @@ def from_io(io)
raise(ID3v2Error, "can't find version_maj ('#{version_maj}')") unless [2, 3, 4].include?(version_maj)
@version_maj, @version_min = version_maj, version_min
@tag_length = @io.get_syncsafe

@parsed = true
begin
case @version_maj
Expand Down Expand Up @@ -430,6 +445,40 @@ def to_bin

private

def split_popm(popm)
# NOTE: this does not support ratings for multiple users
popm.nil? ? [nil,nil,nil] : popm.unpack('Z*Cl')
end

def mm_rating(raw)
case raw
when 0 then 0.0
when 1 then 1.0
when 64 then 2.0
when 128 then 3.0
when 196 then 4.0
when 255 then 5.0
when (2..31) then 0.5
when (32..63) then 1.5
when (65..127) then 2.5
when (129..195) then 3.5
when (197..254) then 4.5
else nil
end
end

def wmp_rating(raw)
case raw
when 0 then 0.0
when (1..31) then 1.0
when (32..95) then 2.0
when (96..159) then 3.0
when (160..223) then 4.0
when (224..255) then 5.0
else nil
end
end

def encode_tag(name, value)
puts "encode_tag(#{name.inspect}, #{value.inspect})" if $DEBUG
name = name.to_s
Expand Down Expand Up @@ -501,7 +550,7 @@ def decode_tag(name, raw_value)
else
r = Regexp.new("\x00*$".encode(out.encoding))
end
out.sub!(r, '')
out.sub!(r, '')
end

return out
Expand All @@ -519,7 +568,7 @@ def read_id3v2_3_frames
@io.seek(-4, IO::SEEK_CUR) # 1. find a padding zero,
seek_to_v2_end
break
else
else
if @version_maj == 4
size = @io.get_syncsafe
else
Expand All @@ -531,7 +580,7 @@ def read_id3v2_3_frames
end
break if @io.pos >= @tag_length # 2. reach length from header
end
end
end

### reads id3 ver 2.2.x frames and adds the contents to @tag2 hash
### NOTE: the id3v2 header does not take padding zero's into consideration
Expand All @@ -548,8 +597,8 @@ def read_id3v2_2_frames
break if @io.pos >= @tag_length
end
end
end
end

### Add data to tag2["name"]
### read lang_encoding, decode data if unicode and
### create an array if the key already exists in the tag
Expand All @@ -559,11 +608,11 @@ def add_value_to_tag2(name, size)
if size > 50_000_000
raise ID3v2Error, "tag size is > 50_000_000"
end

data_io = @io.read(size)
data = decode_tag(name, data_io)
if data && !data.empty?
if self.keys.include?(name)
if self.keys.include?(name)
if self[name].is_a?(Array)
unless self[name].include?(data)
self[name] << data
Expand All @@ -572,7 +621,7 @@ def add_value_to_tag2(name, size)
self[name] = [ self[name], data ]
end
else
self[name] = data
self[name] = data
end

if name == "TPOS" && data =~ /(\d+)\s*\/\s*(\d+)/
Expand All @@ -583,7 +632,7 @@ def add_value_to_tag2(name, size)

puts "self[#{name.inspect}] = #{self[name].inspect}" if $DEBUG
end

### runs thru @file one char at a time looking for best guess of first MPEG
### frame, which should be first 0xff byte after id3v2 padding zero's
def seek_to_v2_end
Expand All @@ -592,17 +641,16 @@ def seek_to_v2_end
end
@io.seek(-1, IO::SEEK_CUR)
end

### convert an 32 integer to a syncsafe string
def to_syncsafe(num)
( (num<<3) & 0x7f000000 ) + ( (num<<2) & 0x7f0000 ) + ( (num<<1) & 0x7f00 ) + ( num & 0x7f )
end

### this is especially useful for printing out APIC data because
### only the header of the APIC tag is of interest
def pretty_header(str, chars=128)
"#{str.unpack("a#{chars}").first}<<<...snip...>>>".inspect[1..-2]
end

end