Module: Base91

Defined in:
lib/base91.rb,
lib/base91/version.rb

Constant Summary collapse

AVERAGE_ENCODING_RATIO = 
1.2297
ENCODING_TABLE = 
[
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
    'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
    'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '!', '#', '$', '%',
     '&', '(', ')', '*', '+', ',', '.', '/', ':', ';','<', '=',
     '>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~',
    '"'
]
DECODING_TABLE = 
[
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 62, 90, 63, 64, 65, 66, 91, 67, 68, 69, 70, 71, 91, 72, 73,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 74, 75, 76, 77, 78, 79,
    80,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 81, 91, 82, 83, 84,
    85, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 86, 87, 88, 89, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
    91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91
]
VERSION = 
"0.0.1"

Class Method Summary collapse

Class Method Details

.decode(data) ⇒ Object 



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# File 'lib/base91.rb', line 116

def self.decode data
    len = data.length
    estimated_size = (len / AVERAGE_ENCODING_RATIO).to_i | 0
    dbq = 0
    dn = 0
    dv = -1
    i = 0
    o = -1
    byte = 0
    output = Array.new(estimated_size) ##check here
    if data.is_a? String
        (0..len-1).each do |i|
            byte = data[i].ord
            if DECODING_TABLE[byte] != 91
                if dv == -1
                    dv = DECODING_TABLE[byte]
                else
                    dv+=(DECODING_TABLE[byte] * 91)
                    dbq =  dbq | (dv << dn)
                    if dv & 8191 > 88
                        dn+=13
                    else
                        dn+=14
                    end
                    loop do 
                        if ((o+=1) > estimated_size)
                            output << (dbq & 0xFF)
                        else
                            output[o] = dbq & 0xFF
                        end
                        dbq = dbq >> 8
                        dn-=8
                        break if dn<=7
                    end
                    dv = -1
                end
            end 
        end
    else
        (0..len-1).each do |i|
            byte = data[i]
            if DECODING_TABLE[byte] != 91
                if dv == -1
                    dv =DECODING_TABLE[byte]
                else
                    dv += (DECODING_TABLE[byte] * 91)
                    dbq = dbq | dv << dn
                    if (dv & 8191) > 88
                        dn += 13
                    else
                        dn += 14
                    end
                    loop do 
                        if ((o+=1) > estimated_size)
                            output << (dbq & 0xFF)
                        else
                            output[o] = (dbq & 0xFF)
                        end
                        dbq = dbq >> 8
                        dn-=8
                        break if dn<=7
                    end
                    dv = -1
                end
            end
        end
    end
    if dv != -1
        if (o+=1) >= estimated_size
            output << (dbq | dv << dn)
        else
            output[o] = (dbq | dv << dn)
        end
    end
    if o > -1 && o < estimated_size -1
        output = output[0..o+1]
    end
    return output.map(&:chr).join("")
end

.encode(data) ⇒ Object 



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# File 'lib/base91.rb', line 35

def self.encode data
    len = data.length
    output = ''
    ebq = 0
    en = 0
    ev = 0
    j = 0
    byte = 0
    lenj = 0

    if data.is_a? String
        (0..len-1).each do |i|
            byte = data[i].ord
            if byte < 128
                lenj = 1
            elsif byte > 127 && byte < 2048
                lenj = 2
            else
                lenj = 3
            end
            for j in 0..lenj-1
                if lenj == 1
                    ebq = ebq | byte << en
                elsif lenj == 2
                    if j == 0
                        ebq = ebq | (((byte >> 6) | 192)) << en
                    else
                        ebq = ebq | ((byte & 63) | 128) << en
                    end
                else
                    if j == 0
                        ebq = ebq | (((byte >> 12) | 224) << en)
                    elsif j == 1
                        ebq = ebq | ((((byte >> 6) & 63) | 128) << en)
                    else
                        ebq = ebq | (((byte & 63) | 128) << en)
                    end                
                end
            end
            en+=8
            if en > 13
                ev = ebq & 8191
                if ev > 88
                    ebq = ebq >> 13
                    en-=13
                else
                    ev = ebq & 16383
                    ebq = ebq >> 14
                    ebq-=14
                end
                output << "#{ENCODING_TABLE[ev%91]}#{ENCODING_TABLE[(ev/91) | 0]}"
            end
        end
    else
        (0..len-1).each do |i|
            ebq = ebq | (data[i] & 255) << en
            en += 8
            if en > 13
                ev = ebq & 8191
                if ev > 88
                    ebq = eqb >> 13
                    en -= 13
                else
                    ev = ebq & 16383
                    ebq = ebq >> 14
                    en -= 14                    
                end
                output << "#{ENCODING_TABLE[ev%91]}#{ENCODING_TABLE[(ev/91) | 0]}"
            end
        end
    end

    if en > 0 
        output+= ENCODING_TABLE[ebq % 91]
        if en > 7 || ebq > 90
            output << ENCODING_TABLE[(ebq / 91) | 0]
        end
    end
    return output
end