Module: RSmaz

Defined in:

lib/rsmaz.rb

Overview

RSmaz is too small to bother splitting into separate files, so I’ll be lazy..

Constant Summary

VERSION =

'0.0.3'

CODEBOOK =

From github.com/antirez/smaz/blob/4b913924e15b7663ee0240af19cedfd266052aab/smaz.c

["\002s,\266", "\003had\232\002leW", "\003on \216", "", "\001yS",
"\002ma\255\002li\227", "\003or \260", "", "\002ll\230\003s t\277",
"\004fromg\002mel", "", "\003its\332", "\001z\333", "\003ingF", "\001>\336",
"\001 \000\003   (\002nc\344", "\002nd=\003 on\312",
"\002ne\213\003hat\276\003re q", "", "\002ngT\003herz\004have\306\003s o\225",
"", "\003ionk\003s a\254\002ly\352", "\003hisL\003 inN\003 be\252", "",
"\003 fo\325\003 of \003 ha\311", "", "\002of\005",
"\003 co\241\002no\267\003 ma\370", "", "", "\003 cl\356\003enta\003 an7",
"\002ns\300\001\"e", "\003n t\217\002ntP\003s, \205",
"\002pe\320\003 we\351\002om\223", "\002on\037", "", "\002y G", "\003 wa\271",
"\003 re\321\002or*", "", "\002=\"\251\002ot\337", "\003forD\002ou[",
"\003 toR", "\003 th\r", "\003 it\366",
"\003but\261\002ra\202\003 wi\363\002</\361", "\003 wh\237", "\002  4",
"\003nd ?", "\002re!", "", "\003ng c", "",
"\003ly \307\003ass\323\001a\004\002rir", "", "", "", "\002se_", "\003of \"",
"\003div\364\002ros\003ere\240", "", "\002ta\310\001bZ\002si\324", "",
"\003and\a\002rs\335", "\002rt\362", "\002teE", "\003ati\316", "\002so\263",
"\002th\021", "\002tiJ\001c\034\003allp", "\003ate\345", "\002ss\246",
"\002stM", "", "\002><\346", "\002to\024", "\003arew", "\001d\030",
"\002tr\303", "", "\001\n1\003 a \222", "\003f tv\002veo", "\002un\340", "",
"\003e o\242", "\002a \243\002wa\326\001e\002", "\002ur\226\003e a\274",
"\002us\244\003\n\r\n\247", "\002ut\304\003e c\373", "\002we\221", "", "",
"\002wh\302", "\001f,", "", "", "", "\003d t\206", "", "", "\003th \343",
"\001g;", "", "", "\001\r9\003e s\265", "\003e t\234", "", "\003to Y",
"\003e\r\n\236", "\002d \036\001h\022", "", "\001,Q", "\002 a\031", "\002 b^",
"\002\r\n\025\002 cI", "\002 d\245", "\002 e\253", "\002 fh\001i\b\002e \v",
"", "\002 hU\001-\314", "\002 i8", "", "", "\002 l\315", "\002 m{",
"\002f :\002 n\354", "\002 o\035", "\002 p}\001.n\003\r\n\r\250", "",
"\002 r\275", "\002 s>", "\002 t\016", "", "\002g \235\005which+\003whi\367",
"\002 w5", "\001/\305", "\003as \214", "\003at \207", "", "\003who\331", "",
"\001l\026\002h \212", "", "\002, $", "", "\004withV", "", "", "", "\001m-", "",
"", "\002ac\357", "\002ad\350", "\003TheH", "", "", "\004this\233\001n\t",
"", "\002. y", "", "\002alX\003e, \365", "\003tio\215\002be\\",
"\002an\032\003ver\347", "", "\004that0\003tha\313\001o\006", "\003was2",
"\002arO", "\002as.", "\002at'\003the\001\004they\200\005there\322\005theird",
"\002ce\210", "\004were]", "", "\002ch\231\002l \264\001p<", "", "",
"\003one\256", "", "\003he \023\002dej", "\003ter\270", "\002cou", "",
"\002by\177\002di\201\002eax", "", "\002ec\327", "\002edB", "\002ee\353", "",
"", "\001r\f\002n )", "", "", "", "\002el\262", "", "\003in i\002en3", "",
"\002o `\001s\n", "", "\002er\033", "\003is t\002es6", "", "\002ge\371",
"\004.com\375", "\002fo\334\003our\330", "\003ch \301\001t\003", "\002hab", "",
"\003men\374", "", "\002he\020", "", "", "\001u&", "\002hif", "",
"\003not\204\002ic\203", "\003ed @\002id\355", "", "", "\002ho\273",
"\002r K\001vm", "", "", "", "\003t t\257\002il\360", "\002im\342",
"\003en \317\002in\017", "\002io\220", "\002s \027\001wA", "", "\003er |",
"\003es ~\002is%", "\002it/", "", "\002iv\272", "",
"\002t #\ahttp://C\001x\372", "\002la\211", "\001<\341", "\003, a\224"]

REVERSE_CODEBOOK =

From github.com/antirez/smaz/blob/4b913924e15b7663ee0240af19cedfd266052aab/smaz.c

[" ", "the", "e", "t", "a", "of", "o", "and", "i", "n", "s", "e ", "r", " th",
" t", "in", "he", "th", "h", "he ", "to", "\r\n", "l", "s ", "d", " a", "an",
"er", "c", " o", "d ", "on", " of", "re", "of ", "t ", ", ", "is", "u", "at",
"   ", "n ", "or", "which", "f", "m", "as", "it", "that", "\n", "was", "en",
"  ", " w", "es", " an", " i", "\r", "f ", "g", "p", "nd", " s", "nd ", "ed ",
"w", "ed", "http://", "for", "te", "ing", "y ", "The", " c", "ti", "r ", "his",
"st", " in", "ar", "nt", ",", " to", "y", "ng", " h", "with", "le", "al", "to ",
"b", "ou", "be", "were", " b", "se", "o ", "ent", "ha", "ng ", "their", "\"",
"hi", "from", " f", "in ", "de", "ion", "me", "v", ".", "ve", "all", "re ",
"ri", "ro", "is ", "co", "f t", "are", "ea", ". ", "her", " m", "er ", " p",
"es ", "by", "they", "di", "ra", "ic", "not", "s, ", "d t", "at ", "ce", "la",
"h ", "ne", "as ", "tio", "on ", "n t", "io", "we", " a ", "om", ", a", "s o",
"ur", "li", "ll", "ch", "had", "this", "e t", "g ", "e\r\n", " wh", "ere",
" co", "e o", "a ", "us", " d", "ss", "\n\r\n", "\r\n\r", "=\"", " be", " e",
"s a", "ma", "one", "t t", "or ", "but", "el", "so", "l ", "e s", "s,", "no",
"ter", " wa", "iv", "ho", "e a", " r", "hat", "s t", "ns", "ch ", "wh", "tr",
"ut", "/", "have", "ly ", "ta", " ha", " on", "tha", "-", " l", "ati", "en ",
"pe", " re", "there", "ass", "si", " fo", "wa", "ec", "our", "who", "its", "z",
"fo", "rs", ">", "ot", "un", "<", "im", "th ", "nc", "ate", "><", "ver", "ad",
" we", "ly", "ee", " n", "id", " cl", "ac", "il", "</", "rt", " wi", "div",
"e, ", " it", "whi", " ma", "ge", "x", "e c", "men", ".com"]

Class Method Summary

• .compress(input) ⇒ Object

  Compress a string to Smaz encoding.

• .decompress(input) ⇒ Object

  Decompress a Smaz encoded string back to normal plain text.

Class Method Details

.compress(input) ⇒ Object

Compress a string to Smaz encoding

# File 'lib/rsmaz.rb', line 90

def self.compress(input)
  verb = ""
  out = ""
  input = input.dup
  
  # This algorithm has been ported to Ruby from C and only
  # slightly Rubyized.. still a lonnnng way to go. Wanna give it a crack?
  while (input && input.length > 0)
    h1 = h2 = input.ord << 3
    h2 += input[1,1].ord if (input.length > 1)
    h3 = (input.length > 2) ? h2 ^ input[2,1].ord : 0
    q = []

    [input.length, 7].min.downto(1) do |j|
      slot = if j == 1
        CODEBOOK[h1 % 241].dup
      elsif j == 2
        CODEBOOK[h2 % 241].dup
      else
        CODEBOOK[h3 % 241].dup
      end

      while (slot && slot[0]) do
        if (slot.ord == j && (slot[1,j] == input[0,j]))
          # Match found in hash table
          
          # Add verbatim data, if any (yes, it's quicker with the check)
          unless verb.empty?
            q << verb
            verb = ""
          end
          
          # Add encoded data and ditch unnecessary part of input string
          q << slot[slot.ord+1,1].ord
          input.slice!(0..j-1)
          break
        else
          # This in-place hack is quicker than slot = slot[1..-1]
          
          slot.reverse!.chop!.reverse!
          #slot.slice!(0)
          #slot[0] = ''
        end
      end
    end
    
    # No queue? It means we matched nothing, so add the current byte to the verbatim buffer
    if q.empty?
      verb << input[0,1] if input[0]
      input.slice!(0)
    end

    # If the verbatim buffer is getting too long or we're at the end of the doc
    # throw the verbatim buffer to the output queue
    q << verb if verb.length == 256 || (verb.length > 0 && input.length == 0)
 
    # Turn the queue into correctly encoded data
    out << q.collect do |item|
      if item.class == String && item.length == 1
        "\376" + item
      elsif item.class == String && item.length > 1
        "\377" + (item.length - 1).chr + item
      elsif item.class == Fixnum
        item.chr
      end
    end.join

  end

  out
end

.decompress(input) ⇒ Object

Decompress a Smaz encoded string back to normal plain text

# File 'lib/rsmaz.rb', line 163

def self.decompress(input)
  out = ""
  s = StringScanner.new(input)
  until s.eos?
    bv = s.get_byte.ord
    if (bv == 254) 
      out << s.get_byte
    elsif (bv == 255)
      len = s.get_byte.ord + 1
      len.times do 
        out << s.get_byte
      end
    else
      out << REVERSE_CODEBOOK[bv]
    end
  end
  
  out
end