share/common/quvi/util.lua

   1 -- libquvi-scripts
   2 -- Copyright (C) 2010-2013  Toni Gundogdu <legatvs@gmail.com>
   3 --
   4 -- This file is part of libquvi-scripts <http://quvi.sourceforge.net/>.
   5 --
   6 -- This program is free software: you can redistribute it and/or
   7 -- modify it under the terms of the GNU Affero General Public
   8 -- License as published by the Free Software Foundation, either
   9 -- version 3 of the License, or (at your option) any later version.
  10 --
  11 -- This program is distributed in the hope that it will be useful,
  12 -- but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 -- GNU Affero General Public License for more details.
  15 --
  16 -- You should have received a copy of the GNU Affero General
  17 -- Public License along with this program.  If not, see
  18 -- <http://www.gnu.org/licenses/>.
  19 --
  20
  21 local M = {}
  22
  23 --[[
  24 Check whether a string A ends with string B.
  25 Parameters:
  26   a .. String A
  27   b .. String B
  28 Returns:
  29   true if string A ends with string B.
  30 ]]--
  31 function M.ends_with(a, b) -- http://lua-users.org/wiki/StringRecipes
  32   return a:sub(-#b) == b
  33 end
  34
  35 --[[
  36 Compare quality properties of two media entities. Compares the height, then
  37 the width, followed by the bitrate property comparison (if it is set).
  38 Parameters:
  39   a .. Media entity A
  40   b .. Media entity B
  41 Returns:
  42   true if entity A is the higher quality, otherwise false.
  43 ]]--
  44 function M.is_higher_quality(a, b)
  45   if a.height > b.height then
  46     if a.width > b.width then
  47       if a['bitrate'] then -- Optional
  48         if a.bitrate > b.bitrate then return true end
  49       else
  50         return true
  51       end
  52     end
  53   end
  54   return false
  55 end
  56
  57 --[[
  58 Compare quality properties of two media entities. Compares the height, then
  59 the width, followed by the bitrate property comparison (if it is set).
  60 Parameters:
  61   a .. Media entity A
  62   b .. Media entity B
  63 Returns:
  64   true if entity A is the lower quality, otherwise false.
  65 ]]--
  66 function M.is_lower_quality(a, b)
  67   if a.height < b.height then
  68     if a.width < b.width then
  69       if a['bitrate'] then -- Optional
  70         if a.bitrate < b.bitrate then return true end
  71       else
  72         return true
  73       end
  74     end
  75   end
  76   return false
  77 end
  78
  79 --[[
  80 Decode a string.
  81 Parameters:
  82   s .. String to decode
  83 Returns:
  84   Decoded string.
  85 ]]--
  86 function M.decode(s) -- http://www.lua.org/pil/20.3.html
  87   r = {}
  88   for n,v in s:gmatch("([^&=]+)=([^&=]+)") do
  89     n = M.unescape(n)
  90     r[n] = v
  91   end
  92   return r
  93 end
  94
  95 --[[
  96 Unescape a string.
  97 Parameters:
  98   s .. String to unescape
  99 Returns:
 100   Unescaped string
 101 ]]--
 102 function M.unescape(s) -- http://www.lua.org/pil/20.3.html
 103   s = s:gsub('+', ' ')
 104   return (s:gsub('%%(%x%x)',
 105             function(h)
 106               return string.char(tonumber(h, 16))
 107             end))
 108 end
 109
 110 --[[
 111 Unescape slashed string.
 112 Parameters:
 113   s .. String to unescape
 114 Returns:
 115   Unescaped string
 116 ]]--
 117 function M.slash_unescape(s)
 118   return (s:gsub('\\(.)', '%1'))
 119 end
 120
 121 --[[
 122 Trim a string removing leading and trailing whitespace.
 123 Parameters:
 124   s .. String to trim
 125 Returns:
 126   The trimmed string.
 127 ]]--
 128 function M.trim(s)
 129   s = s:gsub('^%s+(.)', '%1')
 130   return s:gsub('(.)%s+$', '%1')
 131 end
 132
 133 --[[
 134 Tokenize a string.
 135 Parameters:
 136   s   .. String to tokenize
 137   sep .. Separator
 138 Returns:
 139   Tokenized items in a table.
 140 ]]--
 141 function M.tokenize(s,sep) -- Based on http://lua-users.org/wiki/SplitJoin
 142   local sep, fields = sep or ':', {}
 143   local pattern = string.format('([^%s]+)', sep)
 144                     s:gsub(pattern, function(c) fields[#fields+1] = c
 145                   end)
 146   return fields
 147 end
 148
 149 -- Uncomment to test
 150 --[[
 151 package.path = package.path .. ';../?.lua'
 152 for _,v in pairs(M.tokenize('a,b,c,d,e',',')) do print(v) end
 153 ]]--
 154
 155 return M
 156
 157 -- vim: set ts=2 sw=2 tw=72 expandtab: