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 Tokenize a string.
  81 Parameters:
  82   s .. String to tokenize
  83   p .. Pattern (e.g. "[%w-_]+")
  84 Returns:
  85   An array of tokens.
  86 ]]--
  87 function M.tokenize(s, p)
  88   return s:gmatch(p)
  89 end
  90
  91 --[[
  92 Decode a string.
  93 Parameters:
  94   s .. String to decode
  95 Returns:
  96   Decoded string.
  97 ]]--
  98 function M.decode(s) -- http://www.lua.org/pil/20.3.html
  99   r = {}
 100   for n,v in s:gmatch ("([^&=]+)=([^&=]+)") do
 101     n = M.unescape(n)
 102     r[n] = v
 103   end
 104   return r
 105 end
 106
 107 --[[
 108 Unescape a string.
 109 Parameters:
 110   s .. String to unescape
 111 Returns:
 112   Unescaped string
 113 ]]--
 114 function M.unescape(s) -- http://www.lua.org/pil/20.3.html
 115   s = s:gsub('+', ' ')
 116   return (s:gsub('%%(%x%x)',
 117             function(h)
 118               return string.char(tonumber(h, 16))
 119             end))
 120 end
 121
 122 --[[
 123 Unescape slashed string.
 124 Parameters:
 125   s .. String to unescape
 126 Returns:
 127   Unescaped string
 128 ]]--
 129 function M.slash_unescape(s)
 130   return (s:gsub('\\(.)', '%1'))
 131 end
 132
 133 --[[
 134 Trim a string removing leading and trailing whitespace.
 135 Parameters:
 136   s .. String to trim
 137 Returns:
 138   The trimmed string.
 139 ]]--
 140 function M.trim(s)
 141   s = s:gsub('^%s+(.)', '%1')
 142   return s:gsub('(.)%s+$', '%1')
 143 end
 144
 145 --[[
 146 Tokenize a string.
 147 Parameters:
 148   s   .. String to tokenize
 149   sep .. Separator
 150 Returns:
 151   Tokenized items in a table.
 152 ]]--
 153 function M.tokenize(s,sep) -- Based on http://lua-users.org/wiki/SplitJoin
 154   local sep, fields = sep or ':', {}
 155   local pattern = string.format('([^%s]+)', sep)
 156                     s:gsub(pattern, function(c) fields[#fields+1] = c
 157                   end)
 158   return fields
 159 end
 160
 161 -- Uncomment to test
 162 --[[
 163 package.path = package.path .. ';../?.lua'
 164 for _,v in pairs(M.tokenize('a,b,c,d,e',',')) do print(v) end
 165 ]]--
 166
 167 return M
 168
 169 -- vim: set ts=2 sw=2 tw=72 expandtab: