String Library In Lua

 -- basic tests of stringinlua.lua
 
 local S = require "stringinlua"
 
 -- a few example table array interfaces
 local TA = require "tablearray"
 local FA = require "filearray"
 local SA = require "stringarray"
 
 local function tuple(...) return {n=select('#',...), ...} end
 
 -- test on array of chars
 local s1 = TA'abc123def{45}'
 assert(S.match(s1, SA'%d%a') == TA'3d')
 assert(S.match(s1, SA'%d(%a)') == TA'd')
 assert(S.match(s1, SA'%b{}') == TA'{45}')
 assert(S.match(TA'23', SA'2') == TA'2')
 assert(S.sub(s1,1,1) == TA'a')
 assert(S.sub(s1,1,-1) == s1)
 assert(S.len(s1) == 13)
 
 -- test on file array
 -- Run test on Lua 5.1.4 manual (from Lua distribution).
 local s = FA 'manual.html'
 if s then
   --print(s)
   assert(S.match(s,TA'block ::= (%w+)') == 'chunk')
   assert(S.match(s,TA'(%b<>)setfenv') == '<code>')
   s:close()
 else
   print 'WARNING: manual.html not tested'
 end
 
 -- test on array of non-chars
 assert(S.match(TA{2,false,"test","test",2}, TA{false,"test", '+'})
  == TA{false,"test", "test"})
 
 -- Replace Lua functions with reimplementations.
 -- and then run tests from Lua 5.1. test suite
 -- http://www.inf.puc-rio.br/~roberto/lua/lua5.1-tests.tar.gz
 function string.find(s1, s2, init, plain)
   return S.find(SA(s1), SA(s2), init, plain)
 end
 function string.match(s1, s2, init)
   return S.match(SA(s1), SA(s2), init)
 end
 function string.sub(s, a, b)
   return S.sub(SA(s), a, b)
 end
 function string.len(s)
   return S.len(SA(s))
 end
 local f = loadfile 'strings.lua'
 if f then f() else print 'WARNING: strings.lua not tested' end
 local f = loadfile 'pm.lua'
 if f then f() else print 'WARNING: pm.lua not tested' end
 
 print'DONE'
 

 -- stringarray.lua - string with array-like interface.
 --
 -- Example:
 --   local SA = require 'stringarray'
 --   local s = SA 'test'
 --   assert(s[3] == 's') -- access third element
 
 
 local string_sub = string.sub
 
 local mt = {}
 function mt:__tostring() return self.s end
 function mt.__eq(a,b) return a.s == b.s end
 function mt:__len() return #self.s end
 function mt:__substring(sb,se) return string_sub(self.s,sb,se) end
 function mt:__index(i)
   return i <= #self.s and string_sub(self.s, i, i) or nil
 end
 
 local function new(s)
   assert(type(s) == 'string')
   return setmetatable({s=s}, mt)
 end
 
 return new
 

 -- tablearray.lua - table with array-like interface.
 --
 -- Example:
 --   local TA = require 'tablearray'
 --   local s = TA {'t', 'e', 's', 't'}
 --   assert(s[3] == 's') -- access third element
 --   local s = TA 'test' -- equivalent to above
 --   assert(s[3] == 's') -- access third element
 
 
 local string_sub = string.sub
 local table_concat = table.concat
 
 local mt = {}
 function mt:__tostring()
   local ts = {}
   for i=1,self.n do ts[#ts+1] = tostring(self[i]) end
   return table_concat(ts)
 end
 function mt.__eq(a,b)
   if a.n ~= b.n then return false end
   for i=1,a.n do
     if a[i] ~= b[i] then return false end
   end
   return true
 end
 function mt:__len()
   return self.n
 end
 function mt.__substring(bs,sb,se)
   local str = setmetatable({}, mt)
   local l = se-sb+1
   for p=1,l do str[p] = bs[sb+p-1] end
   str.n = l
   return str
 end
 
 local function new(s)
   local self
   if type(s) == 'string' then  -- convenience
     self = setmetatable({}, mt)
     for i=1,#s do self[i] = string_sub(s, i, i) end
     self.n = #s
   elseif type(s) == 'table' then
     self = setmetatable(s, mt)
     self.n = #s
   else
     assert(false)
   end
   return self
 end
 
 return new
 

 -- filearray.lua - file with array-like interface.
 --
 -- Example:
 --   local FA = require 'filearray'
 --   local s = FA 'manual.html'
 --   print(s[100]) -- print 100th byte of file
 --   s:close()
 --
 -- Note: access is buffered.
 
 local SZBLOCK = 1024
 
 local string_sub = string.sub
 local table_concat = table.concat
 local tostring = tostring
 
 local mt = {}
 function mt:__tostring()
   local ts = {}
   for i=1,self.n do ts[#ts+1] = tostring(self[i]) end
   return table_concat(ts)
 end
 function mt.__eq(a,b)
   if a.n ~= b.n then return false end
   for i=1,a.n do
     if a[i] ~= b[i] then return false end
   end
   return true
 end
 function mt:__len() return self.n end
 function mt:__index(i)
   i = i - 1
   local ipos = i % SZBLOCK
   local iblock = (i - ipos) / SZBLOCK
   if self.iblock ~= iblock then
     self.fh:seek('set', iblock * SZBLOCK)
     self.block = self.fh:read(SZBLOCK)
     self.iblock = iblock
   end
   return string_sub(self.block, ipos+1, ipos+1)
 end
 function mt.__substring(bs,sb,se)
   local str = {}
   for p=1,se-sb+1 do str[p] = bs[sb+p-1] end
   return table_concat(str, '')
 end
 
 local function new(s)
   local self = setmetatable({block=false, iblock=false}, mt)
   if type(s) == 'string' then  -- convenience
     local fh, msg = io.open(s, 'rb')
     if not fh then return nil, msg end
     self.fh = fh
     self.n = self.fh:seek("end")
     self.owned = true
   elseif io.type(s) == 'file' then
     self.fh = s
     self.n = self.fh:seek("end")
     self.owned = false
   else
     assert(false)
   end
   function self:close()
     if self.owned then self.fh:close() end
     self.fh = nil
     self.owned = false
   end
   return self
 end
 
 
 return new
 

 -- performance test
 
 local isreplaced = true  -- replace string library implementation
 local isprofile = true   -- enable profiler
 local N = 1              -- number of iterations
 
 if isreplaced then
   local S = require 'stringinlua'
   local SA = require 'stringarray'
   function string.find(s1, s2, init, plain)
     return S.find(SA(s1), SA(s2), init, plain)
   end
   function string.match(s1, s2, init)
     return S.match(SA(s1), SA(s2), init)
   end
   function string.sub(s, a, b)
     return S.sub(SA(s), a, b)
   end
   function string.len(s)
     return S.len(SA(s))
   end
 end
 
 local prof
 if isprofile then
   require "profiler"  -- http://lua-users.org/wiki/PepperfishProfiler
   prof = newProfiler()
   prof:start()
 end
 
 for i=1,N do
   dofile 'pm.lua'  -- from Lua 5.1 test suite
 end
 
 if isprofile then
   prof:stop()
   local outfile = io.open( "profile.txt", "w" )
   prof:report( outfile )
   outfile:close()
 end