1 files changed, 61 insertions, 0 deletions
diff --git a/acf/path.lua b/acf/path.lua
new file mode 100644
index 0000000..9b709e9
--- /dev/null
+++ b/acf/path.lua
@@ -0,0 +1,61 @@
+--[[
+Copyright (c) 2012 Kaarle Ritvanen
+See LICENSE file for license details
+--]]
+
+module(..., package.seeall)
+
+require 'stringy'
+
+local function filter(func, tbl)
+   local res = {}
+   for k, v in pairs(tbl) do if func(v) then res[k] = v end end
+   return res
+end
+
+
+function is_absolute(path)
+   return string.sub(path, 1, 1) == '/'
+end
+
+function to_absolute(path, base)
+   if not is_absolute(path) then
+      path = base..(base ~= '/' and '/' or '')..path
+   end
+   local comps = split(path)
+   local i = 1
+   while i <= #comps do
+      if comps[i] == '..' then
+	 if i == 1 then error('Invalid path: '..path) end
+	 table.remove(comps, i - 1)
+	 table.remove(comps, i - 1)
+	 i = i - 1
+      else i = i + 1 end
+   end
+   return '/'..table.concat(comps, '/')
+end
+
+function join(p1, p2, ...)
+   if not p2 then return p1 end
+   if not is_absolute(p2) then p2 = '/'..p2 end
+   return join((p1 == '/' and '' or p1)..p2, unpack(arg))
+end
+
+function split(path)
+   -- assume absolute paths
+   assert(is_absolute(path))
+   if path == '/' then return {} end
+   return filter(function(s) return s > '' end,
+		 stringy.split(string.sub(path, 2, -1), '/'))
+end
+
+function parent(path)
+   local comps = split(path)
+   table.remove(comps)
+   return join('/', unpack(comps))
+end
+
+function name(path)
+   local comps = split(path)
+   return comps[#comps]
+end