added ufs, a tiny filesystem library for embedded systems

Embedded/ufs.lua

@@ -0,0 +1,92 @@
+fs = {}
+fs.mounts = {}
+
+-- basics
+function fs.segments(path)
+ local segments = {}
+ for segment in path:gmatch("[^/]+") do
+  segments[#segments+1] = segment
+ end
+ return segments
+end
+function fs.resolve(path)
+ local segments, rpath = fs.segments(path), "/"
+ for i = 2, #segments do
+  rpath = rpath .. segments[i] .. "/"
+ end
+ return segments[1],rpath
+end
+
+-- generate some simple functions
+for k,v in pairs({"makeDirectory","exists","isDirectory","list","lastModified","remove","size","spaceUsed","isReadOnly","getLabel"}) do
+ fs[v] = function(path)
+  local fsi,path = fs.resolve(path)
+  return fs.mounts[fsi][v](path)
+ end
+end
+
+local function fread(self,length)
+ if length == "*a" then
+  length = math.huge
+ end
+ local rstr, lstr = "", ""
+ repeat
+  lstr = fs.mounts[self.fs].read(self.fid,math.min(2^16,length-rstr:len())) or ""
+  rstr = rstr .. lstr
+ until rstr:len() == length or lstr == ""
+ return rstr
+end
+local function fwrite(self,data)
+ fs.mounts[self.fs].write(self.fid,data)
+end
+local function fclose(self)
+ fs.mounts[self.fs].close(self.fid)
+end
+
+function fs.open(path,mode)
+ mode = mode or "rb"
+ local fsi,path = fs.resolve(path)
+ if not fs.mounts[fsi] then return false end
+ local fid = fs.mounts[fsi].open(path,mode)
+ if fid then
+  local fobj = {["fs"]=fsi,["fid"]=fid,["close"]=fclose}
+  if mode:sub(1,1) == "r" then
+   fobj.read = fread
+  else
+   fobj.write = fwrite
+  end
+  return fobj
+ end
+ return false
+end
+
+function fs.copy(from,to)
+ local of = fs.open(from,"rb")
+ local df = fs.open(to,"wb")
+ if not of or not df then
+  return false
+ end
+ df:write(of:read("*a"))
+ df:close()
+ of:close()
+end
+
+function fs.rename(from,to)
+ local ofsi, opath = fs.resolve(from)
+ local dfsi, dpath = fs.resolve(to)
+ if ofsi == dfsi then
+  fs.mounts[ofsi].rename(opath,dpath)
+  return true
+ end
+ fs.copy(from,to)
+ fs.remove(from)
+ return true
+end
+
+fs.mounts.temp = component.proxy(computer.tmpAddress())
+if computer.getBootAddress then
+ fs.mounts.boot = component.proxy(computer.getBootAddress())
+end
+for addr, _ in component.list("filesystem") do
+ fs.mounts[addr:sub(1,3)] = component.proxy(addr)
+end