From 45bf02a843fb221f77c888cafb7294aa3f3d3eb8 Mon Sep 17 00:00:00 2001
From: XeonSquared <redtailedairways@gmail.com>
Date: Sun, 1 Oct 2023 13:40:26 +1000
Subject: [PATCH] rtfs v1 adding fragmentation. restructure the rtfs libraries,
 for reasons that will become clear.

---
 .../rtfs.lua => rtfs-v0/lib/fs/rtfs/v0.lua    |  49 +-
 rtfs-v0/package.cfg                           |   3 +
 rtfs/lib/fs/rtfs/init.lua                     |  66 +++
 rtfs/lib/fs/rtfs/v1.lua                       | 508 ++++++++++++++++++
 4 files changed, 582 insertions(+), 44 deletions(-)
 rename rtfs/lib/rtfs.lua => rtfs-v0/lib/fs/rtfs/v0.lua (93%)
 create mode 100644 rtfs-v0/package.cfg
 create mode 100644 rtfs/lib/fs/rtfs/init.lua
 create mode 100644 rtfs/lib/fs/rtfs/v1.lua

diff --git a/rtfs/lib/rtfs.lua b/rtfs-v0/lib/fs/rtfs/v0.lua
similarity index 93%
rename from rtfs/lib/rtfs.lua
rename to rtfs-v0/lib/fs/rtfs/v0.lua
index 40aeb6e..1736c14 100644
--- a/rtfs/lib/rtfs.lua
+++ b/rtfs-v0/lib/fs/rtfs/v0.lua
@@ -1,6 +1,5 @@
-local rtfs, internal = {}, {}
-local proxy = {}
-proxy.cacheSize = 8
+local common = require "fs.rtfs"
+local rtfs, proxy = {}, setmetatable({},{__index=common.proxy})
 local ieformat = ">BI8I8c47" -- ftype, start, len, name
 local iesize = string.packsize(ieformat)
 local sbformat = ">c4I2I8c18" -- "rtfs" magic, version, index size in entries, label. label length subject to change.
@@ -18,9 +17,7 @@ function proxy:log(message,level)
 end
 
 -- data mangling functions
-local function fnormalize(s)
- return table.concat(fs.segments(s),"/")
-end
+local fnormalize = common.fnormalize
 function proxy:cSOI(n)
  n=n-1
  local ms = self.capacity / self.blockSize
@@ -31,42 +28,6 @@ function proxy:cSOI(n)
  return ms - s, so+1, eo
 end
 
--- just for ease-of-use
-local function getProxy(addr)
- if type(addr) == "string" then
-  return component.proxy(component.get(addr,"partition") or component.get(addr) or addr)
- end
- return addr
-end
-
--- cache stuff
-function proxy:cacheClean()
- while #self.cache > self.cacheSize do
-  table.remove(self.cache, 1)
- end
-end
-function proxy:cachedRead(s)
- for k,v in ipairs(self.cache) do
-  if v[1] == s then
-   self.cacheHits = self.cacheHits + 1
-   return v[2]
-  end
- end
- self.cache[#self.cache + 1] = {s, self.d.readSector(s)}
- self.cacheMisses = self.cacheMisses + 1
- return self.cache[#self.cache][2]
-end
-function proxy:cachedWrite(s,d)
- for k,v in ipairs(self.cache) do
-  if v[1] == s then
-   table.remove(self.cache, k)
-  end
- end
- self.cache[#self.cache + 1] = {s, d}
- self:cacheClean()
- return self.d.writeSector(s,d)
-end
-
 -- superblock stuff
 function proxy:updateSB()
  self:cachedWrite(1,string.pack(sbformat, "rtfs", 0, self.isize, self.label))
@@ -412,7 +373,7 @@ end
 ----------
 
 function rtfs.mount(d)
- d=getProxy(d)
+ d=common.getProxy(d)
  local p = setmetatable({}, {__index=proxy})
  local magic, version, isize, label = string.unpack(sbformat,d.readSector(1))
  assert(magic == "rtfs", "incorrect magic")
@@ -536,7 +497,7 @@ function rtfs.mount(d)
 end
 
 function rtfs.format(d,label)
- d=getProxy(d)
+ d=common.getProxy(d)
  print(d.address)
  d.writeSector(1, string.pack(sbformat,"rtfs", 0, 1, label or ""))
  rtfs.mount(d):writeIEntry(1, ftypes.empty, 2, (d.getCapacity() / d.getSectorSize()) - 2, "")
diff --git a/rtfs-v0/package.cfg b/rtfs-v0/package.cfg
new file mode 100644
index 0000000..f43856e
--- /dev/null
+++ b/rtfs-v0/package.cfg
@@ -0,0 +1,3 @@
+{["name"]="rtfs-v0",
+ ["description"]="RT-11 filesystem clone",
+ ["authors"]="Izaya"}
diff --git a/rtfs/lib/fs/rtfs/init.lua b/rtfs/lib/fs/rtfs/init.lua
new file mode 100644
index 0000000..a037187
--- /dev/null
+++ b/rtfs/lib/fs/rtfs/init.lua
@@ -0,0 +1,66 @@
+local cache = (package.loaded["fs.rtfs"] or {}).cache or {hitsR=0, hitsW=0, missesR=0, missesW=0}
+local proxy = {}
+local rtfs = {proxy=proxy, cache=cache}
+local sbformat = ">c4I2I8c18" -- "rtfs" magic, version, index size in entries, label. label length subject to change.
+
+rtfs.cacheSize = computer.totalMemory() // 1024 // 16
+
+-- data mangling functions
+function rtfs.fnormalize(s)
+ return table.concat(fs.segments(s),"/")
+end
+function proxy:log(message,level)
+ syslog(message,level or syslog.debug,"rtfs:"..self.label)
+end
+
+
+-- just for ease-of-use
+function rtfs.getProxy(addr)
+ if type(addr) == "string" then
+  return component.proxy(component.get(addr,"partition") or component.get(addr) or addr)
+ end
+ return addr
+end
+
+-- cache stuff
+local function cacheClean()
+ while #cache > rtfs.cacheSize do
+  table.remove(cache, 1)
+ end
+end
+function proxy:cachedRead(s)
+ for k,v in ipairs(cache) do
+  if v[1] == self.d.address and v[2] == s then
+   rtfs.cache.hitsR = rtfs.cache.hitsR + 1
+   return v[3]
+  end
+ end
+ cache[#cache + 1] = {self.d.address, s, self.d.readSector(s)}
+ rtfs.cache.missesR = rtfs.cache.missesR + 1
+ cacheClean()
+ return cache[#cache][3]
+end
+function proxy:cachedWrite(s,d)
+ for k,v in ipairs(cache) do
+  if v[1] == self.d.address and v[2] == s then
+   table.remove(cache, k)
+  end
+ end
+ cache[#cache + 1] = {self.d.address, s, d}
+ cacheClean()
+ return self.d.writeSector(s,d)
+end
+
+function rtfs.mount(a)
+ local d = rtfs.getProxy(a)
+ local magic, version = string.unpack(sbformat, d.readSector(1))
+ assert(magic == "rtfs","not an rtfs filesystem")
+ local w, l = pcall(require, string.format("fs.rtfs.v%i", version))
+ if w then return l.mount(a) end
+ error("incompatible rtfs version")
+end
+function rtfs.format(a,l)
+ return require("fs.rtfs.v1").format(a,l)
+end
+
+return rtfs
diff --git a/rtfs/lib/fs/rtfs/v1.lua b/rtfs/lib/fs/rtfs/v1.lua
new file mode 100644
index 0000000..70358da
--- /dev/null
+++ b/rtfs/lib/fs/rtfs/v1.lua
@@ -0,0 +1,508 @@
+local common = require "fs.rtfs"
+local rtfs, proxy = {}, setmetatable({},{__index=common.proxy})
+local ieformat = ">I2I8I8c46" -- type (4 bits) and index (12 bits), start sector (32 bits), lenth in bytes (32 bits), name/path (46 bytes)
+local sbformat = ">c4I2I8c18" -- "rtfs" magic, version, index size in entries, label. label length subject to change.
+local iesize = string.packsize(ieformat)
+local ftypes = {
+ empty = 0,
+ dfile = 1,
+ dfext = 2,
+ ddir = 3,
+ ddex = 4,
+ dtfile = 5,
+ dtext = 6,
+ dlink = 7,
+ unused = 8,
+ file = 9,
+ fext = 10,
+ dir = 11,
+ dex = 12,
+ tfile = 13,
+ text = 14,
+ link = 15
+}
+
+-- data mangling functions
+local fnormalize = common.fnormalize
+function proxy:cSOI(n)
+ n=n-1
+ local ms = self.capacity / self.blockSize
+ local ePS = self.blockSize // iesize
+ local s = n // ePS
+ local so = self.blockSize - iesize - ((n % ePS) * iesize)
+ local eo = so + iesize
+ return ms - s, so+1, eo
+end
+
+-- superblock stuff
+function proxy:updateSB()
+ self:cachedWrite(1,string.pack(sbformat, "rtfs", 1, self.isize, self.label))
+end 
+function proxy:setISize(n)
+ if self.isize ~= n then
+  self.isize = n
+  self:updateSB()
+ end
+end
+
+-- index I/O
+function proxy:readIEntry(n)
+ local sector, sstart, send = self:cSOI(n)
+ local rt = {string.unpack(ieformat,self:cachedRead(sector):sub(sstart, send))}
+ local et, ex = rt[1]>>12, rt[1]&0x1FF
+ rt[4] = rt[4]:gsub("\0","")
+ rt[5] = nil
+ return et, ex, table.unpack(rt,2)
+end
+function proxy:writeIEntry(n,et,ex,es,el,en) -- index, type, extent index, extent start, extent length, extent name
+ local ne = string.pack(ieformat, (et<<12) | (ex & 0x1FF), es, el, en)
+ local sector, sstart, send = self:cSOI(n)
+ -- check if there's an extent in the way of this entry
+ while self:findIEntry(nil,nil,nil,nil,nil,sector) do
+  self:log("auto-compact triggered")
+  -- compactIndex will shrink the extent if it is safe to overwrite (deleted, free, etc)
+  n = self:compactIndex(n) or self.isize + 1
+  local newn = n == self.isize + 1
+  -- if that fails, because it can't be shrunk, we need to move it ourselves
+  local fi, ft = self:findIEntry(nil,nil,nil,nil,nil,sector)
+  if fi and ft[1] > ftypes.unused then
+   self:log("auto-compact unsuccessful, trying to relocate extent")
+   -- try to find a suitable free space
+   local lfi, lfis = self:bestFree()
+   local lf = {self:readIEntry(lfi)}
+   -- if it's not big enough, give up.
+   assert(lf[4] >= ft[4], "unable to relocate extent to write index entry")
+   -- if it is, create an extent structure at the end of the free space
+   local de = {ft[1], ft[2], lf[3] + lf[4]//self.blockSize - math.ceil(ft[4]/self.blockSize), ft[4], ft[5]}
+   lf[4] = lf[4] - (math.ceil(ft[4] / self.blockSize) * self.blockSize)
+   -- move the data to the new extent
+   for i = 0, ft[4]//self.blockSize do
+    self:writeExtent(de, i, self:readExtent(ft, i))
+   end
+   -- overwrite the old entries, which shouldn't get us back here
+   self:writeIEntry(fi, table.unpack(de))
+   self:writeIEntry(lfi, table.unpack(lf))
+   -- and finally, make a new entry for the now old data, sans one sector
+   self:writeIEntry(self:nextEntry(), ft[1]-8, ft[2], ft[3], ft[4] - self.blockSize, ft[5])
+  end
+  -- if the aim was to make a new entry, update n so it will do so
+  n = newn and self.isize + 1 or n
+  sector, sstart, send = self:cSOI(n)
+ end
+ local pes = self:cachedRead(sector)
+ local ns = pes:sub(1, sstart - 1) .. ne .. pes:sub(send + 1)
+ self:cachedWrite(sector, ns)
+ self:setISize(math.max(self.isize, n))
+ return n
+end
+function proxy:allIEntries()
+ local i = 0
+ return function()
+  if i < self.isize then
+   i = i + 1
+   return i, self:readIEntry(i)
+  end
+  return nil
+ end
+end
+
+-- for debugging
+function proxy:dumpIndex()
+ local t = {}
+ for i, tp, ei, st, sl, n in self:allIEntries() do
+  t[#t+1] = {i,tp,ei,st,sl,(st+math.ceil(sl/self.blockSize))-1,n}
+ end
+ table.sort(t, function(a,b) return a[4] < b[4] end)
+ print(" # ty ext# init      len  end name")
+ for k,v in ipairs(t) do
+  if k % 23 == 0 then
+   io.read()
+   print(" # ty ext# init      len  end name")
+  end
+  print(string.format("%2i  %1x %4i %4i %8i %4i %s",table.unpack(v)))
+ end
+end
+
+-- index searching
+function proxy:findIEntry(et,ex,es,el,en,ef) -- number number number string number -- Find an entry matching all provided parameters and ignoring any not specified.
+ local ri, rt
+ for i, tp, ix, st, sl, n in self:allIEntries() do
+  local sf = st + math.ceil(sl/self.blockSize) - 1
+  if (et or tp) == tp and (ex or ix) == ix and (es or st) == st and (el or sl) == sl and (en or n) == n and (ef or sf) == sf then
+   ri, rt = i, {self:readIEntry(i)}
+   break
+  end
+ end
+ return ri, rt
+end
+function proxy:nextEntry()
+ local ni = self.isize+1
+ for i, tp in self:allIEntries() do
+  if tp == ftypes.unused then
+   ni = i
+   break
+  end
+ end
+ return ni
+end
+
+-- extent allocation
+function proxy:bestFree(last)
+ local ri, sri
+ local bs, sbs = 0, 0
+ if last then
+  ri, rs = self:findIEntry(nil,nil,last[3]+math.ceil(last[4]/self.blockSize))
+  if ri and rs and rs[1] <= ftypes.ddex then
+   return ri, false, true
+  end
+ end
+ for i, tp, ei, st, sl, n in self:allIEntries() do
+  if tp <= ftypes.ddex then
+   if sl > bs then
+    sri, sbs = ri, bs
+    ri, bs = i, sl
+   end
+  end
+ end
+ return bs/2 > sbs and ri or sri, bs/2 > sbs
+end
+function proxy:allocateExtent(name, etype, ei, esize, last)
+ etype, ei, esize = etype or ftypes.tfile, ei or 0, math.ceil(math.max(4096,esize or self.capacity / 256)/self.blockSize)*self.blockSize
+ self:compactIndex()
+ local lfi,lfis,lfext = self:bestFree(last)
+ local lf = {self:readIEntry(lfi)}
+ local esize = math.min(esize, lf[4])
+ local lfs, es = lf[4]//self.blockSize, esize//self.blockSize
+ -- if biggest available area, split and put extent in the middle
+ if lfis then
+  local new = {etype, ei, lf[3] + math.floor(lfs/2), esize, name}
+  lf[4] = math.floor(lfs/2) * self.blockSize
+  local free = {ftypes.empty, 0, new[3] + es, lfs*self.blockSize - new[4] - lf[4], ""}
+  self:writeIEntry(lfi, table.unpack(lf))
+  self:writeIEntry(self:nextEntry(), table.unpack(new))
+  self:writeIEntry(self:nextEntry(), table.unpack(free))
+  return self:findIEntry(etype, ei, nil, nil, name)
+ else -- otherwise, put it at the start
+  local new = {etype, ei, lf[3], esize, name}
+  local free = {ftypes.empty, 0, new[3] + es, lfs*self.blockSize - new[4], ""}
+  local efi, eff
+  if last then
+   last={table.unpack(last)}
+   efi, eff = self:findIEntry(table.unpack(last))
+  end
+  -- if a previous entry was provided and the name matches, continue the extent
+  if lfext and efi and name == eff[5] then
+   last[4] = math.ceil((last[4] + new[4]) / self.blockSize) * self.blockSize
+   new = last
+   self:writeIEntry(efi, table.unpack(new))
+   self:writeIEntry(lfi, table.unpack(free))
+   lfi=efi
+  -- failing that, replace the free space entry with the new extent and
+  -- write a new free space entry
+  else
+   self:writeIEntry(lfi, table.unpack(new))
+   self:writeIEntry(self:nextEntry(), table.unpack(free))
+  end
+  return lfi, new, lfext and new[4]
+ end
+ return false
+end
+
+function proxy:writeExtent(ft, o, d) -- write a sector to an extent
+ assert(o >= 0 and o < (ft[4]//self.blockSize) + 1, "out of range")
+ assert(#d <= self.blockSize, "block too large")
+ return self.d.writeSector(ft[3] + o, d .. ("\0"):rep(self.blockSize - #d))
+end
+function proxy:readExtent(ft, o) -- read a sector from an extent
+ assert(o >= 0 and o < (ft[4]//self.blockSize) + 1, "out of range")
+ return self.d.readSector(ft[3] + o):sub(1, math.min(self.blockSize, ft[4] - (o*self.blockSize)))
+end
+
+function proxy:openHandle(name, mode, fmt)
+ name, fmt = fnormalize(name), fmt or {ftypes.file, ftypes.fext, ftypes.tfile, ftypes.text}
+ local handle, xt = {aft={},fmt=fmt,buffer="",bytes=0}
+ for c in mode:gmatch(".") do
+  handle[c] = true
+ end
+ local fi, oft = self:findIEntry(fmt[1], nil, nil, nil, name)
+ if handle.r then
+  if not fi then
+   return false, "file not found"
+  end
+  handle.ft, handle.aft[1] = oft, oft
+ elseif handle.w or handle.a then
+  if handle.a and fi then
+   local lfi, lf = self:findIEntry(fmt[2], oft[2], nil, nil, oft[5])
+   fi, handle.ft, xt = self:allocateExtent(name, fmt[4], oft[2] + 1, nil, lf or oft)
+   -- if in append mode, put the file extent into the "all extents" table to be updated later
+   handle.aft[1], handle.bytes = oft, xt and (lfi and lf[4] or oft[4]) or 0
+   -- read the last sector into the write buffer so it can be written back to disk with new data
+   -- then rewind the counter so it does get written
+   if handle.bytes%self.blockSize ~= 0 then
+    handle.buffer = self:readExtent(lf or oft, handle.bytes//512)
+    handle.bytes = handle.bytes - #handle.buffer
+   end
+  else
+   -- allocate the new extent to write into
+   fi, handle.ft = self:allocateExtent(name, fmt[3])
+  end
+  handle.aft[#handle.aft+(xt and 0 or 1)] = handle.ft
+ end
+ local ni = #self.handles+1
+ self.handles[ni] = handle
+ return ni
+end
+
+function proxy:closeHandle(h)
+ local handle = self.handles[h]
+ if handle.w or handle.a then
+  -- flush the buffer just in case
+  self:writeHandle(h, "", true)
+  local fs = handle.ft[4] - handle.bytes
+  -- update each index entry 
+  self:compactIndex()
+  -- mark any old entries with a matching name as deleted when not appending
+  if not handle.a then
+   for i, tp, ei, st, sl, n in self:allIEntries() do
+    if n == handle.aft[1][5] and tp > 8 then
+     self:writeIEntry(i, tp-8, ei, st, sl, n)
+    end
+   end
+  end
+  for k,v in ipairs(handle.aft) do
+   local fi, ft = self:findIEntry(table.unpack(v))
+   self:writeIEntry(fi,
+    -- determine if it's the file or extent part
+    (v[1] == handle.fmt[3] or v[1] == handle.fmt[1]) and handle.fmt[1] or handle.fmt[2],
+    -- file part wants the number of extents, extents want their index
+    (v[1] == handle.fmt[3] or v[1] == handle.fmt[1]) and handle.ft[2] or v[2],
+    -- the rest is fine as is, unless it's the last item
+    v[3], v == handle.ft and handle.bytes or v[4], v[5]
+   )
+  end
+  if fs > self.blockSize then
+   self:writeIEntry(self:nextEntry(), ftypes.empty, 0, handle.ft[3] + math.ceil(handle.bytes / self.blockSize), (fs//self.blockSize)*self.blockSize, "")
+   self:compactIndex()
+  end
+ end
+ self.handles[h] = nil
+end
+
+function proxy:writeHandle(h,d,f)
+ local handle = self.handles[h]
+ assert(handle.w or handle.a, "file not open in writable mode")
+ handle.buffer = handle.buffer .. d
+ local rv
+ -- only attempt to write when there's enough data, or forced
+ while #handle.buffer >= self.blockSize or f do 
+  f = false
+  -- allocate a new extent if this one is full
+  if handle.bytes >= handle.ft[4] then
+   local fi, ft, xt = self:allocateExtent(handle.ft[5], handle.fmt[4], handle.ft[2] + 1, nil, handle.ft)
+   if xt then
+    handle.aft[#handle.aft], handle.ft = ft, ft
+   else
+    handle.aft[#handle.aft+1], handle.ft, handle.bytes = ft, ft, 0
+   end
+  end
+  -- write a block and increment the counter
+  local wb = handle.buffer:sub(1, self.blockSize)
+  handle.buffer = handle.buffer:sub(self.blockSize + 1)
+  rv = self:writeExtent(handle.ft, handle.bytes//self.blockSize, wb)
+  handle.bytes = handle.bytes + #wb
+ end
+ return rv
+end
+
+function proxy:readHandle(h)
+ local handle = self.handles[h]
+ assert(handle.r, "file not open in read mode")
+ -- if there's no more data in the extent, find the next
+ if handle.bytes >= handle.ft[4] then
+  local ce = handle.ft[1] == handle.fmt[2] and handle.ft[2] or 0
+  if ce >= handle.aft[1][2] then
+   return nil
+  end
+  local fi, ft = self:findIEntry(handle.fmt[2], ce + 1, nil, nil, handle.ft[5])
+  handle.aft[#handle.aft+1], handle.ft, handle.bytes = ft, ft, 0
+ end
+ local rb = self:readExtent(handle.ft, handle.bytes//512)
+ handle.bytes = handle.bytes + #rb
+ return rb
+end
+
+function proxy:compactIndex(ti)
+ -- compact contingous free space
+ for i, tp, ei, st, sl, n in self:allIEntries() do
+  if tp <= ftypes.ddex then
+   sl=math.max(sl/self.blockSize)
+   local ni, nt = self:findIEntry(nil,nil,st+sl)
+   if ni and nt and nt[1] <= ftypes.ddex then
+    self:writeIEntry(i,tp,ei,st,(sl*self.blockSize)+nt[4],n)
+    self:writeIEntry(ni,ftypes.unused,0,0,0,"")
+   elseif tp <= ftypes.ddex and sl < 1 then
+    self:writeIEntry(i,ftypes.unused,0,0,0,"")
+   end
+  end
+ end
+ local ri
+ -- reverse walk the index to find holes
+ for i = self.isize, 1, -1 do
+  local ne = self:nextEntry() or self.isize
+  local ft = {self:readIEntry(i)}
+  if ne < i then
+   self:writeIEntry(ne, table.unpack(ft))
+   self:setISize(i-1)
+   ri = (ti == i) and ne or ri
+  end 
+ end
+
+ -- resize space at end of disk
+ local li, ls, lt = 0, 0, nil
+ for i, tp, ei, st, sl, n in self:allIEntries() do
+  sl=math.max(sl/self.blockSize)
+  if st+sl > ls then
+   li, ls = i, st+sl
+   lt = {tp, ei, st, sl, n}
+  end
+ end
+ if lt[1] <= ftypes.text then
+  local lastsec = (self.capacity / self.blockSize) - math.ceil(self.isize / (self.blockSize / iesize))
+  self:writeIEntry(li, lt[1], lt[2], lt[3], (lastsec - lt[3])*self.blockSize, lt[5])
+ end
+ return ri
+end
+
+function rtfs.mount(p)
+ local d = common.getProxy(p)
+ local p = setmetatable({}, {__index=proxy})
+ p.d = d
+ p.fstype, p.version, p.isize, p.label = string.unpack(sbformat,d.readSector(1))
+ assert(p.fstype == "rtfs", "incorrect magic")
+ assert(p.version == 1, "incompatible rtfs version")
+ p.d = d
+ p.cache, p.handles = {}, {}
+ p.cacheHits, p.cacheMisses = 0, 0
+ p.blockSize, p.capacity, p.label = d.getSectorSize(), d.getCapacity(), p.label:gsub("\0","")
+
+ -- FS proxy functions
+ function p.exists(name)
+  name = fnormalize(name)
+  for i, tp, ex, st, sl, n in p:allIEntries() do
+   if (tp == ftypes.file or tp == ftypes.dir) and n == name then
+    return true
+   end
+  end
+ end
+ function p.isDirectory(name)
+  name = fnormalize(name)
+  return name == "" and true or p:findIEntry(ftypes.dir, nil, nil, nil, name) ~= nil
+ end
+ function p.size(name)
+  name = fnormalize(name)
+  local rv = 0
+  for i, tp, ex, st, sl, n in p:allIEntries() do
+   if n == name and tp > ftypes.unused then
+    rv = rv + sl
+   end
+  end
+  return rv
+ end
+ function p.spaceUsed()
+  local c = 0
+  for i, tp, ex, st, sl, n in p:allIEntries() do
+   if tp > ftypes.unused then
+    c = c + sl
+   end
+  end
+  return c
+ end
+ function p.spaceTotal()
+  return p.capacity - (math.ceil(p.isize / (p.blockSize / iesize))*p.blockSize) - p.blockSize
+ end
+ p.isReadOnly = p.d.isReadOnly
+
+ function p.list(name)
+  name = fnormalize(name)
+  local rt = {}
+  for i, tp, ex, st, sl, n in p:allIEntries() do
+   local seg = fs.segments(n)
+   local pn = table.concat(seg,"/",1,#seg-1)
+   local fn = seg[#seg]
+   if (tp == ftypes.file or tp == ftypes.dir) and pn == name then
+    rt[#rt+1] = fn .. ((tp == ftypes.dir and "/") or "")
+   end
+  end
+  return rt
+ end
+ function p.makeDirectory(name)
+  name = fnormalize(name)
+  if #name < 1 or p:findIEntry(nil,nil,nil,nil,name) then return false end
+  local seg = fs.segments(name)
+  for j = 1, #seg-1 do
+   p.makeDirectory(table.concat(seg, "/", 1, j))
+  end
+  if not p.isDirectory(table.concat(seg,"/",1,#seg-1)) then return false end
+  local ni = p:nextEntry()
+  p:writeIEntry(ni, ftypes.dir, 0, 0, 0, name)
+--  p:setISize(math.max(p.isize, ni))
+  return true
+ end
+
+ function p.remove(name)
+  name = fnormalize(name)
+  for i, tp, ex, st, sl, n in p:allIEntries() do
+   if n == name and tp > ftypes.unused then
+    p:writeIEntry(i, tp-8, ex, st, sl, n)
+   end
+  end
+ end
+
+ function p.rename(from, to)
+  from, to = fnormalize(from), fnormalize(to)
+  if p.exists(from) then
+   if p.exists(to) then
+    p.remove(to)
+   end
+   local fi, ft = p:findIEntry(p.isDirectory(name) and ftypes.dir or ftypes.file, nil, nil, to)
+   ft[5] = to
+   p:writeIEntry(fi, table.unpack(ft))
+  end
+ end
+ function p.lastModified()
+  return 0
+ end
+
+ function p.open(name, mode)
+  name, mode = fnormalize(name), mode or "r"
+  return p:openHandle(name, mode)
+ end
+ function p.write(h,v)
+  return p:writeHandle(h,v)
+ end
+ function p.read(h,v)
+  return p:readHandle(h,v)
+ end
+ function p.close(h)
+  return p:closeHandle(h)
+ end
+
+ function p.getLabel()
+  return p.label
+ end
+ function p.setLabel(label)
+  p.label = label
+  p:updateSB()
+ end
+
+ return p
+end
+
+function rtfs.format(p, label)
+ local d = common.getProxy(p)
+ print(d.address)
+ d.writeSector(1, string.pack(sbformat,"rtfs", 1, 1, label or ""))
+ rtfs.mount(d):writeIEntry(1, ftypes.empty, 0, 2, d.getCapacity() - (d.getSectorSize() * 2), "")
+end
+
+return rtfs