first work on generalised diskpart

diskpart/lib/diskpart.lua

@@ -1,24 +1,4 @@
-local partition = {}
-
-local eformat = "c20c4>I4>I4"
-function partition.parse(s)
- local rt = {}
- for i = 1, s:len(), 32 do
-  local n, t, start, length = string.unpack(eformat, s, i)
-  n = n:gsub("\0", "")
-  if n ~= "" then
-   rt[#rt+1] = {n,t,start,length}
-  end
- end
- return rt
-end
-function partition.generate(pt)
- local ps = ""
- for k,v in ipairs(pt) do
-  ps = ps .. string.pack(eformat, table.unpack(v))
- end
- return ps
-end
+local partition = {types={"mtpt","osdi","openupt"}}
 
 local function getProxy(addr)
  if type(addr) == "string" then
@@ -26,37 +6,89 @@ local function getProxy(addr)
  end
  return addr
 end
+local function aop(td,n,mn,...)
+ local rts = td.seek(-math.huge)
+ td.seek(n)
+ local rv = {td[mn](...)}
+ td.seek(-math.huge)
+ td.seek(rts)
+ return table.unpack(rv)
+end
+
+local function rf()
+ return false
+end
+local function getlib(f)
+ local drop = package.loaded["part/"..f] == nil
+ local w,r = pcall(require,"part/"..f)
+ if drop then package.loaded["part/"..f] = nil end
+ return w and r or {getPartitions=rf, setPartitions=rf}
+end
 
 function partition.getPartitions(drive)
  drive = getProxy(drive)
- local rv = partition.parse(drive.readSector(drive.getCapacity() / drive.getSectorSize()))
- return rv[1][2] == "mtpt" and rv or {}
+ for _, t in ipairs(partition.types) do
+  local pt = getlib(t).getPartitions(drive)
+  if pt then
+   return pt, t
+  end
+ end
+ return {}, partition.types[1]
 end
 function partition.setPartitions(drive, pt, name)
  drive = getProxy(drive)
- name = name or ""
- if pt[1][2] ~= "mtpt" then table.insert(pt, 1, {name, "mtpt", 0, 0}) end
- local ns = partition.generate(pt)
- return drive.writeSector(drive.getCapacity() / drive.getSectorSize(), ns .. ("\0"):rep(drive.getSectorSize() - #ns))
+ local _, ptt = partition.getPartitions(drive)
+ return getlib(ptt or partition.types[1]).setPartitions(drive, pt, name)
 end
 
 function partition.proxyPartition(drive, index)
  drive = getProxy(drive)
  local part = partition.getPartitions(drive)[index]
  local sectorOffset, byteOffset, finish = part[3] - 1, (part[3]-1) * drive.getSectorSize()
- local proxy = {label=part[1],ptype=part[2]}
+ local proxy = {label=part[1],ptype=part[2],type="partition",address=string.format("%s/%i",drive.address,index)}
 
- function proxy.getCapacity()
-  return drive.getSectorSize() * part[4]
- end
  function proxy.getLabel()
   return part[1]
  end
  function proxy.setLabel()
   return false
  end
+ if drive.type == "tape_drive" then
+  local function checkBounds(n)
+   assert(n >= 0 and n <= len*bs, "invalid offset, not in a usable sector")
+   if n < 0 or n > len * bs then
+    error("invalid offset, not in a usable sector")
+   end
+   return (start * bs) + n
+  end
+  function proxy.readSector(n)
+   return aop(td, checkBounds((n-1) * bs), "read", bs)
+  end
+  function proxy.writeSector(n,d)
+   return aop(td, checkBounds((n-1) * bs), "write", d .. ("\0"):rep(512-#d))
+  end
+  function proxy.readByte(n)
+   return aop(td, checkBounds(n-1), "read")
+  end
+  function proxy.writeByte(n,d)
+   return aop(td, checkBounds(n-1), "write",d)
+  end
+
+  function proxy.getSectorSize()
+   return bs
+  end
+  function proxy.getCapacity()
+   return len * 512
+  end
+  return proxy
+ end
+
+ function proxy.getCapacity()
+  return drive.getSectorSize() * part[4]
+ end
 
  local function offsetSector(sector)
+  assert(sector > 0 and sector <= part[4], "invalid offset, not in a usable sector")
   if sector < 1 or sector > part[4] then error("invalid offset, not in a usable sector") end
   return sectorOffset + sector
  end

diskpart/lib/part/mtpt.lua

@@ -0,0 +1,56 @@
+local mtpt = {}
+
+local eformat = "c20c4>I4>I4"
+
+local function aop(td,n,mn,...)
+ local rts = td.seek(-math.huge)
+ td.seek(n)
+ local rv = {td[mn](...)}
+ td.seek(-math.huge)
+ td.seek(rts)
+ return table.unpack(rv)
+end
+
+function mtpt.parse(s)
+ local rt = {}
+ for i = 1, s:len(), 32 do
+  local n, t, start, length = string.unpack(eformat, s, i)
+  n = n:gsub("\0", "")
+  if n ~= "" then
+   rt[#rt+1] = {n,t,start,length}
+  end
+ end
+ return rt
+end
+function mtpt.generate(pt)
+ local ps = ""
+ for k,v in ipairs(pt) do
+  ps = ps .. string.pack(eformat, table.unpack(v))
+ end
+ return ps
+end
+
+function mtpt.getPartitions(drive)
+ local rv
+ if drive.type == "tape_drive" then
+  local ts = drive.getSize()
+  local lso = (math.floor(ts / 512) - 1) * 512
+  rv = mtpt.parse(aop(drive, lso, "read", ts - lso))
+ else
+  rv = mtpt.parse(drive.readSector(drive.getCapacity() / drive.getSectorSize()))
+ end
+ return rv[1][2] == "mtpt" and rv
+end
+function mtpt.setPartitions(drive, pt, name)
+ name = name or ""
+ if pt[1][2] ~= "mtpt" then table.insert(pt, 1, {name, "mtpt", 0, 0}) end
+ local ns = mtpt.generate(pt)
+ if drive.type == "tape_drive" then
+  local ts = drive.getSize()
+  local lso = (math.floor(ts / 512) - 1) * 512
+  return aop(drive, lso, "write", ns .. ("\0"):rep(ts - lso - #ns))
+ end
+ return drive.writeSector(drive.getCapacity() / drive.getSectorSize(), ns .. ("\0"):rep(drive.getSectorSize() - #ns))
+end
+
+return mtpt