moved the unarchive function out of libmtar, making it significantly simpler and more compact, and allowing implementations to deal with the implementation details

mtar/OpenOS/usr/bin/mtar.lua

@@ -1,5 +1,6 @@
 local shell = require "shell"
 local mtar = require "libmtar"
+local fs = require "filesystem"
 
 local args, opts = shell.parse(...)
 
@@ -30,43 +31,78 @@ local function vp(...)
  end
 end
 
-if opts.x then
+local function cleanPath(path)
+ local pt = {}
+ for segment in path:gmatch("[^/]+") do
+  if segment == ".." then
+   pt[#pt] = nil
+  elseif segment ~= "." then
+   pt[#pt+1] = segment
+  end
+ end
+ return table.concat(pt,"/")
+end
+
+function unarchive(stream,dest,verbose,csize)
+ csize = csize or 2048
+ function vwrite(...)
+  if verbose then
+   io.write(...)
+  end
+ end
+ for fname, read, len in mtar.iter(stream) do
+  local written = 0
+  fname = cleanPath(fname)
+  vwrite(string.format("%s %i... ",fname,len))
+  local dir = fname:match("(.+)/.*%.?.+")
+  if dir then
+   if dir:sub(1,1) ~= "/" then
+    dir = os.getenv("PWD").."/"..dir
+   end
+   fs.makeDirectory(dest.."/"..dir)
+  end
+  local f = io.open(dest.."/"..fname,"wb")
+  if f then
+   repeat
+    local rb = read(csize)
+    written = written + rb:len()
+    f:write(rb)
+    vwrite(written)
+    vwrite(" ")
+   until written == len
+   f:close()
+   vwrite("done\n")
+  else
+   vwrite("failed to open "..fname.."\n")
+  end
+ end
+end
+
+function open(fn,mode)
  local f
  if opts.z then
-  f = lz16.open(args[1],"rb")
+  f = lz16.open(fn, mode)
  else
-  f = io.open(args[1],"rb")
+  f = io.open(fn, mode)
  end
+ return f
+end
+
+if opts.x then
+ local f = open(args[1],"rb")
  if not f then error("unable to open file") end
- local w, r = mtar.unarchive(f,args[2] or ".",opts.v)
+ local w, r = unarchive(f,args[2] or ".",opts.v)
  f:close()
 elseif opts.t then
- local f
- if opts.z then
-  f = lz16.open(args[1],"rb")
- else
-  f = io.open(args[1],"rb")
- end
+ local f = open(args[1],"rb")
  if not f then error("unable to open file") end
- while true do
-  local nlen = toint(f:read(2))
-  if nlen == 0 then
-   break
-  end
-  local name = f:read(nlen)
-  local fsize = toint(f:read(2) or "\0\0")
-  f:read(fsize)
+ for name, _, fsize in mtar.iter(f) do
   print(name..": "..tostring(fsize))
  end
  f:close()
 elseif opts.c then
  local mode = (opts.r and "ab") or "wb"
- local f
- if opts.z then
-  f = lz16.open(args[1],mode)
- else
-  f = io.open(args[1],mode)
- end
+ local f = open(args[1],mode)
  if not f then error("unable to open file") end
  table.remove(args,1)
  local fs = require "filesystem"
@@ -122,5 +158,6 @@ Operations:
  t: list contents of archive
 Flags:
  v: be verbose
- z: use LZSS compression (requires liblz16)]])
+ z: use LZSS compression (requires liblz16)
+ r: append rather than overwrite]])
 end

mtar/libmtar.lua

@@ -1,24 +1,5 @@
 local mtar = {}
 
-if _OSVERSION then
- if _OSVERSION:sub(1,8) == "OpenOS" then
-  OPENOS = true
- elseif _OSVERSION:sub(1,9) == "PsychOS" then
-  PSYCHOS = true
- end
-else
- LINUX = true
-end
-
-local function mkdir(dir)
- if OPENOS or LINUX then
-  os.execute("mkdir "..dest.."/"..dir.." &> /dev/null")
- elseif PSYCHOS then
-  -- todo: write PsychOS support
- end
-end
-
 local function toint(s)
  local n = 0
  local i = 1
@@ -38,18 +19,6 @@ local function cint(n,l)
  return string.reverse(string.char(table.unpack(t)):sub(1,l))
 end
 
-local function cleanPath(path)
- local pt = {}
- for segment in path:gmatch("[^/]+") do
-  if segment == ".." then
-   pt[#pt] = nil
-  elseif segment ~= "." then
-   pt[#pt+1] = segment
-  end
- end
- return table.concat(pt,"/")
-end
-
 function mtar.genHeader(fname,len) -- generate a header for file *fname* when provided with file length *len*
  return string.format("%s%s%s",cint(fname:len(),2),fname,cint(len,2))
 end
@@ -67,46 +36,11 @@ function mtar.iter(stream) -- table -- function -- Given buffer *stream*, return
   if nlen == 0 then
    return
   end
-  local name = cleanPath(stream:read(nlen))
+  local name = stream:read(nlen)
   local fsize = toint(stream:read(2))
   remain = fsize
   return name, read, fsize
  end
 end
 
-function mtar.unarchive(stream,dest,verbose) -- Extract mtar archive read from *stream* to *dest*. If *verbose*, print status.
- dest = dest or "."
- while true do
-  local nlen = toint(stream:read(2) or "\0\0")
-  if nlen == 0 then
-   break
-  end
-  local name = cleanPath(stream:read(nlen))
-  local fsize = toint(stream:read(2))
-  if verbose then
-   io.write(name.." "..tostring(fsize).."... ")
-  end
-  local dir = name:match("(.+)/.*%.?.+")
-  if (dir) then
-   mkdir(dir)
-  end
-  local f = io.open(dest.."/"..name,"wb")
-  local rsize,buf = fsize, ""
-  if f then
-   repeat
-    buf = stream:read(math.min(rsize,2048))
-    f:write(buf)
-    rsize = rsize - buf:len()
-    if verbose then
-     io.write(tostring(rsize).." ")
-    end
-   until rsize <= 1
-   f:close()
-  end
-  if verbose then
-   print("done.")
-  end
- end
-end
-
 return mtar