Adding sample Unicode I/O library

git-svn-id: file:///var/svn/lua-iconv/trunk@58 9538949d-8f27-0410-946f-ce01ef448559

uniopen.lua

@@ -0,0 +1,37 @@
+
+-- Simple (and incomplete) Unicode I/O layer.
+
+module("uniopen", package.seeall)
+
+require "iconv"
+
+local mt = { __index = _M }
+
+function open(fname, mode, fromcharset, tocharset)
+  assert(mode == "r" or mode == "rb", "Only read modes are supported yet")
+  tocharset = tocharset or "utf8"
+  local cd = assert(iconv.new(fromcharset, tocharset), "Bad charset")
+  local fp = io.open(fname, mode)
+  if not fp then
+    return nil
+  end
+  local o =  { fp = fp, cd = cd }
+  setmetatable(o, mt)
+  return o;
+end
+
+function read(fp, mod)
+  assert(fp and fp.fp and fp.cd, "Bad file descriptor")
+  local ret = fp.fp:read(mod)
+  if ret then
+    return fp.cd:iconv(ret)  -- returns: string, error code
+  else
+    return nil
+  end
+end
+
+function close(fp)
+  assert(fp and fp.fp, "Bad file descriptor")
+  fp.fp:close()
+end
+