add layer and param

2 files changed, 25 insertions, 4 deletions

diff --git a/io/init.lua b/io/init.lua
index 1288bd4..2fa38e6 100644
--- a/io/init.lua
+++ b/io/init.lua
@@ -5,3 +5,24 @@ function nerv.ParamFile:write_chunkdata(metadata, writer)
     end
     return self:_write_chunkdata(table.tostring(metadata), writer)
 end
+
+function nerv.ParamFile:write_param(param)
+    local id = param.id
+    local type = param.__typename
+    if id == nil then
+        nerv_error("id of param %s must be specified", type)
+    end
+    self:write_chunkdata({id = id,
+                            type = type,
+                            info = param:get_info()}, param)
+end
+
+function nerv.ParamFile:read_param(id)
+    local metadata = self.metadata[id]
+    if metadata == nil then
+        nerv_error("param with id %s does not exist", id)
+    end
+    local param = assert(loadstring("return " .. metadata.type .. "(" .. id .. ")"))()
+    param:set_info(metadata.info)
+    param:read(self:get_chunkdata(id))
+end
diff --git a/io/param.c b/io/param.c
index 627c815..477df28 100644
--- a/io/param.c
+++ b/io/param.c
@@ -220,12 +220,12 @@ int nerv_param_file_write_chunkdata(lua_State *L) {
     write_param_metadata(pfh->fp, metadata_str, &status);
     CHECK_WRITE(status);
     lua_pushvalue(L, 3);
-    lua_getfield(L, -1, "save");
+    lua_getfield(L, -1, "write");
     if (!lua_isfunction(L, -1))
-        nerv_error(L, "\"save\" method must be implemented");
+        nerv_error(L, "\"write\" method must be implemented");
     lua_pushvalue(L, -2);
-    lua_pushvalue(L, 4); /* pass handle as parameter to save() */
-    lua_call(L, 2, 0); /* let the save() to write */
+    lua_pushvalue(L, 4); /* pass handle as parameter to write() */
+    lua_call(L, 2, 0); /* let the write() to write */
     lua_pop(L, 1);
     size = ftello(pfh->fp) - start;
     fseeko(pfh->fp, start, SEEK_SET);