# HG changeset patch
# User jbe
# Date 1406904010 -7200
# Node ID ce208edffcc9b12e3cadfb46bfa3ce59b2dbe091
# Parent  c055d6d6458656139e572827bdf3166d679de37a
Code cleanup in json.object and json.array functions

diff -r c055d6d64586 -r ce208edffcc9 libraries/json/json.c
--- a/libraries/json/json.c	Fri Aug 01 13:09:15 2014 +0200
+++ b/libraries/json/json.c	Fri Aug 01 16:40:10 2014 +0200
@@ -49,16 +49,21 @@
 // converts a Lua table to a  JSON object or JSON array:
 // (does never modify the argument, returns an empty object or array if argument is nil)
 static int json_convert(lua_State *L, int array) {
-  lua_settop(L, 1);
+  int arrayidx = 0;
+  // determine is argument is given:
   if (lua_isnoneornil(L, json_convert_source_idx)) {
+    // if no argument is given (or if argument is nil),
+    // create table with shadow table, and leave first table on top of stack:
     json_regfetch(L, shadowtbl);
     lua_newtable(L);
     lua_pushvalue(L, -1);
     lua_newtable(L);
     lua_rawset(L, -4);
   } else {
-    // push iterator function on stack position 2 if existent,
+    // if an argument was given,
+    // push its iterator function on stack position 2 if existent,
     // else push null for normal tables:
+    lua_settop(L, 1);
     if (lua_getmetatable(L, json_convert_source_idx)) {
       lua_getfield(L, -1, array ? "__ipairs" : "__pairs");
       if (lua_isnil(L, -1)) luaL_checktype(L, 1, LUA_TTABLE);
@@ -68,7 +73,7 @@
     } else {
       lua_pushnil(L);
     }
-    // create table on stack position 3:
+    // create result table on stack position 3:
     lua_newtable(L);
     // create shadow table on stack position 4:
     json_regfetch(L, shadowtbl);
@@ -77,22 +82,47 @@
     lua_pushvalue(L, -2);
     lua_rawset(L, -4);
     lua_replace(L, -2);
+    // check if iterator function exists:
     if (lua_isnil(L, json_convert_iterator_idx)) {
-      for (lua_pushnil(L); lua_next(L, json_convert_source_idx); lua_pop(L, 1)) {
-        lua_pushvalue(L, -2);
-        lua_pushvalue(L, -2);
-        lua_rawset(L, json_convert_shadow_idx);
+      // if there is no iterator function,
+      // distinguish between objects and arrays:
+      if (array == 0) {
+        // for an object, copy all string key value pairs to shadow table:
+        for (lua_pushnil(L); lua_next(L, json_convert_source_idx); lua_pop(L, 1)) {
+          if (lua_type(L, -2) == LUA_TSTRING) {
+            lua_pushvalue(L, -2);
+            lua_pushvalue(L, -2);
+            lua_rawset(L, json_convert_shadow_idx);
+          }
+        }
+      } else {
+        // for an array, copy consecutive integer value pairs to shadow table:
+        while (1) {
+          // TODO: Lua 5.3 may support more elements
+          if (arrayidx == INT_MAX) {
+            lua_pushnumber(L, (size_t)INT_MAX+1);
+            lua_rawget(L, json_convert_source_idx);
+            if (lua_isnil(L, -1)) break;
+            return luaL_error(L, "Array exceeded length of %d elements", INT_MAX);
+          }
+          arrayidx++;
+          lua_rawgeti(L, json_convert_source_idx, arrayidx);
+          if (lua_isnil(L, -1)) break;
+          lua_rawseti(L, json_convert_shadow_idx, arrayidx);
+        }
       }
     } else {
+      // TODO: implement conversion using iterator metamethods
       return luaL_error(L, "Using %s metamethod not implemented yet", array ? "__ipairs" : "__pairs");
     }
+    // let result table be on top of stack:
     lua_settop(L, json_convert_output_idx);
   }
-  // set metatable:
-  if (array) json_regfetch(L, arraymt);
-  else json_regfetch(L, objectmt);
+  // set metatable (for result table on top of stack):
+  if (array == 0) json_regfetch(L, objectmt);
+  else json_regfetch(L, arraymt);
   lua_setmetatable(L, -2);
-  // return table:
+  // return table on top of stack:
   return 1;
 }