1.1 --- a/libraries/json/json.c	Sun Jul 27 01:51:45 2014 +0200
     1.2 +++ b/libraries/json/json.c	Sun Jul 27 03:54:39 2014 +0200
     1.3 @@ -3,9 +3,8 @@
     1.4  #include <stdlib.h>
     1.5  #include <string.h>
     1.6  
     1.7 -#define JSON_UPVAL_METATABLE lua_upvalueindex(1)
     1.8 -#define JSON_UPVAL_NULLS lua_upvalueindex(2)
     1.9 -#define JSON_UPVAL_ARYLEN lua_upvalueindex(3)
    1.10 +#define JSON_UPVAL_NULLS lua_upvalueindex(1)
    1.11 +#define JSON_UPVAL_METATABLE lua_upvalueindex(2)
    1.12  
    1.13  #define JSON_STATE_VALUE 0
    1.14  #define JSON_STATE_OBJECT_KEY 1
    1.15 @@ -76,10 +75,7 @@
    1.16    case ']':
    1.17      if (mode != JSON_STATE_ARRAY_VALUE && mode != JSON_STATE_ARRAY_SEPARATOR)
    1.18        goto json_import_syntax_error;
    1.19 -    lua_pushvalue(L, -2);  // use array table as key
    1.20 -    lua_insert(L, -2);  // use length of array as value
    1.21 -    lua_rawset(L, JSON_UPVAL_ARYLEN);  // store length in ephemeron table
    1.22 -    // leaves array table on top of stack
    1.23 +    lua_pop(L, 1);  // pop length information
    1.24    json_import_close:
    1.25      pos++;
    1.26      lua_pop(L, 1);  // pop table that stores set of NULL values
    1.27 @@ -220,12 +216,53 @@
    1.28  }
    1.29  
    1.30  static int json_arylen(lua_State *L) {
    1.31 +  int lower, middle;
    1.32 +  int upper = 1;
    1.33 +  // TODO: check input for valid array!
    1.34    lua_settop(L, 1);
    1.35 -  lua_rawget(L, JSON_UPVAL_ARYLEN);
    1.36 +  lua_pushvalue(L, 1);
    1.37 +  lua_rawget(L, JSON_UPVAL_NULLS);
    1.38 +  if (lua_isnil(L, -1)) goto json_arylen_default;
    1.39 +  lua_pushnil(L);
    1.40 +  if (!lua_next(L, -2)) goto json_arylen_default;
    1.41 +  lua_pop(L, 2);
    1.42 +  while (1) {
    1.43 +    lua_rawgeti(L, 1, upper);
    1.44 +    if (lua_isnil(L, -1)) {
    1.45 +      // TODO: require metatable set?
    1.46 +      lua_pop(L, 1);
    1.47 +      lua_pushinteger(L, upper);
    1.48 +      lua_rawget(L, 2);
    1.49 +    }
    1.50 +    if (lua_isnil(L, -1)) break;
    1.51 +    lua_pop(L, 1);
    1.52 +    upper *= 2;
    1.53 +    // TODO: avoid integer overflow!
    1.54 +  }
    1.55 +  lua_pop(L, 1);
    1.56 +  lower = upper / 2;
    1.57 +  while (upper - lower > 1) {
    1.58 +    middle = (lower + upper) / 2;
    1.59 +    lua_rawgeti(L, 1, middle);
    1.60 +    if (lua_isnil(L, -1)) {
    1.61 +      // TODO: require metatable set?
    1.62 +      lua_pop(L, 1);
    1.63 +      lua_pushinteger(L, middle);
    1.64 +      lua_rawget(L, 2);
    1.65 +    }
    1.66 +    if (lua_isnil(L, -1)) upper = middle;
    1.67 +    else lower = middle;
    1.68 +    lua_pop(L, 1);
    1.69 +  }
    1.70 +  lua_pushinteger(L, lower);
    1.71 +  return 1;
    1.72 +json_arylen_default:
    1.73 +  lua_pushinteger(L, lua_rawlen(L, 1));
    1.74    return 1;
    1.75  }
    1.76  
    1.77  static int json_isnull(lua_State *L) {
    1.78 +  // TODO: require metatable set?
    1.79    lua_pushvalue(L, 1);
    1.80    lua_rawget(L, JSON_UPVAL_NULLS);
    1.81    if (lua_isnil(L, -1)) goto json_isnull_false;
    1.82 @@ -244,20 +281,26 @@
    1.83    {NULL, NULL}
    1.84  };
    1.85  
    1.86 +static const struct luaL_Reg json_metatable_functions[] = {
    1.87 +  {"__len", json_arylen},
    1.88 +  {NULL, NULL}
    1.89 +};
    1.90 +
    1.91  int luaopen_json(lua_State *L) {
    1.92 -  lua_newtable(L);  // library table
    1.93 -  lua_newtable(L);  // metatable for JSON objects and JSON arrays
    1.94 -  lua_pushvalue(L, -1);
    1.95 -  lua_setfield(L, -3, "metatable");
    1.96 -  lua_newtable(L);  // ephemeron table to store a set of keys associated with JSON-null values
    1.97 -  lua_newtable(L);  // ephemeron table to store the length of arrays (that may contain nil's)
    1.98 -  lua_newtable(L);  // meta table for ephemeron table
    1.99 +  lua_settop(L, 0);
   1.100 +  lua_newtable(L);  // 1: library table on stack position
   1.101 +  lua_newtable(L);  // 2: ephemeron table to store a set of keys associated with JSON-null values
   1.102 +  lua_newtable(L);  // 3: meta table for ephemeron table
   1.103    lua_pushliteral(L, "__mode");
   1.104    lua_pushliteral(L, "k");
   1.105 -  lua_rawset(L, -3);
   1.106 -  lua_pushvalue(L, -1);
   1.107 -  lua_setmetatable(L, -3);
   1.108 -  lua_setmetatable(L, -2);
   1.109 -  luaL_setfuncs(L, json_module_functions, 3);
   1.110 +  lua_rawset(L, 3);
   1.111 +  lua_setmetatable(L, 2);
   1.112 +  lua_newtable(L);  // 3: metatable for JSON objects and JSON arrays
   1.113 +  lua_pushvalue(L, 3);
   1.114 +  lua_setfield(L, 1, "metatable");
   1.115 +  lua_pushvalue(L, 2);
   1.116 +  lua_pushvalue(L, 3);
   1.117 +  luaL_setfuncs(L, json_metatable_functions, 2);
   1.118 +  luaL_setfuncs(L, json_module_functions, 2);
   1.119    return 1;
   1.120  }