rev |
line source |
jbe@121
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1 #include <lua.h>
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jbe@121
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2 #include <lauxlib.h>
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jbe@122
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3 #include <stdlib.h>
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4 #include <string.h>
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jbe@154
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5 #include <math.h>
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6
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jbe@144
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7 // maximum number of nested JSON values (objects and arrays):
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jbe@150
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8 // NOTE: The Lua reference states that the stack may typically contain at least
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9 // "a few thousand elements". Since every nested level consumes
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10 // 3 elements on the Lua stack (the object/array, its shadow table,
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11 // a string key or a placeholder), we limit the number of nested levels
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12 // to 500. If a stack overflow would still happen in the import function,
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13 // this is detected nevertheless and an error is thrown (instead of
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14 // returning nil and an error string).
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jbe@150
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15 #define JSON_MAXDEPTH 500
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jbe@142
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16
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jbe@155
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17 // generate dummy memory addresses that represents null values:
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18 char json_nullmark;
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19 #define json_isnullmark(L, i) (lua_touserdata((L), (i)) == &json_nullmark)
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jbe@155
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20 #define json_pushnullmark(L) lua_pushlightuserdata((L), &json_nullmark)
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21
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jbe@144
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22 // macros for usage of Lua registry:
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23 #define JSON_REGENT char
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24 #define JSON_REGPOINTER void *
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25 #define json_regpointer(x) (&json_registry.x)
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26 #define json_regfetchpointer(L, x) lua_rawgetp((L), LUA_REGISTRYINDEX, (x))
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27 #define json_regfetch(L, x) json_regfetchpointer(L, json_regpointer(x))
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28 #define json_regstore(L, x) lua_rawsetp(L, LUA_REGISTRYINDEX, json_regpointer(x))
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29
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30 // generate dummy memory addresses that represent Lua objects
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31 // via lightuserdata keys and LUA_REGISTRYINDEX:
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32 static struct {
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33 JSON_REGENT shadowtbl; // ephemeron table that maps tables to their corresponding shadow table
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34 JSON_REGENT objectmt; // metatable for JSON objects
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35 JSON_REGENT arraymt; // metatable for JSON arrays
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36 } json_registry;
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jbe@138
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37
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jbe@157
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38 // returns the string "<JSON null marker>":
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39 static int json_nullmark_tostring(lua_State *L) {
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40 lua_pushliteral(L, "<JSON null marker>");
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jbe@157
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41 return 1;
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jbe@157
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42 }
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43
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jbe@145
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44 // marks a Lua table as JSON object or JSON array:
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45 // (returns its modified argument or a new table if argument is nil)
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jbe@145
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46 static int json_mark(lua_State *L, JSON_REGPOINTER mt) {
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jbe@145
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47 // check if argument is nil
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jbe@136
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48 if (lua_isnoneornil(L, 1)) {
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49 // create new table at stack position 1:
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50 lua_settop(L, 0);
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51 lua_newtable(L);
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52 // create shadow table (leaving previously created table on stack position 1):
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53 json_regfetch(L, shadowtbl);
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54 lua_pushvalue(L, 1);
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55 lua_newtable(L);
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jbe@143
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56 lua_rawset(L, -3);
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jbe@143
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57 } else {
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58 // push shadow table on top of stack:
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59 json_regfetch(L, shadowtbl);
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jbe@143
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60 lua_pushvalue(L, 1);
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61 lua_rawget(L, -2);
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jbe@145
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62 // if shadow table does not exist:
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63 if (lua_isnil(L, -1)) {
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64 // create shadow table and leave it on top of stack:
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65 lua_newtable(L);
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66 lua_pushvalue(L, 1);
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67 lua_pushvalue(L, -2);
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68 lua_rawset(L, -5);
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69 }
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70 // move elements from original table to shadow table (that's expected on top of stack):
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71 for(lua_pushnil(L); lua_next(L, 1); lua_pop(L, 1)) {
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72 lua_pushvalue(L, -2);
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73 lua_pushnil(L);
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74 lua_rawset(L, 1);
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jbe@143
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75 lua_pushvalue(L, -2);
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76 lua_pushvalue(L, -2);
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jbe@143
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77 lua_rawset(L, -5);
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jbe@143
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78 }
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jbe@136
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79 }
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jbe@138
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80 // discard everything but table to return:
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81 lua_settop(L, 1);
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jbe@136
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82 // set metatable:
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83 json_regfetchpointer(L, mt);
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84 lua_setmetatable(L, 1);
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jbe@138
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85 // return table:
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86 return 1;
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87 }
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88
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89 // marks a table as JSON object:
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90 // (returns its modified argument or a new table if argument is nil)
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91 static int json_object(lua_State *L) {
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92 return json_mark(L, json_regpointer(objectmt));
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93 }
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94
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95 // marks a table as JSON array:
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96 // (returns its modified argument or a new table if argument is nil)
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97 static int json_array(lua_State *L) {
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98 return json_mark(L, json_regpointer(arraymt));
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99 }
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100
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jbe@145
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101 // internal states of JSON parser:
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jbe@124
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102 #define JSON_STATE_VALUE 0
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jbe@124
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103 #define JSON_STATE_OBJECT_KEY 1
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104 #define JSON_STATE_OBJECT_KEY_TERMINATOR 2
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jbe@124
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105 #define JSON_STATE_OBJECT_VALUE 3
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106 #define JSON_STATE_OBJECT_SEPARATOR 4
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107 #define JSON_STATE_ARRAY_VALUE 5
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108 #define JSON_STATE_ARRAY_SEPARATOR 6
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jbe@124
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109 #define JSON_STATE_END 7
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110
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jbe@145
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111 // special Lua stack indicies for json_import function:
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jbe@138
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112 #define json_import_objectmt_idx 2
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113 #define json_import_arraymt_idx 3
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jbe@138
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114 #define json_import_shadowtbl_idx 4
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115
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jbe@136
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116 // decodes a JSON document:
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117 static int json_import(lua_State *L) {
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118 const char *str; // string to parse
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119 size_t total; // total length of string to parse
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120 size_t pos = 0; // current position in string to parse
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121 size_t level = 0; // nested levels of objects/arrays currently being processed
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jbe@145
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122 int mode = JSON_STATE_VALUE; // state of parser (i.e. "what's expected next?")
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jbe@136
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123 char c; // variable to store a single character to be processed
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jbe@145
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124 luaL_Buffer luabuf; // Lua buffer to decode JSON string values
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125 char *cbuf; // C buffer to decode JSON string values
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jbe@136
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126 size_t writepos; // write position of decoded strings in C buffer
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jbe@152
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127 size_t arraylen; // variable to temporarily store the array length
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jbe@147
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128 // stack shall contain one function argument:
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jbe@138
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129 lua_settop(L, 1);
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jbe@147
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130 // push objectmt onto stack position 2:
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jbe@144
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131 json_regfetch(L, objectmt);
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132 // push arraymt onto stack position 3:
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133 json_regfetch(L, arraymt);
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jbe@147
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134 // push shadowtbl onto stack position 4:
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135 json_regfetch(L, shadowtbl);
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jbe@136
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136 // require string as first argument:
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137 str = luaL_checklstring(L, 1, &total);
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jbe@136
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138 // if string contains a NULL byte, this is a syntax error
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jbe@136
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139 if (strlen(str) != total) goto json_import_syntax_error;
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jbe@136
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140 // main loop of parser:
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jbe@136
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141 json_import_loop:
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jbe@136
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142 // skip whitespace and store next character in variable 'c':
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143 while (c = str[pos],
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144 c == ' ' ||
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145 c == '\f' ||
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jbe@146
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146 c == '\n' ||
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147 c == '\r' ||
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148 c == '\t' ||
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149 c == '\v'
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150 ) pos++;
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jbe@136
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151 // switch statement to handle certain (single) characters:
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jbe@121
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152 switch (c) {
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153 // handle end of JSON document:
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jbe@121
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154 case 0:
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jbe@136
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155 // if end of JSON document was expected, then return top element of stack as result:
|
jbe@124
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156 if (mode == JSON_STATE_END) return 1;
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jbe@136
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157 // otherwise, the JSON document was malformed:
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jbe@121
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158 json_import_unexpected_eof:
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jbe@121
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159 lua_pushnil(L);
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jbe@121
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160 if (level == 0) lua_pushliteral(L, "Empty string");
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161 else lua_pushliteral(L, "Unexpected end of JSON document");
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jbe@121
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162 return 2;
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jbe@136
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163 // new JSON object:
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jbe@121
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164 case '{':
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jbe@136
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165 // if a JSON object is not expected here, then return an error:
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jbe@146
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166 if (
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jbe@146
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167 mode != JSON_STATE_VALUE &&
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jbe@146
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168 mode != JSON_STATE_OBJECT_VALUE &&
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169 mode != JSON_STATE_ARRAY_VALUE
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jbe@146
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170 ) goto json_import_syntax_error;
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jbe@136
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171 // create JSON object on stack:
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jbe@136
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172 lua_newtable(L);
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jbe@136
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173 // set metatable of JSON object:
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jbe@138
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174 lua_pushvalue(L, json_import_objectmt_idx);
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jbe@125
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175 lua_setmetatable(L, -2);
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jbe@136
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176 // create internal shadow table on stack:
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jbe@136
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177 lua_newtable(L);
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jbe@146
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178 // register internal shadow table:
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jbe@123
|
179 lua_pushvalue(L, -2);
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jbe@123
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180 lua_pushvalue(L, -2);
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jbe@138
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181 lua_rawset(L, json_import_shadowtbl_idx);
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jbe@146
|
182 // expect object key (or end of object) to follow:
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jbe@136
|
183 mode = JSON_STATE_OBJECT_KEY;
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jbe@146
|
184 // jump to common code for opening JSON object and JSON array:
|
jbe@142
|
185 goto json_import_open;
|
jbe@136
|
186 // new JSON array:
|
jbe@121
|
187 case '[':
|
jbe@136
|
188 // if a JSON array is not expected here, then return an error:
|
jbe@146
|
189 if (
|
jbe@146
|
190 mode != JSON_STATE_VALUE &&
|
jbe@146
|
191 mode != JSON_STATE_OBJECT_VALUE &&
|
jbe@146
|
192 mode != JSON_STATE_ARRAY_VALUE
|
jbe@146
|
193 ) goto json_import_syntax_error;
|
jbe@136
|
194 // create JSON array on stack:
|
jbe@136
|
195 lua_newtable(L);
|
jbe@136
|
196 // set metatable of JSON array:
|
jbe@138
|
197 lua_pushvalue(L, json_import_arraymt_idx);
|
jbe@125
|
198 lua_setmetatable(L, -2);
|
jbe@136
|
199 // create internal shadow table on stack:
|
jbe@136
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200 lua_newtable(L);
|
jbe@146
|
201 // register internal shadow table:
|
jbe@123
|
202 lua_pushvalue(L, -2);
|
jbe@123
|
203 lua_pushvalue(L, -2);
|
jbe@138
|
204 lua_rawset(L, json_import_shadowtbl_idx);
|
jbe@140
|
205 // add nil as key (needed to keep stack balance) and as magic to detect arrays:
|
jbe@140
|
206 lua_pushnil(L);
|
jbe@146
|
207 // expect array value (or end of array) to follow:
|
jbe@142
|
208 mode = JSON_STATE_ARRAY_VALUE;
|
jbe@142
|
209 // continue with common code for opening JSON object and JSON array:
|
jbe@146
|
210 // common code for opening JSON object or JSON array:
|
jbe@142
|
211 json_import_open:
|
jbe@142
|
212 // limit nested levels:
|
jbe@142
|
213 if (level >= JSON_MAXDEPTH) {
|
jbe@142
|
214 lua_pushnil(L);
|
jbe@142
|
215 lua_pushliteral(L, "Too many nested JSON levels");
|
jbe@142
|
216 return 2;
|
jbe@142
|
217 }
|
jbe@142
|
218 // additional buffer overflow protection:
|
jbe@142
|
219 if (!lua_checkstack(L, LUA_MINSTACK))
|
jbe@142
|
220 return luaL_error(L, "Caught stack overflow in JSON import function (too many nested levels and stack size too small)");
|
jbe@136
|
221 // increment level:
|
jbe@121
|
222 level++;
|
jbe@142
|
223 // consume input character:
|
jbe@142
|
224 pos++;
|
jbe@121
|
225 goto json_import_loop;
|
jbe@136
|
226 // end of JSON object:
|
jbe@121
|
227 case '}':
|
jbe@136
|
228 // if end of JSON object is not expected here, then return an error:
|
jbe@146
|
229 if (
|
jbe@146
|
230 mode != JSON_STATE_OBJECT_KEY &&
|
jbe@146
|
231 mode != JSON_STATE_OBJECT_SEPARATOR
|
jbe@146
|
232 ) goto json_import_syntax_error;
|
jbe@136
|
233 // jump to common code for end of JSON object and JSON array:
|
jbe@121
|
234 goto json_import_close;
|
jbe@136
|
235 // end of JSON array:
|
jbe@121
|
236 case ']':
|
jbe@136
|
237 // if end of JSON array is not expected here, then return an error:
|
jbe@146
|
238 if (
|
jbe@146
|
239 mode != JSON_STATE_ARRAY_VALUE &&
|
jbe@146
|
240 mode != JSON_STATE_ARRAY_SEPARATOR
|
jbe@146
|
241 ) goto json_import_syntax_error;
|
jbe@146
|
242 // pop nil key/magic (that was needed to keep stack balance):
|
jbe@140
|
243 lua_pop(L, 1);
|
jbe@136
|
244 // continue with common code for end of JSON object and JSON array:
|
jbe@136
|
245 // common code for end of JSON object or JSON array:
|
jbe@121
|
246 json_import_close:
|
jbe@136
|
247 // consume input character:
|
jbe@121
|
248 pos++;
|
jbe@136
|
249 // pop shadow table:
|
jbe@136
|
250 lua_pop(L, 1);
|
jbe@136
|
251 // check if nested:
|
jbe@121
|
252 if (--level) {
|
jbe@146
|
253 // if nested,
|
jbe@146
|
254 // check if outer(!) structure is an array or object:
|
jbe@140
|
255 if (lua_isnil(L, -2)) {
|
jbe@136
|
256 // select array value processing:
|
jbe@124
|
257 mode = JSON_STATE_ARRAY_VALUE;
|
jbe@121
|
258 } else {
|
jbe@136
|
259 // select object value processing:
|
jbe@124
|
260 mode = JSON_STATE_OBJECT_VALUE;
|
jbe@121
|
261 }
|
jbe@136
|
262 // store value in outer structure:
|
jbe@121
|
263 goto json_import_process_value;
|
jbe@121
|
264 }
|
jbe@136
|
265 // if not nested, then expect end of JSON document and continue with loop:
|
jbe@136
|
266 mode = JSON_STATE_END;
|
jbe@121
|
267 goto json_import_loop;
|
jbe@136
|
268 // key terminator:
|
jbe@121
|
269 case ':':
|
jbe@136
|
270 // if key terminator is not expected here, then return an error:
|
jbe@124
|
271 if (mode != JSON_STATE_OBJECT_KEY_TERMINATOR)
|
jbe@121
|
272 goto json_import_syntax_error;
|
jbe@136
|
273 // consume input character:
|
jbe@121
|
274 pos++;
|
jbe@146
|
275 // expect object value to follow:
|
jbe@124
|
276 mode = JSON_STATE_OBJECT_VALUE;
|
jbe@146
|
277 // continue with loop:
|
jbe@121
|
278 goto json_import_loop;
|
jbe@136
|
279 // value terminator (NOTE: trailing comma at end of value or key-value list is tolerated by this parser)
|
jbe@121
|
280 case ',':
|
jbe@146
|
281 // branch according to parser state:
|
jbe@124
|
282 if (mode == JSON_STATE_OBJECT_SEPARATOR) {
|
jbe@146
|
283 // expect an object key to follow:
|
jbe@124
|
284 mode = JSON_STATE_OBJECT_KEY;
|
jbe@124
|
285 } else if (mode == JSON_STATE_ARRAY_SEPARATOR) {
|
jbe@146
|
286 // expect an array value to follow:
|
jbe@124
|
287 mode = JSON_STATE_ARRAY_VALUE;
|
jbe@121
|
288 } else {
|
jbe@136
|
289 // if value terminator is not expected here, then return an error:
|
jbe@136
|
290 goto json_import_syntax_error;
|
jbe@121
|
291 }
|
jbe@136
|
292 // consume input character:
|
jbe@121
|
293 pos++;
|
jbe@136
|
294 // continue with loop:
|
jbe@121
|
295 goto json_import_loop;
|
jbe@136
|
296 // string literal:
|
jbe@121
|
297 case '"':
|
jbe@146
|
298 // consume quote character:
|
jbe@146
|
299 pos++;
|
jbe@136
|
300 // prepare buffer to decode string (with maximum possible length) and set write position to zero:
|
jbe@121
|
301 cbuf = luaL_buffinitsize(L, &luabuf, total-pos);
|
jbe@121
|
302 writepos = 0;
|
jbe@146
|
303 // loop through the characters until encountering end quote:
|
jbe@121
|
304 while ((c = str[pos++]) != '"') {
|
jbe@121
|
305 if (c == 0) {
|
jbe@146
|
306 // handle unexpected end of JSON document:
|
jbe@121
|
307 goto json_import_unexpected_eof;
|
jbe@121
|
308 } else if (c < 32 || c == 127) {
|
jbe@136
|
309 // do not allow ASCII control characters:
|
jbe@136
|
310 // NOTE: illegal UTF-8 sequences and extended control characters are not sanitized
|
jbe@136
|
311 // by this parser to allow different encodings than Unicode
|
jbe@121
|
312 lua_pushnil(L);
|
jbe@121
|
313 lua_pushliteral(L, "Unexpected control character in JSON string");
|
jbe@121
|
314 return 2;
|
jbe@121
|
315 } else if (c == '\\') {
|
jbe@136
|
316 // read next char after backslash escape:
|
jbe@121
|
317 c = str[pos++];
|
jbe@121
|
318 switch (c) {
|
jbe@136
|
319 // unexpected end-of-string:
|
jbe@121
|
320 case 0:
|
jbe@121
|
321 goto json_import_unexpected_eof;
|
jbe@136
|
322 // unescaping of quotation mark, slash, and backslash:
|
jbe@121
|
323 case '"':
|
jbe@121
|
324 case '/':
|
jbe@121
|
325 case '\\':
|
jbe@121
|
326 cbuf[writepos++] = c;
|
jbe@121
|
327 break;
|
jbe@136
|
328 // unescaping of backspace:
|
jbe@146
|
329 case 'b': cbuf[writepos++] = '\b'; break;
|
jbe@136
|
330 // unescaping of form-feed:
|
jbe@146
|
331 case 'f': cbuf[writepos++] = '\f'; break;
|
jbe@136
|
332 // unescaping of new-line:
|
jbe@146
|
333 case 'n': cbuf[writepos++] = '\n'; break;
|
jbe@136
|
334 // unescaping of carriage-return:
|
jbe@146
|
335 case 'r': cbuf[writepos++] = '\r'; break;
|
jbe@136
|
336 // unescaping of tabulator:
|
jbe@146
|
337 case 't': cbuf[writepos++] = '\t'; break;
|
jbe@136
|
338 // unescaping of UTF-16 characters
|
jbe@121
|
339 case 'u':
|
jbe@121
|
340 lua_pushnil(L);
|
jbe@121
|
341 lua_pushliteral(L, "JSON unicode escape sequences are not implemented yet"); // TODO
|
jbe@121
|
342 return 2;
|
jbe@136
|
343 // unexpected escape sequence:
|
jbe@121
|
344 default:
|
jbe@121
|
345 lua_pushnil(L);
|
jbe@121
|
346 lua_pushliteral(L, "Unexpected string escape sequence in JSON document");
|
jbe@121
|
347 return 2;
|
jbe@121
|
348 }
|
jbe@121
|
349 } else {
|
jbe@136
|
350 // normal character:
|
jbe@121
|
351 cbuf[writepos++] = c;
|
jbe@121
|
352 }
|
jbe@121
|
353 }
|
jbe@136
|
354 // process buffer to Lua string:
|
jbe@121
|
355 luaL_pushresultsize(&luabuf, writepos);
|
jbe@136
|
356 // continue with processing of decoded string:
|
jbe@121
|
357 goto json_import_process_value;
|
jbe@121
|
358 }
|
jbe@136
|
359 // process values whose type is is not deducible from a single character:
|
jbe@136
|
360 if ((c >= '0' && c <= '9') || c == '-' || c == '+') {
|
jbe@146
|
361 // for numbers,
|
jbe@146
|
362 // use strtod() call to parse a (double precision) floating point number:
|
jbe@122
|
363 char *endptr;
|
jbe@122
|
364 double numval;
|
jbe@122
|
365 numval = strtod(str+pos, &endptr);
|
jbe@146
|
366 // catch parsing errors:
|
jbe@122
|
367 if (endptr == str+pos) goto json_import_syntax_error;
|
jbe@146
|
368 // consume characters that were parsed:
|
jbe@122
|
369 pos += endptr - (str+pos);
|
jbe@146
|
370 // push parsed (double precision) floating point number on Lua stack:
|
jbe@122
|
371 lua_pushnumber(L, numval);
|
jbe@122
|
372 } else if (!strncmp(str+pos, "true", 4)) {
|
jbe@136
|
373 // consume 4 input characters for "true":
|
jbe@121
|
374 pos += 4;
|
jbe@147
|
375 // put Lua true value onto stack:
|
jbe@136
|
376 lua_pushboolean(L, 1);
|
jbe@121
|
377 } else if (!strncmp(str+pos, "false", 5)) {
|
jbe@136
|
378 // consume 5 input characters for "false":
|
jbe@121
|
379 pos += 5;
|
jbe@147
|
380 // put Lua false value onto stack:
|
jbe@136
|
381 lua_pushboolean(L, 0);
|
jbe@121
|
382 } else if (!strncmp(str+pos, "null", 4)) {
|
jbe@136
|
383 // consume 4 input characters for "null":
|
jbe@136
|
384 pos += 4;
|
jbe@153
|
385 // different behavor for top-level and sub-levels:
|
jbe@153
|
386 if (level) {
|
jbe@153
|
387 // if sub-level,
|
jbe@153
|
388 // push special null-marker onto stack:
|
jbe@155
|
389 json_pushnullmark(L);
|
jbe@153
|
390 } else {
|
jbe@153
|
391 // if top-level,
|
jbe@153
|
392 // push nil onto stack:
|
jbe@153
|
393 lua_pushnil(L);
|
jbe@153
|
394 }
|
jbe@121
|
395 } else {
|
jbe@136
|
396 // all other cases are a syntax error:
|
jbe@121
|
397 goto json_import_syntax_error;
|
jbe@121
|
398 }
|
jbe@136
|
399 // process a decoded value or key value pair (expected on top of Lua stack):
|
jbe@136
|
400 json_import_process_value:
|
jbe@121
|
401 switch (mode) {
|
jbe@136
|
402 // an object key has been read:
|
jbe@124
|
403 case JSON_STATE_OBJECT_KEY:
|
jbe@136
|
404 // if an object key is not a string, then this is a syntax error:
|
jbe@121
|
405 if (lua_type(L, -1) != LUA_TSTRING) goto json_import_syntax_error;
|
jbe@146
|
406 // expect key terminator to follow:
|
jbe@124
|
407 mode = JSON_STATE_OBJECT_KEY_TERMINATOR;
|
jbe@146
|
408 // continue with loop:
|
jbe@121
|
409 goto json_import_loop;
|
jbe@136
|
410 // a key value pair has been read:
|
jbe@124
|
411 case JSON_STATE_OBJECT_VALUE:
|
jbe@136
|
412 // store key value pair in outer shadow table:
|
jbe@130
|
413 lua_rawset(L, -3);
|
jbe@146
|
414 // expect value terminator (or end of object) to follow:
|
jbe@124
|
415 mode = JSON_STATE_OBJECT_SEPARATOR;
|
jbe@146
|
416 // continue with loop:
|
jbe@121
|
417 goto json_import_loop;
|
jbe@136
|
418 // an array value has been read:
|
jbe@124
|
419 case JSON_STATE_ARRAY_VALUE:
|
jbe@152
|
420 // get current array length:
|
jbe@152
|
421 arraylen = lua_rawlen(L, -3);
|
jbe@152
|
422 // throw error if array would exceed INT_MAX elements:
|
jbe@152
|
423 // TODO: Lua 5.3 may support more elements
|
jbe@152
|
424 if (arraylen >= INT_MAX) {
|
jbe@152
|
425 lua_pushnil(L);
|
jbe@152
|
426 lua_pushfstring(L, "Array exceeded length of %d elements", INT_MAX);
|
jbe@152
|
427 }
|
jbe@136
|
428 // store value in outer shadow table:
|
jbe@152
|
429 lua_rawseti(L, -3, arraylen + 1);
|
jbe@146
|
430 // expect value terminator (or end of object) to follow:
|
jbe@124
|
431 mode = JSON_STATE_ARRAY_SEPARATOR;
|
jbe@146
|
432 // continue with loop
|
jbe@121
|
433 goto json_import_loop;
|
jbe@136
|
434 // a single value has been read:
|
jbe@124
|
435 case JSON_STATE_VALUE:
|
jbe@136
|
436 // leave value on top of stack, expect end of JSON document, and continue with loop:
|
jbe@124
|
437 mode = JSON_STATE_END;
|
jbe@121
|
438 goto json_import_loop;
|
jbe@121
|
439 }
|
jbe@146
|
440 // syntax error handling (reachable by goto statement):
|
jbe@136
|
441 json_import_syntax_error:
|
jbe@121
|
442 lua_pushnil(L);
|
jbe@121
|
443 lua_pushliteral(L, "Syntax error in JSON document");
|
jbe@121
|
444 return 2;
|
jbe@121
|
445 }
|
jbe@121
|
446
|
jbe@146
|
447 // special Lua stack indicies for json_path function:
|
jbe@138
|
448 #define json_path_shadowtbl_idx 1
|
jbe@146
|
449
|
jbe@146
|
450 // stack offset of arguments to json_path function:
|
jbe@155
|
451 #define json_path_idxshift 1
|
jbe@138
|
452
|
jbe@146
|
453 // gets a value or its type from a JSON document (passed as first argument)
|
jbe@147
|
454 // using a path (passed as variable number of keys after first argument):
|
jbe@137
|
455 static int json_path(lua_State *L, int type_mode) {
|
jbe@146
|
456 int stacktop; // stack index of top of stack (after shifting)
|
jbe@146
|
457 int idx = 2 + json_path_idxshift; // stack index of current argument to process
|
jbe@148
|
458 // insert shadowtbl into stack at position 1 (shifting the arguments):
|
jbe@144
|
459 json_regfetch(L, shadowtbl);
|
jbe@138
|
460 lua_insert(L, 1);
|
jbe@146
|
461 // store stack index of top of stack:
|
jbe@138
|
462 stacktop = lua_gettop(L);
|
jbe@146
|
463 // use first argument as "current value" (stored on top of stack):
|
jbe@138
|
464 lua_pushvalue(L, 1 + json_path_idxshift);
|
jbe@146
|
465 // process each "path key" (2nd argument and following arguments):
|
jbe@138
|
466 while (idx <= stacktop) {
|
jbe@146
|
467 // if "current value" (on top of stack) is nil, then the path cannot be walked and nil is returned:
|
jbe@137
|
468 if (lua_isnil(L, -1)) return 1;
|
jbe@137
|
469 // try to get shadow table of "current value":
|
jbe@130
|
470 lua_pushvalue(L, -1);
|
jbe@138
|
471 lua_rawget(L, json_path_shadowtbl_idx);
|
jbe@126
|
472 if (lua_isnil(L, -1)) {
|
jbe@137
|
473 // if no shadow table is found,
|
jbe@130
|
474 if (lua_type(L, -1) == LUA_TTABLE) {
|
jbe@146
|
475 // and if "current value" is a table,
|
jbe@146
|
476 // drop nil from stack:
|
jbe@146
|
477 lua_pop(L, 1);
|
jbe@137
|
478 // get "next value" using the "path key":
|
jbe@130
|
479 lua_pushvalue(L, idx++);
|
jbe@130
|
480 lua_gettable(L, -2);
|
jbe@130
|
481 } else {
|
jbe@137
|
482 // if "current value" is not a table,
|
jbe@146
|
483 // then the path cannot be walked and nil (already on top of stack) is returned:
|
jbe@137
|
484 return 1;
|
jbe@130
|
485 }
|
jbe@130
|
486 } else {
|
jbe@137
|
487 // if a shadow table is found,
|
jbe@137
|
488 // set "current value" to its shadow table:
|
jbe@130
|
489 lua_replace(L, -2);
|
jbe@137
|
490 // get "next value" using the "path key":
|
jbe@130
|
491 lua_pushvalue(L, idx++);
|
jbe@130
|
492 lua_rawget(L, -2);
|
jbe@126
|
493 }
|
jbe@137
|
494 // the "next value" replaces the "current value":
|
jbe@130
|
495 lua_replace(L, -2);
|
jbe@126
|
496 }
|
jbe@137
|
497 if (!type_mode) {
|
jbe@137
|
498 // if a value (and not its type) was requested,
|
jbe@137
|
499 // check if value is the null-marker, and store nil on top of Lua stack in that case:
|
jbe@155
|
500 if (json_isnullmark(L, -1)) lua_pushnil(L);
|
jbe@137
|
501 } else {
|
jbe@137
|
502 // if the type was requested,
|
jbe@137
|
503 // check if value is the null-marker:
|
jbe@155
|
504 if (json_isnullmark(L, -1)) {
|
jbe@137
|
505 // if yes, store string "null" on top of Lua stack:
|
jbe@130
|
506 lua_pushliteral(L, "null");
|
jbe@137
|
507 } else {
|
jbe@137
|
508 // otherwise,
|
jbe@138
|
509 // check if metatable indicates "object" or "array":
|
jbe@138
|
510 if (lua_getmetatable(L, -1)) {
|
jbe@144
|
511 json_regfetch(L, objectmt);
|
jbe@138
|
512 if (lua_rawequal(L, -2, -1)) {
|
jbe@146
|
513 // if value has metatable for JSON objects,
|
jbe@138
|
514 // return string "object":
|
jbe@138
|
515 lua_pushliteral(L, "object");
|
jbe@138
|
516 return 1;
|
jbe@138
|
517 }
|
jbe@144
|
518 json_regfetch(L, arraymt);
|
jbe@138
|
519 if (lua_rawequal(L, -3, -1)) {
|
jbe@146
|
520 // if value has metatable for JSON arrays,
|
jbe@146
|
521 // return string "object":
|
jbe@138
|
522 lua_pushliteral(L, "array");
|
jbe@138
|
523 return 1;
|
jbe@138
|
524 }
|
jbe@146
|
525 // remove 3 metatables (one of the value, two for comparison) from stack:
|
jbe@138
|
526 lua_pop(L, 3);
|
jbe@138
|
527 }
|
jbe@138
|
528 // otherwise, get the Lua type:
|
jbe@138
|
529 lua_pushstring(L, lua_typename(L, lua_type(L, -1)));
|
jbe@126
|
530 }
|
jbe@126
|
531 }
|
jbe@137
|
532 // return the top most value on the Lua stack:
|
jbe@137
|
533 return 1;
|
jbe@130
|
534 }
|
jbe@130
|
535
|
jbe@147
|
536 // gets a value from a JSON document (passed as first argument)
|
jbe@147
|
537 // using a path (passed as variable number of keys after first argument):
|
jbe@130
|
538 static int json_get(lua_State *L) {
|
jbe@137
|
539 return json_path(L, 0);
|
jbe@130
|
540 }
|
jbe@130
|
541
|
jbe@147
|
542 // gets a value's type from a JSON document (passed as first argument)
|
jbe@147
|
543 // using a path (variable number of keys after first argument):
|
jbe@130
|
544 static int json_type(lua_State *L) {
|
jbe@137
|
545 return json_path(L, 1);
|
jbe@130
|
546 }
|
jbe@130
|
547
|
jbe@147
|
548 // returns the length of a JSON array (or zero for a table without numeric keys):
|
jbe@130
|
549 static int json_len(lua_State *L) {
|
jbe@147
|
550 // stack shall contain one function argument:
|
jbe@130
|
551 lua_settop(L, 1);
|
jbe@148
|
552 // try to get corresponding shadow table for first argument:
|
jbe@144
|
553 json_regfetch(L, shadowtbl);
|
jbe@130
|
554 lua_pushvalue(L, 1);
|
jbe@138
|
555 lua_rawget(L, -2);
|
jbe@147
|
556 // if shadow table does not exist, return length of argument, else length of shadow table:
|
jbe@147
|
557 lua_pushnumber(L, lua_rawlen(L, lua_isnil(L, -1) ? 1 : -1));
|
jbe@123
|
558 return 1;
|
jbe@123
|
559 }
|
jbe@123
|
560
|
jbe@130
|
561 static int json_index(lua_State *L) {
|
jbe@148
|
562 // stack shall contain two function arguments:
|
jbe@130
|
563 lua_settop(L, 2);
|
jbe@155
|
564 // get corresponding shadow table for first argument:
|
jbe@144
|
565 json_regfetch(L, shadowtbl);
|
jbe@130
|
566 lua_pushvalue(L, 1);
|
jbe@155
|
567 lua_rawget(L, -2);
|
jbe@148
|
568 // throw error if no shadow table was found:
|
jbe@139
|
569 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
|
jbe@148
|
570 // use key passed as second argument to lookup value in shadow table:
|
jbe@130
|
571 lua_pushvalue(L, 2);
|
jbe@130
|
572 lua_rawget(L, -2);
|
jbe@148
|
573 // if value is null-marker, then push nil onto stack:
|
jbe@155
|
574 if (json_isnullmark(L, -1)) lua_pushnil(L);
|
jbe@148
|
575 // return either looked up value, or nil
|
jbe@127
|
576 return 1;
|
jbe@127
|
577 }
|
jbe@127
|
578
|
jbe@130
|
579 static int json_newindex(lua_State *L) {
|
jbe@148
|
580 // stack shall contain three function arguments:
|
jbe@130
|
581 lua_settop(L, 3);
|
jbe@148
|
582 // get corresponding shadow table for first argument:
|
jbe@144
|
583 json_regfetch(L, shadowtbl);
|
jbe@123
|
584 lua_pushvalue(L, 1);
|
jbe@143
|
585 lua_rawget(L, -2);
|
jbe@148
|
586 // throw error if no shadow table was found:
|
jbe@130
|
587 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
|
jbe@148
|
588 // replace first argument with shadow table:
|
jbe@130
|
589 lua_replace(L, 1);
|
jbe@148
|
590 // reset stack and use second and third argument to write to shadow table:
|
jbe@139
|
591 lua_settop(L, 3);
|
jbe@130
|
592 lua_rawset(L, 1);
|
jbe@148
|
593 // return nothing:
|
jbe@148
|
594 return 0;
|
jbe@121
|
595 }
|
jbe@121
|
596
|
jbe@135
|
597 static int json_pairs_iterfunc(lua_State *L) {
|
jbe@149
|
598 // stack shall contain two function arguments:
|
jbe@135
|
599 lua_settop(L, 2);
|
jbe@155
|
600 // get corresponding shadow table for first argument:
|
jbe@144
|
601 json_regfetch(L, shadowtbl);
|
jbe@135
|
602 lua_pushvalue(L, 1);
|
jbe@155
|
603 lua_rawget(L, -2);
|
jbe@149
|
604 // throw error if no shadow table was found:
|
jbe@135
|
605 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
|
jbe@149
|
606 // get next key value pair from shadow table (using previous key from argument 2)
|
jbe@149
|
607 // and return nothing if there is no next pair:
|
jbe@135
|
608 lua_pushvalue(L, 2);
|
jbe@135
|
609 if (!lua_next(L, -2)) return 0;
|
jbe@149
|
610 // replace null-marker with nil:
|
jbe@155
|
611 if (json_isnullmark(L, -1)) {
|
jbe@135
|
612 lua_pop(L, 1);
|
jbe@135
|
613 lua_pushnil(L);
|
jbe@135
|
614 }
|
jbe@149
|
615 // return key and value (or key and nil, if null-marker was found):
|
jbe@135
|
616 return 2;
|
jbe@135
|
617 }
|
jbe@135
|
618
|
jbe@149
|
619 // returns a triple such that 'for key, value in pairs(obj) do ... end'
|
jbe@149
|
620 // iterates through all key value pairs (including JSON null keys represented as Lua nil):
|
jbe@135
|
621 static int json_pairs(lua_State *L) {
|
jbe@149
|
622 // return triple of function json_pairs_iterfunc, first argument, and nil:
|
jbe@139
|
623 lua_pushcfunction(L, json_pairs_iterfunc);
|
jbe@135
|
624 lua_pushvalue(L, 1);
|
jbe@135
|
625 lua_pushnil(L);
|
jbe@135
|
626 return 3;
|
jbe@135
|
627 }
|
jbe@135
|
628
|
jbe@134
|
629 static int json_ipairs_iterfunc(lua_State *L) {
|
jbe@152
|
630 lua_Integer idx;
|
jbe@149
|
631 // stack shall contain two function arguments:
|
jbe@134
|
632 lua_settop(L, 2);
|
jbe@149
|
633 // calculate new index by incrementing second argument:
|
jbe@134
|
634 idx = lua_tointeger(L, 2) + 1;
|
jbe@149
|
635 // get corresponding shadow table for first argument:
|
jbe@155
|
636 json_regfetch(L, shadowtbl);
|
jbe@134
|
637 lua_pushvalue(L, 1);
|
jbe@155
|
638 lua_rawget(L, -2);
|
jbe@149
|
639 // throw error if no shadow table was found:
|
jbe@134
|
640 if (lua_isnil(L, -1)) return luaL_error(L, "Shadow table not found");
|
jbe@149
|
641 // do integer lookup in shadow table:
|
jbe@134
|
642 lua_rawgeti(L, -1, idx);
|
jbe@149
|
643 // return nothing if there was no value:
|
jbe@134
|
644 if (lua_isnil(L, -1)) return 0;
|
jbe@149
|
645 // return new index and
|
jbe@149
|
646 // either the looked up value if it is not equal to the null-marker
|
jbe@149
|
647 // or nil instead of null-marker:
|
jbe@134
|
648 lua_pushinteger(L, idx);
|
jbe@155
|
649 if (json_isnullmark(L, -2)) lua_pushnil(L);
|
jbe@134
|
650 else lua_pushvalue(L, -2);
|
jbe@134
|
651 return 2;
|
jbe@134
|
652 }
|
jbe@134
|
653
|
jbe@149
|
654 // returns a triple such that 'for idx, value in ipairs(ary) do ... end'
|
jbe@149
|
655 // iterates through all values (including JSON null represented as Lua nil):
|
jbe@134
|
656 static int json_ipairs(lua_State *L) {
|
jbe@149
|
657 // return triple of function json_ipairs_iterfunc, first argument, and zero:
|
jbe@139
|
658 lua_pushcfunction(L, json_ipairs_iterfunc);
|
jbe@134
|
659 lua_pushvalue(L, 1);
|
jbe@134
|
660 lua_pushinteger(L, 0);
|
jbe@134
|
661 return 3;
|
jbe@134
|
662 }
|
jbe@134
|
663
|
jbe@154
|
664 #define JSON_TABLETYPE_UNKNOWN 0
|
jbe@154
|
665 #define JSON_TABLETYPE_OBJECT 1
|
jbe@154
|
666 #define JSON_TABLETYPE_ARRAY 2
|
jbe@154
|
667
|
jbe@154
|
668 static int json_export(lua_State *L) {
|
jbe@154
|
669 lua_Number num;
|
jbe@154
|
670 const char *str;
|
jbe@154
|
671 unsigned char c;
|
jbe@154
|
672 size_t strlen;
|
jbe@154
|
673 size_t pos = 0;
|
jbe@154
|
674 luaL_Buffer buf;
|
jbe@154
|
675 char hexcode[7]; // backslash, character 'u', 4 hex digits, and terminating NULL byte
|
jbe@154
|
676 int luatype;
|
jbe@154
|
677 int tabletype = JSON_TABLETYPE_UNKNOWN;
|
jbe@154
|
678 int needsep = 0;
|
jbe@154
|
679 lua_Integer idx;
|
jbe@154
|
680 lua_settop(L, 1);
|
jbe@157
|
681 if (json_isnullmark(L, 1)) {
|
jbe@157
|
682 lua_pushnil(L);
|
jbe@157
|
683 lua_replace(L, 1);
|
jbe@157
|
684 }
|
jbe@154
|
685 switch (lua_type(L, 1)) {
|
jbe@154
|
686 case LUA_TNIL:
|
jbe@154
|
687 lua_pushliteral(L, "null");
|
jbe@154
|
688 return 1;
|
jbe@154
|
689 case LUA_TNUMBER:
|
jbe@154
|
690 num = lua_tonumber(L, 1);
|
jbe@154
|
691 if (isnan(num)) return luaL_error(L, "JSON export not possible for NaN value");
|
jbe@154
|
692 if (isinf(num)) return luaL_error(L, "JSON export not possible for infinite numbers");
|
jbe@154
|
693 lua_tostring(L, 1);
|
jbe@154
|
694 return 1;
|
jbe@154
|
695 case LUA_TBOOLEAN:
|
jbe@154
|
696 if (lua_toboolean(L, 1)) lua_pushliteral(L, "true");
|
jbe@154
|
697 else lua_pushliteral(L, "false");
|
jbe@154
|
698 return 1;
|
jbe@154
|
699 case LUA_TSTRING:
|
jbe@154
|
700 str = lua_tolstring(L, 1, &strlen);
|
jbe@154
|
701 luaL_buffinit(L, &buf);
|
jbe@154
|
702 luaL_addchar(&buf, '"');
|
jbe@154
|
703 while (pos < strlen) {
|
jbe@154
|
704 c = str[pos++];
|
jbe@154
|
705 if (c == '"') luaL_addstring(&buf, "\\\"");
|
jbe@154
|
706 else if (c == '\\') luaL_addstring(&buf, "\\\\");
|
jbe@154
|
707 else if (c == 127) luaL_addstring(&buf, "\\u007F");
|
jbe@154
|
708 else if (c >= 32) luaL_addchar(&buf, c);
|
jbe@154
|
709 else if (c == '\b') luaL_addstring(&buf, "\\b");
|
jbe@154
|
710 else if (c == '\f') luaL_addstring(&buf, "\\f");
|
jbe@154
|
711 else if (c == '\n') luaL_addstring(&buf, "\\n");
|
jbe@154
|
712 else if (c == '\r') luaL_addstring(&buf, "\\r");
|
jbe@154
|
713 else if (c == '\t') luaL_addstring(&buf, "\\t");
|
jbe@154
|
714 else if (c == '\v') luaL_addstring(&buf, "\\v");
|
jbe@154
|
715 else {
|
jbe@154
|
716 sprintf(hexcode, "\\u%04X", c);
|
jbe@154
|
717 luaL_addstring(&buf, hexcode);
|
jbe@154
|
718 }
|
jbe@154
|
719 }
|
jbe@154
|
720 luaL_addchar(&buf, '"');
|
jbe@154
|
721 luaL_pushresult(&buf);
|
jbe@154
|
722 return 1;
|
jbe@154
|
723 case LUA_TTABLE:
|
jbe@154
|
724 if (lua_getmetatable(L, 1)) {
|
jbe@154
|
725 json_regfetch(L, objectmt);
|
jbe@154
|
726 if (lua_rawequal(L, -2, -1)) {
|
jbe@154
|
727 tabletype = JSON_TABLETYPE_OBJECT;
|
jbe@154
|
728 } else {
|
jbe@154
|
729 json_regfetch(L, arraymt);
|
jbe@154
|
730 if (lua_rawequal(L, -3, -1)) tabletype = JSON_TABLETYPE_ARRAY;
|
jbe@154
|
731 }
|
jbe@154
|
732 }
|
jbe@154
|
733 json_regfetch(L, shadowtbl);
|
jbe@154
|
734 lua_pushvalue(L, 1);
|
jbe@154
|
735 lua_rawget(L, -2);
|
jbe@154
|
736 if (!lua_isnil(L, -1)) lua_replace(L, 1);
|
jbe@154
|
737 lua_settop(L, 1);
|
jbe@154
|
738 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
|
jbe@154
|
739 for (lua_pushnil(L); lua_next(L, 1); lua_pop(L, 1)) {
|
jbe@154
|
740 luatype = lua_type(L, -2);
|
jbe@154
|
741 if (tabletype == JSON_TABLETYPE_UNKNOWN) {
|
jbe@154
|
742 if (luatype == LUA_TSTRING) tabletype = JSON_TABLETYPE_OBJECT;
|
jbe@154
|
743 else if (luatype == LUA_TNUMBER) tabletype = JSON_TABLETYPE_ARRAY;
|
jbe@154
|
744 } else if (
|
jbe@154
|
745 (tabletype == JSON_TABLETYPE_OBJECT && luatype == LUA_TNUMBER) ||
|
jbe@154
|
746 (tabletype == JSON_TABLETYPE_ARRAY && luatype == LUA_TSTRING)
|
jbe@154
|
747 ) {
|
jbe@154
|
748 goto json_export_tabletype_error;
|
jbe@154
|
749 }
|
jbe@154
|
750 }
|
jbe@154
|
751 }
|
jbe@154
|
752 switch (tabletype) {
|
jbe@154
|
753 case JSON_TABLETYPE_OBJECT:
|
jbe@154
|
754 lua_settop(L, 3);
|
jbe@154
|
755 luaL_buffinit(L, &buf);
|
jbe@154
|
756 luaL_addchar(&buf, '{');
|
jbe@154
|
757 for (lua_pushnil(L); lua_next(L, 1); ) {
|
jbe@154
|
758 if (lua_type(L, -2) == LUA_TSTRING) {
|
jbe@154
|
759 lua_replace(L, 3);
|
jbe@154
|
760 lua_replace(L, 2);
|
jbe@154
|
761 if (needsep) luaL_addchar(&buf, ',');
|
jbe@154
|
762 else needsep = 1;
|
jbe@154
|
763 lua_pushcfunction(L, json_export);
|
jbe@154
|
764 lua_pushvalue(L, 2);
|
jbe@154
|
765 lua_call(L, 1, 1);
|
jbe@154
|
766 luaL_addvalue(&buf);
|
jbe@154
|
767 luaL_addchar(&buf, ':');
|
jbe@155
|
768 if (json_isnullmark(L, 3)) {
|
jbe@154
|
769 luaL_addstring(&buf, "null");
|
jbe@154
|
770 } else {
|
jbe@154
|
771 lua_pushcfunction(L, json_export);
|
jbe@154
|
772 lua_pushvalue(L, 3);
|
jbe@154
|
773 lua_call(L, 1, 1);
|
jbe@154
|
774 luaL_addvalue(&buf);
|
jbe@154
|
775 }
|
jbe@154
|
776 lua_pushvalue(L, 2);
|
jbe@154
|
777 } else {
|
jbe@154
|
778 lua_pop(L, 1);
|
jbe@154
|
779 }
|
jbe@154
|
780 }
|
jbe@154
|
781 luaL_addchar(&buf, '}');
|
jbe@154
|
782 luaL_pushresult(&buf);
|
jbe@154
|
783 return 1;
|
jbe@154
|
784 case JSON_TABLETYPE_ARRAY:
|
jbe@154
|
785 lua_settop(L, 2);
|
jbe@154
|
786 luaL_buffinit(L, &buf);
|
jbe@154
|
787 luaL_addchar(&buf, '[');
|
jbe@154
|
788 for (idx = 1; ; idx++) {
|
jbe@154
|
789 lua_rawgeti(L, 1, idx);
|
jbe@154
|
790 if (lua_isnil(L, -1)) {
|
jbe@154
|
791 lua_pop(L, 1);
|
jbe@154
|
792 break;
|
jbe@154
|
793 }
|
jbe@154
|
794 lua_replace(L, 2);
|
jbe@154
|
795 if (needsep) luaL_addchar(&buf, ',');
|
jbe@154
|
796 else needsep = 1;
|
jbe@154
|
797 lua_pushcfunction(L, json_export);
|
jbe@154
|
798 lua_pushvalue(L, 2);
|
jbe@154
|
799 lua_call(L, 1, 1);
|
jbe@154
|
800 luaL_addvalue(&buf);
|
jbe@154
|
801 }
|
jbe@154
|
802 luaL_addchar(&buf, ']');
|
jbe@154
|
803 luaL_pushresult(&buf);
|
jbe@154
|
804 return 1;
|
jbe@154
|
805 }
|
jbe@154
|
806 json_export_tabletype_error:
|
jbe@154
|
807 return luaL_error(L, "JSON export not possible for ambiguous table (cannot decide whether it is an object or array)");
|
jbe@154
|
808 }
|
jbe@154
|
809 return luaL_error(L, "JSON export not possible for values of type \"%s\"", lua_typename(L, lua_type(L, 1)));
|
jbe@154
|
810 }
|
jbe@154
|
811
|
jbe@149
|
812 // functions in library module:
|
jbe@121
|
813 static const struct luaL_Reg json_module_functions[] = {
|
jbe@133
|
814 {"object", json_object},
|
jbe@133
|
815 {"array", json_array},
|
jbe@121
|
816 {"import", json_import},
|
jbe@154
|
817 {"export", json_export},
|
jbe@130
|
818 {"get", json_get},
|
jbe@127
|
819 {"type", json_type},
|
jbe@121
|
820 {NULL, NULL}
|
jbe@121
|
821 };
|
jbe@121
|
822
|
jbe@149
|
823 // metamethods for JSON objects, JSON arrays, and unknown JSON collections (object or array):
|
jbe@126
|
824 static const struct luaL_Reg json_metatable_functions[] = {
|
jbe@130
|
825 {"__len", json_len},
|
jbe@130
|
826 {"__index", json_index},
|
jbe@130
|
827 {"__newindex", json_newindex},
|
jbe@135
|
828 {"__pairs", json_pairs},
|
jbe@134
|
829 {"__ipairs", json_ipairs},
|
jbe@160
|
830 {"__tostring", json_export},
|
jbe@126
|
831 {NULL, NULL}
|
jbe@126
|
832 };
|
jbe@126
|
833
|
jbe@157
|
834 // metamethods for JSON null marker:
|
jbe@157
|
835 static const struct luaL_Reg json_nullmark_metamethods[] = {
|
jbe@157
|
836 {"__tostring", json_nullmark_tostring},
|
jbe@157
|
837 {NULL, NULL}
|
jbe@157
|
838 };
|
jbe@157
|
839
|
jbe@149
|
840 // initializes json library:
|
jbe@121
|
841 int luaopen_json(lua_State *L) {
|
jbe@149
|
842 // empty stack:
|
jbe@126
|
843 lua_settop(L, 0);
|
jbe@149
|
844 // push library module onto stack position 1:
|
jbe@149
|
845 lua_newtable(L);
|
jbe@149
|
846 // register library functions:
|
jbe@149
|
847 luaL_setfuncs(L, json_module_functions, 0);
|
jbe@149
|
848 // create and store objectmt:
|
jbe@138
|
849 lua_newtable(L);
|
jbe@138
|
850 luaL_setfuncs(L, json_metatable_functions, 0);
|
jbe@144
|
851 json_regstore(L, objectmt);
|
jbe@149
|
852 // create and store arraymt:
|
jbe@138
|
853 lua_newtable(L);
|
jbe@138
|
854 luaL_setfuncs(L, json_metatable_functions, 0);
|
jbe@144
|
855 json_regstore(L, arraymt);
|
jbe@149
|
856 // create and store ephemeron table to store shadow tables for each JSON object/array
|
jbe@149
|
857 // to allow NULL values returned as nil
|
jbe@149
|
858 lua_newtable(L);
|
jbe@138
|
859 lua_newtable(L); // metatable for ephemeron table
|
jbe@121
|
860 lua_pushliteral(L, "__mode");
|
jbe@121
|
861 lua_pushliteral(L, "k");
|
jbe@138
|
862 lua_rawset(L, -3);
|
jbe@138
|
863 lua_setmetatable(L, -2);
|
jbe@144
|
864 json_regstore(L, shadowtbl);
|
jbe@157
|
865 // set metatable of null marker and make it available through library module:
|
jbe@157
|
866 json_pushnullmark(L);
|
jbe@157
|
867 lua_newtable(L);
|
jbe@157
|
868 luaL_setfuncs(L, json_nullmark_metamethods, 0);
|
jbe@157
|
869 lua_setmetatable(L, -2);
|
jbe@157
|
870 lua_setfield(L, 1, "null");
|
jbe@157
|
871 // return library module (that's expected on top of stack):
|
jbe@121
|
872 return 1;
|
jbe@121
|
873 }
|