JSMN, a JSON minimal parser, ported for Adventure Game Studio.
If you wish to handle things more manually, you can use a thiner parser that is also faster:
String json_string = "{ \"name\":\"John\", \"age\":30, \"car\":null }";
JsonParser* parser = new JsonParser;
int token_count = 8;
JsonToken* t[] = JsonToken.NewArray(token_count);
int r = parser.Parse(json_string, t, token_count);
// now that you have the Tokens, you can use them to parse as you wish!
if (r < 0) Display("Failed to parse JSON: %d\n", r);
if (r < 1 || t[0].type != eJSON_Tok_OBJECT) Display("Object expected\n");
for(int i=0; i<r ; i++){
JsonToken* tok = t[i];
Display(String.Format("%d ; %s ; %d ; %s ; %d ; %d ; %d",
i, tok.ToString(json_string), tok.size , tok.TypeAsString, tok.start , tok.end , tok.parent ));
}
Display("JSON Parsing has FINISHED for string\n\n%s", json_string);This module also packs a more approacheable (but less tested) parser:
String json_string = "";
json_string = json_string.Append("{\"squadName\":\"Super squad\",\"formed\":2016,\"active\":true,\"members\":[");
json_string = json_string.Append("{\"name\":\"Molecule Man\",\"age\":29,\"secretIdentity\":\"Dan Jukes\",\"powers\":[\"Radiation resistance\",\"Radiation blast\"]},");
json_string = json_string.Append("{\"name\":\"Madam Uppercut\",\"age\":39,\"secretIdentity\":\"Jane Wilson\",\"powers\":[\"Million punch\",\"Super reflexes\"]},");
json_string = json_string.Append("{\"name\":\"Eternal Flame\",\"age\":100,\"secretIdentity\":\"Unknown\",\"powers\":[\"Immortality\",\"Heat Immunity\",\"Interdimensional jump\"]}]}");
MiniJsonParser jp;
jp.Init(json_string); // parse json_string and internally generate the tokens
while(jp.NextToken()) // advance the current token and exit when there are no tokens left
{
if(jp.CurrentTokenIsLeaf) // usually the interesting information is on the leafs
{
Display(String.Format("%s: %s", jp.CurrentFullKey, jp.CurrentTokenAsString));
}
}
Display("JSON Parsing has FINISHED for string\n\n%s", json_string);int JsonParser.Parse(String json_string, JsonToken *tokens[], int num_tokens)
Parses a JSON data string into and array of tokens, each describing a single JSON object. Negative return is a JsonError, otherwise it's the number of used tokens.
void JsonParser.Reset()
Marks the parser for reset, useful if you want to use it again with a different file. Reset only actually happens when Parse is called.
int JsonParser.pos
offset in the JSON string
int JsonParser.toknext
next token to allocate
int JsonParser.toksuper
superior token node, e.g. parent object or array
static JsonToken* [] JsonToken.NewArray(int count)
Static helper to ease Token Array creation. Ex: JsonToken* t[] = JsonToken.NewArray(token_count);
String JsonToken.ToString(String json_string)
pass the json_string that was parsed and generated this token to recover the string this token refers to
JsonTokenType JsonToken.type
The type of the token: object, array, string etc.
int JsonToken.start
The start position in JSON data string.
int JsonToken.end
The end position in JSON data string.
int JsonToken.size
The size tells about the direct children of the token, 0 if it's a leaf value, 1 or bigger if it's a key or object/array.
int JsonToken.parent
If it's a child, is the index position of the parent in the token array.
readonly attribute Strin JsonToken.TypeAsString
Utility function for debugging, returns the type of the token in a String format.
eJSON_Tok_UNDEFINED, a valid token should never have this type.eJSON_Tok_OBJECT, an object, it holds keys and values, values can be any other type.eJSON_Tok_ARRAY, an array, the token will contain direct ordered children.eJSON_Tok_STRING, the token is a string, could be a key, could be a value, context is needed.eJSON_Tok_PRIMITIVE, the token is either a number (float or integer), a boolean (trueorfalse) ornull.
Used to check parse results.
eJSON_Error_InsuficientTokens, Not enough tokens were provided. Please use more tokens.eJSON_Error_InvalidCharacter, Invalid character inside JSON string.eJSON_Error_Partial, The string is not a full JSON packet, more bytes expected.
void MiniJsonParser.Init(String json_string)
Initialize the parser passing a JSON as a string. Common usage is: MiniJsonParser jp; jp.Init(json_string);.
bool MiniJsonParser.NextToken()
Advances to the next token. Returns false if no tokens left.
readonly attribute String MiniJsonParser.CurrentTokenAsString
The current token content, as a String.
readonly attribute JsonTokenType MiniJsonParser.CurrentTokenType
The current token type.
readonly attribute int MiniJsonParser.CurrentTokenSize
The current token size, 0 if it's a leaf value, 1 or bigger if it's a key or object/array.
readonly attribute MiniJsonParserState MiniJsonParser.CurrentState
The current state of our mini parser. Helps understanding the JSON tokens we got when parsing.
readonly attribute String MiniJsonParser.CurrentFullKey
Gets the current dot separated key.
readonly attribute bool MiniJsonParser.CurrentTokenIsLeaf
Checks if the state and key type currently are a leaf. True if it's, usually leafs are the interesting tokens we want when parsing.
eJP_State_START, The parser just started.eJP_State_KEY, The current token is key in an object.eJP_State_VALUE, The current token is a value in an object.eJP_State_ARRVALUE, The current token is a value in an array.eJP_State_STOP, Don't parse anything in this state, but the parser is not necessarily done.
This code is licensed with MIT LICENSE. The code on this module is based on Serge's JSMN, which is also MIT licensed and is referenced in the license.