Merge pull request #1272 from BaerMitUmlaut/json-parser

Add JSON parse and encode function

addons/hashes/CfgFunctions.hpp

@@ -14,6 +14,8 @@ class CfgFunctions {
             PATHTO_FNC(parseYAML);
             PATHTO_FNC(serializeNamespace);
             PATHTO_FNC(deserializeNamespace);
+            PATHTO_FNC(encodeJSON);
+            PATHTO_FNC(parseJSON);
         };
     };
 };

addons/hashes/fnc_encodeJSON.sqf

@@ -0,0 +1,95 @@
+#include "script_component.hpp"
+/* ----------------------------------------------------------------------------
+Function: CBA_fnc_encodeJSON
+
+Description:
+    Serializes input to a JSON string. Can handle
+    - ARRAY
+    - BOOL
+    - CONTROL
+    - GROUP
+    - LOCATION
+    - NAMESPACE
+    - NIL (ANY)
+    - NUMBER
+    - OBJECT
+    - STRING
+    - TASK
+    - TEAM_MEMBER
+    - Everything else will simply be stringified.
+
+Parameters:
+    _object - Object to serialize. <ARRAY, ...>
+
+Returns:
+    _json   - JSON string containing serialized object.
+
+Examples:
+    (begin example)
+        private _settings = call CBA_fnc_createNamespace;
+        _settings setVariable ["enabled", true];
+        private _json = [_settings] call CBA_fnc_encodeJSON;
+    (end)
+
+Author:
+    BaerMitUmlaut
+---------------------------------------------------------------------------- */
+SCRIPT(encodeJSON);
+params ["_object"];
+
+if (isNil "_object") exitWith { "null" };
+
+switch (typeName _object) do {
+    case "SCALAR";
+    case "BOOL": {
+        str _object;
+    };
+
+    case "STRING": {
+        {
+            _object = [_object, _x#0, _x#1] call CBA_fnc_replace;
+        } forEach [
+            ["\", "\\"],
+            ["""", "\"""],
+            [toString [8], "\b"],
+            [toString [12], "\f"],
+            [endl, "\n"],
+            [toString [10], "\n"],
+            [toString [13], "\r"],
+            [toString [9], "\t"]
+        ];
+        // Stringify without escaping inter string quote marks.
+        """" + _object + """"
+    };
+
+    case "ARRAY": {
+        if ([_object] call CBA_fnc_isHash) then {
+            private _json = (([_object] call CBA_fnc_hashKeys) apply {
+                private _name = _x;
+                private _value = [_object, _name] call CBA_fnc_hashGet;
+
+                format ["%1: %2", [_name] call CBA_fnc_encodeJSON, [_value] call CBA_fnc_encodeJSON]
+            }) joinString ", ";
+            "{" + _json + "}"
+        } else {
+            private _json = (_object apply {[_x] call CBA_fnc_encodeJSON}) joinString ", ";
+            "[" + _json + "]"
+        };
+    };
+
+    default {
+        if !(typeName _object in (supportInfo "u:allVariables*" apply {_x splitString " " select 1})) exitWith {
+            [str _object] call CBA_fnc_encodeJSON
+        };
+
+        if (isNull _object) exitWith { "null" };
+
+        private _json = ((allVariables _object) apply {
+            private _name = _x;
+            private _value = _object getVariable _name;
+
+            format ["%1: %2", [_name] call CBA_fnc_encodeJSON, [_value] call CBA_fnc_encodeJSON]
+        }) joinString ", ";
+        "{" + _json + "}"
+    };
+};

addons/hashes/fnc_parseJSON.sqf

@@ -0,0 +1,255 @@
+#include "script_component.hpp"
+/* ----------------------------------------------------------------------------
+Function: CBA_fnc_parseJSON
+
+Description:
+    Deserializes a JSON string.
+
+Parameters:
+    _json      - String containing valid JSON. <STRING>
+    _useHashes - Output CBA hashes instead of namespaces
+                 (optional, default: false) <BOOLEAN>
+
+Returns:
+    _object    - The deserialized JSON object or nil if JSON is invalid.
+                 <LOCATION, ARRAY, STRING, NUMBER, BOOL, NIL>
+
+Examples:
+    (begin example)
+        private _json = "{ ""enabled"": true }";
+        private _settings = [_json] call CBA_fnc_parseJSON;
+        private _enabled = _settings getVariable "enabled";
+
+        loadFile "data\config.json" call CBA_fnc_parseJSON
+        [preprocessFile "data\config.json", true] call CBA_fnc_parseJSON
+    (end)
+
+Author:
+    BaerMitUmlaut
+---------------------------------------------------------------------------- */
+SCRIPT(parseJSON);
+params ["_json", ["_useHashes", false]];
+
+// Wrappers for creating "objects" and setting values on them
+private ["_objectSet", "_createObject"];
+if (_useHashes) then {
+    _createObject = CBA_fnc_hashCreate;
+    _objectSet = CBA_fnc_hashSet;
+} else {
+    _createObject = CBA_fnc_createNamespace;
+    _objectSet = {
+        params ["_obj", "_key", "_val"];
+        _obj setVariable [_key, _val];
+    };
+};
+
+// Handles escaped characters, except for unicode escapes (\uXXXX)
+private _unescape = {
+    params ["_char"];
+
+    switch (_char) do {
+        case """": { """" };
+        case "\": { "\" };
+        case "/": { "/" };
+        case "b": { toString [8] };
+        case "f": { toString [12] };
+        case "n": { endl };
+        case "r": { toString [13] };
+        case "t": { toString [9] };
+        default { "" };
+    };
+};
+
+// Splits the input string into tokens
+// Tokens can be numbers, strings, null, true, false and symbols
+// Strings are prefixed with $ to distinguish them from symbols
+private _tokenize = {
+    params ["_input"];
+
+    // Split string into chars, works with unicode unlike splitString
+    _input = toArray _input apply {toString [_x]};
+
+    private _tokens  = [];
+    private _numeric = "+-.0123456789e" splitString "";
+    private _symbols = "{}[]:," splitString "";
+    private _consts  = "tfn" splitString "";
+
+    while {count _input > 0} do {
+        private _c = _input deleteAt 0;
+
+        switch (true) do {
+            // Symbols ({}[]:,) are passed directly into the tokens
+            case (_c in _symbols): {
+                _tokens pushBack _c;
+            };
+
+            // Number parsing
+            // This can fail with some invalid JSON numbers, like e10
+            // Those would require some additional logic or regex
+            // Valid numbers are all parsed correctly though
+            case (_c in _numeric): {
+                private _numStr = _c;
+                while { _c = _input deleteAt 0; !isNil "_c" && {_c in _numeric} } do {
+                    _numStr = _numStr + _c;
+                };
+                _tokens pushBack parseNumber _numStr;
+
+                if (!isNil "_c") then {
+                    _input = [_c] + _input;
+                };
+            };
+
+            // true, false and null
+            // Only check first char and assume JSON is valid
+            case (_c in _consts): {
+                switch (_c) do {
+                    case "t": {
+                        _input deleteRange [0, 3];
+                        _tokens pushBack true;
+                    };
+                    case "f": {
+                        _input deleteRange [0, 4];
+                        _tokens pushBack false;
+                    };
+                    case "n": {
+                        _input deleteRange [0, 3];
+                        _tokens pushBack objNull;
+                    };
+                };
+            };
+
+            // String parsing
+            case (_c == """"): {
+                private _str = "$";
+
+                while {true} do {
+                    _c = _input deleteAt 0;
+
+                    if (_c == """") exitWith {};
+
+                    if (_c == "\") then {
+                        _str = _str + ((_input deleteAt 0) call _unescape);
+                    } else {
+                        _str = _str + _c;
+                    };
+                };
+
+                _tokens pushBack _str;
+            };
+        };
+    };
+
+    _tokens
+};
+
+// Appends the next token to the parsing stack
+// Returns true unless no more tokens left
+private _shift = {
+    params ["_parseStack", "_tokens"];
+
+    if (count _tokens > 0) then {
+        _parseStack pushBack (_tokens deleteAt 0);
+        true
+    } else {
+        false
+    };
+};
+
+// Tries to reduce the current parsing stack (collect arrays or objects)
+// Returns true if parsing stack could be reduced
+private _reduce = {
+    params ["_parseStack", "_tokens"];
+
+    // Nothing to reduce
+    if (count _parseStack == 0) exitWith { false };
+
+    // Check top of stack
+    switch (_parseStack#(count _parseStack - 1)) do {
+
+        // Reached end of array, time to collect elements
+        case "]": {
+            private _array = [];
+
+            // Empty arrays need special handling
+            if !(_parseStack#(count _parseStack - 2) isEqualTo "[") then {
+                // Get next token, if [ beginning is reached, otherwise assume
+                // valid JSON and that the token is a comma
+                while {_parseStack deleteAt (count _parseStack - 1) != "["} do {
+                    private _element = _parseStack deleteAt (count _parseStack - 1);
+
+                    // Remove $ prefix from string
+                    if (_element isEqualType "") then {
+                        _element = _element select [1];
+                    };
+
+                    _array pushBack _element;
+                };
+
+                reverse _array;
+            } else {
+                _parseStack resize (count _parseStack - 2);
+            };
+
+            _parseStack pushBack _array;
+            true
+        };
+
+        // Reached end of array, time to collect elements
+        // Works very similar to arrays
+        case "}": {
+            private _object = [] call _createObject;
+
+            // Empty objects need special handling
+            if !(_parseStack#(count _parseStack - 2) isEqualTo "{") then {
+                // Get next token, if { beginning is reached, otherwise assume
+                // valid JSON and that token is comma
+                while {_parseStack deleteAt (count _parseStack - 1) != "{"} do {
+                    private _value = _parseStack deleteAt (count _parseStack - 1);
+                    private _colon = _parseStack deleteAt (count _parseStack - 1);
+                    private _name  = _parseStack deleteAt (count _parseStack - 1);
+
+                    // Remove $ prefix from strings
+                    if (_value isEqualType "") then {
+                        _value = _value select [1];
+                    };
+                    _name = _name select [1];
+
+                    [_object, _name, _value] call _objectSet;
+                };
+            } else {
+                _parseStack resize (count _parseStack - 2);
+            };
+
+            _parseStack pushBack _object;
+            true
+        };
+
+        default {
+            false
+        };
+    };
+};
+
+// Simple shift-reduce parser
+private _parse = {
+    params ["_tokens"];
+    private _parseStack = [];
+    private _params = [_parseStack, _tokens];
+
+    while { _params call _reduce || {_params call _shift} } do {};
+
+    if (count _parseStack != 1) then {
+        nil
+    } else {
+        private _object = _parseStack#0;
+
+        // If JSON is just a string, remove $ prefix from it
+        if (_object isEqualType "") then {
+            _object = _object select [1];
+        };
+
+        _object
+    };
+};
+
+[_json call _tokenize] call _parse

addons/hashes/test.sqf

@@ -5,7 +5,7 @@
 #define DEBUG_MODE_FULL
 #include "script_component.hpp"
 
-#define TESTS ["hashEachPair", "hashes", "parseYaml", "hashFilter"]
+#define TESTS ["hashEachPair", "hashes", "parseJSON", "parseYaml", "hashFilter"]
 
 SCRIPT(test-hashes);