[lua] use old/fast json parser

std/lua/_std/haxe/format/JsonParser.hx

@@ -0,0 +1,292 @@
+/*
+ * Copyright (C)2005-2019 Haxe Foundation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package haxe.format;
+
+/**
+	An implementation of JSON parser in Haxe.
+
+	This class is used by `haxe.Json` when native JSON implementation
+	is not available.
+
+	@see https://haxe.org/manual/std-Json-parsing.html
+**/
+class JsonParser {
+	/**
+		Parses given JSON-encoded `str` and returns the resulting object.
+
+		JSON objects are parsed into anonymous structures and JSON arrays
+		are parsed into `Array<Dynamic>`.
+
+		If given `str` is not valid JSON, an exception will be thrown.
+
+		If `str` is null, the result is unspecified.
+	**/
+	static public inline function parse(str:String):Dynamic {
+		return new JsonParser(str).doParse();
+	}
+
+	var str:String;
+	var pos:Int;
+
+	function new(str:String) {
+		this.str = str;
+		this.pos = 0;
+	}
+
+	function doParse():Dynamic {
+		var result = parseRec();
+		var c;
+		while (!StringTools.isEof(c = nextChar())) {
+			switch (c) {
+				case ' '.code, '\r'.code, '\n'.code, '\t'.code:
+				// allow trailing whitespace
+				default:
+					invalidChar();
+			}
+		}
+		return result;
+	}
+
+	function parseRec():Dynamic {
+		while (true) {
+			var c = nextChar();
+			switch (c) {
+				case ' '.code, '\r'.code, '\n'.code, '\t'.code:
+				// loop
+				case '{'.code:
+					var obj = {}, field = null, comma:Null<Bool> = null;
+					while (true) {
+						var c = nextChar();
+						switch (c) {
+							case ' '.code, '\r'.code, '\n'.code, '\t'.code:
+							// loop
+							case '}'.code:
+								if (field != null || comma == false)
+									invalidChar();
+								return obj;
+							case ':'.code:
+								if (field == null)
+									invalidChar();
+								Reflect.setField(obj, field, parseRec());
+								field = null;
+								comma = true;
+							case ','.code:
+								if (comma) comma = false else invalidChar();
+							case '"'.code:
+								if (field != null || comma) invalidChar();
+								field = parseString();
+							default:
+								invalidChar();
+						}
+					}
+				case '['.code:
+					var arr = [], comma:Null<Bool> = null;
+					while (true) {
+						var c = nextChar();
+						switch (c) {
+							case ' '.code, '\r'.code, '\n'.code, '\t'.code:
+							// loop
+							case ']'.code:
+								if (comma == false) invalidChar();
+								return arr;
+							case ','.code:
+								if (comma) comma = false else invalidChar();
+							default:
+								if (comma) invalidChar();
+								pos--;
+								arr.push(parseRec());
+								comma = true;
+						}
+					}
+				case 't'.code:
+					var save = pos;
+					if (nextChar() != 'r'.code || nextChar() != 'u'.code || nextChar() != 'e'.code) {
+						pos = save;
+						invalidChar();
+					}
+					return true;
+				case 'f'.code:
+					var save = pos;
+					if (nextChar() != 'a'.code || nextChar() != 'l'.code || nextChar() != 's'.code || nextChar() != 'e'.code) {
+						pos = save;
+						invalidChar();
+					}
+					return false;
+				case 'n'.code:
+					var save = pos;
+					if (nextChar() != 'u'.code || nextChar() != 'l'.code || nextChar() != 'l'.code) {
+						pos = save;
+						invalidChar();
+					}
+					return null;
+				case '"'.code:
+					return parseString();
+				case '0'.code, '1'.code, '2'.code, '3'.code, '4'.code, '5'.code, '6'.code, '7'.code, '8'.code, '9'.code, '-'.code:
+					return parseNumber(c);
+				default:
+					invalidChar();
+			}
+		}
+	}
+
+	function parseString() {
+		// eq( haxe.format.JsonParser.parse('"\\u00E9"'), "é" );
+		var start = pos;
+		var buf:StringBuf = null;
+		var prev = -1;
+		inline function cancelSurrogate() {
+			// invalid high surrogate (not followed by low surrogate)
+			buf.addChar(0xFFFD);
+			prev = -1;
+		}
+		while (true) {
+			var c = nextChar();
+			if (c == '"'.code)
+				break;
+			if (c == '\\'.code) {
+				if (buf == null) {
+					buf = new StringBuf();
+				}
+				buf.addSub(str, start, pos - start - 1);
+				c = nextChar();
+				switch (c) {
+					case "r".code:
+						buf.addChar("\r".code);
+					case "n".code:
+						buf.addChar("\n".code);
+					case "t".code:
+						buf.addChar("\t".code);
+					case "b".code:
+						buf.addChar(8);
+					case "f".code:
+						buf.addChar(12);
+					case "/".code, '\\'.code, '"'.code:
+						buf.addChar(c);
+					case 'u'.code:
+						var uc:Int = Std.parseInt("0x" + str.substr(pos, 4));
+						pos += 4;
+						if (prev != -1) {
+							if (uc < 0xDC00 || uc > 0xDFFF)
+								cancelSurrogate();
+							else {
+								buf.addChar(((prev - 0xD800) << 10) + (uc - 0xDC00) + 0x10000);
+								prev = -1;
+							}
+						} else if (uc >= 0xD800 && uc <= 0xDBFF)
+							prev = uc;
+						else
+							buf.addChar(uc);
+					default:
+						throw "Invalid escape sequence \\" + String.fromCharCode(c) + " at position " + (pos - 1);
+				}
+				start = pos;
+			}
+			// ensure utf8 chars are not cut
+			else if (c >= 0x80) {
+				pos++;
+				if (c >= 0xFC)
+					pos += 4;
+				else if (c >= 0xF8)
+					pos += 3;
+				else if (c >= 0xF0)
+					pos += 2;
+				else if (c >= 0xE0)
+					pos++;
+			}
+		else if (StringTools.isEof(c))
+			throw "Unclosed string";
+		}
+		if (buf == null) {
+			return str.substr(start, pos - start - 1);
+		} else {
+			buf.addSub(str, start, pos - start - 1);
+			return buf.toString();
+		}
+	}
+
+	inline function parseNumber(c:Int):Dynamic {
+		var start = pos - 1;
+		var minus = c == '-'.code, digit = !minus, zero = c == '0'.code;
+		var point = false, e = false, pm = false, end = false;
+		while (true) {
+			c = nextChar();
+			switch (c) {
+				case '0'.code:
+					if (zero && !point)
+						invalidNumber(start);
+					if (minus) {
+						minus = false;
+						zero = true;
+					}
+					digit = true;
+				case '1'.code, '2'.code, '3'.code, '4'.code, '5'.code, '6'.code, '7'.code, '8'.code, '9'.code:
+					if (zero && !point)
+						invalidNumber(start);
+					if (minus)
+						minus = false;
+					digit = true;
+					zero = false;
+				case '.'.code:
+					if (minus || point || e)
+						invalidNumber(start);
+					digit = false;
+					point = true;
+				case 'e'.code, 'E'.code:
+					if (minus || zero || e)
+						invalidNumber(start);
+					digit = false;
+					e = true;
+				case '+'.code, '-'.code:
+					if (!e || pm)
+						invalidNumber(start);
+					digit = false;
+					pm = true;
+				default:
+					if (!digit)
+						invalidNumber(start);
+					pos--;
+					end = true;
+			}
+			if (end)
+				break;
+		}
+
+		var f = Std.parseFloat(str.substr(start, pos - start));
+		var i = Std.int(f);
+		return if (i == f) i else f;
+	}
+
+    function nextChar() {
+        pos++;
+        return lua.NativeStringTools.byte(str, pos);
+	}
+
+	function invalidChar() {
+		pos--; // rewind
+		throw "Invalid char " + lua.NativeStringTools.byte(str, pos) + " at position " + pos;
+	}
+
+	function invalidNumber(start:Int) {
+		throw "Invalid number at position " + start + ": " + str.substr(start, pos - start);
+	}
+}