--- parser3/src/include/pa_string.h	2001/03/10 12:12:50	1.28
+++ parser3/src/include/pa_string.h	2024/03/14 03:17:01	1.232
@@ -1,138 +1,710 @@
-/*
-  $Id: pa_string.h,v 1.28 2001/03/10 12:12:50 paf Exp $
-*/
-
-/*
-
-	String				Chunk0
-	======				========
-	head--------------->[ptr, size, ...]
-	append_here-------->[ptr, size, ...]
-						.
-						.
-						[ptr, size, ...]
-	link_row----------->[link to the next chunk]
+/** @file
+	Parser: string class decl.
 
+	Copyright (c) 2001-2023 Art. Lebedev Studio (http://www.artlebedev.com)
+	Authors: Konstantin Morshnev <moko@design.ru>, Alexandr Petrosian <paf@design.ru>
 */
 
 #ifndef PA_STRING_H
 #define PA_STRING_H
 
-#ifdef HAVE_CONFIG_H
-#include "pa_config.h"
+#define IDENT_PA_STRING_H "$Id: pa_string.h,v 1.232 2024/03/14 03:17:01 moko Exp $"
+
+// includes
+#include "pa_types.h"
+#include "pa_array.h"
+
+extern "C" { // cord's author forgot to do that
+#define CORD_NO_IO
+#include "../lib/cord/include/cord.h"
+
+#ifdef CORD_CAT_OPTIMIZATION
+#define CORD_cat(x, y) CORD_cat_optimized(x, y)
+#define CORD_cat_char_star(x, y, leny) CORD_cat_char_star_optimized(x, y, leny)
 #endif
+}
 
-#include <stddef.h>
+// defines
 
-#include "pa_pool.h"
-#include "pa_types.h"
+// cache hash code in String::Body for faster hash access
+#define HASH_CODE_CACHING
+
+// cache String::Body.length() for char* strings only, CORDs have own length
+#define STRING_LENGTH_CACHING
 
-#ifndef NO_STRING_ORIGIN
-#	define STRING_APPEND_PARAMS const char *src, size_t size, bool tainted, char *file, uint line
-#	define APPEND(src, size, file, line) real_append(src, size, false, file, line)
-#	define APPEND_TAINTED(src, size, file, line) real_append(src, size, true, file, line)
-#else
-#	define STRING_APPEND_PARAMS const char *src, size_t size, bool tainted
-#	define APPEND(src, size, file, line) real_append(src, size, false)
-#	define APPEND_TAINTED(src, size, file, line) real_append(src, size, true)
+
+// cord extension
+/* Returns true if x does contain                                       */
+/* char not_c at positions i..i+n. Value i,i+n must be < CORD_len(x).	*/
+int CORD_range_contains_chr_greater_then(CORD x, size_t i, size_t n, int c);
+size_t CORD_block_count(CORD x);
+
+// forwards
+
+class Charset;
+class Table;
+class SQL_Connection;
+class Dictionary;
+class Request_charsets;
+class String;
+class VRegex;
+
+#ifdef NDEBUG
+typedef Array<const String*> ArrayString;
+#else
+class ArrayString : public Array<const String*> {
+public:
+	inline ArrayString(size_t initial=0) : Array(initial){
+	}
+	inline Array& operator+=(element_type src) {
+		assert(src != NULL);
+		return Array::operator+=(src);
+	}
+
+	inline element_type get(size_t index) const {
+		element_type result=Array::get(index);
+		assert(result != NULL);
+		return result;
+	}
+};
 #endif
-#define	APPEND_CONST(src) APPEND(src, 0, 0, 0)
 
-class String : public Pooled {
+// generally useful
+
+double pa_atod(const char* str, const String* problem_source);
+int pa_atoi(const char* str, int base=10, const String* problem_source=0);
+unsigned int pa_atoui(const char *str, int base=10, const String* problem_source=0);
+uint64_t pa_atoul(const char *str, int base=10, const String* problem_source=0);
+
+/// this is result of pos functions which mean that substr were not found
+#define STRING_NOT_FOUND ((size_t)-1)
+
+/// CORD can't be empty string, thus checking it in assigment
+#define AS_CORD(v) ((v) && *(v) ? (CORD)(v):0)
+
+/** 
+	String which knows the lang of all it's langs.
+
+	All pieces remember 
+	- whether they are tainted or not, 
+	  and the lang which should be used to detaint them
+*/
+
+
+class String: public PA_Object {
+	friend class StringSplitHelper;
 public:
-	enum {
-		CR_PREALLOCATED_COUNT=5,
-		CR_GROW_PERCENT=60
-	};
-
-	enum Untaint_lang {
-		NO, // clean
-		YES,  // tainted, untaint language as assigned later 
-		// untaint languages. assigned by ^untaint[lang]{...}
-		PASS_APPENDED,
-			// leave language built into string being appended
-			// just a flag, that value not stored
-		AS_IS,
-		SQL,
-		JS,
-		TABLE,
-		HTML,
-		HTML_TYPO
+
+	/** piece is tainted or not. the lang to use when detaint
+		remember to change String_Untaint_lang_name @ untaint.C along
+
+		WARNING WARNING WARNING WARNING WARNING WARNING 
+		
+		pos function compares(<=) languages, that is used in searching
+		for table column separator being L_CLEAN or L_AS_IS.
+		they search for AS_IS, meaning AS_IS|CLEAN [doing <=L_AS_IS check].
+		
+		letters assigned for debugging, but it's important for no language-letter
+		come before L_AS_IS other then L_CLEAN
+
+		WARNING WARNING WARNING WARNING WARNING WARNING 
+	*/
+
+#if _MSC_VER >= 1900
+	/// required for VS2015+ to make sizeof(Languages::opt) == sizeof(CORD), will be 16 byte under x64 without it
+	enum Language : size_t {
+#else
+	enum Language {
+#endif
+		L_UNSPECIFIED=0,	///< no real string has parts of this lange: it's just convinient to check when string's empty
+		// these two must go before others, there are checks for >L_AS_IS
+		L_CLEAN='0',		///< clean  WARNING: read above warning before changing
+		L_AS_IS='A',		///< leave all characters intact  WARNING: read above warning before changing
+
+		L_TAINTED='T',		///< tainted, untaint lang as assigned later
+		// untaint langs. assigned by ^untaint[lang]{...}
+		L_FILE_SPEC='F',	///< file specification
+		L_HTTP_HEADER='h',	///< text in HTTP response header
+		L_MAIL_HEADER='m',	///< text in mail header
+		L_URI='U',		///< text in uri
+		L_SQL='Q',		///< ^table:sql body
+		L_JS='J',		///< JavaScript code
+		L_XML='X',		///< ^xdoc:create xml
+		L_HTML='H',		///< HTML code
+		L_REGEX='R',		///< RegExp
+		L_JSON='S',		///< JSON code
+		L_HTTP_COOKIE='C',	///< cookies encoded as %uXXXX for compartibility with js functions encode/decode
+		L_PARSER_CODE='p',	///< ^process body
+		// READ WARNING ABOVE BEFORE ADDING ANYTHING
+		L_OPTIMIZE_BIT = 0x80  ///< flag, requiring cstr whitespace optimization
 	};
 
-public:
+	enum Trim_kind {
+		TRIM_BOTH,
+		TRIM_START,
+		TRIM_END
+	};
 
-	String(Pool& apool);
-	String(const String& src);
-	size_t size() const { return fsize; }
-	int used_rows() const { return fused_rows; }
-	char *cstr() const;
-	String& real_append(STRING_APPEND_PARAMS);
-	int cmp (const String& src) const;
-	bool operator < (const String& src) const {	return cmp(src)<0; }
-	bool operator > (const String& src) const {	return cmp(src)>0; }
-	bool operator <= (const String& src) const { return cmp(src)<=0; }
-	bool operator >= (const String& src) const { return cmp(src)>=0; }
-	bool operator == (const String& src) const {
-		if(size()!=src.size()) // can speed up in trivial case
-			return false;
-		return cmp(src)==0;
-	}
-	bool operator != (const String& src) const { return cmp(src)!=0; }
+	class Body;
+
+	union Languages {
+
+		struct {
+#ifdef PA_LITTLE_ENDIAN
+			Language lang:8;
+			size_t is_not_just_lang:sizeof(CORD)*8-8;
+#elif defined(PA_BIG_ENDIAN)
+			size_t is_not_just_lang:sizeof(CORD)*8-8;
+			Language lang:8;
+#else
+#	error word endianness not determined for some obscure reason
+#endif
+		} opt;
+		CORD langs;
+
+		CORD make_langs(const Body& current) const {
+			return opt.is_not_just_lang?langs:CORD_chars((char)opt.lang, current.length());
+		}
+
+		CORD make_langs(size_t aoffset, size_t alength)  const {
+			return opt.is_not_just_lang?
+				CORD_substr(langs, aoffset, alength, 0)
+				:CORD_chars((char)opt.lang, alength);
+		}
+
+		/// appending when 'langs' already contain something [simple cases handled elsewhere]
+		void append(size_t current, const CORD to_nonempty_target_langs) {
+			assert(langs);
+			if(opt.is_not_just_lang)
+				langs=CORD_cat(langs, to_nonempty_target_langs);
+			else {
+				assert(current);
+				langs=CORD_cat(CORD_chars((char)opt.lang, current), to_nonempty_target_langs);
+			}
+		}
+
+		void append(const Body& current, const CORD to_nonempty_target_langs) {
+			assert(langs);
+			if(opt.is_not_just_lang)
+				langs=CORD_cat(langs, to_nonempty_target_langs);
+			else {
+				size_t current_size=current.length();
+				assert(current_size);
+				langs=CORD_cat(CORD_chars((char)opt.lang, current_size), to_nonempty_target_langs);
+			}
+		}
+
+	public:
+
+		const char* visualize() const;
+		void dump() const;
+
+		Languages(): langs(0) {}
+		Languages(Language alang) {
+			opt.lang=alang;
+			opt.is_not_just_lang=0;
+		}
+
+		/// MUST be called exactly prior to modification of current [uses it's length]
+		void append(size_t current, Language alang, size_t length) {
+			assert(alang);
+			assert(length);
+
+			if(!opt.is_not_just_lang) {
+				if(opt.lang) {
+					if(opt.lang==alang) // same language? ignoring
+						return;
+				} else {
+					opt.lang=alang; // to uninitialized
+					return;
+				}
+			}
+
+			append(current, CORD_chars((char)alang, length));
+		}
+
+		void append(const Body &current, Language alang, size_t length) {
+			assert(alang);
+			assert(length);
+
+			if(!opt.is_not_just_lang) {
+				if(opt.lang) {
+					if(opt.lang==alang) // same language? ignoring
+						return;
+				} else {
+					opt.lang=alang; // to uninitialized
+					return;
+				}
+			}
+
+			append(current, CORD_chars((char)alang, length));
+		}
+
+		void appendHelper(const Body& current, Language alang, const Body &length_helper) {
+			assert(alang);
+
+			if(!opt.is_not_just_lang) {
+				if(opt.lang) {
+					if(opt.lang==alang) // same language? ignoring
+						return;
+				} else {
+					opt.lang=alang; // to uninitialized
+					return;
+				}
+			}
+
+			append(current, CORD_chars((char)alang, length_helper.length()));
+		}
+
+		void appendHelper(const Body& current, const Languages &src, const Body& length_helper) {
+			if(!langs){
+				langs=src.langs; // to uninitialized
+#ifdef CORD_CAT_OPTIMIZATION
+				if(opt.is_not_just_lang && !CORD_IS_STRING(langs))
+					CORD_concatenation_protect(langs);
+#endif
+			}
+			else if(!src.opt.is_not_just_lang)
+				appendHelper(current, src.opt.lang, length_helper); // simplifying when simple source
+			else
+				append(current, src.make_langs(length_helper));
+		}
+
+		/// MUST be called exactly prior to modification of current [uses it's length]
+		void append(const Body& current, const Languages src, size_t aoffset, size_t alength) {
+			assert(alength);
+
+			if(!langs) // to uninitialized?
+				if(src.opt.is_not_just_lang)
+					langs=CORD_substr(src.langs, aoffset, alength, 0); // to uninitialized complex
+				else
+					opt.lang=src.opt.lang; // to uninitialized simple
+			else 
+				if(!opt.is_not_just_lang && !src.opt.is_not_just_lang && opt.lang==src.opt.lang) // both simple & of same language?
+					return; // ignoring
+				else
+					append(current, src.make_langs(aoffset, alength));
+		}
+
+		/// checks if we have lang<=alang all from aoffset to aoffset+alength
+		bool check_lang(Language alang, size_t aoffset, size_t alength) const {
+			if(alang==L_UNSPECIFIED) // ignore lang?
+				return true;
+
+			if(opt.is_not_just_lang)
+				return CORD_range_contains_chr_greater_then(langs, aoffset, alength, (unsigned)alang)==0;
+			else
+				return (unsigned)opt.lang<=(unsigned)alang;
+		}
+
+		/// @returns count of blocks
+		/// @todo currently there can be adjucent blocks of same language. someday merge them
+		size_t count() const {
+			return opt.is_not_just_lang?
+				CORD_block_count(langs)
+				: opt.lang?
+					1
+					: 0;
+		};
+
+		template<typename I> 
+		void for_each(size_t current, int callback(char, size_t, I), I info) const {
+			if(opt.is_not_just_lang)
+				CORD_block_iter(langs, 0, (CORD_block_iter_fn)callback, info);
+			else
+				callback(opt.lang, current, info);
+		}
+
+		template<typename I> 
+		void for_each(const Body& current, int callback(char, size_t, I), I info) const {
+			if(opt.is_not_just_lang)
+				CORD_block_iter(langs, 0, (CORD_block_iter_fn)callback, info);
+			else
+				callback(opt.lang, current.length(), info);
+		}
+
+		bool invariant(size_t current_length) const {
+			if(!langs)
+				return current_length==0;
+			if(opt.is_not_just_lang)
+				return CORD_len(langs)==current_length;
+			return true; // uncheckable, actually
+		}
+	};
+
+	struct C {
+		const char *str;
+		size_t length;
+		C(): str(0), length(0) {}
+		C(const char *astr, size_t asize): str(astr), length(asize) {}
+		explicit C(Body abody): str(abody.cstr()), length(abody.length()) {}
+	};
+
+	struct Cm {
+		char *str;
+		size_t length;
+		Cm(): str(0), length(0) {}
+		Cm(char *astr, size_t asize): str(astr), length(asize) {}
+		explicit Cm(Body abody): str(abody.cstrm()), length(abody.length()) {}
+	};
+
+	class Body {
+
+		CORD body;
+
+#ifdef HASH_CODE_CACHING
+		// cached hash code is not reseted on write operations as test shows 
+		// that string body does not change after it is stored as a hash key
+		mutable uint hash_code;
+#define INIT_HASH_CODE(c) ,hash_code(c)
+#define ZERO_HASH_CODE hash_code=0;
+#else
+#define INIT_HASH_CODE(c)
+#define ZERO_HASH_CODE
+#endif
+
+#ifdef STRING_LENGTH_CACHING
+		// cached length is reseted on modification, used only for char*, not CORD
+		mutable size_t string_length;
+#define INIT_LENGTH(l) ,string_length(l)
+#define ZERO_LENGTH string_length=0;
+#else
+#define INIT_LENGTH(l)
+#define ZERO_LENGTH
+#endif
+
+	public:
+
+		void dump() const;
+
+		Body(): body(CORD_EMPTY) INIT_HASH_CODE(0) INIT_LENGTH(0) {}
+		Body(const char *abody): body(AS_CORD(abody)) INIT_HASH_CODE(0) INIT_LENGTH(0) {}
+		Body(CORD abody, uint ahash_code): body(abody) INIT_HASH_CODE(ahash_code) INIT_LENGTH(0) {}
+		explicit Body(C ac): body(AS_CORD(ac.str)) INIT_HASH_CODE(0) INIT_LENGTH(ac.length) {}
+		explicit Body(CORD abody): body(abody) INIT_HASH_CODE(0) INIT_LENGTH(0) {
+#ifdef CORD_CAT_OPTIMIZATION
+			assert(!body // no body
+				|| *body // ordinary string
+				|| body[1]==1 // CONCAT_HDR
+				|| body[1]==3 // CONCAT_HDR_READ_ONLY
+				|| body[1]==4 // FN_HDR 
+				|| body[1]==6 // SUBSTR_HDR 
+				);
+#else
+			assert(!body // no body
+				|| *body // ordinary string
+				|| body[1]==1 // CONCAT_HDR
+				|| body[1]==4 // FN_HDR 
+				|| body[1]==6 // SUBSTR_HDR 
+				);
+#endif
+		}
 
-	bool operator == (char* src) const;
-	String& append(const String& src, Untaint_lang lang);
 
-	uint hash_code() const;
+		static Body Format(int value);
 
-	const Origin& origin() const { return head.rows[0].item.origin; }
+		void clear() { ZERO_LENGTH ZERO_HASH_CODE body=CORD_EMPTY; }
+
+		bool operator! () const { return is_empty(); }
+
+		inline CORD get_cord() const { return body; }
+		uint get_hash_code() const;
+
+		// never null
+		const char* cstr() const {
+#ifdef STRING_LENGTH_CACHING
+			string_length = length();
+			if(string_length){
+				const char *result=CORD_to_const_char_star(body, string_length);
+				const_cast<Body*>(this)->body=(CORD)result;
+				return result;
+			}
+#endif
+			return CORD_to_const_char_star(body, length());
+		}
+
+		// never null
+		char* cstrm() const { return CORD_to_char_star(body, length()); }
+
+#ifdef STRING_LENGTH_CACHING
+		void set_length(size_t alength){ string_length = alength; }
+		size_t length() const { return body ? CORD_IS_STRING(body) ? string_length ? string_length : (string_length=strlen((const char *)body)) : CORD_len(body) : 0; }
+#else
+		size_t length() const { return CORD_len(body); }
+#endif
+
+		inline bool is_empty() const { return body==CORD_EMPTY; }
+
+		void append_know_length(const char *str, size_t known_length) {
+			if(known_length){
+				if(body){
+					body = CORD_cat_char_star(body, str, known_length);
+					ZERO_LENGTH 
+				} else {
+					body=(CORD)str;
+#ifdef STRING_LENGTH_CACHING
+					string_length=known_length;
+#endif
+				}
+			}
+		}
+		void append_strdup_know_length(const char* str, size_t known_length) {
+			if(known_length)
+				append_know_length(pa_strdup(str, known_length), known_length);
+		}
+		void append(char c) { ZERO_LENGTH body=CORD_cat_char(body, c); }
+		Body& operator << (const Body src) { ZERO_LENGTH body=CORD_cat(body, src.body); return *this; }
+
+		Body& operator << (const char* str) { append_know_length(str, strlen(str)); return *this; }
+
+		bool operator < (const Body src) const { return CORD_cmp(body, src.body)<0; }
+		bool operator > (const Body src) const { return CORD_cmp(body, src.body)>0; }
+		bool operator <= (const Body src) const { return CORD_cmp(body, src.body)<=0; }
+		bool operator >= (const Body src) const { return CORD_cmp(body, src.body)>=0; }
+
+		bool operator != (const Body src) const { return CORD_cmp(body, src.body)!=0; }
+		bool operator == (const Body src) const { return CORD_cmp(body, src.body)==0; }
+
+		bool operator != (const char *src) const { return CORD_cmp(body, AS_CORD(src))!=0; }
+		bool operator == (const char *src) const { return CORD_cmp(body, AS_CORD(src))==0; }
+
+		int ncmp(size_t x_begin, const Body y, size_t y_begin, size_t size) const {
+			return CORD_ncmp(body, x_begin, y.body, y_begin, size);
+		}
+
+		char fetch(size_t index) const { return CORD_fetch(body, index); }
+		Body mid(size_t aindex, size_t alength) const { return Body(CORD_substr(body, aindex, alength, length())); }
+		size_t pos(const char* substr, size_t offset=0) const { return CORD_str(body, offset, AS_CORD(substr), length()); }
+		size_t pos(const Body substr, size_t offset=0) const { 
+			if(substr.is_empty())
+				return STRING_NOT_FOUND; // in this case CORD_str returns 0 [parser users got used to -1]
+
+			// CORD_str checks for bad offset [CORD_chr does not]
+			return CORD_str(body, offset, substr.body, length()); 
+		}
+		size_t pos(char c, size_t offset=0) const {
+			if(offset>=length()) // CORD_chr does not check that [and ABORT's in that case]
+				return STRING_NOT_FOUND;
+
+			return CORD_chr(body, offset, c);
+		}
+
+		size_t strrpbrk(const char* chars, size_t left, size_t right) const;
+
+		size_t rskipchars(const char* chars, size_t left, size_t right) const;
+
+		template<typename I>
+		int for_each(int (*f)(char c, I), I info) const {
+			return CORD_iter(body, (CORD_iter_fn)f, (void*)info);
+		}
+
+		template<typename I>
+		int for_each(int (*f1)(char c, I), int (*f2)(const char* s, I), I info) const {
+			return CORD_iter5(body, 0, (CORD_iter_fn)f1, (CORD_batched_iter_fn)f2, info);
+		}
+
+		void set_pos(CORD_pos& pos, size_t index) const { CORD_set_pos(pos, body, index); }
+
+		/// @returns this or 0 or mid. if returns this or 0 out_* are not filled
+		Body trim(Trim_kind kind=TRIM_BOTH, const char* chars=0,
+			size_t* out_start=0, size_t* out_length=0, Charset* source_charset=0) const;
+	};
 
 private:
 
-	struct Chunk {
-		// the number of rows in chunk
-		int count;
-		union Row {
-			// fragment
-			struct { 
-				const char *ptr;  // pointer to the start
-				size_t size;  // length
-				Untaint_lang lang; // untaint flag, later untaint language
-#ifndef NO_STRING_ORIGIN
-				Origin origin;  // origin
-#endif
-			} item;
-			Chunk *link;  // link to the next chunk in chain
-		} rows[CR_PREALLOCATED_COUNT];
-		// next rows are here
-		Chunk *preallocated_link;
+	Body body; ///< all characters of string
+	Languages langs; ///< string characters lang
+
+	void dump() const;
+	#define ASSERT_STRING_INVARIANT(string) \
+		assert((string).langs.invariant((string).body.length()))
+
+public:
+
+	static const String Empty;
+
+	explicit String(){};
+	explicit String(const char* cstr, Language alang=L_CLEAN) : body(cstr){
+		if(body.get_cord()){
+			langs=alang;
+		}
+	}
+	explicit String(C ac, Language alang=L_CLEAN) : body(ac){
+		if(body.get_cord()){
+			langs=alang;
+		}
+	}
+	String(Body abody, Language alang): body(abody), langs(alang) {
+		ASSERT_STRING_INVARIANT(*this);
+	}
+	String(const String& src): body(src.body), langs(src.langs) {
+		ASSERT_STRING_INVARIANT(*this);
+	}
+	String(int value, const char *format);
+
+	/// for convinient hash lookup
+#ifdef HASH_CODE_CACHING
+	operator const Body&() const { return body; }
+#else
+	operator const Body() const { return body; }
+#endif
+
+	bool is_empty() const { return body.is_empty(); }
+	size_t length() const { return body.length(); }
+	size_t length(Charset& charset) const;
+
+	/// convert to CORD forcing lang tainting
+	Body cstr_to_string_body_taint(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const;
+	/// convert to CORD with tainting dirty to lang
+	Body cstr_to_string_body_untaint(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const;
+
+	/// from body
+	const char* cstr() const { return body.cstr(); }
+	char* cstrm() const { return body.cstrm(); }
+
+	/// convert to constant C string forcing lang tainting
+	const char* taint_cstr(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const {
+		return cstr_to_string_body_taint(lang, connection, charsets).cstr();
+	}
+	char *taint_cstrm(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const {
+		return cstr_to_string_body_taint(lang, connection, charsets).cstrm();
+	}
+
+	/// convert to constant C string with tainting dirty to lang
+	const char* untaint_cstr(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const {
+		return cstr_to_string_body_untaint(lang, connection, charsets).cstr();
+	}
+	char *untaint_cstrm(Language lang, SQL_Connection* connection=0, const Request_charsets *charsets=0) const {
+		return cstr_to_string_body_untaint(lang, connection, charsets).cstrm();
 	}
-		head;  // the head chunk of the chunk chain
 
-	// next append would write to this record
-	Chunk::Row *append_here;
+	const char* untaint_and_transcode_cstr(Language lang, const Request_charsets *charsets) const;
+
+	bool is_not_just_lang() const {
+		return langs.opt.is_not_just_lang !=0;
+	}
 	
-	// the address of place where lies address 
-	// of the link to the next chunk to allocate
-	Chunk::Row *link_row;
+	Language just_lang() const {
+		return langs.opt.lang;
+	}
 
-private:
-	// last chunk
-	Chunk *last_chunk;
+	char* visualize_langs() const;
+
+	/// puts pieces to buf
+	Cm serialize(size_t prolog_size) const;
+	/// appends pieces from buf to self
+	bool deserialize(size_t prolog_size, void *buf, size_t buf_size);
+	/// @see Body::append_know_length
+	String& append_know_length(const char* str, size_t known_length, Language lang);
+	/// @see Body::append_help_length
+	String& append_help_length(const char* str, size_t helper_length, Language lang);
+	String& append_strdup(const char* str, size_t helper_length, Language lang);
+
+	bool operator == (const char* y) const { return body==Body(y); }
+	bool operator != (const char* y) const { return body!=Body(y); }
+
+	/// this starts with y
+	bool starts_with(const char* y) const {
+		return body.ncmp(0/*x_begin*/, Body(y), 0/*y_begin*/, strlen(y))==0;
+	}
+	/// x starts with this
+	bool this_starts(const char* x) const {
+		return Body(x).ncmp(0/*x_begin*/, body, 0/*y_begin*/, length())==0;
+	}
 
-	// string size
-	size_t fsize;
+	String& append_to(String& dest) const;
+	String& append_to(String& dest, Language lang, bool forced=false) const;
+	String& append(const String& src, Language lang, bool forced=false) { 
+		return src.append_to(*this, lang, forced);
+	}
+	String& append_quoted(const String* src, Language lang=L_JSON){
+		*this << "\"";
+		if(src)
+			this->append(*src, lang, true/*forced lang*/);
+		*this << "\"";
+		return *this;
+	}
 
-	// used rows in all chunks
-	int fused_rows;
+	String& operator << (const String& src) { return src.append_to(*this); }
+	String& operator << (const char* src) { return append_help_length(src, 0, L_AS_IS); }
+	String& operator << (const Body& src){
+		langs.appendHelper(body, L_AS_IS, src);
+		body<<src;
+		return *this;
+	}
 
-private:
+	char first_char() const {
+		return is_empty()?0:body.fetch(0);
+	}
+
+	char last_char() const {
+		return is_empty()?0:body.fetch(body.length()-1);
+	}
 
-	bool chunk_is_full() {
-		return append_here == link_row;
+	bool operator < (const String& src) const { return body<src.body; }
+	bool operator > (const String& src) const { return body>src.body; }
+	bool operator <= (const String& src) const { return body<=src.body; }
+	bool operator >= (const String& src) const { return body>=src.body; }
+	bool operator != (const String& src) const { return body!=src.body; }
+	bool operator == (const String& src) const { return body==src.body; }
+
+	/// extracts [start, finish) piece of string
+	String& mid(size_t substr_begin, size_t substr_end) const;
+	String& mid(Charset& charset, size_t from, size_t to, size_t helper_length=0) const;
+
+	/** 
+		ignore lang if it's L_UNSPECIFIED
+		but when specified: look for substring that lies in ONE fragment in THAT lang
+		@return position of substr in string, -1 means "not found" [const char* version]
+	*/
+	size_t pos(const Body substr, size_t this_offset=0, Language lang=L_UNSPECIFIED) const;
+	/// String version of @see pos(const char*, int, Language)
+	size_t pos(const String& substr, size_t this_offset=0, Language lang=L_UNSPECIFIED) const;
+	size_t pos(char c, size_t this_offset=0) const {
+		return body.pos(c, this_offset);
 	}
-	void expand();
-	void set_lang(Chunk::Row *row, Untaint_lang lang, size_t size);
+	size_t pos(Charset& charset, const String& substr, size_t this_offset=0, Language lang=L_UNSPECIFIED) const;
+
+	size_t strrpbrk(const char* chars, size_t left=0) const {
+		return (length()) ? body.strrpbrk(chars, left, length()-1) : STRING_NOT_FOUND;
+	}
+	size_t strrpbrk(const char* chars, size_t left, size_t right) const {
+		return body.strrpbrk(chars, left, right);
+	}
+
+	size_t rskipchars(const char* chars, size_t left=0) const {
+		return (length()) ? body.rskipchars(chars, left, length()-1) : STRING_NOT_FOUND;
+	}
+	size_t rskipchars(const char* chars, size_t left, size_t right) const {
+		return body.rskipchars(chars, left, right);
+	}
+
+	void split(ArrayString& result, size_t pos_after, const char* delim, Language lang=L_UNSPECIFIED) const;
+	void split(ArrayString& result, size_t pos_after, const String& delim, Language lang=L_UNSPECIFIED) const;
+
+	typedef void (*Row_action)(Table& table, ArrayString* row, int prestart, int prefinish, int poststart, int postfinish, void *info);
+
+	/**
+		@return table of found items, if any.
+		table format is defined and fixed[can be used by others]: 
+		@verbatim
+			prematch/match/postmatch/1/2/3/...
+		@endverbatim
+	*/
+	Table* match(VRegex* vregex, Row_action row_action, void *info, int& matches_count) const;
+
+	enum Change_case_kind {
+		CC_UPPER,
+		CC_LOWER
+	};
+	String& change_case(Charset& source_charset, Change_case_kind kind) const;
+
+	const String& replace(const Dictionary& dict) const;
+	const String& trim(Trim_kind kind=TRIM_BOTH, const char* chars=0, Charset* source_charset=0) const;
+	double as_double() const { return pa_atod(cstr(), this); }
+	int as_int() const { return pa_atoi(cstr(), 0, this); }
+	bool as_bool() const { return as_int()!=0; }
+	const String& escape(Charset& source_charset) const;
 
 private: //disabled
 
@@ -140,4 +712,12 @@ private: //disabled
 
 };
 
+#ifndef HASH_CODE_CACHING
+/// simple hash code of string. used by Hash
+inline uint hash_code(const String::Body self) {
+	return self.get_hash_code();
+}
+#endif
+
+
 #endif