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string_res.cfa@ 831b2ec

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Last change on this file since 831b2ec was 9018dcf, checked in by Peter A. Buhr <pabuhr@…>, 9 months ago
updates to string type
Property mode set to `100644`
File size: 40.7 KB

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// string_res -- variable-length, mutable run of text, with resource semantics
8	//
9	// Author : Michael L. Brooks
10	// Created On : Fri Sep 03 11:00:00 2021
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Wed Apr 9 08:44:17 2025
13	// Update Count : 128
14	//
15
16	#include "string_res.hfa"
17	#include "string_sharectx.hfa"
18	#include "stdlib.hfa"
19	#include <ctype.h>
20
21	// Workaround for observed performance penalty from calling CFA's alloc.
22	// Workaround is: EndVbyte = TEMP_ALLOC(char, CurrSize)
23	// Should be: EndVbyte = alloc(CurrSize)
24	#define TEMP_ALLOC(T, n) (( T * ) malloc( n * sizeof( T ) ))
25
26	#include <assert.h>
27	#include <complex.h> // creal, cimag
28
29	//######################### VbyteHeap "header" #########################
30
31	#ifdef VbyteDebug
32	HandleNode *HeaderPtr;
33	#endif // VbyteDebug
34
35	struct VbyteHeap {
36	int NoOfCompactions; // number of compactions of the byte area
37	int NoOfExtensions; // number of extensions in the size of the byte area
38	int NoOfReductions; // number of reductions in the size of the byte area
39
40	int InitSize; // initial number of bytes in the byte-string area
41	int CurrSize; // current number of bytes in the byte-string area
42	char *StartVbyte; // pointer to the `st byte of the start of the byte-string area
43	char *EndVbyte; // pointer to the next byte after the end of the currently used portion of byte-string area
44	void *ExtVbyte; // pointer to the next byte after the end of the byte-string area
45
46	HandleNode Header; // header node for handle list
47	}; // VbyteHeap
48
49
50	static void compaction( VbyteHeap & ); // compaction of the byte area
51	static void garbage( VbyteHeap &, int ); // garbage collect the byte area
52	static void extend( VbyteHeap &, int ); // extend the size of the byte area
53	static void reduce( VbyteHeap &, int ); // reduce the size of the byte area
54
55	static void ?{}( VbyteHeap &, size_t = 1000 );
56	static void ^?{}( VbyteHeap & );
57
58	static int ByteCmp( char , int, int, char , int, int ); // compare 2 blocks of bytes
59	static char *VbyteAlloc( VbyteHeap &, int ); // allocate a block bytes in the heap
60	static char *VbyteTryAdjustLast( VbyteHeap &, int );
61
62	static void AddThisAfter( HandleNode &, HandleNode & );
63	static void DeleteNode( HandleNode & );
64	static void MoveThisAfter( HandleNode &, const HandleNode & ); // move current handle after parameter handle
65
66
67	// Allocate the storage for the variable sized area and intialize the heap variables.
68
69	static void ?{}( VbyteHeap & s, size_t Size ) with(s) {
70	#ifdef VbyteDebug
71	serr \| "enter:VbyteHeap::VbyteHeap, s:" \| &s \| " Size:" \| Size;
72	#endif // VbyteDebug
73	NoOfCompactions = NoOfExtensions = NoOfReductions = 0;
74	InitSize = CurrSize = Size;
75	StartVbyte = EndVbyte = TEMP_ALLOC(char, CurrSize);
76	ExtVbyte = (void *)( StartVbyte + CurrSize );
77	Header.flink = Header.blink = &Header;
78	Header.ulink = &s;
79	#ifdef VbyteDebug
80	HeaderPtr = &Header;
81	serr \| "exit:VbyteHeap::VbyteHeap, s:" \| &s;
82	#endif // VbyteDebug
83	} // VbyteHeap
84
85
86	// Release the dynamically allocated storage for the byte area.
87
88	static void ^?{}( VbyteHeap & s ) with(s) {
89	free( StartVbyte );
90	} // ~VbyteHeap
91
92
93	//######################### HandleNode #########################
94
95
96	// Create a handle node. The handle is not linked into the handle list. This is the responsibilitiy of the handle
97	// creator.
98
99	static void ?{}( HandleNode & s ) with(s) {
100	#ifdef VbyteDebug
101	serr \| "enter:HandleNode::HandleNode, s:" \| &s;
102	#endif // VbyteDebug
103	s = 0;
104	lnth = 0;
105	#ifdef VbyteDebug
106	serr \| "exit:HandleNode::HandleNode, s:" \| &s;
107	#endif // VbyteDebug
108	} // HandleNode
109
110	// Create a handle node. The handle is linked into the handle list at the end. This means that this handle will NOT be
111	// in order by string address, but this is not a problem because a string with length zero does nothing during garbage
112	// collection.
113
114	static void ?{}( HandleNode & s, VbyteHeap & vh ) with(s) {
115	#ifdef VbyteDebug
116	serr \| "enter:HandleNode::HandleNode, s:" \| &s;
117	#endif // VbyteDebug
118	s = 0;
119	lnth = 0;
120	ulink = &vh;
121	AddThisAfter( s, *vh.Header.blink );
122	#ifdef VbyteDebug
123	serr \| "exit:HandleNode::HandleNode, s:" \| &s;
124	#endif // VbyteDebug
125	} // HandleNode
126
127
128	// Delete a node from the handle list by unchaining it from the list. If the handle node was allocated dynamically, it
129	// is the responsibility of the creator to destroy it.
130
131	static void ^?{}( HandleNode & s ) with(s) {
132	#ifdef VbyteDebug
133	serr \| "enter:HandleNode::~HandleNode, s:" \| & s;
134	{
135	serr \| nlOff;
136	serr \| " lnth:" \| lnth \| " s:" \| (void *)s \| ",\"";
137	for ( i; lnth ) {
138	serr \| s[i];
139	} // for
140	serr \| "\" flink:" \| flink \| " blink:" \| blink \| nl;
141	serr \| nlOn;
142	}
143	#endif // VbyteDebug
144	DeleteNode( s );
145	} // ~HandleNode
146
147
148	//######################### String Sharing Context #########################
149
150	static string_sharectx * ambient_string_sharectx; // fickle top of stack
151	static string_sharectx default_string_sharectx = {NEW_SHARING}; // stable bottom of stack
152
153	void ?{}( string_sharectx & s, StringSharectx_Mode mode ) with( s ) {
154	(older){ ambient_string_sharectx };
155	if ( mode == NEW_SHARING ) {
156	(activeHeap){ new( (size_t) 1000 ) };
157	} else {
158	verify( mode == NO_SHARING );
159	(activeHeap){ 0p };
160	}
161	ambient_string_sharectx = & s;
162	}
163
164	void ^?{}( string_sharectx & s ) with( s ) {
165	if ( activeHeap ) delete( activeHeap );
166
167	// unlink s from older-list starting from ambient_string_sharectx
168	// usually, s==ambient_string_sharectx and the loop runs zero times
169	string_sharectx *& c = ambient_string_sharectx;
170	while ( c != &s ) &c = &c->older; // find s
171	c = s.older; // unlink
172	}
173
174	//######################### String Resource #########################
175
176
177	VbyteHeap * DEBUG_string_heap() {
178	assert( ambient_string_sharectx->activeHeap && "No sharing context is active" );
179	return ambient_string_sharectx->activeHeap;
180	}
181
182	size_t DEBUG_string_bytes_avail_until_gc( VbyteHeap * heap ) {
183	return ((char *)heap->ExtVbyte) - heap->EndVbyte;
184	}
185
186	size_t DEBUG_string_bytes_in_heap( VbyteHeap * heap ) {
187	return heap->CurrSize;
188	}
189
190	const char * DEBUG_string_heap_start( VbyteHeap * heap ) {
191	return heap->StartVbyte;
192	}
193
194	// Output operator
195	ofstream & ?\|?(ofstream & out, const string_res & s) {
196	// CFA string is NOT null terminated, so print exactly lnth characters in a minimum width of 0.
197	return out \| wd( 0, s.Handle.lnth, s.Handle.s ) \| nonl;
198	}
199
200	void ?\|?(ofstream & out, const string_res & s) {
201	(ofstream &)(out \| s); ends( out );
202	}
203
204	// Input operator
205	ifstream & ?\|?(ifstream & in, string_res & s) {
206	// Reading into a temp before assigning to s is near zero overhead in typical cases because of sharing.
207	// If s is a substring of something larger, simple assignment takes care of that case correctly.
208	// But directly reading a variable amount of text into the middle of a larger context is not practical.
209	string_res temp;
210
211	// Read in chunks. Often, one chunk is enough. Keep the string that accumulates chunks last in the heap,
212	// so available room is rest of heap. When a chunk fills the heap, force growth then take the next chunk.
213	for (bool cont = true; cont; ) {
214	cont = false;
215
216	// Append dummy content to temp, forcing expansion when applicable (occurs always on subsequent loops)
217	// length 2 ensures room for at least one real char, plus scanf/pipe-cstr's null terminator
218	temp += "--";
219	assert( temp.Handle.ulink->EndVbyte == temp.Handle.s + temp.Handle.lnth ); // last in heap
220
221	// reset, to overwrite the appended "--"
222	temp.Handle.lnth -= 2;
223	temp.Handle.ulink->EndVbyte -= 2;
224
225	// rest of heap is available to read into
226	int lenReadable = (char *)temp.Handle.ulink->ExtVbyte - temp.Handle.ulink->EndVbyte;
227	assert (lenReadable >= 2);
228
229	// get bytes
230	try {
231	*(temp.Handle.ulink->EndVbyte) = '\0'; // pre-assign empty cstring
232	in \| wdi( lenReadable, temp.Handle.ulink->EndVbyte );
233	} catch (cstring_length *) {
234	cont = true;
235	}
236	int lenWasRead = strlen(temp.Handle.ulink->EndVbyte);
237
238	// update metadata
239	temp.Handle.lnth += lenWasRead;
240	temp.Handle.ulink->EndVbyte += lenWasRead;
241	}
242
243	if ( temp.Handle.lnth > 0 ) s = temp;
244	return in;
245	}
246
247	ifstream & ?\|?( ifstream & is, _Istream_Rquoted f ) with( f.rstr ) {
248	if ( eof( is ) ) throwResume ExceptionInst( end_of_file );
249	int args;
250	fini: {
251	char rfmt[5] = { ' ', delimiters[0], '%', 'n', '\0' };
252	int l = -1; // may not be set in fmt
253	args = fmt( is, rfmt, &l ); // remove leading whitespace and quote
254	if ( eof( is ) \|\| l == -1 ) break fini;
255
256	// Change the remainder of the read into a getline by reseting the closing delimiter.
257	if ( delimiters[1] != '\0' ) {
258	delimiters[0] = delimiters[1];
259	delimiters[1] = '\0';
260	} // if
261	flags.delimiter = true;
262	return is \| (_Istream_Rstr )&f;
263	} // fini
264	// read failed => no pattern match => set string to null
265	if ( ! flags.ignore && s != 0p && args == 0 ) s[0] = '\0';
266	if ( args == 1 && eof( is ) ) { // data but scan ended at EOF
267	clear( is ); // => reset EOF => detect again on next read
268	} // if
269	return is;
270	}
271
272	ifstream & ?\|?( ifstream & is, _Istream_Rstr f ) {
273	// .---------------,
274	// \| \| \| \| \|...\|0\|0\| null terminator and guard if missing
275	// `---------------'
276	enum { gwd = 128 + 1, wd = gwd - 1 }; // guard and unguard width
277	char cstr[gwd]; // read in chunks
278	bool cont = false;
279
280	_Istream_Cwidth cf = { cstr, (_Istream_str_base)f };
281	if ( ! cf.flags.rwd ) cf.wd = wd;
282
283	cstr[wd] = '\0'; // guard null terminate string
284	try {
285	cstr[0] = '\0'; // pre-assign as empty cstring
286	is \| cf;
287	} catch( cstring_length * ) {
288	cont = true;
289	} finally {
290	if ( ! cf.flags.ignore // ok to initialize string
291	// && cstr[0] != '\0' // something was read
292	) {
293	*(f.s) = cstr;
294	}
295	} // try
296	for ( ; cont; ) { // overflow read ?
297	cont = false;
298	try {
299	cstr[0] = '\0'; // pre-assign as empty cstring
300	is \| cf;
301	} catch( cstring_length * ) {
302	cont = true; // continue not allowed
303	} finally {
304	if ( ! cf.flags.ignore && cstr[0] != '\0' ) { // something was read
305	*(f.s) += cstr; // build string chunk at a time
306	}
307	} // try
308	} // for
309	return is;
310	} // ?\|?
311
312	// Empty constructor
313	void ?{}(string_res & s) with(s) {
314	if( ambient_string_sharectx->activeHeap ) {
315	(Handle){ * ambient_string_sharectx->activeHeap };
316	(shareSet_owns_ulink){ false };
317	verify( Handle.s == 0p && Handle.lnth == 0 );
318	} else {
319	(Handle){ * new( (size_t) 10 ) }; // TODO: can I lazily avoid allocating for empty string
320	(shareSet_owns_ulink){ true };
321	Handle.s = Handle.ulink->StartVbyte;
322	verify( Handle.lnth == 0 );
323	}
324	s.shareSet_prev = &s;
325	s.shareSet_next = &s;
326	}
327
328	static void eagerCopyCtorHelper(string_res & s, const char * rhs, size_t rhslnth) with(s) {
329	if( ambient_string_sharectx->activeHeap ) {
330	(Handle){ * ambient_string_sharectx->activeHeap };
331	(shareSet_owns_ulink){ false };
332	} else {
333	(Handle){ * new( rhslnth ) };
334	(shareSet_owns_ulink){ true };
335	}
336	Handle.s = VbyteAlloc(*Handle.ulink, rhslnth);
337	Handle.lnth = rhslnth;
338	memmove( Handle.s, rhs, rhslnth );
339	s.shareSet_prev = &s;
340	s.shareSet_next = &s;
341	}
342
343	// Constructor from a raw buffer and size
344	void ?{}(string_res & s, const char * rhs, size_t rhslnth) with(s) {
345	eagerCopyCtorHelper(s, rhs, rhslnth);
346	}
347
348	void ?{}( string_res & s, ssize_t rhs ) {
349	char buf[64];
350	int l;
351	snprintf( buf, sizeof(buf)-1, "%zd%n", rhs, &l );
352	( s ){ buf, l };
353	}
354	void ?{}( string_res & s, size_t rhs ) {
355	char buf[64];
356	int l;
357	snprintf( buf, sizeof(buf)-1, "%zu%n", rhs, &l );
358	( s ){ buf, l };
359	}
360	void ?{}( string_res & s, double rhs ) {
361	char buf[64];
362	int l;
363	snprintf( buf, sizeof(buf)-1, "%g%n", rhs, &l );
364	( s ){ buf, l };
365	}
366	void ?{}( string_res & s, long double rhs ) {
367	char buf[64];
368	int l;
369	snprintf( buf, sizeof(buf)-1, "%Lg%n", rhs, &l );
370	( s ){ buf, l };
371	}
372	void ?{}( string_res & s, double _Complex rhs ) {
373	char buf[64];
374	int l;
375	snprintf( buf, sizeof(buf)-1, "%g+%gi%n", creal( rhs ), cimag( rhs ), &l );
376	( s ){ buf, l };
377	}
378	void ?{}( string_res & s, long double _Complex rhs ) {
379	char buf[64];
380	int l;
381	snprintf( buf, sizeof(buf)-1, "%Lg+%Lgi%n", creall( rhs ), cimagl( rhs ), &l );
382	( s ){ buf, l };
383	}
384
385	// private ctor (not in header): use specified heap (ignore ambient) and copy chars in
386	void ?{}( string_res & s, VbyteHeap & heap, const char * rhs, size_t rhslnth ) with(s) {
387	(Handle){ heap };
388	Handle.s = VbyteAlloc(*Handle.ulink, rhslnth);
389	Handle.lnth = rhslnth;
390	(s.shareSet_owns_ulink){ false };
391	memmove( Handle.s, rhs, rhslnth );
392	s.shareSet_prev = &s;
393	s.shareSet_next = &s;
394	}
395
396
397	// General copy constructor
398	void ?{}(string_res & s, const string_res & s2, StrResInitMode mode, size_t start, size_t len ) {
399	size_t end = start + len;
400	verify( start <= end && end <= s2.Handle.lnth );
401
402	if (s2.Handle.ulink != ambient_string_sharectx->activeHeap && mode == COPY_VALUE) {
403	// crossing heaps (including private): copy eagerly
404	eagerCopyCtorHelper(s, s2.Handle.s + start, end - start);
405	verify(s.shareSet_prev == &s);
406	verify(s.shareSet_next == &s);
407	} else {
408	(s.Handle){};
409	s.Handle.s = s2.Handle.s + start;
410	s.Handle.lnth = end - start;
411	s.Handle.ulink = s2.Handle.ulink;
412
413	AddThisAfter(s.Handle, s2.Handle ); // insert this handle after rhs handle
414	// ^ bug? skip others at early point in string
415
416	if (mode == COPY_VALUE) {
417	verify(s2.Handle.ulink == ambient_string_sharectx->activeHeap);
418	// requested logical copy in same heap: defer copy until write
419
420	(s.shareSet_owns_ulink){ false };
421
422	// make s alone in its shareSet
423	s.shareSet_prev = &s;
424	s.shareSet_next = &s;
425	} else {
426	verify( mode == SHARE_EDITS );
427	// sharing edits with source forces same heap as source (ignore context)
428
429	(s.shareSet_owns_ulink){ s2.shareSet_owns_ulink };
430
431	// s2 is logically const but not implementation const
432	string_res & s2mod = (string_res &) s2;
433
434	// insert s after s2 on shareSet
435	s.shareSet_next = s2mod.shareSet_next;
436	s.shareSet_prev = &s2mod;
437	s.shareSet_next->shareSet_prev = &s;
438	s.shareSet_prev->shareSet_next = &s;
439	}
440	}
441	}
442
443	static void assignEditSet(string_res & s, string_res * shareSetStartPeer, string_res * shareSetEndPeer,
444	char * resultSesStart,
445	size_t resultSesLnth,
446	HandleNode * resultPadPosition, size_t bsize ) {
447
448	char * beforeBegin = shareSetStartPeer->Handle.s;
449	size_t beforeLen = s.Handle.s - beforeBegin;
450
451	char * afterBegin = s.Handle.s + s.Handle.lnth;
452	size_t afterLen = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - afterBegin;
453
454	size_t oldLnth = s.Handle.lnth;
455
456	s.Handle.s = resultSesStart + beforeLen;
457	s.Handle.lnth = bsize;
458	if (resultPadPosition)
459	MoveThisAfter( s.Handle, *resultPadPosition );
460
461	// adjust all substring string and handle locations, and check if any substring strings are outside the new base string
462	char *limit = resultSesStart + resultSesLnth;
463	for ( string_res * p = s.shareSet_next; p != &s; p = p->shareSet_next ) {
464	verify (p->Handle.s >= beforeBegin);
465	if ( p->Handle.s >= afterBegin ) {
466	verify ( p->Handle.s <= afterBegin + afterLen );
467	verify ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
468	// p starts after the edit
469	// take start and end as end-anchored
470	size_t startOffsetFromEnd = afterBegin + afterLen - p->Handle.s;
471	p->Handle.s = limit - startOffsetFromEnd;
472	// p->Handle.lnth unaffected
473	} else if ( p->Handle.s <= beforeBegin + beforeLen ) {
474	// p starts before, or at the start of, the edit
475	if ( p->Handle.s + p->Handle.lnth <= beforeBegin + beforeLen ) {
476	// p ends before the edit
477	// take end as start-anchored too
478	// p->Handle.lnth unaffected
479	} else if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
480	// p ends during the edit; p does not include the last character replaced
481	// clip end of p to end at start of edit
482	p->Handle.lnth = beforeLen - ( p->Handle.s - beforeBegin );
483	} else {
484	// p ends after the edit
485	verify ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
486	// take end as end-anchored
487	// stretch-shrink p according to the edit
488	p->Handle.lnth += s.Handle.lnth;
489	p->Handle.lnth -= oldLnth;
490	}
491	// take start as start-anchored
492	size_t startOffsetFromStart = p->Handle.s - beforeBegin;
493	p->Handle.s = resultSesStart + startOffsetFromStart;
494	} else {
495	verify ( p->Handle.s < afterBegin );
496	// p starts during the edit
497	verify( p->Handle.s + p->Handle.lnth >= beforeBegin + beforeLen );
498	if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
499	// p ends during the edit; p does not include the last character replaced
500	// set p to empty string at start of edit
501	p->Handle.s = s.Handle.s;
502	p->Handle.lnth = 0;
503	} else {
504	// p includes the end of the edit
505	// clip start of p to start at end of edit
506	int charsToClip = afterBegin - p->Handle.s;
507	p->Handle.s = s.Handle.s + s.Handle.lnth;
508	p->Handle.lnth -= charsToClip;
509	}
510	}
511	if (resultPadPosition)
512	MoveThisAfter( p->Handle, *resultPadPosition ); // move substring handle to maintain sorted order by string position
513	}
514	}
515
516	// traverse the share-edit set (SES) to recover the range of a base string to which `s` belongs
517	static void locateInShareSet( string_res & s, string_res & shareSetStartPeer, string_res & shareSetEndPeer ) {
518	shareSetStartPeer = & s;
519	shareSetEndPeer = & s;
520	for (string_res * editPeer = s.shareSet_next; editPeer != &s; editPeer = editPeer->shareSet_next) {
521	if ( editPeer->Handle.s < shareSetStartPeer->Handle.s ) {
522	shareSetStartPeer = editPeer;
523	}
524	if ( shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth < editPeer->Handle.s + editPeer->Handle.lnth) {
525	shareSetEndPeer = editPeer;
526	}
527	}
528	}
529
530	static string_res & assign_(string_res & s, const char * buffer, size_t bsize, const string_res & valSrc) {
531	string_res * shareSetStartPeer;
532	string_res * shareSetEndPeer;
533	locateInShareSet( s, shareSetStartPeer, shareSetEndPeer );
534
535	verify( shareSetEndPeer->Handle.s >= shareSetStartPeer->Handle.s );
536	size_t origEditSetLength = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - shareSetStartPeer->Handle.s;
537	verify( origEditSetLength >= s.Handle.lnth );
538
539	if ( s.shareSet_owns_ulink ) { // assigning to private context
540	// ok to overwrite old value within LHS
541	char * prefixStartOrig = shareSetStartPeer->Handle.s;
542	int prefixLen = s.Handle.s - prefixStartOrig;
543	char * suffixStartOrig = s.Handle.s + s.Handle.lnth;
544	int suffixLen = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - suffixStartOrig;
545
546	int delta = bsize - s.Handle.lnth;
547	if ( char * oldBytes = VbyteTryAdjustLast( *s.Handle.ulink, delta ) ) {
548	// growing: copy from old to new
549	char * dest = VbyteAlloc( *s.Handle.ulink, origEditSetLength + delta );
550	char *destCursor = dest; memcpy(destCursor, prefixStartOrig, prefixLen);
551	destCursor += prefixLen; memcpy(destCursor, buffer , bsize );
552	destCursor += bsize; memcpy(destCursor, suffixStartOrig, suffixLen);
553	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
554	dest,
555	origEditSetLength + delta,
556	0p, bsize);
557	free( oldBytes );
558	} else {
559	// room is already allocated in-place: bubble suffix and overwite middle
560	memmove( suffixStartOrig + delta, suffixStartOrig, suffixLen );
561	memcpy( s.Handle.s, buffer, bsize );
562
563	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
564	shareSetStartPeer->Handle.s,
565	origEditSetLength + delta,
566	0p, bsize);
567	}
568
569	} else if ( // assigning to shared context
570	s.Handle.lnth == origEditSetLength && // overwriting entire run of SES
571	& valSrc && // sourcing from a managed string
572	valSrc.Handle.ulink == s.Handle.ulink ) { // sourcing from same heap
573
574	// SES's result will only use characters from the source string => reuse source
575	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
576	valSrc.Handle.s,
577	valSrc.Handle.lnth,
578	&((string_res&)valSrc).Handle, bsize);
579
580	} else {
581	// overwriting a proper substring of some string: mash characters from old and new together (copy on write)
582	// OR we are importing characters: need to copy eagerly (can't refer to source)
583
584	// full string is from start of shareSetStartPeer thru end of shareSetEndPeer
585	// `s` occurs in the middle of it, to be replaced
586	// build up the new text in `pasting`
587
588	string_res pasting = {
589	* s.Handle.ulink, // maintain same heap, regardless of context
590	shareSetStartPeer->Handle.s, // start of SES
591	s.Handle.s - shareSetStartPeer->Handle.s }; // length of SES, before s
592	append( pasting,
593	buffer, // start of replacement for s
594	bsize ); // length of replacement for s
595	append( pasting,
596	s.Handle.s + s.Handle.lnth, // start of SES after s
597	shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth -
598	(s.Handle.s + s.Handle.lnth) ); // length of SES, after s
599
600	// The above string building can trigger compaction.
601	// The reference points (that are arguments of the string building) may move during that building.
602	// From s point on, they are stable.
603
604	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
605	pasting.Handle.s,
606	pasting.Handle.lnth,
607	&pasting.Handle, bsize);
608	}
609
610	return s;
611	}
612
613	string_res & assign(string_res & s, const string_res & src, size_t maxlen) {
614	return assign_(s, src.Handle.s, min(src.Handle.lnth, maxlen), *0p);
615	}
616
617	string_res & assign(string_res & s, const char * buffer, size_t bsize) {
618	return assign_(s, buffer, bsize, *0p);
619	}
620
621	string_res & ?=?(string_res & s, char c) {
622	return assign(s, &c, 1);
623	}
624
625	string_res & ?=?( string_res & s, ssize_t rhs ) {
626	string_res rhs2 = rhs;
627	s = rhs2;
628	return s;
629	}
630	string_res & ?=?( string_res & s, size_t rhs ) {
631	string_res rhs2 = rhs;
632	s = rhs2;
633	return s;
634	}
635	string_res & ?=?( string_res & s, double rhs ) {
636	string_res rhs2 = rhs;
637	s = rhs2;
638	return s;
639	}
640	string_res & ?=?( string_res & s, long double rhs ) {
641	string_res rhs2 = rhs;
642	s = rhs2;
643	return s;
644	}
645	string_res & ?=?( string_res & s, double _Complex rhs ) {
646	string_res rhs2 = rhs;
647	s = rhs2;
648	return s;
649	}
650	string_res & ?=?( string_res & s, long double _Complex rhs ) {
651	string_res rhs2 = rhs;
652	s = rhs2;
653	return s;
654	}
655
656	// Copy assignment operator
657	string_res & ?=?(string_res & s, const string_res & rhs) with( s ) {
658	return assign_(s, rhs.Handle.s, rhs.Handle.lnth, rhs);
659	}
660
661	string_res & ?=?(string_res & s, string_res & rhs) with( s ) {
662	const string_res & rhs2 = rhs;
663	return s = rhs2;
664	}
665
666
667	// Destructor
668	void ^?{}(string_res & s) with(s) {
669	// much delegated to implied ^VbyteSM
670
671	// sever s from its share-edit peers, if any (four no-ops when already solo)
672	s.shareSet_prev->shareSet_next = s.shareSet_next;
673	s.shareSet_next->shareSet_prev = s.shareSet_prev;
674	// s.shareSet_next = &s;
675	// s.shareSet_prev = &s;
676
677	if (shareSet_owns_ulink && s.shareSet_next == &s) { // last one out
678	delete( s.Handle.ulink );
679	}
680	}
681
682
683	// Returns the character at the given index
684	// With unicode support, this may be different from just the byte at the given
685	// offset from the start of the string.
686	char ?[?](const string_res & s, size_t index) with(s) {
687	//TODO: Check if index is valid (no exceptions yet)
688	return Handle.s[index];
689	}
690
691	void assignAt(const string_res & s, size_t index, char val) {
692	// caution: not tested (not reachable by string-api-coverage interface)
693	// equivalent form at string level is `s[index] = val`,
694	// which uses the overload that returns a length-1 string
695	string_res editZone = { s, SHARE_EDITS, index, 1 };
696	assign(editZone, &val, 1);
697	}
698
699
700	///////////////////////////////////////////////////////////////////
701	// Concatenation
702
703	void append(string_res & str1, const char * buffer, size_t bsize) {
704	size_t clnth = str1.Handle.lnth + bsize;
705	if ( str1.Handle.s + str1.Handle.lnth == buffer ) { // already juxtapose ?
706	// no-op
707	} else { // must copy some text
708	if ( str1.Handle.s + str1.Handle.lnth == VbyteAlloc(*str1.Handle.ulink, 0) ) { // str1 at end of string area ?
709	VbyteAlloc( *str1.Handle.ulink, bsize ); // create room for 2nd part at the end of string area
710	} else { // copy the two parts
711	char * str1newBuf = VbyteAlloc( *str1.Handle.ulink, clnth );
712	char * str1oldBuf = str1.Handle.s; // must read after VbyteAlloc call in case it gs's
713	str1.Handle.s = str1newBuf;
714	memcpy( str1.Handle.s, str1oldBuf, str1.Handle.lnth );
715	} // if
716	memcpy( str1.Handle.s + str1.Handle.lnth, buffer, bsize );
717	} // if
718	str1.Handle.lnth = clnth;
719	}
720
721	void append( string_res & s, const string_res & s2, size_t maxlen ) {
722	append( s, s2.Handle.s, min( s2.Handle.lnth, maxlen ) );
723	}
724
725	///////////////////////////////////////////////////////////////////
726	// Repetition
727
728	void ?*=?(string_res & s, size_t factor) {
729	string_res s2 = { s, COPY_VALUE };
730	s = "";
731	for (factor) s += s2;
732	}
733
734	//////////////////////////////////////////////////////////
735	// Comparisons
736
737	int strcmp$( const char * s1, size_t l1, const char * s2, size_t l2 ) {
738	int ret = memcmp( s1, s2, min( l1, l2 ) );
739	if ( ret != 0 ) return ret;
740	return l1 - l2;
741	}
742
743	//////////////////////////////////////////////////////////
744	// Search
745
746	bool contains(const string_res & s, char ch) {
747	for ( i; len(s) ) {
748	if (s[i] == ch) return true;
749	}
750	return false;
751	}
752
753	// int find$( const string_res & s, ssize_t start, ssize_t len, const string_res & k, ssize_t kstart, ssize_t klen ) {
754	// if ( start < 0 ) start = s.Handle.lnth + start; // adjust negative starting locations
755	// if ( kstart < 0 ) kstart = k.Handle.lnth + kstart;
756
757	// if ( start + len > s.Handle.lnth ) return start + 1; // cannot be there
758	// if ( kstart + len > k.Handle.lnth ) return start + 1;
759	// if ( klen > len ) return start + 1;
760
761	// int i, r;
762
763	// for ( i = max( start, 1 ); ; i += 1 ) {
764	// if ( i > s.Handle.lnth - k.Handle.lnth + 1 ) {
765	// r = s.Handle.lnth + 1;
766	// break;
767	// } // exit
768	// if ( HeapArea->ByteCmp( s.Handle.s, i, k.Handle.lnth, k.Handle.s, 1, k.Handle.lnth ) == 0 ) {
769	// r = i;
770	// break;
771	// } // exit
772	// } // for
773	// return r;
774	// }
775
776	int find( const string_res & s, char search ) {
777	return findFrom(s, 0, search);
778	}
779
780	int findFrom( const string_res & s, size_t fromPos, char search ) {
781	// FIXME: This paricular overload (find of single char) is optimized to use memchr.
782	// The general overload (find of string, memchr applying to its first character) and `contains` should be adjusted to match.
783	char * searchFrom = s.Handle.s + fromPos;
784	size_t searchLnth = s.Handle.lnth - fromPos;
785	int searchVal = search;
786	char * foundAt = (char *) memchr(searchFrom, searchVal, searchLnth);
787	if (foundAt == 0p) return s.Handle.lnth;
788	else return foundAt - s.Handle.s;
789	}
790
791	int find(const string_res & s, const string_res & search) {
792	return findFrom(s, 0, search);
793	}
794
795	int findFrom(const string_res & s, size_t fromPos, const string_res & search) {
796	return findFrom(s, fromPos, search.Handle.s, search.Handle.lnth);
797	}
798
799	int find(const string_res & s, const char * search) {
800	return findFrom(s, 0, search);
801	}
802	int findFrom(const string_res & s, size_t fromPos, const char * search) {
803	return findFrom(s, fromPos, search, strlen(search));
804	}
805
806	int find(const string_res & s, const char * search, size_t searchsize) {
807	return findFrom(s, 0, search, searchsize);
808	}
809
810	int findFrom(const string_res & s, size_t fromPos, const char * search, size_t searchsize) {
811	/* Remaining implementations essentially ported from Sunjay's work */
812
813	// FIXME: This is a naive algorithm. We probably want to switch to someting
814	// like Boyer-Moore in the future.
815	// https://en.wikipedia.org/wiki/String_searching_algorithm
816
817	// Always find the empty string
818	if (searchsize == 0) {
819	return 0;
820	}
821
822	for ( i; fromPos ~ s.Handle.lnth ) {
823	size_t remaining = s.Handle.lnth - i;
824	// Never going to find the search string if the remaining string is
825	// smaller than search
826	if (remaining < searchsize) {
827	break;
828	}
829
830	bool matched = true;
831	for ( j; searchsize ) {
832	if (search[j] != s.Handle.s[i + j]) {
833	matched = false;
834	break;
835	}
836	}
837	if (matched) {
838	return i;
839	}
840	}
841	return s.Handle.lnth;
842	}
843
844	bool includes(const string_res & s, const string_res & search) {
845	return includes(s, search.Handle.s, search.Handle.lnth);
846	}
847
848	bool includes(const string_res & s, const char * search) {
849	return includes(s, search, strlen(search));
850	}
851
852	bool includes(const string_res & s, const char * search, size_t searchsize) {
853	return find(s, search, searchsize) < s.Handle.lnth;
854	}
855
856	bool startsWith(const string_res & s, const string_res & prefix) {
857	return startsWith(s, prefix.Handle.s, prefix.Handle.lnth);
858	}
859
860	bool startsWith(const string_res & s, const char * prefix) {
861	return startsWith(s, prefix, strlen(prefix));
862	}
863
864	bool startsWith(const string_res & s, const char * prefix, size_t prefixsize) {
865	if (s.Handle.lnth < prefixsize) {
866	return false;
867	}
868	return memcmp(s.Handle.s, prefix, prefixsize) == 0;
869	}
870
871	bool endsWith(const string_res & s, const string_res & suffix) {
872	return endsWith(s, suffix.Handle.s, suffix.Handle.lnth);
873	}
874
875	bool endsWith(const string_res & s, const char * suffix) {
876	return endsWith(s, suffix, strlen(suffix));
877	}
878
879	bool endsWith(const string_res & s, const char * suffix, size_t suffixsize) {
880	if (s.Handle.lnth < suffixsize) {
881	return false;
882	}
883	// Amount to offset the bytes pointer so that we are comparing the end of s
884	// to suffix. s.bytes + offset should be the first byte to compare against suffix
885	size_t offset = s.Handle.lnth - suffixsize;
886	return memcmp(s.Handle.s + offset, suffix, suffixsize) == 0;
887	}
888
889	/* Back to Mike's work */
890
891	///////////////////////////////////////////////////////////////////////////
892	// charclass, include, exclude
893
894	void ?{}( charclass_res & s, const string_res & chars) {
895	(s){ chars.Handle.s, chars.Handle.lnth };
896	}
897
898	void ?{}( charclass_res & s, const char * chars ) {
899	(s){ chars, strlen(chars) };
900	}
901
902	void ?{}( charclass_res & s, const char * chars, size_t charssize ) {
903	(s.chars){ chars, charssize };
904	// now sort it ?
905	}
906
907	void ^?{}( charclass_res & s ) {
908	^(s.chars){};
909	}
910
911	static bool test( const charclass_res & mask, char c ) {
912	// instead, use sorted char list?
913	return contains( mask.chars, c );
914	}
915
916	int exclude(const string_res & s, const charclass_res & mask) {
917	for ( i; len(s) ) {
918	if ( test(mask, s[i]) ) return i;
919	}
920	return len(s);
921	}
922
923	int include(const string_res & s, const charclass_res & mask) {
924	for ( i; len(s) ) {
925	if ( ! test(mask, s[i]) ) return i;
926	}
927	return len(s);
928	}
929
930	//######################### VbyteHeap "implementation" #########################
931
932
933	// Add a new HandleNode node n after the current HandleNode node.
934
935	static void AddThisAfter( HandleNode & s, HandleNode & n ) with(s) {
936	#ifdef VbyteDebug
937	serr \| "enter:AddThisAfter, s:" \| &s \| " n:" \| &n;
938	#endif // VbyteDebug
939	// Performance note: we are on the critical path here. MB has ensured that the verifies don't contribute to runtime (are compiled away, like they're supposed to be).
940	verify( n.ulink != 0p );
941	verify( s.ulink == n.ulink );
942	flink = n.flink;
943	blink = &n;
944	n.flink->blink = &s;
945	n.flink = &s;
946	#ifdef VbyteDebug
947	{
948	serr \| "HandleList:";
949	serr \| nlOff;
950	for ( HandleNode *ni = HeaderPtr->flink; ni != HeaderPtr; ni = ni->flink ) {
951	serr \| "\tnode:" \| ni \| " lnth:" \| ni->lnth \| " s:" \| (void *)ni->s \| ",\"";
952	for ( i; ni->lnth ) {
953	serr \| ni->s[i];
954	} // for
955	serr \| "\" flink:" \| ni->flink \| " blink:" \| ni->blink \| nl;
956	} // for
957	serr \| nlOn;
958	}
959	serr \| "exit:AddThisAfter";
960	#endif // VbyteDebug
961	} // AddThisAfter
962
963
964	// Delete the current HandleNode node.
965
966	static void DeleteNode( HandleNode & s ) with(s) {
967	#ifdef VbyteDebug
968	serr \| "enter:DeleteNode, s:" \| &s;
969	#endif // VbyteDebug
970	flink->blink = blink;
971	blink->flink = flink;
972	#ifdef VbyteDebug
973	serr \| "exit:DeleteNode";
974	#endif // VbyteDebug
975	} // DeleteNode
976
977
978	// Allocates specified storage for a string from byte-string area. If not enough space remains to perform the
979	// allocation, the garbage collection routine is called.
980
981	static char * VbyteAlloc( VbyteHeap & s, int size ) with(s) {
982	#ifdef VbyteDebug
983	serr \| "enter:VbyteAlloc, size:" \| size;
984	#endif // VbyteDebug
985	uintptr_t NoBytes;
986	char *r;
987
988	NoBytes = ( uintptr_t )EndVbyte + size;
989	if ( NoBytes > ( uintptr_t )ExtVbyte ) { // enough room for new byte-string ?
990	garbage( s, size ); // firer up the garbage collector
991	verify( (( uintptr_t )EndVbyte + size) <= ( uintptr_t )ExtVbyte && "garbage run did not free up required space" );
992	} // if
993	r = EndVbyte;
994	EndVbyte += size;
995	#ifdef VbyteDebug
996	serr \| "exit:VbyteAlloc, r:" \| (void )r \| " EndVbyte:" \| (void )EndVbyte \| " ExtVbyte:" \| ExtVbyte;
997	#endif // VbyteDebug
998	return r;
999	} // VbyteAlloc
1000
1001
1002	// Adjusts the last allocation in this heap by delta bytes, or resets this heap to be able to offer
1003	// new allocations of its original size + delta bytes. Positive delta means bigger;
1004	// negative means smaller. A null return indicates that the original heap location has room for
1005	// the requested growth. A non-null return indicates that copying to a new location is required
1006	// but has not been done; the returned value is the old heap storage location; `this` heap is
1007	// modified to reference the new location. In the copy-requred case, the caller should use
1008	// VbyteAlloc to claim the new space, while doing optimal copying from old to new, then free old.
1009
1010	static char * VbyteTryAdjustLast( VbyteHeap & s, int delta ) with(s) {
1011	if ( ( uintptr_t )EndVbyte + delta <= ( uintptr_t )ExtVbyte ) {
1012	// room available
1013	EndVbyte += delta;
1014	return 0p;
1015	}
1016
1017	char *oldBytes = StartVbyte;
1018
1019	NoOfExtensions += 1;
1020	CurrSize *= 2;
1021	StartVbyte = EndVbyte = TEMP_ALLOC(char, CurrSize);
1022	ExtVbyte = StartVbyte + CurrSize;
1023
1024	return oldBytes;
1025	}
1026
1027
1028	// Move an existing HandleNode node h somewhere after the current HandleNode node so that it is in ascending order by
1029	// the address in the byte string area.
1030
1031	static void MoveThisAfter( HandleNode & s, const HandleNode & h ) with(s) {
1032	#ifdef VbyteDebug
1033	serr \| "enter:MoveThisAfter, s:" \| & s \| " h:" \| & h;
1034	#endif // VbyteDebug
1035	verify( h.ulink != 0p );
1036	verify( s.ulink == h.ulink );
1037	if ( s < h.s ) { // check argument values
1038	// serr \| "VbyteSM: Error - Cannot move byte string starting at:" \| s \| " after byte string starting at:"
1039	// \| ( h->s ) \| " and keep handles in ascending order";
1040	// exit(-1 );
1041	verify( 0 && "VbyteSM: Error - Cannot move byte strings as requested and keep handles in ascending order");
1042	} // if
1043
1044	HandleNode *i;
1045	for ( i = h.flink; i->s != 0 && s > ( i->s ); i = i->flink ); // find the position for this node after h
1046	if ( & s != i->blink ) {
1047	DeleteNode( s );
1048	AddThisAfter( s, *i->blink );
1049	} // if
1050	#ifdef VbyteDebug
1051	{
1052	serr \| "HandleList:";
1053	serr \| nlOff;
1054	for ( HandleNode *n = HeaderPtr->flink; n != HeaderPtr; n = n->flink ) {
1055	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1056	for ( i; n->lnth ) {
1057	serr \| n->s[i];
1058	} // for
1059	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink \| nl;
1060	} // for
1061	serr \| nlOn;
1062	}
1063	serr \| "exit:MoveThisAfter";
1064	#endif // VbyteDebug
1065	} // MoveThisAfter
1066
1067
1068	//######################### VbyteHeap #########################
1069
1070	// Compare two byte strings in the byte-string area. The routine returns the following values:
1071	//
1072	// 1 => Src1-byte-string > Src2-byte-string
1073	// 0 => Src1-byte-string = Src2-byte-string
1074	// -1 => Src1-byte-string < Src2-byte-string
1075
1076	int ByteCmp( char Src1, int Src1Start, int Src1Lnth, char Src2, int Src2Start, int Src2Lnth ) {
1077	#ifdef VbyteDebug
1078	serr \| "enter:ByteCmp, Src1Start:" \| Src1Start \| " Src1Lnth:" \| Src1Lnth \| " Src2Start:" \| Src2Start \| " Src2Lnth:" \| Src2Lnth;
1079	#endif // VbyteDebug
1080	int cmp;
1081
1082	CharZip: for ( int i = 0; ; i += 1 ) {
1083	if ( i == Src2Lnth - 1 ) {
1084	for ( ; ; i += 1 ) {
1085	if ( i == Src1Lnth - 1 ) {
1086	cmp = 0;
1087	break CharZip;
1088	} // exit
1089	if ( Src1[Src1Start + i] != ' ') {
1090	// SUSPECTED BUG: this could be be why Peter got the bug report about == " " (why is this case here at all?)
1091	cmp = 1;
1092	break CharZip;
1093	} // exit
1094	} // for
1095	} // exit
1096	if ( i == Src1Lnth - 1 ) {
1097	for ( ; ; i += 1 ) {
1098	if ( i == Src2Lnth - 1 ) {
1099	cmp = 0;
1100	break CharZip;
1101	} // exit
1102	if ( Src2[Src2Start + i] != ' ') {
1103	cmp = -1;
1104	break CharZip;
1105	} // exit
1106	} // for
1107	} // exit
1108	if ( Src2[Src2Start + i] != Src1[Src1Start+ i]) {
1109	cmp = Src1[Src1Start + i] > Src2[Src2Start + i] ? 1 : -1;
1110	break CharZip;
1111	} // exit
1112	} // for
1113	#ifdef VbyteDebug
1114	serr \| "exit:ByteCmp, cmp:" \| cmp;
1115	#endif // VbyteDebug
1116	return cmp;
1117	} // ByteCmp
1118
1119
1120	// The compaction moves all of the byte strings currently in use to the beginning of the byte-string area and modifies
1121	// the handles to reflect the new positions of the byte strings. Compaction assumes that the handle list is in ascending
1122	// order by pointers into the byte-string area. The strings associated with substrings do not have to be moved because
1123	// the containing string has been moved. Hence, they only require that their string pointers be adjusted.
1124
1125	void compaction(VbyteHeap & s) with(s) {
1126	HandleNode *h;
1127	char obase, nbase, *limit;
1128
1129	NoOfCompactions += 1;
1130	EndVbyte = StartVbyte;
1131	h = Header.flink; // ignore header node
1132	for () {
1133	memmove( EndVbyte, h->s, h->lnth );
1134	obase = h->s;
1135	h->s = EndVbyte;
1136	nbase = h->s;
1137	EndVbyte += h->lnth;
1138	limit = obase + h->lnth;
1139	h = h->flink;
1140
1141	// check if any substrings are allocated within a string
1142
1143	for () {
1144	if ( h == &Header ) break; // end of header list ?
1145	if ( h->s >= limit ) break; // outside of current string ?
1146	h->s = nbase + (( uintptr_t )h->s - ( uintptr_t )obase );
1147	h = h->flink;
1148	} // for
1149	if ( h == &Header ) break; // end of header list ?
1150	} // for
1151	} // compaction
1152
1153
1154	static double heap_expansion_freespace_threshold = 0.1; // default inherited from prior work: expand heap when less than 10% "free" (i.e. garbage)
1155	// probably an unreasonable default, but need to assess early-round tests on changing it
1156
1157	void TUNING_set_string_heap_liveness_threshold( double val ) {
1158	heap_expansion_freespace_threshold = 1.0 - val;
1159	}
1160
1161
1162	// Garbage determines the amount of free space left in the heap and then reduces, leave the same, or extends the size of
1163	// the heap. The heap is then compacted in the existing heap or into the newly allocated heap.
1164
1165	void garbage(VbyteHeap & s, int minreq ) with(s) {
1166	#ifdef VbyteDebug
1167	serr \| "enter:garbage";
1168	{
1169	serr \| "HandleList:";
1170	for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
1171	serr \| nlOff;
1172	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1173	for ( i; n->lnth ) {
1174	serr \| n->s[i];
1175	} // for
1176	serr \| nlOn;
1177	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink;
1178	} // for
1179	}
1180	#endif // VbyteDebug
1181	int AmountUsed, AmountFree;
1182
1183	AmountUsed = 0;
1184	for ( HandleNode *i = Header.flink; i != &Header; i = i->flink ) { // calculate amount of byte area used
1185	AmountUsed += i->lnth;
1186	} // for
1187	AmountFree = ( uintptr_t )ExtVbyte - ( uintptr_t )StartVbyte - AmountUsed;
1188
1189	if ( ( double ) AmountFree < ( CurrSize * heap_expansion_freespace_threshold ) \|\| AmountFree < minreq ) { // free space less than threshold or not enough to serve cur request
1190
1191	extend( s, max( CurrSize, minreq ) ); // extend the heap
1192
1193	// Peter says, "This needs work before it should be used."
1194	// } else if ( AmountFree > CurrSize / 2 ) { // free space greater than 3 times the initial allocation ?
1195	// reduce(( AmountFree / CurrSize - 3 ) * CurrSize ); // reduce the memory
1196
1197	// `extend` implies a `compaction` during the copy
1198
1199	} else {
1200	compaction(s); // in-place
1201	}// if
1202	#ifdef VbyteDebug
1203	{
1204	serr \| "HandleList:";
1205	for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
1206	serr \| nlOff;
1207	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1208	for ( i; n->lnth ) {
1209	serr \| n->s[i];
1210	} // for
1211	serr \| nlOn;
1212	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink;
1213	} // for
1214	}
1215	serr \| "exit:garbage";
1216	#endif // VbyteDebug
1217	} // garbage
1218
1219	#undef VbyteDebug
1220
1221
1222
1223	// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
1224	// area is deleted.
1225
1226	void extend( VbyteHeap & s, int size ) with (s) {
1227	#ifdef VbyteDebug
1228	serr \| "enter:extend, size:" \| size;
1229	#endif // VbyteDebug
1230	char *OldStartVbyte;
1231
1232	NoOfExtensions += 1;
1233	OldStartVbyte = StartVbyte; // save previous byte area
1234
1235	CurrSize += size > InitSize ? size : InitSize; // minimum extension, initial size
1236	StartVbyte = EndVbyte = TEMP_ALLOC(char, CurrSize);
1237	ExtVbyte = (void *)( StartVbyte + CurrSize );
1238	compaction(s); // copy from old heap to new & adjust pointers to new heap
1239	free( OldStartVbyte ); // release old heap
1240	#ifdef VbyteDebug
1241	serr \| "exit:extend, CurrSize:" \| CurrSize;
1242	#endif // VbyteDebug
1243	} // extend
1244
1245	//WIP
1246	#if 0
1247
1248	// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
1249	// area is deleted.
1250
1251	void VbyteHeap::reduce( int size ) {
1252	#ifdef VbyteDebug
1253	serr \| "enter:reduce, size:" \| size;
1254	#endif // VbyteDebug
1255	char *OldStartVbyte;
1256
1257	NoOfReductions += 1;
1258	OldStartVbyte = StartVbyte; // save previous byte area
1259
1260	CurrSize -= size;
1261	StartVbyte = EndVbyte = new char[CurrSize];
1262	ExtVbyte = (void *)( StartVbyte + CurrSize );
1263	compaction(); // copy from old heap to new & adjust pointers to new heap
1264	delete OldStartVbyte; // release old heap
1265	#ifdef VbyteDebug
1266	!serr \| "exit:reduce, CurrSize:" \| CurrSize;
1267	#endif // VbyteDebug
1268	} // reduce
1269
1270
1271	#endif

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