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string_res.cfa@ 3c1e432

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Last change on this file since 3c1e432 was 768d091, checked in by Peter A. Buhr <pabuhr@…>, 9 months ago
rename I/O function "clear" to "clearerr"
Property mode set to `100644`
File size: 40.9 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 : Mon Apr 14 20:45:39 2025
13	// Update Count : 130
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	forall( ostype & \| basic_ostream( ostype ) )
196	ostype & ?\|?( ostype & out, const string_res & s ) {
197	// CFA string is NOT null terminated, so print exactly lnth characters in a minimum width of 0.
198	return out \| wd( 0, s.Handle.lnth, s.Handle.s ) \| nonl;
199	}
200
201	forall( ostype & \| basic_ostream( ostype ) )
202	void ?\|?( ostype & out, const string_res & s ) {
203	(ostype &)(out \| s); ends( out );
204	}
205
206	// Input operator
207	forall( istype & \| basic_istream( istype ) )
208	istype & ?\|?( istype & in, string_res & s ) {
209	// Reading into a temp before assigning to s is near zero overhead in typical cases because of sharing.
210	// If s is a substring of something larger, simple assignment takes care of that case correctly.
211	// But directly reading a variable amount of text into the middle of a larger context is not practical.
212	string_res temp;
213
214	// Read in chunks. Often, one chunk is enough. Keep the string that accumulates chunks last in the heap,
215	// so available room is rest of heap. When a chunk fills the heap, force growth then take the next chunk.
216	for (bool cont = true; cont; ) {
217	cont = false;
218
219	// Append dummy content to temp, forcing expansion when applicable (occurs always on subsequent loops)
220	// length 2 ensures room for at least one real char, plus scanf/pipe-cstr's null terminator
221	temp += "--";
222	assert( temp.Handle.ulink->EndVbyte == temp.Handle.s + temp.Handle.lnth ); // last in heap
223
224	// reset, to overwrite the appended "--"
225	temp.Handle.lnth -= 2;
226	temp.Handle.ulink->EndVbyte -= 2;
227
228	// rest of heap is available to read into
229	int lenReadable = (char *)temp.Handle.ulink->ExtVbyte - temp.Handle.ulink->EndVbyte;
230	assert (lenReadable >= 2);
231
232	// get bytes
233	try {
234	*(temp.Handle.ulink->EndVbyte) = '\0'; // pre-assign empty cstring
235	in \| wdi( lenReadable, temp.Handle.ulink->EndVbyte );
236	} catch (cstring_length *) {
237	cont = true;
238	}
239	int lenWasRead = strlen(temp.Handle.ulink->EndVbyte);
240
241	// update metadata
242	temp.Handle.lnth += lenWasRead;
243	temp.Handle.ulink->EndVbyte += lenWasRead;
244	}
245
246	if ( temp.Handle.lnth > 0 ) s = temp;
247	return in;
248	}
249
250	forall( istype & \| basic_istream( istype ) )
251	istype & ?\|?( istype & is, _Istream_Rquote f ) with( f.rstr ) {
252	if ( eof( is ) ) throwResume ExceptionInst( end_of_file );
253	int args;
254	fini: {
255	char rfmt[5] = { ' ', delimiters[0], '%', 'n', '\0' };
256	int l = -1; // may not be set in fmt
257	args = fmt( is, rfmt, &l ); // remove leading whitespace and quote
258	if ( eof( is ) \|\| l == -1 ) break fini;
259
260	// Change the remainder of the read into a getline by reseting the closing delimiter.
261	if ( delimiters[1] != '\0' ) {
262	delimiters[0] = delimiters[1];
263	delimiters[1] = '\0';
264	} // if
265	flags.delimiter = true;
266	return is \| (_Istream_Rstr )&f;
267	} // fini
268	// read failed => no pattern match => set string to null
269	if ( ! flags.ignore && s != 0p && args == 0 ) s[0] = '\0';
270	if ( args == 1 && eof( is ) ) { // data but scan ended at EOF
271	clearerr( is ); // => reset EOF => detect again on next read
272	} // if
273	return is;
274	}
275
276	forall( istype & \| basic_istream( istype ) )
277	istype & ?\|?( istype & is, _Istream_Rstr f ) {
278	// .---------------,
279	// \| \| \| \| \|...\|0\|0\| null terminator and guard if missing
280	// `---------------'
281	enum { gwd = 128 + 1, wd = gwd - 1 }; // guard and unguard width
282	char cstr[gwd]; // read in chunks
283	bool cont = false;
284
285	_Istream_Cwidth cf = { cstr, (_Istream_str_base)f };
286	if ( ! cf.flags.rwd ) cf.wd = wd;
287
288	cstr[wd] = '\0'; // guard null terminate string
289	try {
290	cstr[0] = '\0'; // pre-assign as empty cstring
291	is \| cf;
292	} catch( cstring_length * ) {
293	cont = true;
294	} finally {
295	if ( ! cf.flags.ignore // ok to initialize string
296	// && cstr[0] != '\0' // something was read
297	) {
298	*(f.s) = cstr;
299	}
300	} // try
301	for ( ; cont; ) { // overflow read ?
302	cont = false;
303	try {
304	cstr[0] = '\0'; // pre-assign as empty cstring
305	is \| cf;
306	} catch( cstring_length * ) {
307	cont = true; // continue not allowed
308	} finally {
309	if ( ! cf.flags.ignore && cstr[0] != '\0' ) { // something was read
310	*(f.s) += cstr; // build string chunk at a time
311	}
312	} // try
313	} // for
314	return is;
315	} // ?\|?
316
317	// Empty constructor
318	void ?{}(string_res & s) with(s) {
319	if( ambient_string_sharectx->activeHeap ) {
320	(Handle){ * ambient_string_sharectx->activeHeap };
321	(shareSet_owns_ulink){ false };
322	verify( Handle.s == 0p && Handle.lnth == 0 );
323	} else {
324	(Handle){ * new( (size_t) 10 ) }; // TODO: can I lazily avoid allocating for empty string
325	(shareSet_owns_ulink){ true };
326	Handle.s = Handle.ulink->StartVbyte;
327	verify( Handle.lnth == 0 );
328	}
329	s.shareSet_prev = &s;
330	s.shareSet_next = &s;
331	}
332
333	static void eagerCopyCtorHelper(string_res & s, const char * rhs, size_t rhslnth) with(s) {
334	if( ambient_string_sharectx->activeHeap ) {
335	(Handle){ * ambient_string_sharectx->activeHeap };
336	(shareSet_owns_ulink){ false };
337	} else {
338	(Handle){ * new( rhslnth ) };
339	(shareSet_owns_ulink){ true };
340	}
341	Handle.s = VbyteAlloc(*Handle.ulink, rhslnth);
342	Handle.lnth = rhslnth;
343	memmove( Handle.s, rhs, rhslnth );
344	s.shareSet_prev = &s;
345	s.shareSet_next = &s;
346	}
347
348	// Constructor from a raw buffer and size
349	void ?{}(string_res & s, const char * rhs, size_t rhslnth) with(s) {
350	eagerCopyCtorHelper(s, rhs, rhslnth);
351	}
352
353	void ?{}( string_res & s, ssize_t rhs ) {
354	char buf[64];
355	int l;
356	snprintf( buf, sizeof(buf)-1, "%zd%n", rhs, &l );
357	( s ){ buf, l };
358	}
359	void ?{}( string_res & s, size_t rhs ) {
360	char buf[64];
361	int l;
362	snprintf( buf, sizeof(buf)-1, "%zu%n", rhs, &l );
363	( s ){ buf, l };
364	}
365	void ?{}( string_res & s, double rhs ) {
366	char buf[64];
367	int l;
368	snprintf( buf, sizeof(buf)-1, "%g%n", rhs, &l );
369	( s ){ buf, l };
370	}
371	void ?{}( string_res & s, long double rhs ) {
372	char buf[64];
373	int l;
374	snprintf( buf, sizeof(buf)-1, "%Lg%n", rhs, &l );
375	( s ){ buf, l };
376	}
377	void ?{}( string_res & s, double _Complex rhs ) {
378	char buf[64];
379	int l;
380	snprintf( buf, sizeof(buf)-1, "%g+%gi%n", creal( rhs ), cimag( rhs ), &l );
381	( s ){ buf, l };
382	}
383	void ?{}( string_res & s, long double _Complex rhs ) {
384	char buf[64];
385	int l;
386	snprintf( buf, sizeof(buf)-1, "%Lg+%Lgi%n", creall( rhs ), cimagl( rhs ), &l );
387	( s ){ buf, l };
388	}
389
390	// private ctor (not in header): use specified heap (ignore ambient) and copy chars in
391	void ?{}( string_res & s, VbyteHeap & heap, const char * rhs, size_t rhslnth ) with(s) {
392	(Handle){ heap };
393	Handle.s = VbyteAlloc(*Handle.ulink, rhslnth);
394	Handle.lnth = rhslnth;
395	(s.shareSet_owns_ulink){ false };
396	memmove( Handle.s, rhs, rhslnth );
397	s.shareSet_prev = &s;
398	s.shareSet_next = &s;
399	}
400
401
402	// General copy constructor
403	void ?{}(string_res & s, const string_res & s2, StrResInitMode mode, size_t start, size_t len ) {
404	size_t end = start + len;
405	verify( start <= end && end <= s2.Handle.lnth );
406
407	if (s2.Handle.ulink != ambient_string_sharectx->activeHeap && mode == COPY_VALUE) {
408	// crossing heaps (including private): copy eagerly
409	eagerCopyCtorHelper(s, s2.Handle.s + start, end - start);
410	verify(s.shareSet_prev == &s);
411	verify(s.shareSet_next == &s);
412	} else {
413	(s.Handle){};
414	s.Handle.s = s2.Handle.s + start;
415	s.Handle.lnth = end - start;
416	s.Handle.ulink = s2.Handle.ulink;
417
418	AddThisAfter(s.Handle, s2.Handle ); // insert this handle after rhs handle
419	// ^ bug? skip others at early point in string
420
421	if (mode == COPY_VALUE) {
422	verify(s2.Handle.ulink == ambient_string_sharectx->activeHeap);
423	// requested logical copy in same heap: defer copy until write
424
425	(s.shareSet_owns_ulink){ false };
426
427	// make s alone in its shareSet
428	s.shareSet_prev = &s;
429	s.shareSet_next = &s;
430	} else {
431	verify( mode == SHARE_EDITS );
432	// sharing edits with source forces same heap as source (ignore context)
433
434	(s.shareSet_owns_ulink){ s2.shareSet_owns_ulink };
435
436	// s2 is logically const but not implementation const
437	string_res & s2mod = (string_res &) s2;
438
439	// insert s after s2 on shareSet
440	s.shareSet_next = s2mod.shareSet_next;
441	s.shareSet_prev = &s2mod;
442	s.shareSet_next->shareSet_prev = &s;
443	s.shareSet_prev->shareSet_next = &s;
444	}
445	}
446	}
447
448	static void assignEditSet(string_res & s, string_res * shareSetStartPeer, string_res * shareSetEndPeer,
449	char * resultSesStart,
450	size_t resultSesLnth,
451	HandleNode * resultPadPosition, size_t bsize ) {
452
453	char * beforeBegin = shareSetStartPeer->Handle.s;
454	size_t beforeLen = s.Handle.s - beforeBegin;
455
456	char * afterBegin = s.Handle.s + s.Handle.lnth;
457	size_t afterLen = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - afterBegin;
458
459	size_t oldLnth = s.Handle.lnth;
460
461	s.Handle.s = resultSesStart + beforeLen;
462	s.Handle.lnth = bsize;
463	if (resultPadPosition)
464	MoveThisAfter( s.Handle, *resultPadPosition );
465
466	// adjust all substring string and handle locations, and check if any substring strings are outside the new base string
467	char *limit = resultSesStart + resultSesLnth;
468	for ( string_res * p = s.shareSet_next; p != &s; p = p->shareSet_next ) {
469	verify (p->Handle.s >= beforeBegin);
470	if ( p->Handle.s >= afterBegin ) {
471	verify ( p->Handle.s <= afterBegin + afterLen );
472	verify ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
473	// p starts after the edit
474	// take start and end as end-anchored
475	size_t startOffsetFromEnd = afterBegin + afterLen - p->Handle.s;
476	p->Handle.s = limit - startOffsetFromEnd;
477	// p->Handle.lnth unaffected
478	} else if ( p->Handle.s <= beforeBegin + beforeLen ) {
479	// p starts before, or at the start of, the edit
480	if ( p->Handle.s + p->Handle.lnth <= beforeBegin + beforeLen ) {
481	// p ends before the edit
482	// take end as start-anchored too
483	// p->Handle.lnth unaffected
484	} else if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
485	// p ends during the edit; p does not include the last character replaced
486	// clip end of p to end at start of edit
487	p->Handle.lnth = beforeLen - ( p->Handle.s - beforeBegin );
488	} else {
489	// p ends after the edit
490	verify ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
491	// take end as end-anchored
492	// stretch-shrink p according to the edit
493	p->Handle.lnth += s.Handle.lnth;
494	p->Handle.lnth -= oldLnth;
495	}
496	// take start as start-anchored
497	size_t startOffsetFromStart = p->Handle.s - beforeBegin;
498	p->Handle.s = resultSesStart + startOffsetFromStart;
499	} else {
500	verify ( p->Handle.s < afterBegin );
501	// p starts during the edit
502	verify( p->Handle.s + p->Handle.lnth >= beforeBegin + beforeLen );
503	if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
504	// p ends during the edit; p does not include the last character replaced
505	// set p to empty string at start of edit
506	p->Handle.s = s.Handle.s;
507	p->Handle.lnth = 0;
508	} else {
509	// p includes the end of the edit
510	// clip start of p to start at end of edit
511	int charsToClip = afterBegin - p->Handle.s;
512	p->Handle.s = s.Handle.s + s.Handle.lnth;
513	p->Handle.lnth -= charsToClip;
514	}
515	}
516	if (resultPadPosition)
517	MoveThisAfter( p->Handle, *resultPadPosition ); // move substring handle to maintain sorted order by string position
518	}
519	}
520
521	// traverse the share-edit set (SES) to recover the range of a base string to which `s` belongs
522	static void locateInShareSet( string_res & s, string_res & shareSetStartPeer, string_res & shareSetEndPeer ) {
523	shareSetStartPeer = & s;
524	shareSetEndPeer = & s;
525	for (string_res * editPeer = s.shareSet_next; editPeer != &s; editPeer = editPeer->shareSet_next) {
526	if ( editPeer->Handle.s < shareSetStartPeer->Handle.s ) {
527	shareSetStartPeer = editPeer;
528	}
529	if ( shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth < editPeer->Handle.s + editPeer->Handle.lnth) {
530	shareSetEndPeer = editPeer;
531	}
532	}
533	}
534
535	static string_res & assign_(string_res & s, const char * buffer, size_t bsize, const string_res & valSrc) {
536	string_res * shareSetStartPeer;
537	string_res * shareSetEndPeer;
538	locateInShareSet( s, shareSetStartPeer, shareSetEndPeer );
539
540	verify( shareSetEndPeer->Handle.s >= shareSetStartPeer->Handle.s );
541	size_t origEditSetLength = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - shareSetStartPeer->Handle.s;
542	verify( origEditSetLength >= s.Handle.lnth );
543
544	if ( s.shareSet_owns_ulink ) { // assigning to private context
545	// ok to overwrite old value within LHS
546	char * prefixStartOrig = shareSetStartPeer->Handle.s;
547	int prefixLen = s.Handle.s - prefixStartOrig;
548	char * suffixStartOrig = s.Handle.s + s.Handle.lnth;
549	int suffixLen = shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth - suffixStartOrig;
550
551	int delta = bsize - s.Handle.lnth;
552	if ( char * oldBytes = VbyteTryAdjustLast( *s.Handle.ulink, delta ) ) {
553	// growing: copy from old to new
554	char * dest = VbyteAlloc( *s.Handle.ulink, origEditSetLength + delta );
555	char *destCursor = dest; memcpy(destCursor, prefixStartOrig, prefixLen);
556	destCursor += prefixLen; memcpy(destCursor, buffer , bsize );
557	destCursor += bsize; memcpy(destCursor, suffixStartOrig, suffixLen);
558	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
559	dest,
560	origEditSetLength + delta,
561	0p, bsize);
562	free( oldBytes );
563	} else {
564	// room is already allocated in-place: bubble suffix and overwite middle
565	memmove( suffixStartOrig + delta, suffixStartOrig, suffixLen );
566	memcpy( s.Handle.s, buffer, bsize );
567
568	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
569	shareSetStartPeer->Handle.s,
570	origEditSetLength + delta,
571	0p, bsize);
572	}
573
574	} else if ( // assigning to shared context
575	s.Handle.lnth == origEditSetLength && // overwriting entire run of SES
576	& valSrc && // sourcing from a managed string
577	valSrc.Handle.ulink == s.Handle.ulink ) { // sourcing from same heap
578
579	// SES's result will only use characters from the source string => reuse source
580	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
581	valSrc.Handle.s,
582	valSrc.Handle.lnth,
583	&((string_res&)valSrc).Handle, bsize);
584
585	} else {
586	// overwriting a proper substring of some string: mash characters from old and new together (copy on write)
587	// OR we are importing characters: need to copy eagerly (can't refer to source)
588
589	// full string is from start of shareSetStartPeer thru end of shareSetEndPeer
590	// `s` occurs in the middle of it, to be replaced
591	// build up the new text in `pasting`
592
593	string_res pasting = {
594	* s.Handle.ulink, // maintain same heap, regardless of context
595	shareSetStartPeer->Handle.s, // start of SES
596	s.Handle.s - shareSetStartPeer->Handle.s }; // length of SES, before s
597	append( pasting,
598	buffer, // start of replacement for s
599	bsize ); // length of replacement for s
600	append( pasting,
601	s.Handle.s + s.Handle.lnth, // start of SES after s
602	shareSetEndPeer->Handle.s + shareSetEndPeer->Handle.lnth -
603	(s.Handle.s + s.Handle.lnth) ); // length of SES, after s
604
605	// The above string building can trigger compaction.
606	// The reference points (that are arguments of the string building) may move during that building.
607	// From s point on, they are stable.
608
609	assignEditSet(s, shareSetStartPeer, shareSetEndPeer,
610	pasting.Handle.s,
611	pasting.Handle.lnth,
612	&pasting.Handle, bsize);
613	}
614
615	return s;
616	}
617
618	string_res & assign(string_res & s, const string_res & src, size_t maxlen) {
619	return assign_(s, src.Handle.s, min(src.Handle.lnth, maxlen), *0p);
620	}
621
622	string_res & assign(string_res & s, const char * buffer, size_t bsize) {
623	return assign_(s, buffer, bsize, *0p);
624	}
625
626	string_res & ?=?(string_res & s, char c) {
627	return assign(s, &c, 1);
628	}
629
630	string_res & ?=?( string_res & s, ssize_t rhs ) {
631	string_res rhs2 = rhs;
632	s = rhs2;
633	return s;
634	}
635	string_res & ?=?( string_res & s, size_t rhs ) {
636	string_res rhs2 = rhs;
637	s = rhs2;
638	return s;
639	}
640	string_res & ?=?( string_res & s, double rhs ) {
641	string_res rhs2 = rhs;
642	s = rhs2;
643	return s;
644	}
645	string_res & ?=?( string_res & s, long double rhs ) {
646	string_res rhs2 = rhs;
647	s = rhs2;
648	return s;
649	}
650	string_res & ?=?( string_res & s, double _Complex rhs ) {
651	string_res rhs2 = rhs;
652	s = rhs2;
653	return s;
654	}
655	string_res & ?=?( string_res & s, long double _Complex rhs ) {
656	string_res rhs2 = rhs;
657	s = rhs2;
658	return s;
659	}
660
661	// Copy assignment operator
662	string_res & ?=?(string_res & s, const string_res & rhs) with( s ) {
663	return assign_(s, rhs.Handle.s, rhs.Handle.lnth, rhs);
664	}
665
666	string_res & ?=?(string_res & s, string_res & rhs) with( s ) {
667	const string_res & rhs2 = rhs;
668	return s = rhs2;
669	}
670
671
672	// Destructor
673	void ^?{}(string_res & s) with(s) {
674	// much delegated to implied ^VbyteSM
675
676	// sever s from its share-edit peers, if any (four no-ops when already solo)
677	s.shareSet_prev->shareSet_next = s.shareSet_next;
678	s.shareSet_next->shareSet_prev = s.shareSet_prev;
679	// s.shareSet_next = &s;
680	// s.shareSet_prev = &s;
681
682	if (shareSet_owns_ulink && s.shareSet_next == &s) { // last one out
683	delete( s.Handle.ulink );
684	}
685	}
686
687
688	// Returns the character at the given index
689	// With unicode support, this may be different from just the byte at the given
690	// offset from the start of the string.
691	char ?[?](const string_res & s, size_t index) with(s) {
692	//TODO: Check if index is valid (no exceptions yet)
693	return Handle.s[index];
694	}
695
696	void assignAt(const string_res & s, size_t index, char val) {
697	// caution: not tested (not reachable by string-api-coverage interface)
698	// equivalent form at string level is `s[index] = val`,
699	// which uses the overload that returns a length-1 string
700	string_res editZone = { s, SHARE_EDITS, index, 1 };
701	assign(editZone, &val, 1);
702	}
703
704
705	///////////////////////////////////////////////////////////////////
706	// Concatenation
707
708	void append(string_res & str1, const char * buffer, size_t bsize) {
709	size_t clnth = str1.Handle.lnth + bsize;
710	if ( str1.Handle.s + str1.Handle.lnth == buffer ) { // already juxtapose ?
711	// no-op
712	} else { // must copy some text
713	if ( str1.Handle.s + str1.Handle.lnth == VbyteAlloc(*str1.Handle.ulink, 0) ) { // str1 at end of string area ?
714	VbyteAlloc( *str1.Handle.ulink, bsize ); // create room for 2nd part at the end of string area
715	} else { // copy the two parts
716	char * str1newBuf = VbyteAlloc( *str1.Handle.ulink, clnth );
717	char * str1oldBuf = str1.Handle.s; // must read after VbyteAlloc call in case it gs's
718	str1.Handle.s = str1newBuf;
719	memcpy( str1.Handle.s, str1oldBuf, str1.Handle.lnth );
720	} // if
721	memcpy( str1.Handle.s + str1.Handle.lnth, buffer, bsize );
722	} // if
723	str1.Handle.lnth = clnth;
724	}
725
726	void append( string_res & s, const string_res & s2, size_t maxlen ) {
727	append( s, s2.Handle.s, min( s2.Handle.lnth, maxlen ) );
728	}
729
730	///////////////////////////////////////////////////////////////////
731	// Repetition
732
733	void ?*=?(string_res & s, size_t factor) {
734	string_res s2 = { s, COPY_VALUE };
735	s = "";
736	for (factor) s += s2;
737	}
738
739	//////////////////////////////////////////////////////////
740	// Comparisons
741
742	int strcmp$( const char * s1, size_t l1, const char * s2, size_t l2 ) {
743	int ret = memcmp( s1, s2, min( l1, l2 ) );
744	if ( ret != 0 ) return ret;
745	return l1 - l2;
746	}
747
748	//////////////////////////////////////////////////////////
749	// Search
750
751	bool contains(const string_res & s, char ch) {
752	for ( i; len(s) ) {
753	if (s[i] == ch) return true;
754	}
755	return false;
756	}
757
758	// int find$( const string_res & s, ssize_t start, ssize_t len, const string_res & k, ssize_t kstart, ssize_t klen ) {
759	// if ( start < 0 ) start = s.Handle.lnth + start; // adjust negative starting locations
760	// if ( kstart < 0 ) kstart = k.Handle.lnth + kstart;
761
762	// if ( start + len > s.Handle.lnth ) return start + 1; // cannot be there
763	// if ( kstart + len > k.Handle.lnth ) return start + 1;
764	// if ( klen > len ) return start + 1;
765
766	// int i, r;
767
768	// for ( i = max( start, 1 ); ; i += 1 ) {
769	// if ( i > s.Handle.lnth - k.Handle.lnth + 1 ) {
770	// r = s.Handle.lnth + 1;
771	// break;
772	// } // exit
773	// if ( HeapArea->ByteCmp( s.Handle.s, i, k.Handle.lnth, k.Handle.s, 1, k.Handle.lnth ) == 0 ) {
774	// r = i;
775	// break;
776	// } // exit
777	// } // for
778	// return r;
779	// }
780
781	int find( const string_res & s, char search ) {
782	return findFrom(s, 0, search);
783	}
784
785	int findFrom( const string_res & s, size_t fromPos, char search ) {
786	// FIXME: This paricular overload (find of single char) is optimized to use memchr.
787	// The general overload (find of string, memchr applying to its first character) and `contains` should be adjusted to match.
788	char * searchFrom = s.Handle.s + fromPos;
789	size_t searchLnth = s.Handle.lnth - fromPos;
790	int searchVal = search;
791	char * foundAt = (char *) memchr(searchFrom, searchVal, searchLnth);
792	if (foundAt == 0p) return s.Handle.lnth;
793	else return foundAt - s.Handle.s;
794	}
795
796	int find(const string_res & s, const string_res & search) {
797	return findFrom(s, 0, search);
798	}
799
800	int findFrom(const string_res & s, size_t fromPos, const string_res & search) {
801	return findFrom(s, fromPos, search.Handle.s, search.Handle.lnth);
802	}
803
804	int find(const string_res & s, const char * search) {
805	return findFrom(s, 0, search);
806	}
807	int findFrom(const string_res & s, size_t fromPos, const char * search) {
808	return findFrom(s, fromPos, search, strlen(search));
809	}
810
811	int find(const string_res & s, const char * search, size_t searchsize) {
812	return findFrom(s, 0, search, searchsize);
813	}
814
815	int findFrom(const string_res & s, size_t fromPos, const char * search, size_t searchsize) {
816	/* Remaining implementations essentially ported from Sunjay's work */
817
818	// FIXME: This is a naive algorithm. We probably want to switch to someting
819	// like Boyer-Moore in the future.
820	// https://en.wikipedia.org/wiki/String_searching_algorithm
821
822	// Always find the empty string
823	if (searchsize == 0) {
824	return 0;
825	}
826
827	for ( i; fromPos ~ s.Handle.lnth ) {
828	size_t remaining = s.Handle.lnth - i;
829	// Never going to find the search string if the remaining string is
830	// smaller than search
831	if (remaining < searchsize) {
832	break;
833	}
834
835	bool matched = true;
836	for ( j; searchsize ) {
837	if (search[j] != s.Handle.s[i + j]) {
838	matched = false;
839	break;
840	}
841	}
842	if (matched) {
843	return i;
844	}
845	}
846	return s.Handle.lnth;
847	}
848
849	bool includes(const string_res & s, const string_res & search) {
850	return includes(s, search.Handle.s, search.Handle.lnth);
851	}
852
853	bool includes(const string_res & s, const char * search) {
854	return includes(s, search, strlen(search));
855	}
856
857	bool includes(const string_res & s, const char * search, size_t searchsize) {
858	return find(s, search, searchsize) < s.Handle.lnth;
859	}
860
861	bool startsWith(const string_res & s, const string_res & prefix) {
862	return startsWith(s, prefix.Handle.s, prefix.Handle.lnth);
863	}
864
865	bool startsWith(const string_res & s, const char * prefix) {
866	return startsWith(s, prefix, strlen(prefix));
867	}
868
869	bool startsWith(const string_res & s, const char * prefix, size_t prefixsize) {
870	if (s.Handle.lnth < prefixsize) {
871	return false;
872	}
873	return memcmp(s.Handle.s, prefix, prefixsize) == 0;
874	}
875
876	bool endsWith(const string_res & s, const string_res & suffix) {
877	return endsWith(s, suffix.Handle.s, suffix.Handle.lnth);
878	}
879
880	bool endsWith(const string_res & s, const char * suffix) {
881	return endsWith(s, suffix, strlen(suffix));
882	}
883
884	bool endsWith(const string_res & s, const char * suffix, size_t suffixsize) {
885	if (s.Handle.lnth < suffixsize) {
886	return false;
887	}
888	// Amount to offset the bytes pointer so that we are comparing the end of s
889	// to suffix. s.bytes + offset should be the first byte to compare against suffix
890	size_t offset = s.Handle.lnth - suffixsize;
891	return memcmp(s.Handle.s + offset, suffix, suffixsize) == 0;
892	}
893
894	/* Back to Mike's work */
895
896	///////////////////////////////////////////////////////////////////////////
897	// charclass, include, exclude
898
899	void ?{}( charclass_res & s, const string_res & chars) {
900	(s){ chars.Handle.s, chars.Handle.lnth };
901	}
902
903	void ?{}( charclass_res & s, const char * chars ) {
904	(s){ chars, strlen(chars) };
905	}
906
907	void ?{}( charclass_res & s, const char * chars, size_t charssize ) {
908	(s.chars){ chars, charssize };
909	// now sort it ?
910	}
911
912	void ^?{}( charclass_res & s ) {
913	^(s.chars){};
914	}
915
916	static bool test( const charclass_res & mask, char c ) {
917	// instead, use sorted char list?
918	return contains( mask.chars, c );
919	}
920
921	int exclude(const string_res & s, const charclass_res & mask) {
922	for ( i; len(s) ) {
923	if ( test(mask, s[i]) ) return i;
924	}
925	return len(s);
926	}
927
928	int include(const string_res & s, const charclass_res & mask) {
929	for ( i; len(s) ) {
930	if ( ! test(mask, s[i]) ) return i;
931	}
932	return len(s);
933	}
934
935	//######################### VbyteHeap "implementation" #########################
936
937
938	// Add a new HandleNode node n after the current HandleNode node.
939
940	static void AddThisAfter( HandleNode & s, HandleNode & n ) with(s) {
941	#ifdef VbyteDebug
942	serr \| "enter:AddThisAfter, s:" \| &s \| " n:" \| &n;
943	#endif // VbyteDebug
944	// 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).
945	verify( n.ulink != 0p );
946	verify( s.ulink == n.ulink );
947	flink = n.flink;
948	blink = &n;
949	n.flink->blink = &s;
950	n.flink = &s;
951	#ifdef VbyteDebug
952	{
953	serr \| "HandleList:";
954	serr \| nlOff;
955	for ( HandleNode *ni = HeaderPtr->flink; ni != HeaderPtr; ni = ni->flink ) {
956	serr \| "\tnode:" \| ni \| " lnth:" \| ni->lnth \| " s:" \| (void *)ni->s \| ",\"";
957	for ( i; ni->lnth ) {
958	serr \| ni->s[i];
959	} // for
960	serr \| "\" flink:" \| ni->flink \| " blink:" \| ni->blink \| nl;
961	} // for
962	serr \| nlOn;
963	}
964	serr \| "exit:AddThisAfter";
965	#endif // VbyteDebug
966	} // AddThisAfter
967
968
969	// Delete the current HandleNode node.
970
971	static void DeleteNode( HandleNode & s ) with(s) {
972	#ifdef VbyteDebug
973	serr \| "enter:DeleteNode, s:" \| &s;
974	#endif // VbyteDebug
975	flink->blink = blink;
976	blink->flink = flink;
977	#ifdef VbyteDebug
978	serr \| "exit:DeleteNode";
979	#endif // VbyteDebug
980	} // DeleteNode
981
982
983	// Allocates specified storage for a string from byte-string area. If not enough space remains to perform the
984	// allocation, the garbage collection routine is called.
985
986	static char * VbyteAlloc( VbyteHeap & s, int size ) with(s) {
987	#ifdef VbyteDebug
988	serr \| "enter:VbyteAlloc, size:" \| size;
989	#endif // VbyteDebug
990	uintptr_t NoBytes;
991	char *r;
992
993	NoBytes = ( uintptr_t )EndVbyte + size;
994	if ( NoBytes > ( uintptr_t )ExtVbyte ) { // enough room for new byte-string ?
995	garbage( s, size ); // firer up the garbage collector
996	verify( (( uintptr_t )EndVbyte + size) <= ( uintptr_t )ExtVbyte && "garbage run did not free up required space" );
997	} // if
998	r = EndVbyte;
999	EndVbyte += size;
1000	#ifdef VbyteDebug
1001	serr \| "exit:VbyteAlloc, r:" \| (void )r \| " EndVbyte:" \| (void )EndVbyte \| " ExtVbyte:" \| ExtVbyte;
1002	#endif // VbyteDebug
1003	return r;
1004	} // VbyteAlloc
1005
1006
1007	// Adjusts the last allocation in this heap by delta bytes, or resets this heap to be able to offer
1008	// new allocations of its original size + delta bytes. Positive delta means bigger;
1009	// negative means smaller. A null return indicates that the original heap location has room for
1010	// the requested growth. A non-null return indicates that copying to a new location is required
1011	// but has not been done; the returned value is the old heap storage location; `this` heap is
1012	// modified to reference the new location. In the copy-requred case, the caller should use
1013	// VbyteAlloc to claim the new space, while doing optimal copying from old to new, then free old.
1014
1015	static char * VbyteTryAdjustLast( VbyteHeap & s, int delta ) with(s) {
1016	if ( ( uintptr_t )EndVbyte + delta <= ( uintptr_t )ExtVbyte ) {
1017	// room available
1018	EndVbyte += delta;
1019	return 0p;
1020	}
1021
1022	char *oldBytes = StartVbyte;
1023
1024	NoOfExtensions += 1;
1025	CurrSize *= 2;
1026	StartVbyte = EndVbyte = TEMP_ALLOC(char, CurrSize);
1027	ExtVbyte = StartVbyte + CurrSize;
1028
1029	return oldBytes;
1030	}
1031
1032
1033	// Move an existing HandleNode node h somewhere after the current HandleNode node so that it is in ascending order by
1034	// the address in the byte string area.
1035
1036	static void MoveThisAfter( HandleNode & s, const HandleNode & h ) with(s) {
1037	#ifdef VbyteDebug
1038	serr \| "enter:MoveThisAfter, s:" \| & s \| " h:" \| & h;
1039	#endif // VbyteDebug
1040	verify( h.ulink != 0p );
1041	verify( s.ulink == h.ulink );
1042	if ( s < h.s ) { // check argument values
1043	// serr \| "VbyteSM: Error - Cannot move byte string starting at:" \| s \| " after byte string starting at:"
1044	// \| ( h->s ) \| " and keep handles in ascending order";
1045	// exit(-1 );
1046	verify( 0 && "VbyteSM: Error - Cannot move byte strings as requested and keep handles in ascending order");
1047	} // if
1048
1049	HandleNode *i;
1050	for ( i = h.flink; i->s != 0 && s > ( i->s ); i = i->flink ); // find the position for this node after h
1051	if ( & s != i->blink ) {
1052	DeleteNode( s );
1053	AddThisAfter( s, *i->blink );
1054	} // if
1055	#ifdef VbyteDebug
1056	{
1057	serr \| "HandleList:";
1058	serr \| nlOff;
1059	for ( HandleNode *n = HeaderPtr->flink; n != HeaderPtr; n = n->flink ) {
1060	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1061	for ( i; n->lnth ) {
1062	serr \| n->s[i];
1063	} // for
1064	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink \| nl;
1065	} // for
1066	serr \| nlOn;
1067	}
1068	serr \| "exit:MoveThisAfter";
1069	#endif // VbyteDebug
1070	} // MoveThisAfter
1071
1072
1073	//######################### VbyteHeap #########################
1074
1075	// Compare two byte strings in the byte-string area. The routine returns the following values:
1076	//
1077	// 1 => Src1-byte-string > Src2-byte-string
1078	// 0 => Src1-byte-string = Src2-byte-string
1079	// -1 => Src1-byte-string < Src2-byte-string
1080
1081	int ByteCmp( char Src1, int Src1Start, int Src1Lnth, char Src2, int Src2Start, int Src2Lnth ) {
1082	#ifdef VbyteDebug
1083	serr \| "enter:ByteCmp, Src1Start:" \| Src1Start \| " Src1Lnth:" \| Src1Lnth \| " Src2Start:" \| Src2Start \| " Src2Lnth:" \| Src2Lnth;
1084	#endif // VbyteDebug
1085	int cmp;
1086
1087	CharZip: for ( int i = 0; ; i += 1 ) {
1088	if ( i == Src2Lnth - 1 ) {
1089	for ( ; ; i += 1 ) {
1090	if ( i == Src1Lnth - 1 ) {
1091	cmp = 0;
1092	break CharZip;
1093	} // exit
1094	if ( Src1[Src1Start + i] != ' ') {
1095	// SUSPECTED BUG: this could be be why Peter got the bug report about == " " (why is this case here at all?)
1096	cmp = 1;
1097	break CharZip;
1098	} // exit
1099	} // for
1100	} // exit
1101	if ( i == Src1Lnth - 1 ) {
1102	for ( ; ; i += 1 ) {
1103	if ( i == Src2Lnth - 1 ) {
1104	cmp = 0;
1105	break CharZip;
1106	} // exit
1107	if ( Src2[Src2Start + i] != ' ') {
1108	cmp = -1;
1109	break CharZip;
1110	} // exit
1111	} // for
1112	} // exit
1113	if ( Src2[Src2Start + i] != Src1[Src1Start+ i]) {
1114	cmp = Src1[Src1Start + i] > Src2[Src2Start + i] ? 1 : -1;
1115	break CharZip;
1116	} // exit
1117	} // for
1118	#ifdef VbyteDebug
1119	serr \| "exit:ByteCmp, cmp:" \| cmp;
1120	#endif // VbyteDebug
1121	return cmp;
1122	} // ByteCmp
1123
1124
1125	// The compaction moves all of the byte strings currently in use to the beginning of the byte-string area and modifies
1126	// the handles to reflect the new positions of the byte strings. Compaction assumes that the handle list is in ascending
1127	// order by pointers into the byte-string area. The strings associated with substrings do not have to be moved because
1128	// the containing string has been moved. Hence, they only require that their string pointers be adjusted.
1129
1130	void compaction(VbyteHeap & s) with(s) {
1131	HandleNode *h;
1132	char obase, nbase, *limit;
1133
1134	NoOfCompactions += 1;
1135	EndVbyte = StartVbyte;
1136	h = Header.flink; // ignore header node
1137	for () {
1138	memmove( EndVbyte, h->s, h->lnth );
1139	obase = h->s;
1140	h->s = EndVbyte;
1141	nbase = h->s;
1142	EndVbyte += h->lnth;
1143	limit = obase + h->lnth;
1144	h = h->flink;
1145
1146	// check if any substrings are allocated within a string
1147
1148	for () {
1149	if ( h == &Header ) break; // end of header list ?
1150	if ( h->s >= limit ) break; // outside of current string ?
1151	h->s = nbase + (( uintptr_t )h->s - ( uintptr_t )obase );
1152	h = h->flink;
1153	} // for
1154	if ( h == &Header ) break; // end of header list ?
1155	} // for
1156	} // compaction
1157
1158
1159	static double heap_expansion_freespace_threshold = 0.1; // default inherited from prior work: expand heap when less than 10% "free" (i.e. garbage)
1160	// probably an unreasonable default, but need to assess early-round tests on changing it
1161
1162	void TUNING_set_string_heap_liveness_threshold( double val ) {
1163	heap_expansion_freespace_threshold = 1.0 - val;
1164	}
1165
1166
1167	// Garbage determines the amount of free space left in the heap and then reduces, leave the same, or extends the size of
1168	// the heap. The heap is then compacted in the existing heap or into the newly allocated heap.
1169
1170	void garbage(VbyteHeap & s, int minreq ) with(s) {
1171	#ifdef VbyteDebug
1172	serr \| "enter:garbage";
1173	{
1174	serr \| "HandleList:";
1175	for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
1176	serr \| nlOff;
1177	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1178	for ( i; n->lnth ) {
1179	serr \| n->s[i];
1180	} // for
1181	serr \| nlOn;
1182	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink;
1183	} // for
1184	}
1185	#endif // VbyteDebug
1186	int AmountUsed, AmountFree;
1187
1188	AmountUsed = 0;
1189	for ( HandleNode *i = Header.flink; i != &Header; i = i->flink ) { // calculate amount of byte area used
1190	AmountUsed += i->lnth;
1191	} // for
1192	AmountFree = ( uintptr_t )ExtVbyte - ( uintptr_t )StartVbyte - AmountUsed;
1193
1194	if ( ( double ) AmountFree < ( CurrSize * heap_expansion_freespace_threshold ) \|\| AmountFree < minreq ) { // free space less than threshold or not enough to serve cur request
1195
1196	extend( s, max( CurrSize, minreq ) ); // extend the heap
1197
1198	// Peter says, "This needs work before it should be used."
1199	// } else if ( AmountFree > CurrSize / 2 ) { // free space greater than 3 times the initial allocation ?
1200	// reduce(( AmountFree / CurrSize - 3 ) * CurrSize ); // reduce the memory
1201
1202	// `extend` implies a `compaction` during the copy
1203
1204	} else {
1205	compaction(s); // in-place
1206	}// if
1207	#ifdef VbyteDebug
1208	{
1209	serr \| "HandleList:";
1210	for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
1211	serr \| nlOff;
1212	serr \| "\tnode:" \| n \| " lnth:" \| n->lnth \| " s:" \| (void *)n->s \| ",\"";
1213	for ( i; n->lnth ) {
1214	serr \| n->s[i];
1215	} // for
1216	serr \| nlOn;
1217	serr \| "\" flink:" \| n->flink \| " blink:" \| n->blink;
1218	} // for
1219	}
1220	serr \| "exit:garbage";
1221	#endif // VbyteDebug
1222	} // garbage
1223
1224	#undef VbyteDebug
1225
1226
1227
1228	// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
1229	// area is deleted.
1230
1231	void extend( VbyteHeap & s, int size ) with (s) {
1232	#ifdef VbyteDebug
1233	serr \| "enter:extend, size:" \| size;
1234	#endif // VbyteDebug
1235	char *OldStartVbyte;
1236
1237	NoOfExtensions += 1;
1238	OldStartVbyte = StartVbyte; // save previous byte area
1239
1240	CurrSize += size > InitSize ? size : InitSize; // minimum extension, initial size
1241	StartVbyte = EndVbyte = TEMP_ALLOC(char, CurrSize);
1242	ExtVbyte = (void *)( StartVbyte + CurrSize );
1243	compaction(s); // copy from old heap to new & adjust pointers to new heap
1244	free( OldStartVbyte ); // release old heap
1245	#ifdef VbyteDebug
1246	serr \| "exit:extend, CurrSize:" \| CurrSize;
1247	#endif // VbyteDebug
1248	} // extend
1249
1250	//WIP
1251	#if 0
1252
1253	// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
1254	// area is deleted.
1255
1256	void VbyteHeap::reduce( int size ) {
1257	#ifdef VbyteDebug
1258	serr \| "enter:reduce, size:" \| size;
1259	#endif // VbyteDebug
1260	char *OldStartVbyte;
1261
1262	NoOfReductions += 1;
1263	OldStartVbyte = StartVbyte; // save previous byte area
1264
1265	CurrSize -= size;
1266	StartVbyte = EndVbyte = new char[CurrSize];
1267	ExtVbyte = (void *)( StartVbyte + CurrSize );
1268	compaction(); // copy from old heap to new & adjust pointers to new heap
1269	delete OldStartVbyte; // release old heap
1270	#ifdef VbyteDebug
1271	!serr \| "exit:reduce, CurrSize:" \| CurrSize;
1272	#endif // VbyteDebug
1273	} // reduce
1274
1275
1276	#endif

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