source: libcfa/src/containers/string_res.cfa @ 6cc87c0

Last change on this file since 6cc87c0 was 6cc87c0, checked in by Michael Brooks <mlbrooks@…>, 3 months ago

String bug fixes and new tests.

Enabled white-box visibility (DEBUG_ functions) into the string representation for heap-oriented tests.

string-gc/basicFillCompact

  • newly testable, now with the DEBUG_ visibility, but was basically already working

string-gc/fillCompact_withSharedEdits

  • new check for bug fixed here, where an append that triggers a compaction left substrings with dangling pointers

to the old text-pad range; fix is how string_res/assign now sequences growth-pushing operations before grabbing
pointers into the ranges of the old-version

string-overwrite

  • new broad check a few of whose cases are fixed here; fixes are the adjustments to the case priorities and

edge-case classifications in string_res/assign "adjust all substring string and handle locations" section

  • Property mode set to 100644
File size: 29.9 KB
Line 
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 : Michael L. Brooks
12// Last Modified On : Fri Sep 03 11:00:00 2021
13// Update Count     : 1
14//
15
16#include "string_res.hfa"
17#include <stdlib.hfa>  // e.g. malloc
18#include <string.h>    // e.g. strlen
19
20//######################### VbyteHeap "header" #########################
21
22
23
24
25
26
27
28
29// DON'T COMMIT:
30// #define VbyteDebug
31
32
33
34
35
36#ifdef VbyteDebug
37HandleNode *HeaderPtr;
38#endif // VbyteDebug
39
40struct VbyteHeap {
41
42    int NoOfCompactions;                                // number of compactions of the byte area
43    int NoOfExtensions;                                 // number of extensions in the size of the byte area
44    int NoOfReductions;                                 // number of reductions in the size of the byte area
45   
46    int InitSize;                                       // initial number of bytes in the byte-string area
47    int CurrSize;                                       // current number of bytes in the byte-string area
48    char *StartVbyte;                                   // pointer to the `st byte of the start of the byte-string area
49    char *EndVbyte;                                     // pointer to the next byte after the end of the currently used portion of byte-string area
50    void *ExtVbyte;                                     // pointer to the next byte after the end of the byte-string area
51
52    HandleNode Header;                                  // header node for handle list
53}; // VbyteHeap
54
55   
56static inline void compaction( VbyteHeap & );                           // compaction of the byte area
57static inline void garbage( VbyteHeap & );                              // garbage collect the byte area
58static inline void extend( VbyteHeap &, int );                  // extend the size of the byte area
59static inline void reduce( VbyteHeap &, int );                  // reduce the size of the byte area
60
61static inline void ?{}( VbyteHeap &, int = 1000 );
62static inline void ^?{}( VbyteHeap & );
63static inline void ByteCopy( VbyteHeap &, char *, int, int, char *, int, int ); // copy a block of bytes from one location in the heap to another
64static inline int ByteCmp( VbyteHeap &, char *, int, int, char *, int, int );   // compare 2 blocks of bytes
65static inline char *VbyteAlloc( VbyteHeap &, int );                     // allocate a block bytes in the heap
66
67
68static inline void AddThisAfter( HandleNode &, HandleNode & );
69static inline void DeleteNode( HandleNode & );
70static inline void MoveThisAfter( HandleNode &, const HandleNode & );           // move current handle after parameter handle
71
72
73// Allocate the storage for the variable sized area and intialize the heap variables.
74
75static inline void ?{}( VbyteHeap & this, int Size ) with(this) {
76#ifdef VbyteDebug
77    serr | "enter:VbyteHeap::VbyteHeap, this:" | &this | " Size:" | Size;
78#endif // VbyteDebug
79    NoOfCompactions = NoOfExtensions = NoOfReductions = 0;
80    InitSize = CurrSize = Size;
81    StartVbyte = EndVbyte = alloc(CurrSize);
82    ExtVbyte = (void *)( StartVbyte + CurrSize );
83    Header.flink = Header.blink = &Header;
84#ifdef VbyteDebug
85    HeaderPtr = &Header;
86    serr | "exit:VbyteHeap::VbyteHeap, this:" | &this;
87#endif // VbyteDebug
88} // VbyteHeap
89
90
91// Release the dynamically allocated storage for the byte area.
92
93static inline void ^?{}( VbyteHeap & this ) with(this) {
94    free( StartVbyte );
95} // ~VbyteHeap
96
97
98//######################### HandleNode #########################
99
100
101// Create a handle node. The handle is not linked into the handle list.  This is the responsibilitiy of the handle
102// creator.
103
104void ?{}( HandleNode & this ) with(this) {
105#ifdef VbyteDebug
106    serr | "enter:HandleNode::HandleNode, this:" | &this;
107#endif // VbyteDebug
108    s = 0;
109    lnth = 0;
110#ifdef VbyteDebug
111    serr | "exit:HandleNode::HandleNode, this:" | &this;
112#endif // VbyteDebug
113} // HandleNode
114
115// Create a handle node. The handle is linked into the handle list at the end. This means that this handle will NOT be
116// in order by string address, but this is not a problem because a string with length zero does nothing during garbage
117// collection.
118
119void ?{}( HandleNode & this, VbyteHeap & vh ) with(this) {
120#ifdef VbyteDebug
121    serr | "enter:HandleNode::HandleNode, this:" | &this;
122#endif // VbyteDebug
123    s = 0;
124    lnth = 0;
125    AddThisAfter( this, *vh.Header.blink );
126#ifdef VbyteDebug
127    serr | "exit:HandleNode::HandleNode, this:" | &this;
128#endif // VbyteDebug
129} // HandleNode
130
131
132// Delete a node from the handle list by unchaining it from the list. If the handle node was allocated dynamically, it
133// is the responsibility of the creator to destroy it.
134
135void ^?{}( HandleNode & this ) with(this) {
136#ifdef VbyteDebug
137    serr | "enter:HandleNode::~HandleNode, this:" | & this;
138    {
139        serr | nlOff;
140        serr | " lnth:" | lnth | " s:" | (void *)s | ",\"";
141        for ( int i = 0; i < lnth; i += 1 ) {
142            serr | s[i];
143        } // for
144        serr | "\" flink:" | flink | " blink:" | blink | nl;
145        serr | nlOn;
146    }
147#endif // VbyteDebug
148    DeleteNode( this );
149} // ~HandleNode
150
151//######################### String Resource #########################
152
153
154VbyteHeap HeapArea;
155
156VbyteHeap * DEBUG_string_heap = & HeapArea;
157
158size_t DEBUG_string_bytes_avail_until_gc( VbyteHeap * heap ) {
159    return ((char*)heap->ExtVbyte) - heap->EndVbyte;
160}
161
162const char * DEBUG_string_heap_start( VbyteHeap * heap ) {
163    return heap->StartVbyte;
164}
165
166
167// Returns the size of the string in bytes
168size_t size(const string_res &s) with(s) {
169    return Handle.lnth;
170}
171
172// Output operator
173ofstream & ?|?(ofstream &out, const string_res &s) {
174    // Store auto-newline state so it can be restored
175    bool anl = getANL$(out);
176    nlOff(out);
177    for (size_t i = 0; i < s.Handle.lnth; i++) {
178        out | s[i];
179    }
180    out | sep;
181    // Re-apply newlines after done, for chaining version
182    if (anl) nlOn(out);
183    return out;
184}
185
186void ?|?(ofstream &out, const string_res &s) {
187    // Store auto-newline state so it can be restored
188    bool anl = getANL$(out);
189    nlOff(out);
190    for (size_t i = 0; i < s.Handle.lnth; i++) {
191        // Need to re-apply on the last output operator, for whole-statement version
192        if (anl && i == s.Handle.lnth-1) nlOn(out);
193        out | s[i];
194    }
195    return out;
196}
197
198// Empty constructor
199void ?{}(string_res &s) with(s) {
200    (Handle){ HeapArea };
201    s.shareEditSet_prev = &s;
202    s.shareEditSet_next = &s;
203}
204
205// Constructor from a raw buffer and size
206void ?{}(string_res &s, const char* rhs, size_t rhslnth) with(s) {
207    (Handle){ HeapArea };
208    Handle.s = VbyteAlloc(HeapArea, rhslnth);
209    Handle.lnth = rhslnth;
210    for ( int i = 0; i < rhslnth; i += 1 ) {            // copy characters
211        Handle.s[i] = rhs[i];
212    } // for
213    s.shareEditSet_prev = &s;
214    s.shareEditSet_next = &s;
215}
216
217// String literal constructor
218void ?{}(string_res &s, const char* rhs) {
219    (s){ rhs, strlen(rhs) };
220}
221
222// General copy constructor
223void ?{}(string_res &s, const string_res & s2, StrResInitMode mode, size_t start, size_t end ) {
224
225    (s.Handle){ HeapArea };
226    s.Handle.s = s2.Handle.s + start;
227    s.Handle.lnth = end - start;
228    MoveThisAfter(s.Handle, s2.Handle );                        // insert this handle after rhs handle
229    // ^ bug?  skip others at early point in string
230   
231    if (mode == COPY_VALUE) {
232        // make s alone in its shareEditSet
233        s.shareEditSet_prev = &s;
234        s.shareEditSet_next = &s;
235    } else {
236        assert( mode == SHARE_EDITS );
237
238        // s2 is logically const but not implementation const
239        string_res & s2mod = (string_res &) s2;
240
241        // insert s after s2 on shareEditSet
242        s.shareEditSet_next = s2mod.shareEditSet_next;
243        s.shareEditSet_prev = &s2mod;
244        s.shareEditSet_next->shareEditSet_prev = &s;
245        s.shareEditSet_prev->shareEditSet_next = &s;
246    }
247}
248
249void assign(string_res &this, const char* buffer, size_t bsize) {
250
251    // traverse the incumbent share-edit set (SES) to recover the range of a base string to which `this` belongs
252    string_res * shareEditSetStartPeer = & this;
253    string_res * shareEditSetEndPeer = & this;
254    for (string_res * editPeer = this.shareEditSet_next; editPeer != &this; editPeer = editPeer->shareEditSet_next) {
255        if ( editPeer->Handle.s < shareEditSetStartPeer->Handle.s ) {
256            shareEditSetStartPeer = editPeer;
257        }
258        if ( shareEditSetEndPeer->Handle.s + shareEditSetEndPeer->Handle.lnth < editPeer->Handle.s + editPeer->Handle.lnth) {
259            shareEditSetEndPeer = editPeer;
260        }
261    }
262
263    // full string is from start of shareEditSetStartPeer thru end of shareEditSetEndPeer
264    // `this` occurs in the middle of it, to be replaced
265    // build up the new text in `pasting`
266
267    string_res pasting = {
268        shareEditSetStartPeer->Handle.s,                   // start of SES
269        this.Handle.s - shareEditSetStartPeer->Handle.s }; // length of SES, before this
270    append( pasting,
271        buffer,                                            // start of replacement for this
272        bsize );                                           // length of replacement for this
273    append( pasting,
274        this.Handle.s + this.Handle.lnth,                  // start of SES after this
275        shareEditSetEndPeer->Handle.s + shareEditSetEndPeer->Handle.lnth -
276        (this.Handle.s + this.Handle.lnth) );              // length of SES, after this
277
278    // The above string building can trigger compaction.
279    // The reference points (that are arguments of the string building) may move during that building.
280    // From this point on, they are stable.
281    // So now, capture their values for use in the overlap cases, below.
282    // Do not factor these definitions with the arguments used above.
283
284    char * beforeBegin = shareEditSetStartPeer->Handle.s;
285    size_t beforeLen = this.Handle.s - beforeBegin;
286
287    char * afterBegin = this.Handle.s + this.Handle.lnth;
288    size_t afterLen = shareEditSetEndPeer->Handle.s + shareEditSetEndPeer->Handle.lnth - afterBegin;
289
290    size_t oldLnth = this.Handle.lnth;
291
292    this.Handle.s = pasting.Handle.s + beforeLen;
293    this.Handle.lnth = bsize;
294    MoveThisAfter( this.Handle, pasting.Handle );
295
296    // adjust all substring string and handle locations, and check if any substring strings are outside the new base string
297    char *limit = pasting.Handle.s + pasting.Handle.lnth;
298    for (string_res * p = this.shareEditSet_next; p != &this; p = p->shareEditSet_next) {
299        assert (p->Handle.s >= beforeBegin);
300        if ( p->Handle.s >= afterBegin ) {
301            assert ( p->Handle.s <= afterBegin + afterLen );
302            assert ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
303            // p starts after the edit
304            // take start and end as end-anchored
305            size_t startOffsetFromEnd = afterBegin + afterLen - p->Handle.s;
306            p->Handle.s = limit - startOffsetFromEnd;
307            // p->Handle.lnth unaffected
308        } else if ( p->Handle.s <= beforeBegin + beforeLen ) {
309            // p starts before, or at the start of, the edit
310            if ( p->Handle.s + p->Handle.lnth <= beforeBegin + beforeLen ) {
311                // p ends before the edit
312                // take end as start-anchored too
313                // p->Handle.lnth unaffected
314            } else if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
315                // p ends during the edit; p does not include the last character replaced
316                // clip end of p to end at start of edit
317                p->Handle.lnth = beforeLen - ( p->Handle.s - beforeBegin );
318            } else {
319                // p ends after the edit
320                assert ( p->Handle.s + p->Handle.lnth <= afterBegin + afterLen );
321                // take end as end-anchored
322                // stretch-shrink p according to the edit
323                p->Handle.lnth += this.Handle.lnth;
324                p->Handle.lnth -= oldLnth;
325            }
326            // take start as start-anchored
327            size_t startOffsetFromStart = p->Handle.s - beforeBegin;
328            p->Handle.s = pasting.Handle.s + startOffsetFromStart;
329        } else {
330            assert ( p->Handle.s < afterBegin );
331            // p starts during the edit
332            assert( p->Handle.s + p->Handle.lnth >= beforeBegin + beforeLen );
333            if ( p->Handle.s + p->Handle.lnth < afterBegin ) {
334                // p ends during the edit; p does not include the last character replaced
335                // set p to empty string at start of edit
336                p->Handle.s = this.Handle.s;
337                p->Handle.lnth = 0;
338            } else {
339                // p includes the end of the edit
340                // clip start of p to start at end of edit
341                int charsToClip = afterBegin - p->Handle.s;
342                p->Handle.s = this.Handle.s + this.Handle.lnth;
343                p->Handle.lnth -= charsToClip;
344            }
345        }
346        MoveThisAfter( p->Handle, pasting.Handle );     // move substring handle to maintain sorted order by string position
347    }
348}
349
350void ?=?(string_res &s, const char* other) {
351    assign(s, other, strlen(other));
352}
353
354void ?=?(string_res &s, char other) {
355    assign(s, &other, 1);
356}
357
358// Copy assignment operator
359void ?=?(string_res & this, const string_res & rhs) with( this ) {
360    assign(this, rhs.Handle.s, rhs.Handle.lnth);
361}
362
363void ?=?(string_res & this, string_res & rhs) with( this ) {
364    const string_res & rhs2 = rhs;
365    this = rhs2;
366}
367
368
369// Destructor
370void ^?{}(string_res &s) with(s) {
371    // much delegated to implied ^VbyteSM
372
373    // sever s from its share-edit peers, if any (four no-ops when already solo)
374    s.shareEditSet_prev->shareEditSet_next = s.shareEditSet_next;
375    s.shareEditSet_next->shareEditSet_prev = s.shareEditSet_prev;
376    s.shareEditSet_next = &s;
377    s.shareEditSet_prev = &s;
378}
379
380
381// Returns the character at the given index
382// With unicode support, this may be different from just the byte at the given
383// offset from the start of the string.
384char ?[?](const string_res &s, size_t index) with(s) {
385    //TODO: Check if index is valid (no exceptions yet)
386    return Handle.s[index];
387}
388
389
390///////////////////////////////////////////////////////////////////
391// Concatenation
392
393void append(string_res &str1, const char * buffer, size_t bsize) {
394    size_t clnth = size(str1) + bsize;
395    if ( str1.Handle.s + size(str1) == buffer ) { // already juxtapose ?
396        // no-op
397    } else {                                            // must copy some text
398        if ( str1.Handle.s + size(str1) == VbyteAlloc(HeapArea, 0) ) { // str1 at end of string area ?
399            VbyteAlloc(HeapArea, bsize); // create room for 2nd part at the end of string area
400        } else {                                        // copy the two parts
401            char * str1oldBuf = str1.Handle.s;
402            str1.Handle.s = VbyteAlloc( HeapArea, clnth );
403            ByteCopy( HeapArea, str1.Handle.s, 0, str1.Handle.lnth, str1oldBuf, 0, str1.Handle.lnth);
404        } // if
405        ByteCopy( HeapArea, str1.Handle.s, str1.Handle.lnth, bsize, (char*)buffer, 0, (int)bsize);
406        //       VbyteHeap & this, char *Dst, int DstStart, int DstLnth, char *Src, int SrcStart, int SrcLnth
407    } // if
408    str1.Handle.lnth = clnth;
409}
410
411void ?+=?(string_res &str1, const string_res &str2) {
412    append( str1, str2.Handle.s, str2.Handle.lnth );
413}
414
415void ?+=?(string_res &s, char other) {
416    append( s, &other, 1 );
417}
418
419void ?+=?(string_res &s, const char* other) {
420    append( s, other, strlen(other) );
421}
422
423
424
425
426//////////////////////////////////////////////////////////
427// Comparisons
428
429
430bool ?==?(const string_res &s1, const string_res &s2) {
431    return ByteCmp( HeapArea, s1.Handle.s, 0, s1.Handle.lnth, s2.Handle.s, 0, s2.Handle.lnth) == 0;
432}
433
434bool ?!=?(const string_res &s1, const string_res &s2) {
435    return !(s1 == s2);
436}
437bool ?==?(const string_res &s, const char* other) {
438    string_res sother = other;
439    return s == sother;
440}
441bool ?!=?(const string_res &s, const char* other) {
442    return !(s == other);
443}
444
445
446//////////////////////////////////////////////////////////
447// Search
448
449bool contains(const string_res &s, char ch) {
450    for (i; size(s)) {
451        if (s[i] == ch) return true;
452    }
453    return false;
454}
455
456int find(const string_res &s, char search) {
457    for (i; size(s)) {
458        if (s[i] == search) return i;
459    }
460    return size(s);
461}
462
463    /* Remaining implementations essentially ported from Sunjay's work */
464
465int find(const string_res &s, const string_res &search) {
466    return find(s, search.Handle.s, search.Handle.lnth);
467}
468
469int find(const string_res &s, const char* search) {
470    return find(s, search, strlen(search));
471}
472
473int find(const string_res &s, const char* search, size_t searchsize) {
474    // FIXME: This is a naive algorithm. We probably want to switch to someting
475    // like Boyer-Moore in the future.
476    // https://en.wikipedia.org/wiki/String_searching_algorithm
477
478    // Always find the empty string
479    if (searchsize == 0) {
480        return 0;
481    }
482
483    for (size_t i = 0; i < s.Handle.lnth; i++) {
484        size_t remaining = s.Handle.lnth - i;
485        // Never going to find the search string if the remaining string is
486        // smaller than search
487        if (remaining < searchsize) {
488            break;
489        }
490
491        bool matched = true;
492        for (size_t j = 0; j < searchsize; j++) {
493            if (search[j] != s.Handle.s[i + j]) {
494                matched = false;
495                break;
496            }
497        }
498        if (matched) {
499            return i;
500        }
501    }
502
503    return s.Handle.lnth;
504}
505
506bool includes(const string_res &s, const string_res &search) {
507    return includes(s, search.Handle.s, search.Handle.lnth);
508}
509
510bool includes(const string_res &s, const char* search) {
511    return includes(s, search, strlen(search));
512}
513
514bool includes(const string_res &s, const char* search, size_t searchsize) {
515    return find(s, search, searchsize) < s.Handle.lnth;
516}
517
518bool startsWith(const string_res &s, const string_res &prefix) {
519    return startsWith(s, prefix.Handle.s, prefix.Handle.lnth);
520}
521
522bool startsWith(const string_res &s, const char* prefix) {
523    return startsWith(s, prefix, strlen(prefix));
524}
525
526bool startsWith(const string_res &s, const char* prefix, size_t prefixsize) {
527    if (s.Handle.lnth < prefixsize) {
528        return false;
529    }
530    return memcmp(s.Handle.s, prefix, prefixsize) == 0;
531}
532
533bool endsWith(const string_res &s, const string_res &suffix) {
534    return endsWith(s, suffix.Handle.s, suffix.Handle.lnth);
535}
536
537bool endsWith(const string_res &s, const char* suffix) {
538    return endsWith(s, suffix, strlen(suffix));
539}
540
541bool endsWith(const string_res &s, const char* suffix, size_t suffixsize) {
542    if (s.Handle.lnth < suffixsize) {
543        return false;
544    }
545    // Amount to offset the bytes pointer so that we are comparing the end of s
546    // to suffix. s.bytes + offset should be the first byte to compare against suffix
547    size_t offset = s.Handle.lnth - suffixsize;
548    return memcmp(s.Handle.s + offset, suffix, suffixsize) == 0;
549}
550
551    /* Back to Mike's work */
552
553
554///////////////////////////////////////////////////////////////////////////
555// charclass, include, exclude
556
557void ?{}( charclass_res & this, const string_res & chars) {
558    (this){ chars.Handle.s, chars.Handle.lnth };
559}
560
561void ?{}( charclass_res & this, const char * chars ) {
562    (this){ chars, strlen(chars) };
563}
564
565void ?{}( charclass_res & this, const char * chars, size_t charssize ) {
566    (this.chars){ chars, charssize };
567    // now sort it ?
568}
569
570void ^?{}( charclass_res & this ) {
571    ^(this.chars){};
572}
573
574static bool test( const charclass_res & mask, char c ) {
575    // instead, use sorted char list?
576    return contains( mask.chars, c );
577}
578
579int exclude(const string_res &s, const charclass_res &mask) {
580    for (int i = 0; i < size(s); i++) {
581        if ( test(mask, s[i]) ) return i;
582    }
583    return size(s);
584}
585
586int include(const string_res &s, const charclass_res &mask) {
587    for (int i = 0; i < size(s); i++) {
588        if ( ! test(mask, s[i]) ) return i;
589    }
590    return size(s);
591}
592
593//######################### VbyteHeap "implementation" #########################
594
595
596// Add a new HandleNode node n after the current HandleNode node.
597
598static inline void AddThisAfter( HandleNode & this, HandleNode & n ) with(this) {
599#ifdef VbyteDebug
600    serr | "enter:AddThisAfter, this:" | &this | " n:" | &n;
601#endif // VbyteDebug
602    flink = n.flink;
603    blink = &n;
604    n.flink->blink = &this;
605    n.flink = &this;
606#ifdef VbyteDebug
607    {
608                serr | "HandleList:";
609                serr | nlOff;
610                for ( HandleNode *ni = HeaderPtr->flink; ni != HeaderPtr; ni = ni->flink ) {
611                        serr | "\tnode:" | ni | " lnth:" | ni->lnth | " s:" | (void *)ni->s | ",\"";
612                        for ( int i = 0; i < ni->lnth; i += 1 ) {
613                                serr | ni->s[i];
614                        } // for
615                        serr | "\" flink:" | ni->flink | " blink:" | ni->blink | nl;
616                } // for
617                serr | nlOn;
618    }
619    serr | "exit:AddThisAfter";
620#endif // VbyteDebug
621} // AddThisAfter
622
623
624// Delete the current HandleNode node.
625
626static inline void DeleteNode( HandleNode & this ) with(this) {
627#ifdef VbyteDebug
628    serr | "enter:DeleteNode, this:" | &this;
629#endif // VbyteDebug
630    flink->blink = blink;
631    blink->flink = flink;
632#ifdef VbyteDebug
633    serr | "exit:DeleteNode";
634#endif // VbyteDebug
635} //  DeleteNode
636
637
638
639// Allocates specified storage for a string from byte-string area. If not enough space remains to perform the
640// allocation, the garbage collection routine is called and a second attempt is made to allocate the space. If the
641// second attempt fails, a further attempt is made to create a new, larger byte-string area.
642
643static inline char * VbyteAlloc( VbyteHeap & this, int size ) with(this) {
644#ifdef VbyteDebug
645    serr | "enter:VbyteAlloc, size:" | size;
646#endif // VbyteDebug
647    uintptr_t NoBytes;
648    char *r;
649
650    NoBytes = ( uintptr_t )EndVbyte + size;
651    if ( NoBytes > ( uintptr_t )ExtVbyte ) {            // enough room for new byte-string ?
652                garbage( this );                                        // firer up the garbage collector
653                NoBytes = ( uintptr_t )EndVbyte + size;         // try again
654                if ( NoBytes > ( uintptr_t )ExtVbyte ) {        // enough room for new byte-string ?
655assert( 0 && "need to implement actual growth" );
656                        // extend( size );                              // extend the byte-string area
657                } // if
658    } // if
659    r = EndVbyte;
660    EndVbyte += size;
661#ifdef VbyteDebug
662    serr | "exit:VbyteAlloc, r:" | (void *)r | " EndVbyte:" | (void *)EndVbyte | " ExtVbyte:" | ExtVbyte;
663#endif // VbyteDebug
664    return r;
665} // VbyteAlloc
666
667
668// Move an existing HandleNode node h somewhere after the current HandleNode node so that it is in ascending order by
669// the address in the byte string area.
670
671static inline void MoveThisAfter( HandleNode & this, const HandleNode  & h ) with(this) {
672#ifdef VbyteDebug
673    serr | "enter:MoveThisAfter, this:" | & this | " h:" | & h;
674#endif // VbyteDebug
675    if ( s < h.s ) {                                    // check argument values
676                // serr | "VbyteSM: Error - Cannot move byte string starting at:" | s | " after byte string starting at:"
677                //      | ( h->s ) | " and keep handles in ascending order";
678                // exit(-1 );
679                assert( 0 && "VbyteSM: Error - Cannot move byte strings as requested and keep handles in ascending order");
680    } // if
681
682    HandleNode *i;
683    for ( i = h.flink; i->s != 0 && s > ( i->s ); i = i->flink ); // find the position for this node after h
684    if ( & this != i->blink ) {
685                DeleteNode( this );
686                AddThisAfter( this, *i->blink );
687    } // if
688#ifdef VbyteDebug
689    {
690        serr | "HandleList:";
691        serr | nlOff;
692        for ( HandleNode *n = HeaderPtr->flink; n != HeaderPtr; n = n->flink ) {
693            serr | "\tnode:" | n | " lnth:" | n->lnth | " s:" | (void *)n->s | ",\"";
694            for ( int i = 0; i < n->lnth; i += 1 ) {
695                serr | n->s[i];
696            } // for
697            serr | "\" flink:" | n->flink | " blink:" | n->blink | nl;
698        } // for
699        serr | nlOn;
700    }
701    serr | "exit:MoveThisAfter";
702#endif // VbyteDebug
703} // MoveThisAfter
704
705
706
707
708
709//######################### VbyteHeap #########################
710
711// Move characters from one location in the byte-string area to another. The routine handles the following situations:
712//
713// if the |Src| > |Dst| => truncate
714// if the |Dst| > |Src| => pad Dst with blanks
715
716void ByteCopy( VbyteHeap & this, char *Dst, int DstStart, int DstLnth, char *Src, int SrcStart, int SrcLnth ) {
717    for ( int i = 0; i < DstLnth; i += 1 ) {
718      if ( i == SrcLnth ) {                             // |Dst| > |Src|
719            for ( ; i < DstLnth; i += 1 ) {             // pad Dst with blanks
720                Dst[DstStart + i] = ' ';
721            } // for
722            break;
723        } // exit
724        Dst[DstStart + i] = Src[SrcStart + i];
725    } // for
726} // ByteCopy
727
728// Compare two byte strings in the byte-string area. The routine returns the following values:
729//
730// 1 => Src1-byte-string > Src2-byte-string
731// 0 => Src1-byte-string = Src2-byte-string
732// -1 => Src1-byte-string < Src2-byte-string
733
734int ByteCmp( VbyteHeap & this, char *Src1, int Src1Start, int Src1Lnth, char *Src2, int Src2Start, int Src2Lnth )  with(this) {
735#ifdef VbyteDebug
736    serr | "enter:ByteCmp, Src1Start:" | Src1Start | " Src1Lnth:" | Src1Lnth | " Src2Start:" | Src2Start | " Src2Lnth:" | Src2Lnth;
737#endif // VbyteDebug
738    int cmp;
739
740    CharZip: for ( int i = 0; ; i += 1 ) {
741        if ( i == Src2Lnth - 1 ) {
742            for ( ; ; i += 1 ) {
743                if ( i == Src1Lnth - 1 ) {
744                    cmp = 0;
745                    break CharZip;
746                } // exit
747                if ( Src1[Src1Start + i] != ' ') {
748                        // SUSPECTED BUG:  this could be be why Peter got the bug report about == " "  (why is this case here at all?)
749                    cmp = 1;
750                    break CharZip;
751                } // exit
752            } // for
753        } // exit
754        if ( i == Src1Lnth - 1 ) {
755            for ( ; ; i += 1 ) {
756                if ( i == Src2Lnth - 1 ) {
757                    cmp = 0;
758                    break CharZip;
759                } // exit
760                if ( Src2[Src2Start + i] != ' ') {
761                    cmp = -1;
762                    break CharZip;
763                } // exit
764            } // for
765        } // exit
766      if ( Src2[Src2Start + i] != Src1[Src1Start+ i]) {
767            cmp = Src1[Src1Start + i] > Src2[Src2Start + i] ? 1 : -1;
768            break CharZip;
769        } // exit
770    } // for
771#ifdef VbyteDebug
772    serr | "exit:ByteCmp, cmp:" | cmp;
773#endif // VbyteDebug
774    return cmp;
775} // ByteCmp
776
777
778// The compaction moves all of the byte strings currently in use to the beginning of the byte-string area and modifies
779// the handles to reflect the new positions of the byte strings. Compaction assumes that the handle list is in ascending
780// order by pointers into the byte-string area.  The strings associated with substrings do not have to be moved because
781// the containing string has been moved. Hence, they only require that their string pointers be adjusted.
782
783void compaction(VbyteHeap & this) with(this) {
784    HandleNode *h;
785    char *obase, *nbase, *limit;
786   
787    NoOfCompactions += 1;
788    EndVbyte = StartVbyte;
789    h = Header.flink;                                   // ignore header node
790    for (;;) {
791                ByteCopy( this, EndVbyte, 0, h->lnth, h->s, 0, h->lnth );
792                obase = h->s;
793                h->s = EndVbyte;
794                nbase = h->s;
795                EndVbyte += h->lnth;
796                limit = obase + h->lnth;
797                h = h->flink;
798               
799                // check if any substrings are allocated within a string
800               
801                for (;;) {
802                        if ( h == &Header ) break;                      // end of header list ?
803                        if ( h->s >= limit ) break;                     // outside of current string ?
804                        h->s = nbase + (( uintptr_t )h->s - ( uintptr_t )obase );
805                        h = h->flink;
806                } // for
807                if ( h == &Header ) break;                      // end of header list ?
808    } // for
809} // compaction
810
811
812// Garbage determines the amount of free space left in the heap and then reduces, leave the same, or extends the size of
813// the heap.  The heap is then compacted in the existing heap or into the newly allocated heap.
814
815void garbage(VbyteHeap & this ) with(this) {
816#ifdef VbyteDebug
817    serr | "enter:garbage";
818    {
819                serr | "HandleList:";
820                for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
821                        serr | nlOff;
822                        serr | "\tnode:" | n | " lnth:" | n->lnth | " s:" | (void *)n->s | ",\"";
823                        for ( int i = 0; i < n->lnth; i += 1 ) {
824                                serr | n->s[i];
825                        } // for
826                        serr | nlOn;
827                        serr | "\" flink:" | n->flink | " blink:" | n->blink;
828                } // for
829    }
830#endif // VbyteDebug
831    int AmountUsed, AmountFree;
832
833    AmountUsed = 0;
834    for ( HandleNode *i = Header.flink; i != &Header; i = i->flink ) { // calculate amount of byte area used
835                AmountUsed += i->lnth;
836    } // for
837    AmountFree = ( uintptr_t )ExtVbyte - ( uintptr_t )StartVbyte - AmountUsed;
838   
839    if ( AmountFree < ( int )( CurrSize * 0.1 )) {      // free space less than 10% ?
840
841assert( 0 && "need to implement actual growth" );
842//              extend( CurrSize );                             // extend the heap
843
844                        //  Peter says, "This needs work before it should be used."
845                        //  } else if ( AmountFree > CurrSize / 2 ) {           // free space greater than 3 times the initial allocation ?
846                        //              reduce(( AmountFree / CurrSize - 3 ) * CurrSize ); // reduce the memory
847
848    } // if
849    compaction(this);                                   // compact the byte area, in the same or new heap area
850#ifdef VbyteDebug
851    {
852                serr | "HandleList:";
853                for ( HandleNode *n = Header.flink; n != &Header; n = n->flink ) {
854                        serr | nlOff;
855                        serr | "\tnode:" | n | " lnth:" | n->lnth | " s:" | (void *)n->s | ",\"";
856                        for ( int i = 0; i < n->lnth; i += 1 ) {
857                                serr | n->s[i];
858                        } // for
859                        serr | nlOn;
860                        serr | "\" flink:" | n->flink | " blink:" | n->blink;
861                } // for
862    }
863    serr | "exit:garbage";
864#endif // VbyteDebug
865} // garbage
866
867#undef VbyteDebug
868
869//WIP
870#if 0
871
872
873// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
874// area is deleted.
875
876void VbyteHeap::extend( int size ) {
877#ifdef VbyteDebug
878    serr | "enter:extend, size:" | size;
879#endif // VbyteDebug
880    char *OldStartVbyte;
881
882    NoOfExtensions += 1;
883    OldStartVbyte = StartVbyte;                         // save previous byte area
884   
885    CurrSize += size > InitSize ? size : InitSize;      // minimum extension, initial size
886    StartVbyte = EndVbyte = new char[CurrSize];
887    ExtVbyte = (void *)( StartVbyte + CurrSize );
888    compaction();                                       // copy from old heap to new & adjust pointers to new heap
889    delete OldStartVbyte;                               // release old heap
890#ifdef VbyteDebug
891    serr | "exit:extend, CurrSize:" | CurrSize;
892#endif // VbyteDebug
893} // extend
894
895
896// Extend the size of the byte-string area by creating a new area and copying the old area into it. The old byte-string
897// area is deleted.
898
899void VbyteHeap::reduce( int size ) {
900#ifdef VbyteDebug
901    serr | "enter:reduce, size:" | size;
902#endif // VbyteDebug
903    char *OldStartVbyte;
904
905    NoOfReductions += 1;
906    OldStartVbyte = StartVbyte;                         // save previous byte area
907   
908    CurrSize -= size;
909    StartVbyte = EndVbyte = new char[CurrSize];
910    ExtVbyte = (void *)( StartVbyte + CurrSize );
911    compaction();                                       // copy from old heap to new & adjust pointers to new heap
912    delete  OldStartVbyte;                              // release old heap
913#ifdef VbyteDebug
914    serr | "exit:reduce, CurrSize:" | CurrSize;
915#endif // VbyteDebug
916} // reduce
917
918
919#endif
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