1 /*
2 * Copyright (c) 1993-1994 by Xerox Corporation. All rights reserved.
3 *
4 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
5 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
6 *
7 * Permission is hereby granted to use or copy this program
8 * for any purpose, provided the above notices are retained on all copies.
9 * Permission to modify the code and to distribute modified code is granted,
10 * provided the above notices are retained, and a notice that the code was
11 * modified is included with the above copyright notice.
12 */
13
14 #ifdef HAVE_CONFIG_H
15 # include "config.h"
16 #endif
17 #ifndef CORD_BUILD
18 # define CORD_BUILD
19 #endif
20
21 # include "gc.h"
22 # include "cord.h"
23 # include <stdlib.h>
24 # include <stdio.h>
25 # include <string.h>
26
27 /* An implementation of the cord primitives. These are the only */
28 /* Functions that understand the representation. We perform only */
29 /* minimal checks on arguments to these functions. Out of bounds */
30 /* arguments to the iteration functions may result in client functions */
31 /* invoked on garbage data. In most cases, client functions should be */
32 /* programmed defensively enough that this does not result in memory */
33 /* smashes. */
34
35 typedef void (* oom_fn)(void);
36
37 oom_fn CORD_oom_fn = (oom_fn) 0;
38
39 # define OUT_OF_MEMORY { if (CORD_oom_fn != (oom_fn) 0) (*CORD_oom_fn)(); \
40 ABORT("Out of memory"); }
41 # define ABORT(msg) { fprintf(stderr, "%s\n", msg); abort(); }
42
43 typedef unsigned long word;
44
45 typedef union {
46 struct Concatenation {
47 char null;
48 char header;
49 char depth; /* concatenation nesting depth. */
50 unsigned char left_len;
51 /* Length of left child if it is sufficiently */
52 /* short; 0 otherwise. */
53 # define MAX_LEFT_LEN 255
54 word len;
55 CORD left; /* length(left) > 0 */
56 CORD right; /* length(right) > 0 */
57 } concatenation;
58 struct Function {
59 char null;
60 char header;
61 char depth; /* always 0 */
62 char left_len; /* always 0 */
63 word len;
64 CORD_fn fn;
65 void * client_data;
66 } function;
67 struct Generic {
68 char null;
69 char header;
70 char depth;
71 char left_len;
72 word len;
73 } generic;
74 char string[1];
75 } CordRep;
76
77 # define CONCAT_HDR 1
78
79 # define FN_HDR 4
80 # define SUBSTR_HDR 6
81 /* Substring nodes are a special case of function nodes. */
82 /* The client_data field is known to point to a substr_args */
83 /* structure, and the function is either CORD_apply_access_fn */
84 /* or CORD_index_access_fn. */
85
86 /* The following may be applied only to function and concatenation nodes: */
87 #define IS_CONCATENATION(s) (((CordRep *)s)->generic.header == CONCAT_HDR)
88
89 #define IS_FUNCTION(s) ((((CordRep *)s)->generic.header & FN_HDR) != 0)
90
91 #define IS_SUBSTR(s) (((CordRep *)s)->generic.header == SUBSTR_HDR)
92
93 #define LEN(s) (((CordRep *)s) -> generic.len)
94 #define DEPTH(s) (((CordRep *)s) -> generic.depth)
95 #define GEN_LEN(s) (CORD_IS_STRING(s) ? strlen(s) : LEN(s))
96
97 #define LEFT_LEN(c) ((c) -> left_len != 0? \
98 (c) -> left_len \
99 : (CORD_IS_STRING((c) -> left) ? \
100 (c) -> len - GEN_LEN((c) -> right) \
101 : LEN((c) -> left)))
102
103 #define SHORT_LIMIT (sizeof(CordRep) - 1)
104 /* Cords shorter than this are C strings */
105
106
107 /* Dump the internal representation of x to stdout, with initial */
108 /* indentation level n. */
CORD_dump_inner(CORD x,unsigned n)109 void CORD_dump_inner(CORD x, unsigned n)
110 {
111 register size_t i;
112
113 for (i = 0; i < (size_t)n; i++) {
114 fputs(" ", stdout);
115 }
116 if (x == 0) {
117 fputs("NIL\n", stdout);
118 } else if (CORD_IS_STRING(x)) {
119 for (i = 0; i <= SHORT_LIMIT; i++) {
120 if (x[i] == '\0') break;
121 putchar(x[i]);
122 }
123 if (x[i] != '\0') fputs("...", stdout);
124 putchar('\n');
125 } else if (IS_CONCATENATION(x)) {
126 register struct Concatenation * conc =
127 &(((CordRep *)x) -> concatenation);
128 printf("Concatenation: %p (len: %d, depth: %d)\n",
129 x, (int)(conc -> len), (int)(conc -> depth));
130 CORD_dump_inner(conc -> left, n+1);
131 CORD_dump_inner(conc -> right, n+1);
132 } else /* function */{
133 register struct Function * func =
134 &(((CordRep *)x) -> function);
135 if (IS_SUBSTR(x)) printf("(Substring) ");
136 printf("Function: %p (len: %d): ", x, (int)(func -> len));
137 for (i = 0; i < 20 && i < func -> len; i++) {
138 putchar((*(func -> fn))(i, func -> client_data));
139 }
140 if (i < func -> len) fputs("...", stdout);
141 putchar('\n');
142 }
143 }
144
145 /* Dump the internal representation of x to stdout */
CORD_dump(CORD x)146 void CORD_dump(CORD x)
147 {
148 CORD_dump_inner(x, 0);
149 fflush(stdout);
150 }
151
CORD_cat_char_star(CORD x,const char * y,size_t leny)152 CORD CORD_cat_char_star(CORD x, const char * y, size_t leny)
153 {
154 register size_t result_len;
155 register size_t lenx;
156 register int depth;
157
158 if (x == CORD_EMPTY) return(y);
159 if (leny == 0) return(x);
160 if (CORD_IS_STRING(x)) {
161 lenx = strlen(x);
162 result_len = lenx + leny;
163 if (result_len <= SHORT_LIMIT) {
164 register char * result = GC_MALLOC_ATOMIC(result_len+1);
165
166 if (result == 0) OUT_OF_MEMORY;
167 memcpy(result, x, lenx);
168 memcpy(result + lenx, y, leny);
169 result[result_len] = '\0';
170 return((CORD) result);
171 } else {
172 depth = 1;
173 }
174 } else {
175 register CORD right;
176 register CORD left;
177 register char * new_right;
178 register size_t right_len;
179
180 lenx = LEN(x);
181
182 if (leny <= SHORT_LIMIT/2
183 && IS_CONCATENATION(x)
184 && CORD_IS_STRING(right = ((CordRep *)x) -> concatenation.right)) {
185 /* Merge y into right part of x. */
186 if (!CORD_IS_STRING(left = ((CordRep *)x) -> concatenation.left)) {
187 right_len = lenx - LEN(left);
188 } else if (((CordRep *)x) -> concatenation.left_len != 0) {
189 right_len = lenx - ((CordRep *)x) -> concatenation.left_len;
190 } else {
191 right_len = strlen(right);
192 }
193 result_len = right_len + leny; /* length of new_right */
194 if (result_len <= SHORT_LIMIT) {
195 new_right = GC_MALLOC_ATOMIC(result_len + 1);
196 if (new_right == 0) OUT_OF_MEMORY;
197 memcpy(new_right, right, right_len);
198 memcpy(new_right + right_len, y, leny);
199 new_right[result_len] = '\0';
200 y = new_right;
201 leny = result_len;
202 x = left;
203 lenx -= right_len;
204 /* Now fall through to concatenate the two pieces: */
205 }
206 if (CORD_IS_STRING(x)) {
207 depth = 1;
208 } else {
209 depth = DEPTH(x) + 1;
210 }
211 } else {
212 depth = DEPTH(x) + 1;
213 }
214 result_len = lenx + leny;
215 }
216 {
217 /* The general case; lenx, result_len is known: */
218 register struct Concatenation * result;
219
220 result = GC_NEW(struct Concatenation);
221 if (result == 0) OUT_OF_MEMORY;
222 result->header = CONCAT_HDR;
223 result->depth = depth;
224 if (lenx <= MAX_LEFT_LEN)
225 result->left_len = (unsigned char)lenx;
226 result->len = result_len;
227 result->left = x;
228 result->right = y;
229 if (depth >= MAX_DEPTH) {
230 return(CORD_balance((CORD)result));
231 } else {
232 return((CORD) result);
233 }
234 }
235 }
236
237
CORD_cat(CORD x,CORD y)238 CORD CORD_cat(CORD x, CORD y)
239 {
240 register size_t result_len;
241 register int depth;
242 register size_t lenx;
243
244 if (x == CORD_EMPTY) return(y);
245 if (y == CORD_EMPTY) return(x);
246 if (CORD_IS_STRING(y)) {
247 return(CORD_cat_char_star(x, y, strlen(y)));
248 } else if (CORD_IS_STRING(x)) {
249 lenx = strlen(x);
250 depth = DEPTH(y) + 1;
251 } else {
252 register int depthy = DEPTH(y);
253
254 lenx = LEN(x);
255 depth = DEPTH(x) + 1;
256 if (depthy >= depth) depth = depthy + 1;
257 }
258 result_len = lenx + LEN(y);
259 {
260 register struct Concatenation * result;
261
262 result = GC_NEW(struct Concatenation);
263 if (result == 0) OUT_OF_MEMORY;
264 result->header = CONCAT_HDR;
265 result->depth = depth;
266 if (lenx <= MAX_LEFT_LEN)
267 result->left_len = (unsigned char)lenx;
268 result->len = result_len;
269 result->left = x;
270 result->right = y;
271 if (depth >= MAX_DEPTH) {
272 return(CORD_balance((CORD)result));
273 } else {
274 return((CORD) result);
275 }
276 }
277 }
278
279
280
CORD_from_fn(CORD_fn fn,void * client_data,size_t len)281 CORD CORD_from_fn(CORD_fn fn, void * client_data, size_t len)
282 {
283 if (len <= 0) return(0);
284 if (len <= SHORT_LIMIT) {
285 register char * result;
286 register size_t i;
287 char buf[SHORT_LIMIT+1];
288 register char c;
289
290 for (i = 0; i < len; i++) {
291 c = (*fn)(i, client_data);
292 if (c == '\0') goto gen_case;
293 buf[i] = c;
294 }
295
296 result = GC_MALLOC_ATOMIC(len+1);
297 if (result == 0) OUT_OF_MEMORY;
298 memcpy(result, buf, len);
299 result[len] = '\0';
300 return((CORD) result);
301 }
302 gen_case:
303 {
304 register struct Function * result;
305
306 result = GC_NEW(struct Function);
307 if (result == 0) OUT_OF_MEMORY;
308 result->header = FN_HDR;
309 /* depth is already 0 */
310 result->len = len;
311 result->fn = fn;
312 result->client_data = client_data;
313 return((CORD) result);
314 }
315 }
316
CORD_len(CORD x)317 size_t CORD_len(CORD x)
318 {
319 if (x == 0) {
320 return(0);
321 } else {
322 return(GEN_LEN(x));
323 }
324 }
325
326 struct substr_args {
327 CordRep * sa_cord;
328 size_t sa_index;
329 };
330
CORD_index_access_fn(size_t i,void * client_data)331 char CORD_index_access_fn(size_t i, void * client_data)
332 {
333 register struct substr_args *descr = (struct substr_args *)client_data;
334
335 return(((char *)(descr->sa_cord))[i + descr->sa_index]);
336 }
337
CORD_apply_access_fn(size_t i,void * client_data)338 char CORD_apply_access_fn(size_t i, void * client_data)
339 {
340 register struct substr_args *descr = (struct substr_args *)client_data;
341 register struct Function * fn_cord = &(descr->sa_cord->function);
342
343 return((*(fn_cord->fn))(i + descr->sa_index, fn_cord->client_data));
344 }
345
346 /* A version of CORD_substr that simply returns a function node, thus */
347 /* postponing its work. The fourth argument is a function that may */
348 /* be used for efficient access to the ith character. */
349 /* Assumes i >= 0 and i + n < length(x). */
CORD_substr_closure(CORD x,size_t i,size_t n,CORD_fn f)350 CORD CORD_substr_closure(CORD x, size_t i, size_t n, CORD_fn f)
351 {
352 register struct substr_args * sa = GC_NEW(struct substr_args);
353 CORD result;
354
355 if (sa == 0) OUT_OF_MEMORY;
356 sa->sa_cord = (CordRep *)x;
357 sa->sa_index = i;
358 result = CORD_from_fn(f, (void *)sa, n);
359 if (result == CORD_EMPTY) return CORD_EMPTY; /* n == 0 */
360 ((CordRep *)result) -> function.header = SUBSTR_HDR;
361 return (result);
362 }
363
364 # define SUBSTR_LIMIT (10 * SHORT_LIMIT)
365 /* Substrings of function nodes and flat strings shorter than */
366 /* this are flat strings. Othewise we use a functional */
367 /* representation, which is significantly slower to access. */
368
369 /* A version of CORD_substr that assumes i >= 0, n > 0, and i + n < length(x).*/
CORD_substr_checked(CORD x,size_t i,size_t n)370 CORD CORD_substr_checked(CORD x, size_t i, size_t n)
371 {
372 if (CORD_IS_STRING(x)) {
373 if (n > SUBSTR_LIMIT) {
374 return(CORD_substr_closure(x, i, n, CORD_index_access_fn));
375 } else {
376 register char * result = GC_MALLOC_ATOMIC(n+1);
377
378 if (result == 0) OUT_OF_MEMORY;
379 strncpy(result, x+i, n);
380 result[n] = '\0';
381 return(result);
382 }
383 } else if (IS_CONCATENATION(x)) {
384 register struct Concatenation * conc
385 = &(((CordRep *)x) -> concatenation);
386 register size_t left_len;
387 register size_t right_len;
388
389 left_len = LEFT_LEN(conc);
390 right_len = conc -> len - left_len;
391 if (i >= left_len) {
392 if (n == right_len) return(conc -> right);
393 return(CORD_substr_checked(conc -> right, i - left_len, n));
394 } else if (i+n <= left_len) {
395 if (n == left_len) return(conc -> left);
396 return(CORD_substr_checked(conc -> left, i, n));
397 } else {
398 /* Need at least one character from each side. */
399 register CORD left_part;
400 register CORD right_part;
401 register size_t left_part_len = left_len - i;
402
403 if (i == 0) {
404 left_part = conc -> left;
405 } else {
406 left_part = CORD_substr_checked(conc -> left, i, left_part_len);
407 }
408 if (i + n == right_len + left_len) {
409 right_part = conc -> right;
410 } else {
411 right_part = CORD_substr_checked(conc -> right, 0,
412 n - left_part_len);
413 }
414 return(CORD_cat(left_part, right_part));
415 }
416 } else /* function */ {
417 if (n > SUBSTR_LIMIT) {
418 if (IS_SUBSTR(x)) {
419 /* Avoid nesting substring nodes. */
420 register struct Function * f = &(((CordRep *)x) -> function);
421 register struct substr_args *descr =
422 (struct substr_args *)(f -> client_data);
423
424 return(CORD_substr_closure((CORD)descr->sa_cord,
425 i + descr->sa_index,
426 n, f -> fn));
427 } else {
428 return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
429 }
430 } else {
431 char * result;
432 register struct Function * f = &(((CordRep *)x) -> function);
433 char buf[SUBSTR_LIMIT+1];
434 register char * p = buf;
435 register char c;
436 register int j;
437 register int lim = i + n;
438
439 for (j = i; j < lim; j++) {
440 c = (*(f -> fn))(j, f -> client_data);
441 if (c == '\0') {
442 return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
443 }
444 *p++ = c;
445 }
446 result = GC_MALLOC_ATOMIC(n+1);
447 if (result == 0) OUT_OF_MEMORY;
448 memcpy(result, buf, n);
449 result[n] = '\0';
450 return(result);
451 }
452 }
453 }
454
CORD_substr(CORD x,size_t i,size_t n)455 CORD CORD_substr(CORD x, size_t i, size_t n)
456 {
457 register size_t len = CORD_len(x);
458
459 if (i >= len || n <= 0) return(0);
460 /* n < 0 is impossible in a correct C implementation, but */
461 /* quite possible under SunOS 4.X. */
462 if (i + n > len) n = len - i;
463 return(CORD_substr_checked(x, i, n));
464 }
465
466 /* See cord.h for definition. We assume i is in range. */
CORD_iter5(CORD x,size_t i,CORD_iter_fn f1,CORD_batched_iter_fn f2,void * client_data)467 int CORD_iter5(CORD x, size_t i, CORD_iter_fn f1,
468 CORD_batched_iter_fn f2, void * client_data)
469 {
470 if (x == 0) return(0);
471 if (CORD_IS_STRING(x)) {
472 register const char *p = x+i;
473
474 if (*p == '\0') ABORT("2nd arg to CORD_iter5 too big");
475 if (f2 != CORD_NO_FN) {
476 return((*f2)(p, client_data));
477 } else {
478 while (*p) {
479 if ((*f1)(*p, client_data)) return(1);
480 p++;
481 }
482 return(0);
483 }
484 } else if (IS_CONCATENATION(x)) {
485 register struct Concatenation * conc
486 = &(((CordRep *)x) -> concatenation);
487
488
489 if (i > 0) {
490 register size_t left_len = LEFT_LEN(conc);
491
492 if (i >= left_len) {
493 return(CORD_iter5(conc -> right, i - left_len, f1, f2,
494 client_data));
495 }
496 }
497 if (CORD_iter5(conc -> left, i, f1, f2, client_data)) {
498 return(1);
499 }
500 return(CORD_iter5(conc -> right, 0, f1, f2, client_data));
501 } else /* function */ {
502 register struct Function * f = &(((CordRep *)x) -> function);
503 register size_t j;
504 register size_t lim = f -> len;
505
506 for (j = i; j < lim; j++) {
507 if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
508 return(1);
509 }
510 }
511 return(0);
512 }
513 }
514
515 #undef CORD_iter
CORD_iter(CORD x,CORD_iter_fn f1,void * client_data)516 int CORD_iter(CORD x, CORD_iter_fn f1, void * client_data)
517 {
518 return(CORD_iter5(x, 0, f1, CORD_NO_FN, client_data));
519 }
520
CORD_riter4(CORD x,size_t i,CORD_iter_fn f1,void * client_data)521 int CORD_riter4(CORD x, size_t i, CORD_iter_fn f1, void * client_data)
522 {
523 if (x == 0) return(0);
524 if (CORD_IS_STRING(x)) {
525 register const char *p = x + i;
526 register char c;
527
528 for(;;) {
529 c = *p;
530 if (c == '\0') ABORT("2nd arg to CORD_riter4 too big");
531 if ((*f1)(c, client_data)) return(1);
532 if (p == x) break;
533 p--;
534 }
535 return(0);
536 } else if (IS_CONCATENATION(x)) {
537 register struct Concatenation * conc
538 = &(((CordRep *)x) -> concatenation);
539 register CORD left_part = conc -> left;
540 register size_t left_len;
541
542 left_len = LEFT_LEN(conc);
543 if (i >= left_len) {
544 if (CORD_riter4(conc -> right, i - left_len, f1, client_data)) {
545 return(1);
546 }
547 return(CORD_riter4(left_part, left_len - 1, f1, client_data));
548 } else {
549 return(CORD_riter4(left_part, i, f1, client_data));
550 }
551 } else /* function */ {
552 register struct Function * f = &(((CordRep *)x) -> function);
553 register size_t j;
554
555 for (j = i; ; j--) {
556 if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
557 return(1);
558 }
559 if (j == 0) return(0);
560 }
561 }
562 }
563
CORD_riter(CORD x,CORD_iter_fn f1,void * client_data)564 int CORD_riter(CORD x, CORD_iter_fn f1, void * client_data)
565 {
566 size_t len = CORD_len(x);
567 if (len == 0) return(0);
568 return(CORD_riter4(x, len - 1, f1, client_data));
569 }
570
571 /*
572 * The following functions are concerned with balancing cords.
573 * Strategy:
574 * Scan the cord from left to right, keeping the cord scanned so far
575 * as a forest of balanced trees of exponentially decreasing length.
576 * When a new subtree needs to be added to the forest, we concatenate all
577 * shorter ones to the new tree in the appropriate order, and then insert
578 * the result into the forest.
579 * Crucial invariants:
580 * 1. The concatenation of the forest (in decreasing order) with the
581 * unscanned part of the rope is equal to the rope being balanced.
582 * 2. All trees in the forest are balanced.
583 * 3. forest[i] has depth at most i.
584 */
585
586 typedef struct {
587 CORD c;
588 size_t len; /* Actual length of c */
589 } ForestElement;
590
591 static size_t min_len [ MAX_DEPTH ];
592
593 static int min_len_init = 0;
594
595 int CORD_max_len;
596
597 typedef ForestElement Forest [ MAX_DEPTH ];
598 /* forest[i].len >= fib(i+1) */
599 /* The string is the concatenation */
600 /* of the forest in order of DECREASING */
601 /* indices. */
602
CORD_init_min_len(void)603 void CORD_init_min_len(void)
604 {
605 register int i;
606 register size_t last, previous, current;
607
608 min_len[0] = previous = 1;
609 min_len[1] = last = 2;
610 for (i = 2; i < MAX_DEPTH; i++) {
611 current = last + previous;
612 if (current < last) /* overflow */ current = last;
613 min_len[i] = current;
614 previous = last;
615 last = current;
616 }
617 CORD_max_len = last - 1;
618 min_len_init = 1;
619 }
620
621
CORD_init_forest(ForestElement * forest,size_t max_len)622 void CORD_init_forest(ForestElement * forest, size_t max_len)
623 {
624 register int i;
625
626 for (i = 0; i < MAX_DEPTH; i++) {
627 forest[i].c = 0;
628 if (min_len[i] > max_len) return;
629 }
630 ABORT("Cord too long");
631 }
632
633 /* Add a leaf to the appropriate level in the forest, cleaning */
634 /* out lower levels as necessary. */
635 /* Also works if x is a balanced tree of concatenations; however */
636 /* in this case an extra concatenation node may be inserted above x; */
637 /* This node should not be counted in the statement of the invariants. */
CORD_add_forest(ForestElement * forest,CORD x,size_t len)638 void CORD_add_forest(ForestElement * forest, CORD x, size_t len)
639 {
640 register int i = 0;
641 register CORD sum = CORD_EMPTY;
642 register size_t sum_len = 0;
643
644 while (len > min_len[i + 1]) {
645 if (forest[i].c != 0) {
646 sum = CORD_cat(forest[i].c, sum);
647 sum_len += forest[i].len;
648 forest[i].c = 0;
649 }
650 i++;
651 }
652 /* Sum has depth at most 1 greter than what would be required */
653 /* for balance. */
654 sum = CORD_cat(sum, x);
655 sum_len += len;
656 /* If x was a leaf, then sum is now balanced. To see this */
657 /* consider the two cases in which forest[i-1] either is or is */
658 /* not empty. */
659 while (sum_len >= min_len[i]) {
660 if (forest[i].c != 0) {
661 sum = CORD_cat(forest[i].c, sum);
662 sum_len += forest[i].len;
663 /* This is again balanced, since sum was balanced, and has */
664 /* allowable depth that differs from i by at most 1. */
665 forest[i].c = 0;
666 }
667 i++;
668 }
669 i--;
670 forest[i].c = sum;
671 forest[i].len = sum_len;
672 }
673
CORD_concat_forest(ForestElement * forest,size_t expected_len)674 CORD CORD_concat_forest(ForestElement * forest, size_t expected_len)
675 {
676 register int i = 0;
677 CORD sum = 0;
678 size_t sum_len = 0;
679
680 while (sum_len != expected_len) {
681 if (forest[i].c != 0) {
682 sum = CORD_cat(forest[i].c, sum);
683 sum_len += forest[i].len;
684 }
685 i++;
686 }
687 return(sum);
688 }
689
690 /* Insert the frontier of x into forest. Balanced subtrees are */
691 /* treated as leaves. This potentially adds one to the depth */
692 /* of the final tree. */
CORD_balance_insert(CORD x,size_t len,ForestElement * forest)693 void CORD_balance_insert(CORD x, size_t len, ForestElement * forest)
694 {
695 register int depth;
696
697 if (CORD_IS_STRING(x)) {
698 CORD_add_forest(forest, x, len);
699 } else if (IS_CONCATENATION(x)
700 && ((depth = DEPTH(x)) >= MAX_DEPTH
701 || len < min_len[depth])) {
702 register struct Concatenation * conc
703 = &(((CordRep *)x) -> concatenation);
704 size_t left_len = LEFT_LEN(conc);
705
706 CORD_balance_insert(conc -> left, left_len, forest);
707 CORD_balance_insert(conc -> right, len - left_len, forest);
708 } else /* function or balanced */ {
709 CORD_add_forest(forest, x, len);
710 }
711 }
712
713
CORD_balance(CORD x)714 CORD CORD_balance(CORD x)
715 {
716 Forest forest;
717 register size_t len;
718
719 if (x == 0) return(0);
720 if (CORD_IS_STRING(x)) return(x);
721 if (!min_len_init) CORD_init_min_len();
722 len = LEN(x);
723 CORD_init_forest(forest, len);
724 CORD_balance_insert(x, len, forest);
725 return(CORD_concat_forest(forest, len));
726 }
727
728
729 /* Position primitives */
730
731 /* Private routines to deal with the hard cases only: */
732
733 /* P contains a prefix of the path to cur_pos. Extend it to a full */
734 /* path and set up leaf info. */
735 /* Return 0 if past the end of cord, 1 o.w. */
CORD__extend_path(register CORD_pos p)736 void CORD__extend_path(register CORD_pos p)
737 {
738 register struct CORD_pe * current_pe = &(p[0].path[p[0].path_len]);
739 register CORD top = current_pe -> pe_cord;
740 register size_t pos = p[0].cur_pos;
741 register size_t top_pos = current_pe -> pe_start_pos;
742 register size_t top_len = GEN_LEN(top);
743
744 /* Fill in the rest of the path. */
745 while(!CORD_IS_STRING(top) && IS_CONCATENATION(top)) {
746 register struct Concatenation * conc =
747 &(((CordRep *)top) -> concatenation);
748 register size_t left_len;
749
750 left_len = LEFT_LEN(conc);
751 current_pe++;
752 if (pos >= top_pos + left_len) {
753 current_pe -> pe_cord = top = conc -> right;
754 current_pe -> pe_start_pos = top_pos = top_pos + left_len;
755 top_len -= left_len;
756 } else {
757 current_pe -> pe_cord = top = conc -> left;
758 current_pe -> pe_start_pos = top_pos;
759 top_len = left_len;
760 }
761 p[0].path_len++;
762 }
763 /* Fill in leaf description for fast access. */
764 if (CORD_IS_STRING(top)) {
765 p[0].cur_leaf = top;
766 p[0].cur_start = top_pos;
767 p[0].cur_end = top_pos + top_len;
768 } else {
769 p[0].cur_end = 0;
770 }
771 if (pos >= top_pos + top_len) p[0].path_len = CORD_POS_INVALID;
772 }
773
CORD__pos_fetch(register CORD_pos p)774 char CORD__pos_fetch(register CORD_pos p)
775 {
776 /* Leaf is a function node */
777 struct CORD_pe * pe = &((p)[0].path[(p)[0].path_len]);
778 CORD leaf = pe -> pe_cord;
779 register struct Function * f = &(((CordRep *)leaf) -> function);
780
781 if (!IS_FUNCTION(leaf)) ABORT("CORD_pos_fetch: bad leaf");
782 return ((*(f -> fn))(p[0].cur_pos - pe -> pe_start_pos, f -> client_data));
783 }
784
CORD__next(register CORD_pos p)785 void CORD__next(register CORD_pos p)
786 {
787 register size_t cur_pos = p[0].cur_pos + 1;
788 register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
789 register CORD leaf = current_pe -> pe_cord;
790
791 /* Leaf is not a string or we're at end of leaf */
792 p[0].cur_pos = cur_pos;
793 if (!CORD_IS_STRING(leaf)) {
794 /* Function leaf */
795 register struct Function * f = &(((CordRep *)leaf) -> function);
796 register size_t start_pos = current_pe -> pe_start_pos;
797 register size_t end_pos = start_pos + f -> len;
798
799 if (cur_pos < end_pos) {
800 /* Fill cache and return. */
801 register size_t i;
802 register size_t limit = cur_pos + FUNCTION_BUF_SZ;
803 register CORD_fn fn = f -> fn;
804 register void * client_data = f -> client_data;
805
806 if (limit > end_pos) {
807 limit = end_pos;
808 }
809 for (i = cur_pos; i < limit; i++) {
810 p[0].function_buf[i - cur_pos] =
811 (*fn)(i - start_pos, client_data);
812 }
813 p[0].cur_start = cur_pos;
814 p[0].cur_leaf = p[0].function_buf;
815 p[0].cur_end = limit;
816 return;
817 }
818 }
819 /* End of leaf */
820 /* Pop the stack until we find two concatenation nodes with the */
821 /* same start position: this implies we were in left part. */
822 {
823 while (p[0].path_len > 0
824 && current_pe[0].pe_start_pos != current_pe[-1].pe_start_pos) {
825 p[0].path_len--;
826 current_pe--;
827 }
828 if (p[0].path_len == 0) {
829 p[0].path_len = CORD_POS_INVALID;
830 return;
831 }
832 }
833 p[0].path_len--;
834 CORD__extend_path(p);
835 }
836
CORD__prev(register CORD_pos p)837 void CORD__prev(register CORD_pos p)
838 {
839 register struct CORD_pe * pe = &(p[0].path[p[0].path_len]);
840
841 if (p[0].cur_pos == 0) {
842 p[0].path_len = CORD_POS_INVALID;
843 return;
844 }
845 p[0].cur_pos--;
846 if (p[0].cur_pos >= pe -> pe_start_pos) return;
847
848 /* Beginning of leaf */
849
850 /* Pop the stack until we find two concatenation nodes with the */
851 /* different start position: this implies we were in right part. */
852 {
853 register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
854
855 while (p[0].path_len > 0
856 && current_pe[0].pe_start_pos == current_pe[-1].pe_start_pos) {
857 p[0].path_len--;
858 current_pe--;
859 }
860 }
861 p[0].path_len--;
862 CORD__extend_path(p);
863 }
864
865 #undef CORD_pos_fetch
866 #undef CORD_next
867 #undef CORD_prev
868 #undef CORD_pos_to_index
869 #undef CORD_pos_to_cord
870 #undef CORD_pos_valid
871
CORD_pos_fetch(register CORD_pos p)872 char CORD_pos_fetch(register CORD_pos p)
873 {
874 if (p[0].cur_start <= p[0].cur_pos && p[0].cur_pos < p[0].cur_end) {
875 return(p[0].cur_leaf[p[0].cur_pos - p[0].cur_start]);
876 } else {
877 return(CORD__pos_fetch(p));
878 }
879 }
880
CORD_next(CORD_pos p)881 void CORD_next(CORD_pos p)
882 {
883 if (p[0].cur_pos < p[0].cur_end - 1) {
884 p[0].cur_pos++;
885 } else {
886 CORD__next(p);
887 }
888 }
889
CORD_prev(CORD_pos p)890 void CORD_prev(CORD_pos p)
891 {
892 if (p[0].cur_end != 0 && p[0].cur_pos > p[0].cur_start) {
893 p[0].cur_pos--;
894 } else {
895 CORD__prev(p);
896 }
897 }
898
CORD_pos_to_index(CORD_pos p)899 size_t CORD_pos_to_index(CORD_pos p)
900 {
901 return(p[0].cur_pos);
902 }
903
CORD_pos_to_cord(CORD_pos p)904 CORD CORD_pos_to_cord(CORD_pos p)
905 {
906 return(p[0].path[0].pe_cord);
907 }
908
CORD_pos_valid(CORD_pos p)909 int CORD_pos_valid(CORD_pos p)
910 {
911 return(p[0].path_len != CORD_POS_INVALID);
912 }
913
CORD_set_pos(CORD_pos p,CORD x,size_t i)914 void CORD_set_pos(CORD_pos p, CORD x, size_t i)
915 {
916 if (x == CORD_EMPTY) {
917 p[0].path_len = CORD_POS_INVALID;
918 return;
919 }
920 p[0].path[0].pe_cord = x;
921 p[0].path[0].pe_start_pos = 0;
922 p[0].path_len = 0;
923 p[0].cur_pos = i;
924 CORD__extend_path(p);
925 }
926