Annotation of parser3/src/lib/cord/cordbscs.c, revision 1.1.2.11
1.1.2.1 paf 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: * Author: Hans-J. Boehm (boehm@parc.xerox.com)
14: */
15: /* Boehm, October 3, 1994 5:19 pm PDT */
16: # include "gc.h"
17: # include "cord.h"
18: # include <stdlib.h>
19: # include <stdio.h>
20: # include <string.h>
21:
22: /* An implementation of the cord primitives. These are the only */
23: /* Functions that understand the representation. We perform only */
24: /* minimal checks on arguments to these functions. Out of bounds */
25: /* arguments to the iteration functions may result in client functions */
26: /* invoked on garbage data. In most cases, client functions should be */
27: /* programmed defensively enough that this does not result in memory */
28: /* smashes. */
29:
30: typedef void (* oom_fn)(void);
31:
32: oom_fn CORD_oom_fn = (oom_fn) 0;
33:
34: # define OUT_OF_MEMORY { if (CORD_oom_fn != (oom_fn) 0) (*CORD_oom_fn)(); \
35: ABORT("Out of memory\n"); }
36: # define ABORT(msg) { fprintf(stderr, "%s\n", msg); abort(); }
37:
38: typedef unsigned long word;
39:
40: typedef union {
41: struct Concatenation {
42: char null;
43: char header;
44: char depth; /* concatenation nesting depth. */
45: unsigned char left_len;
46: /* Length of left child if it is sufficiently */
47: /* short; 0 otherwise. */
48: # define MAX_LEFT_LEN 255
49: word len;
50: CORD left; /* length(left) > 0 */
51: CORD right; /* length(right) > 0 */
52: } concatenation;
53: struct Function {
54: char null;
55: char header;
56: char depth; /* always 0 */
57: char left_len; /* always 0 */
58: word len;
59: CORD_fn fn;
60: void * client_data;
61: } function;
62: struct Generic {
63: char null;
64: char header;
65: char depth;
66: char left_len;
67: word len;
68: } generic;
69: char string[1];
70: } CordRep;
71:
72: # define CONCAT_HDR 1
73:
74: # define FN_HDR 4
75: # define SUBSTR_HDR 6
76: /* Substring nodes are a special case of function nodes. */
77: /* The client_data field is known to point to a substr_args */
78: /* structure, and the function is either CORD_apply_access_fn */
79: /* or CORD_index_access_fn. */
80:
81: /* The following may be applied only to function and concatenation nodes: */
82: #define IS_CONCATENATION(s) (((CordRep *)s)->generic.header == CONCAT_HDR)
83:
84: #define IS_FUNCTION(s) ((((CordRep *)s)->generic.header & FN_HDR) != 0)
85:
86: #define IS_SUBSTR(s) (((CordRep *)s)->generic.header == SUBSTR_HDR)
87:
88: #define LEN(s) (((CordRep *)s) -> generic.len)
89: #define DEPTH(s) (((CordRep *)s) -> generic.depth)
90: #define GEN_LEN(s) (CORD_IS_STRING(s) ? strlen(s) : LEN(s))
91:
92: #define LEFT_LEN(c) ((c) -> left_len != 0? \
93: (c) -> left_len \
94: : (CORD_IS_STRING((c) -> left) ? \
95: (c) -> len - GEN_LEN((c) -> right) \
96: : LEN((c) -> left)))
97:
98: #define SHORT_LIMIT (sizeof(CordRep) - 1)
99: /* Cords shorter than this are C strings */
100:
101:
102: /* Dump the internal representation of x to stdout, with initial */
103: /* indentation level n. */
104: void CORD_dump_inner(CORD x, unsigned n)
105: {
106: register size_t i;
107:
108: for (i = 0; i < (size_t)n; i++) {
109: fputs(" ", stdout);
110: }
111: if (x == 0) {
112: fputs("NIL\n", stdout);
113: } else if (CORD_IS_STRING(x)) {
114: for (i = 0; i <= SHORT_LIMIT; i++) {
115: if (x[i] == '\0') break;
116: putchar(x[i]);
117: }
118: if (x[i] != '\0') fputs("...", stdout);
119: putchar('\n');
120: } else if (IS_CONCATENATION(x)) {
121: register struct Concatenation * conc =
122: &(((CordRep *)x) -> concatenation);
123: printf("Concatenation: %p (len: %d, depth: %d)\n",
124: x, (int)(conc -> len), (int)(conc -> depth));
125: CORD_dump_inner(conc -> left, n+1);
126: CORD_dump_inner(conc -> right, n+1);
127: } else /* function */{
128: register struct Function * func =
129: &(((CordRep *)x) -> function);
130: if (IS_SUBSTR(x)) printf("(Substring) ");
131: printf("Function: %p (len: %d): ", x, (int)(func -> len));
132: for (i = 0; i < 20 && i < func -> len; i++) {
133: putchar((*(func -> fn))(i, func -> client_data));
134: }
135: if (i < func -> len) fputs("...", stdout);
136: putchar('\n');
137: }
138: }
139:
140: /* Dump the internal representation of x to stdout */
141: void CORD_dump(CORD x)
142: {
143: CORD_dump_inner(x, 0);
144: fflush(stdout);
145: }
146:
1.1.2.2 paf 147: CORD CORD_cat_char_star(CORD x, const char* y, size_t leny)
1.1.2.1 paf 148: {
149: register size_t result_len;
150: register size_t lenx;
151: register int depth;
1.1.2.3 paf 152:
1.1.2.1 paf 153: if (x == CORD_EMPTY) return(y);
1.1.2.10 paf 154: //if (leny == 0) leny=strlen(y); // PAF
1.1.2.11! paf 155: if (y == 0) ABORT("CORD_cat_char_star(,y,) y==0"); // PAF
! 156: if (*y == 0) ABORT("CORD_cat_char_star(,y,) y==\"\""); // PAF
! 157: if (leny == 0) ABORT("CORD_cat_char_star(,y,) leny==0"); // PAF
1.1.2.5 paf 158:
1.1.2.1 paf 159: if (CORD_IS_STRING(x)) {
160: lenx = strlen(x);
161: result_len = lenx + leny;
162: if (result_len <= SHORT_LIMIT) {
163: register char * result = GC_MALLOC_ATOMIC(result_len+1);
1.1.2.7 paf 164:
1.1.2.1 paf 165: if (result == 0) OUT_OF_MEMORY;
166: memcpy(result, x, lenx);
167: memcpy(result + lenx, y, leny);
168: result[result_len] = '\0';
169: return((CORD) result);
170: } else {
171: depth = 1;
172: }
173: } else {
174: register CORD right;
175: register CORD left;
176: register char * new_right;
177: register size_t right_len;
178:
179: lenx = LEN(x);
180:
181: if (leny <= SHORT_LIMIT/2
182: && IS_CONCATENATION(x)
183: && CORD_IS_STRING(right = ((CordRep *)x) -> concatenation.right)) {
184: /* Merge y into right part of x. */
185: if (!CORD_IS_STRING(left = ((CordRep *)x) -> concatenation.left)) {
186: right_len = lenx - LEN(left);
187: } else if (((CordRep *)x) -> concatenation.left_len != 0) {
188: right_len = lenx - ((CordRep *)x) -> concatenation.left_len;
189: } else {
190: right_len = strlen(right);
191: }
192: result_len = right_len + leny; /* length of new_right */
193: if (result_len <= SHORT_LIMIT) {
194: new_right = GC_MALLOC_ATOMIC(result_len + 1);
195: memcpy(new_right, right, right_len);
196: memcpy(new_right + right_len, y, leny);
197: new_right[result_len] = '\0';
198: y = new_right;
199: leny = result_len;
200: x = left;
201: lenx -= right_len;
202: /* Now fall through to concatenate the two pieces: */
203: }
204: if (CORD_IS_STRING(x)) {
205: depth = 1;
206: } else {
207: depth = DEPTH(x) + 1;
208: }
209: } else {
210: depth = DEPTH(x) + 1;
211: }
212: result_len = lenx + leny;
213: }
214: {
215: /* The general case; lenx, result_len is known: */
216: register struct Concatenation * result;
217:
218: result = GC_NEW(struct Concatenation);
219: if (result == 0) OUT_OF_MEMORY;
220: result->header = CONCAT_HDR;
221: result->depth = depth;
222: if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
223: result->len = result_len;
224: result->left = x;
225: result->right = y;
1.1.2.9 paf 226: if (depth >= MAX_DEPTH) {
1.1.2.1 paf 227: return(CORD_balance((CORD)result));
228: } else {
229: return((CORD) result);
230: }
231: }
232: }
233:
234:
235: CORD CORD_cat(CORD x, CORD y)
236: {
237: register size_t result_len;
238: register int depth;
239: register size_t lenx;
240:
241: if (x == CORD_EMPTY) return(y);
242: if (y == CORD_EMPTY) return(x);
243: if (CORD_IS_STRING(y)) {
244: return(CORD_cat_char_star(x, y, strlen(y)));
245: } else if (CORD_IS_STRING(x)) {
246: lenx = strlen(x);
247: depth = DEPTH(y) + 1;
248: } else {
249: register int depthy = DEPTH(y);
250:
251: lenx = LEN(x);
252: depth = DEPTH(x) + 1;
253: if (depthy >= depth) depth = depthy + 1;
254: }
255: result_len = lenx + LEN(y);
256: {
257: register struct Concatenation * result;
258:
259: result = GC_NEW(struct Concatenation);
260: if (result == 0) OUT_OF_MEMORY;
261: result->header = CONCAT_HDR;
262: result->depth = depth;
1.1.2.8 paf 263: // printf("depth=%d\n", depth);
1.1.2.1 paf 264: if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
265: result->len = result_len;
266: result->left = x;
267: result->right = y;
1.1.2.8 paf 268: // PAF@design.ru bug fix:
1.1.2.9 paf 269: if (depth >= MAX_DEPTH) {
1.1.2.8 paf 270: return(CORD_balance((CORD)result));
271: } else {
272: return((CORD) result);
273: }
1.1.2.1 paf 274: }
275: }
276:
277:
278:
279: CORD CORD_from_fn(CORD_fn fn, void * client_data, size_t len)
280: {
281: if (len <= 0) return(0);
282: if (len <= SHORT_LIMIT) {
283: register char * result;
284: register size_t i;
285: char buf[SHORT_LIMIT+1];
286: register char c;
287:
288: for (i = 0; i < len; i++) {
289: c = (*fn)(i, client_data);
290: if (c == '\0') goto gen_case;
291: buf[i] = c;
292: }
293: buf[i] = '\0';
294: result = GC_MALLOC_ATOMIC(len+1);
295: if (result == 0) OUT_OF_MEMORY;
296: strcpy(result, buf);
297: result[len] = '\0';
298: return((CORD) result);
299: }
300: gen_case:
301: {
302: register struct Function * result;
303:
304: result = GC_NEW(struct Function);
305: if (result == 0) OUT_OF_MEMORY;
306: result->header = FN_HDR;
307: /* depth is already 0 */
308: result->len = len;
309: result->fn = fn;
310: result->client_data = client_data;
311: return((CORD) result);
312: }
313: }
314:
315: size_t CORD_len(CORD x)
316: {
317: if (x == 0) {
318: return(0);
319: } else {
320: return(GEN_LEN(x));
321: }
322: }
323:
324: struct substr_args {
325: CordRep * sa_cord;
326: size_t sa_index;
327: };
328:
329: char CORD_index_access_fn(size_t i, void * client_data)
330: {
331: register struct substr_args *descr = (struct substr_args *)client_data;
332:
333: return(((char *)(descr->sa_cord))[i + descr->sa_index]);
334: }
335:
336: char CORD_apply_access_fn(size_t i, void * client_data)
337: {
338: register struct substr_args *descr = (struct substr_args *)client_data;
339: register struct Function * fn_cord = &(descr->sa_cord->function);
340:
341: return((*(fn_cord->fn))(i + descr->sa_index, fn_cord->client_data));
342: }
343:
344: /* A version of CORD_substr that simply returns a function node, thus */
345: /* postponing its work. The fourth argument is a function that may */
346: /* be used for efficient access to the ith character. */
347: /* Assumes i >= 0 and i + n < length(x). */
348: CORD CORD_substr_closure(CORD x, size_t i, size_t n, CORD_fn f)
349: {
350: register struct substr_args * sa = GC_NEW(struct substr_args);
351: CORD result;
352:
353: if (sa == 0) OUT_OF_MEMORY;
354: sa->sa_cord = (CordRep *)x;
355: sa->sa_index = i;
356: result = CORD_from_fn(f, (void *)sa, n);
357: ((CordRep *)result) -> function.header = SUBSTR_HDR;
358: return (result);
359: }
360:
361: # define SUBSTR_LIMIT (10 * SHORT_LIMIT)
362: /* Substrings of function nodes and flat strings shorter than */
363: /* this are flat strings. Othewise we use a functional */
364: /* representation, which is significantly slower to access. */
365:
366: /* A version of CORD_substr that assumes i >= 0, n > 0, and i + n < length(x).*/
367: CORD CORD_substr_checked(CORD x, size_t i, size_t n)
368: {
369: if (CORD_IS_STRING(x)) {
370: if (n > SUBSTR_LIMIT) {
371: return(CORD_substr_closure(x, i, n, CORD_index_access_fn));
372: } else {
373: register char * result = GC_MALLOC_ATOMIC(n+1);
374:
375: if (result == 0) OUT_OF_MEMORY;
376: strncpy(result, x+i, n);
377: result[n] = '\0';
378: return(result);
379: }
380: } else if (IS_CONCATENATION(x)) {
381: register struct Concatenation * conc
382: = &(((CordRep *)x) -> concatenation);
383: register size_t left_len;
384: register size_t right_len;
385:
386: left_len = LEFT_LEN(conc);
387: right_len = conc -> len - left_len;
388: if (i >= left_len) {
389: if (n == right_len) return(conc -> right);
390: return(CORD_substr_checked(conc -> right, i - left_len, n));
391: } else if (i+n <= left_len) {
392: if (n == left_len) return(conc -> left);
393: return(CORD_substr_checked(conc -> left, i, n));
394: } else {
395: /* Need at least one character from each side. */
396: register CORD left_part;
397: register CORD right_part;
398: register size_t left_part_len = left_len - i;
399:
400: if (i == 0) {
401: left_part = conc -> left;
402: } else {
403: left_part = CORD_substr_checked(conc -> left, i, left_part_len);
404: }
405: if (i + n == right_len + left_len) {
406: right_part = conc -> right;
407: } else {
408: right_part = CORD_substr_checked(conc -> right, 0,
409: n - left_part_len);
410: }
411: return(CORD_cat(left_part, right_part));
412: }
413: } else /* function */ {
414: if (n > SUBSTR_LIMIT) {
415: if (IS_SUBSTR(x)) {
416: /* Avoid nesting substring nodes. */
417: register struct Function * f = &(((CordRep *)x) -> function);
418: register struct substr_args *descr =
419: (struct substr_args *)(f -> client_data);
420:
421: return(CORD_substr_closure((CORD)descr->sa_cord,
422: i + descr->sa_index,
423: n, f -> fn));
424: } else {
425: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
426: }
427: } else {
428: char * result;
429: register struct Function * f = &(((CordRep *)x) -> function);
430: char buf[SUBSTR_LIMIT+1];
431: register char * p = buf;
432: register char c;
433: register int j;
434: register int lim = i + n;
435:
436: for (j = i; j < lim; j++) {
437: c = (*(f -> fn))(j, f -> client_data);
438: if (c == '\0') {
439: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
440: }
441: *p++ = c;
442: }
443: *p = '\0';
444: result = GC_MALLOC_ATOMIC(n+1);
445: if (result == 0) OUT_OF_MEMORY;
446: strcpy(result, buf);
447: return(result);
448: }
449: }
450: }
451:
452: CORD CORD_substr(CORD x, size_t i, size_t n)
453: {
454: register size_t len = CORD_len(x);
455:
456: if (i >= len || n <= 0) return(0);
457: /* n < 0 is impossible in a correct C implementation, but */
458: /* quite possible under SunOS 4.X. */
459: if (i + n > len) n = len - i;
460: # ifndef __STDC__
461: if (i < 0) ABORT("CORD_substr: second arg. negative");
462: /* Possible only if both client and C implementation are buggy. */
463: /* But empirically this happens frequently. */
464: # endif
465: return(CORD_substr_checked(x, i, n));
466: }
467:
468: /* See cord.h for definition. We assume i is in range. */
469: int CORD_iter5(CORD x, size_t i, CORD_iter_fn f1,
470: CORD_batched_iter_fn f2, void * client_data)
471: {
472: if (x == 0) return(0);
473: if (CORD_IS_STRING(x)) {
1.1.2.2 paf 474: register const char* p = x+i;
1.1.2.1 paf 475:
476: if (*p == '\0') ABORT("2nd arg to CORD_iter5 too big");
477: if (f2 != CORD_NO_FN) {
478: return((*f2)(p, client_data));
479: } else {
480: while (*p) {
481: if ((*f1)(*p, client_data)) return(1);
482: p++;
483: }
484: return(0);
485: }
486: } else if (IS_CONCATENATION(x)) {
487: register struct Concatenation * conc
488: = &(((CordRep *)x) -> concatenation);
489:
490:
491: if (i > 0) {
492: register size_t left_len = LEFT_LEN(conc);
493:
494: if (i >= left_len) {
495: return(CORD_iter5(conc -> right, i - left_len, f1, f2,
496: client_data));
497: }
498: }
499: if (CORD_iter5(conc -> left, i, f1, f2, client_data)) {
500: return(1);
501: }
502: return(CORD_iter5(conc -> right, 0, f1, f2, client_data));
503: } else /* function */ {
504: register struct Function * f = &(((CordRep *)x) -> function);
505: register size_t j;
506: register size_t lim = f -> len;
507:
508: for (j = i; j < lim; j++) {
509: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
510: return(1);
511: }
512: }
513: return(0);
514: }
515: }
516:
517: #undef CORD_iter
518: int CORD_iter(CORD x, CORD_iter_fn f1, void * client_data)
519: {
520: return(CORD_iter5(x, 0, f1, CORD_NO_FN, client_data));
521: }
522:
523: int CORD_riter4(CORD x, size_t i, CORD_iter_fn f1, void * client_data)
524: {
525: if (x == 0) return(0);
526: if (CORD_IS_STRING(x)) {
1.1.2.2 paf 527: register const char* p = x + i;
1.1.2.1 paf 528: register char c;
529:
530: for(;;) {
531: c = *p;
532: if (c == '\0') ABORT("2nd arg to CORD_riter4 too big");
533: if ((*f1)(c, client_data)) return(1);
534: if (p == x) break;
535: p--;
536: }
537: return(0);
538: } else if (IS_CONCATENATION(x)) {
539: register struct Concatenation * conc
540: = &(((CordRep *)x) -> concatenation);
541: register CORD left_part = conc -> left;
542: register size_t left_len;
543:
544: left_len = LEFT_LEN(conc);
545: if (i >= left_len) {
546: if (CORD_riter4(conc -> right, i - left_len, f1, client_data)) {
547: return(1);
548: }
549: return(CORD_riter4(left_part, left_len - 1, f1, client_data));
550: } else {
551: return(CORD_riter4(left_part, i, f1, client_data));
552: }
553: } else /* function */ {
554: register struct Function * f = &(((CordRep *)x) -> function);
555: register size_t j;
556:
557: for (j = i; ; j--) {
558: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
559: return(1);
560: }
561: if (j == 0) return(0);
562: }
563: }
564: }
565:
566: int CORD_riter(CORD x, CORD_iter_fn f1, void * client_data)
567: {
568: return(CORD_riter4(x, CORD_len(x) - 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 exponentialy 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:
603: void CORD_init_min_len()
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:
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. */
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:
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. */
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:
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. */
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:
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:
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:
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:
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:
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:
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:
899: size_t CORD_pos_to_index(CORD_pos p)
900: {
901: return(p[0].cur_pos);
902: }
903:
904: CORD CORD_pos_to_cord(CORD_pos p)
905: {
906: return(p[0].path[0].pe_cord);
907: }
908:
909: int CORD_pos_valid(CORD_pos p)
910: {
911: return(p[0].path_len != CORD_POS_INVALID);
912: }
913:
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: }
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