Annotation of OpenXM_contrib2/asir2000/gc/cord/cordbscs.c, Revision 1.4
1.1 noro 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:
147: CORD CORD_cat_char_star(CORD x, const char * y, size_t leny)
148: {
149: register size_t result_len;
150: register size_t lenx;
151: register int depth;
152:
153: if (x == CORD_EMPTY) return(y);
154: if (leny == 0) return(x);
155: if (CORD_IS_STRING(x)) {
156: lenx = strlen(x);
157: result_len = lenx + leny;
158: if (result_len <= SHORT_LIMIT) {
159: register char * result = GC_MALLOC_ATOMIC(result_len+1);
160:
161: if (result == 0) OUT_OF_MEMORY;
162: memcpy(result, x, lenx);
163: memcpy(result + lenx, y, leny);
164: result[result_len] = '\0';
165: return((CORD) result);
166: } else {
167: depth = 1;
168: }
169: } else {
170: register CORD right;
171: register CORD left;
172: register char * new_right;
173: register size_t right_len;
174:
175: lenx = LEN(x);
176:
177: if (leny <= SHORT_LIMIT/2
178: && IS_CONCATENATION(x)
179: && CORD_IS_STRING(right = ((CordRep *)x) -> concatenation.right)) {
180: /* Merge y into right part of x. */
181: if (!CORD_IS_STRING(left = ((CordRep *)x) -> concatenation.left)) {
182: right_len = lenx - LEN(left);
183: } else if (((CordRep *)x) -> concatenation.left_len != 0) {
184: right_len = lenx - ((CordRep *)x) -> concatenation.left_len;
185: } else {
186: right_len = strlen(right);
187: }
188: result_len = right_len + leny; /* length of new_right */
189: if (result_len <= SHORT_LIMIT) {
190: new_right = GC_MALLOC_ATOMIC(result_len + 1);
191: memcpy(new_right, right, right_len);
192: memcpy(new_right + right_len, y, leny);
193: new_right[result_len] = '\0';
194: y = new_right;
195: leny = result_len;
196: x = left;
197: lenx -= right_len;
198: /* Now fall through to concatenate the two pieces: */
199: }
200: if (CORD_IS_STRING(x)) {
201: depth = 1;
202: } else {
203: depth = DEPTH(x) + 1;
204: }
205: } else {
206: depth = DEPTH(x) + 1;
207: }
208: result_len = lenx + leny;
209: }
210: {
211: /* The general case; lenx, result_len is known: */
212: register struct Concatenation * result;
213:
214: result = GC_NEW(struct Concatenation);
215: if (result == 0) OUT_OF_MEMORY;
216: result->header = CONCAT_HDR;
217: result->depth = depth;
218: if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
219: result->len = result_len;
220: result->left = x;
221: result->right = y;
1.4 ! noro 222: if (depth >= MAX_DEPTH) {
1.1 noro 223: return(CORD_balance((CORD)result));
224: } else {
225: return((CORD) result);
226: }
227: }
228: }
229:
230:
231: CORD CORD_cat(CORD x, CORD y)
232: {
233: register size_t result_len;
234: register int depth;
235: register size_t lenx;
236:
237: if (x == CORD_EMPTY) return(y);
238: if (y == CORD_EMPTY) return(x);
239: if (CORD_IS_STRING(y)) {
240: return(CORD_cat_char_star(x, y, strlen(y)));
241: } else if (CORD_IS_STRING(x)) {
242: lenx = strlen(x);
243: depth = DEPTH(y) + 1;
244: } else {
245: register int depthy = DEPTH(y);
246:
247: lenx = LEN(x);
248: depth = DEPTH(x) + 1;
249: if (depthy >= depth) depth = depthy + 1;
250: }
251: result_len = lenx + LEN(y);
252: {
253: register struct Concatenation * result;
254:
255: result = GC_NEW(struct Concatenation);
256: if (result == 0) OUT_OF_MEMORY;
257: result->header = CONCAT_HDR;
258: result->depth = depth;
259: if (lenx <= MAX_LEFT_LEN) result->left_len = lenx;
260: result->len = result_len;
261: result->left = x;
262: result->right = y;
1.4 ! noro 263: if (depth >= MAX_DEPTH) {
! 264: return(CORD_balance((CORD)result));
! 265: } else {
! 266: return((CORD) result);
! 267: }
1.1 noro 268: }
269: }
270:
271:
272:
273: CORD CORD_from_fn(CORD_fn fn, void * client_data, size_t len)
274: {
275: if (len <= 0) return(0);
276: if (len <= SHORT_LIMIT) {
277: register char * result;
278: register size_t i;
279: char buf[SHORT_LIMIT+1];
280: register char c;
281:
282: for (i = 0; i < len; i++) {
283: c = (*fn)(i, client_data);
284: if (c == '\0') goto gen_case;
285: buf[i] = c;
286: }
287: buf[i] = '\0';
288: result = GC_MALLOC_ATOMIC(len+1);
289: if (result == 0) OUT_OF_MEMORY;
290: strcpy(result, buf);
291: result[len] = '\0';
292: return((CORD) result);
293: }
294: gen_case:
295: {
296: register struct Function * result;
297:
298: result = GC_NEW(struct Function);
299: if (result == 0) OUT_OF_MEMORY;
300: result->header = FN_HDR;
301: /* depth is already 0 */
302: result->len = len;
303: result->fn = fn;
304: result->client_data = client_data;
305: return((CORD) result);
306: }
307: }
308:
309: size_t CORD_len(CORD x)
310: {
311: if (x == 0) {
312: return(0);
313: } else {
314: return(GEN_LEN(x));
315: }
316: }
317:
318: struct substr_args {
319: CordRep * sa_cord;
320: size_t sa_index;
321: };
322:
323: char CORD_index_access_fn(size_t i, void * client_data)
324: {
325: register struct substr_args *descr = (struct substr_args *)client_data;
326:
327: return(((char *)(descr->sa_cord))[i + descr->sa_index]);
328: }
329:
330: char CORD_apply_access_fn(size_t i, void * client_data)
331: {
332: register struct substr_args *descr = (struct substr_args *)client_data;
333: register struct Function * fn_cord = &(descr->sa_cord->function);
334:
335: return((*(fn_cord->fn))(i + descr->sa_index, fn_cord->client_data));
336: }
337:
338: /* A version of CORD_substr that simply returns a function node, thus */
339: /* postponing its work. The fourth argument is a function that may */
340: /* be used for efficient access to the ith character. */
341: /* Assumes i >= 0 and i + n < length(x). */
342: CORD CORD_substr_closure(CORD x, size_t i, size_t n, CORD_fn f)
343: {
344: register struct substr_args * sa = GC_NEW(struct substr_args);
345: CORD result;
346:
347: if (sa == 0) OUT_OF_MEMORY;
348: sa->sa_cord = (CordRep *)x;
349: sa->sa_index = i;
350: result = CORD_from_fn(f, (void *)sa, n);
351: ((CordRep *)result) -> function.header = SUBSTR_HDR;
352: return (result);
353: }
354:
355: # define SUBSTR_LIMIT (10 * SHORT_LIMIT)
356: /* Substrings of function nodes and flat strings shorter than */
357: /* this are flat strings. Othewise we use a functional */
358: /* representation, which is significantly slower to access. */
359:
360: /* A version of CORD_substr that assumes i >= 0, n > 0, and i + n < length(x).*/
361: CORD CORD_substr_checked(CORD x, size_t i, size_t n)
362: {
363: if (CORD_IS_STRING(x)) {
364: if (n > SUBSTR_LIMIT) {
365: return(CORD_substr_closure(x, i, n, CORD_index_access_fn));
366: } else {
367: register char * result = GC_MALLOC_ATOMIC(n+1);
368:
369: if (result == 0) OUT_OF_MEMORY;
370: strncpy(result, x+i, n);
371: result[n] = '\0';
372: return(result);
373: }
374: } else if (IS_CONCATENATION(x)) {
375: register struct Concatenation * conc
376: = &(((CordRep *)x) -> concatenation);
377: register size_t left_len;
378: register size_t right_len;
379:
380: left_len = LEFT_LEN(conc);
381: right_len = conc -> len - left_len;
382: if (i >= left_len) {
383: if (n == right_len) return(conc -> right);
384: return(CORD_substr_checked(conc -> right, i - left_len, n));
385: } else if (i+n <= left_len) {
386: if (n == left_len) return(conc -> left);
387: return(CORD_substr_checked(conc -> left, i, n));
388: } else {
389: /* Need at least one character from each side. */
390: register CORD left_part;
391: register CORD right_part;
392: register size_t left_part_len = left_len - i;
393:
394: if (i == 0) {
395: left_part = conc -> left;
396: } else {
397: left_part = CORD_substr_checked(conc -> left, i, left_part_len);
398: }
399: if (i + n == right_len + left_len) {
400: right_part = conc -> right;
401: } else {
402: right_part = CORD_substr_checked(conc -> right, 0,
403: n - left_part_len);
404: }
405: return(CORD_cat(left_part, right_part));
406: }
407: } else /* function */ {
408: if (n > SUBSTR_LIMIT) {
409: if (IS_SUBSTR(x)) {
410: /* Avoid nesting substring nodes. */
411: register struct Function * f = &(((CordRep *)x) -> function);
412: register struct substr_args *descr =
413: (struct substr_args *)(f -> client_data);
414:
415: return(CORD_substr_closure((CORD)descr->sa_cord,
416: i + descr->sa_index,
417: n, f -> fn));
418: } else {
419: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
420: }
421: } else {
422: char * result;
423: register struct Function * f = &(((CordRep *)x) -> function);
424: char buf[SUBSTR_LIMIT+1];
425: register char * p = buf;
426: register char c;
427: register int j;
428: register int lim = i + n;
429:
430: for (j = i; j < lim; j++) {
431: c = (*(f -> fn))(j, f -> client_data);
432: if (c == '\0') {
433: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
434: }
435: *p++ = c;
436: }
437: *p = '\0';
438: result = GC_MALLOC_ATOMIC(n+1);
439: if (result == 0) OUT_OF_MEMORY;
440: strcpy(result, buf);
441: return(result);
442: }
443: }
444: }
445:
446: CORD CORD_substr(CORD x, size_t i, size_t n)
447: {
448: register size_t len = CORD_len(x);
449:
450: if (i >= len || n <= 0) return(0);
451: /* n < 0 is impossible in a correct C implementation, but */
452: /* quite possible under SunOS 4.X. */
453: if (i + n > len) n = len - i;
454: # ifndef __STDC__
455: if (i < 0) ABORT("CORD_substr: second arg. negative");
456: /* Possible only if both client and C implementation are buggy. */
457: /* But empirically this happens frequently. */
458: # endif
459: return(CORD_substr_checked(x, i, n));
460: }
461:
462: /* See cord.h for definition. We assume i is in range. */
463: int CORD_iter5(CORD x, size_t i, CORD_iter_fn f1,
464: CORD_batched_iter_fn f2, void * client_data)
465: {
466: if (x == 0) return(0);
467: if (CORD_IS_STRING(x)) {
468: register const char *p = x+i;
469:
470: if (*p == '\0') ABORT("2nd arg to CORD_iter5 too big");
471: if (f2 != CORD_NO_FN) {
472: return((*f2)(p, client_data));
473: } else {
474: while (*p) {
475: if ((*f1)(*p, client_data)) return(1);
476: p++;
477: }
478: return(0);
479: }
480: } else if (IS_CONCATENATION(x)) {
481: register struct Concatenation * conc
482: = &(((CordRep *)x) -> concatenation);
483:
484:
485: if (i > 0) {
486: register size_t left_len = LEFT_LEN(conc);
487:
488: if (i >= left_len) {
489: return(CORD_iter5(conc -> right, i - left_len, f1, f2,
490: client_data));
491: }
492: }
493: if (CORD_iter5(conc -> left, i, f1, f2, client_data)) {
494: return(1);
495: }
496: return(CORD_iter5(conc -> right, 0, f1, f2, client_data));
497: } else /* function */ {
498: register struct Function * f = &(((CordRep *)x) -> function);
499: register size_t j;
500: register size_t lim = f -> len;
501:
502: for (j = i; j < lim; j++) {
503: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
504: return(1);
505: }
506: }
507: return(0);
508: }
509: }
510:
511: #undef CORD_iter
512: int CORD_iter(CORD x, CORD_iter_fn f1, void * client_data)
513: {
514: return(CORD_iter5(x, 0, f1, CORD_NO_FN, client_data));
515: }
516:
517: int CORD_riter4(CORD x, size_t i, CORD_iter_fn f1, void * client_data)
518: {
519: if (x == 0) return(0);
520: if (CORD_IS_STRING(x)) {
521: register const char *p = x + i;
522: register char c;
523:
524: for(;;) {
525: c = *p;
526: if (c == '\0') ABORT("2nd arg to CORD_riter4 too big");
527: if ((*f1)(c, client_data)) return(1);
528: if (p == x) break;
529: p--;
530: }
531: return(0);
532: } else if (IS_CONCATENATION(x)) {
533: register struct Concatenation * conc
534: = &(((CordRep *)x) -> concatenation);
535: register CORD left_part = conc -> left;
536: register size_t left_len;
537:
538: left_len = LEFT_LEN(conc);
539: if (i >= left_len) {
540: if (CORD_riter4(conc -> right, i - left_len, f1, client_data)) {
541: return(1);
542: }
543: return(CORD_riter4(left_part, left_len - 1, f1, client_data));
544: } else {
545: return(CORD_riter4(left_part, i, f1, client_data));
546: }
547: } else /* function */ {
548: register struct Function * f = &(((CordRep *)x) -> function);
549: register size_t j;
550:
551: for (j = i; ; j--) {
552: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
553: return(1);
554: }
555: if (j == 0) return(0);
556: }
557: }
558: }
559:
560: int CORD_riter(CORD x, CORD_iter_fn f1, void * client_data)
561: {
562: return(CORD_riter4(x, CORD_len(x) - 1, f1, client_data));
563: }
564:
565: /*
566: * The following functions are concerned with balancing cords.
567: * Strategy:
568: * Scan the cord from left to right, keeping the cord scanned so far
569: * as a forest of balanced trees of exponentialy decreasing length.
570: * When a new subtree needs to be added to the forest, we concatenate all
571: * shorter ones to the new tree in the appropriate order, and then insert
572: * the result into the forest.
573: * Crucial invariants:
574: * 1. The concatenation of the forest (in decreasing order) with the
575: * unscanned part of the rope is equal to the rope being balanced.
576: * 2. All trees in the forest are balanced.
577: * 3. forest[i] has depth at most i.
578: */
579:
580: typedef struct {
581: CORD c;
582: size_t len; /* Actual length of c */
583: } ForestElement;
584:
585: static size_t min_len [ MAX_DEPTH ];
586:
587: static int min_len_init = 0;
588:
589: int CORD_max_len;
590:
591: typedef ForestElement Forest [ MAX_DEPTH ];
592: /* forest[i].len >= fib(i+1) */
593: /* The string is the concatenation */
594: /* of the forest in order of DECREASING */
595: /* indices. */
596:
597: void CORD_init_min_len()
598: {
599: register int i;
600: register size_t last, previous, current;
601:
602: min_len[0] = previous = 1;
603: min_len[1] = last = 2;
604: for (i = 2; i < MAX_DEPTH; i++) {
605: current = last + previous;
606: if (current < last) /* overflow */ current = last;
607: min_len[i] = current;
608: previous = last;
609: last = current;
610: }
611: CORD_max_len = last - 1;
612: min_len_init = 1;
613: }
614:
615:
616: void CORD_init_forest(ForestElement * forest, size_t max_len)
617: {
618: register int i;
619:
620: for (i = 0; i < MAX_DEPTH; i++) {
621: forest[i].c = 0;
622: if (min_len[i] > max_len) return;
623: }
624: ABORT("Cord too long");
625: }
626:
627: /* Add a leaf to the appropriate level in the forest, cleaning */
628: /* out lower levels as necessary. */
629: /* Also works if x is a balanced tree of concatenations; however */
630: /* in this case an extra concatenation node may be inserted above x; */
631: /* This node should not be counted in the statement of the invariants. */
632: void CORD_add_forest(ForestElement * forest, CORD x, size_t len)
633: {
634: register int i = 0;
635: register CORD sum = CORD_EMPTY;
636: register size_t sum_len = 0;
637:
638: while (len > min_len[i + 1]) {
639: if (forest[i].c != 0) {
640: sum = CORD_cat(forest[i].c, sum);
641: sum_len += forest[i].len;
642: forest[i].c = 0;
643: }
644: i++;
645: }
646: /* Sum has depth at most 1 greter than what would be required */
647: /* for balance. */
648: sum = CORD_cat(sum, x);
649: sum_len += len;
650: /* If x was a leaf, then sum is now balanced. To see this */
651: /* consider the two cases in which forest[i-1] either is or is */
652: /* not empty. */
653: while (sum_len >= min_len[i]) {
654: if (forest[i].c != 0) {
655: sum = CORD_cat(forest[i].c, sum);
656: sum_len += forest[i].len;
657: /* This is again balanced, since sum was balanced, and has */
658: /* allowable depth that differs from i by at most 1. */
659: forest[i].c = 0;
660: }
661: i++;
662: }
663: i--;
664: forest[i].c = sum;
665: forest[i].len = sum_len;
666: }
667:
668: CORD CORD_concat_forest(ForestElement * forest, size_t expected_len)
669: {
670: register int i = 0;
671: CORD sum = 0;
672: size_t sum_len = 0;
673:
674: while (sum_len != expected_len) {
675: if (forest[i].c != 0) {
676: sum = CORD_cat(forest[i].c, sum);
677: sum_len += forest[i].len;
678: }
679: i++;
680: }
681: return(sum);
682: }
683:
684: /* Insert the frontier of x into forest. Balanced subtrees are */
685: /* treated as leaves. This potentially adds one to the depth */
686: /* of the final tree. */
687: void CORD_balance_insert(CORD x, size_t len, ForestElement * forest)
688: {
689: register int depth;
690:
691: if (CORD_IS_STRING(x)) {
692: CORD_add_forest(forest, x, len);
693: } else if (IS_CONCATENATION(x)
694: && ((depth = DEPTH(x)) >= MAX_DEPTH
695: || len < min_len[depth])) {
696: register struct Concatenation * conc
697: = &(((CordRep *)x) -> concatenation);
698: size_t left_len = LEFT_LEN(conc);
699:
700: CORD_balance_insert(conc -> left, left_len, forest);
701: CORD_balance_insert(conc -> right, len - left_len, forest);
702: } else /* function or balanced */ {
703: CORD_add_forest(forest, x, len);
704: }
705: }
706:
707:
708: CORD CORD_balance(CORD x)
709: {
710: Forest forest;
711: register size_t len;
712:
713: if (x == 0) return(0);
714: if (CORD_IS_STRING(x)) return(x);
715: if (!min_len_init) CORD_init_min_len();
716: len = LEN(x);
717: CORD_init_forest(forest, len);
718: CORD_balance_insert(x, len, forest);
719: return(CORD_concat_forest(forest, len));
720: }
721:
722:
723: /* Position primitives */
724:
725: /* Private routines to deal with the hard cases only: */
726:
727: /* P contains a prefix of the path to cur_pos. Extend it to a full */
728: /* path and set up leaf info. */
729: /* Return 0 if past the end of cord, 1 o.w. */
730: void CORD__extend_path(register CORD_pos p)
731: {
732: register struct CORD_pe * current_pe = &(p[0].path[p[0].path_len]);
733: register CORD top = current_pe -> pe_cord;
734: register size_t pos = p[0].cur_pos;
735: register size_t top_pos = current_pe -> pe_start_pos;
736: register size_t top_len = GEN_LEN(top);
737:
738: /* Fill in the rest of the path. */
739: while(!CORD_IS_STRING(top) && IS_CONCATENATION(top)) {
740: register struct Concatenation * conc =
741: &(((CordRep *)top) -> concatenation);
742: register size_t left_len;
743:
744: left_len = LEFT_LEN(conc);
745: current_pe++;
746: if (pos >= top_pos + left_len) {
747: current_pe -> pe_cord = top = conc -> right;
748: current_pe -> pe_start_pos = top_pos = top_pos + left_len;
749: top_len -= left_len;
750: } else {
751: current_pe -> pe_cord = top = conc -> left;
752: current_pe -> pe_start_pos = top_pos;
753: top_len = left_len;
754: }
755: p[0].path_len++;
756: }
757: /* Fill in leaf description for fast access. */
758: if (CORD_IS_STRING(top)) {
759: p[0].cur_leaf = top;
760: p[0].cur_start = top_pos;
761: p[0].cur_end = top_pos + top_len;
762: } else {
763: p[0].cur_end = 0;
764: }
765: if (pos >= top_pos + top_len) p[0].path_len = CORD_POS_INVALID;
766: }
767:
768: char CORD__pos_fetch(register CORD_pos p)
769: {
770: /* Leaf is a function node */
771: struct CORD_pe * pe = &((p)[0].path[(p)[0].path_len]);
772: CORD leaf = pe -> pe_cord;
773: register struct Function * f = &(((CordRep *)leaf) -> function);
774:
775: if (!IS_FUNCTION(leaf)) ABORT("CORD_pos_fetch: bad leaf");
776: return ((*(f -> fn))(p[0].cur_pos - pe -> pe_start_pos, f -> client_data));
777: }
778:
779: void CORD__next(register CORD_pos p)
780: {
781: register size_t cur_pos = p[0].cur_pos + 1;
782: register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
783: register CORD leaf = current_pe -> pe_cord;
784:
785: /* Leaf is not a string or we're at end of leaf */
786: p[0].cur_pos = cur_pos;
787: if (!CORD_IS_STRING(leaf)) {
788: /* Function leaf */
789: register struct Function * f = &(((CordRep *)leaf) -> function);
790: register size_t start_pos = current_pe -> pe_start_pos;
791: register size_t end_pos = start_pos + f -> len;
792:
793: if (cur_pos < end_pos) {
794: /* Fill cache and return. */
795: register size_t i;
796: register size_t limit = cur_pos + FUNCTION_BUF_SZ;
797: register CORD_fn fn = f -> fn;
798: register void * client_data = f -> client_data;
799:
800: if (limit > end_pos) {
801: limit = end_pos;
802: }
803: for (i = cur_pos; i < limit; i++) {
804: p[0].function_buf[i - cur_pos] =
805: (*fn)(i - start_pos, client_data);
806: }
807: p[0].cur_start = cur_pos;
808: p[0].cur_leaf = p[0].function_buf;
809: p[0].cur_end = limit;
810: return;
811: }
812: }
813: /* End of leaf */
814: /* Pop the stack until we find two concatenation nodes with the */
815: /* same start position: this implies we were in left part. */
816: {
817: while (p[0].path_len > 0
818: && current_pe[0].pe_start_pos != current_pe[-1].pe_start_pos) {
819: p[0].path_len--;
820: current_pe--;
821: }
822: if (p[0].path_len == 0) {
823: p[0].path_len = CORD_POS_INVALID;
824: return;
825: }
826: }
827: p[0].path_len--;
828: CORD__extend_path(p);
829: }
830:
831: void CORD__prev(register CORD_pos p)
832: {
833: register struct CORD_pe * pe = &(p[0].path[p[0].path_len]);
834:
835: if (p[0].cur_pos == 0) {
836: p[0].path_len = CORD_POS_INVALID;
837: return;
838: }
839: p[0].cur_pos--;
840: if (p[0].cur_pos >= pe -> pe_start_pos) return;
841:
842: /* Beginning of leaf */
843:
844: /* Pop the stack until we find two concatenation nodes with the */
845: /* different start position: this implies we were in right part. */
846: {
847: register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
848:
849: while (p[0].path_len > 0
850: && current_pe[0].pe_start_pos == current_pe[-1].pe_start_pos) {
851: p[0].path_len--;
852: current_pe--;
853: }
854: }
855: p[0].path_len--;
856: CORD__extend_path(p);
857: }
858:
859: #undef CORD_pos_fetch
860: #undef CORD_next
861: #undef CORD_prev
862: #undef CORD_pos_to_index
863: #undef CORD_pos_to_cord
864: #undef CORD_pos_valid
865:
866: char CORD_pos_fetch(register CORD_pos p)
867: {
868: if (p[0].cur_start <= p[0].cur_pos && p[0].cur_pos < p[0].cur_end) {
869: return(p[0].cur_leaf[p[0].cur_pos - p[0].cur_start]);
870: } else {
871: return(CORD__pos_fetch(p));
872: }
873: }
874:
875: void CORD_next(CORD_pos p)
876: {
877: if (p[0].cur_pos < p[0].cur_end - 1) {
878: p[0].cur_pos++;
879: } else {
880: CORD__next(p);
881: }
882: }
883:
884: void CORD_prev(CORD_pos p)
885: {
886: if (p[0].cur_end != 0 && p[0].cur_pos > p[0].cur_start) {
887: p[0].cur_pos--;
888: } else {
889: CORD__prev(p);
890: }
891: }
892:
893: size_t CORD_pos_to_index(CORD_pos p)
894: {
895: return(p[0].cur_pos);
896: }
897:
898: CORD CORD_pos_to_cord(CORD_pos p)
899: {
900: return(p[0].path[0].pe_cord);
901: }
902:
903: int CORD_pos_valid(CORD_pos p)
904: {
905: return(p[0].path_len != CORD_POS_INVALID);
906: }
907:
908: void CORD_set_pos(CORD_pos p, CORD x, size_t i)
909: {
910: if (x == CORD_EMPTY) {
911: p[0].path_len = CORD_POS_INVALID;
912: return;
913: }
914: p[0].path[0].pe_cord = x;
915: p[0].path[0].pe_start_pos = 0;
916: p[0].path_len = 0;
917: p[0].cur_pos = i;
918: CORD__extend_path(p);
919: }
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