Annotation of OpenXM_contrib2/asir2000/gc/cord/cordbscs.c, Revision 1.1.1.1
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;
222: if (depth > MAX_DEPTH) {
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;
263: return((CORD) result);
264: }
265: }
266:
267:
268:
269: CORD CORD_from_fn(CORD_fn fn, void * client_data, size_t len)
270: {
271: if (len <= 0) return(0);
272: if (len <= SHORT_LIMIT) {
273: register char * result;
274: register size_t i;
275: char buf[SHORT_LIMIT+1];
276: register char c;
277:
278: for (i = 0; i < len; i++) {
279: c = (*fn)(i, client_data);
280: if (c == '\0') goto gen_case;
281: buf[i] = c;
282: }
283: buf[i] = '\0';
284: result = GC_MALLOC_ATOMIC(len+1);
285: if (result == 0) OUT_OF_MEMORY;
286: strcpy(result, buf);
287: result[len] = '\0';
288: return((CORD) result);
289: }
290: gen_case:
291: {
292: register struct Function * result;
293:
294: result = GC_NEW(struct Function);
295: if (result == 0) OUT_OF_MEMORY;
296: result->header = FN_HDR;
297: /* depth is already 0 */
298: result->len = len;
299: result->fn = fn;
300: result->client_data = client_data;
301: return((CORD) result);
302: }
303: }
304:
305: size_t CORD_len(CORD x)
306: {
307: if (x == 0) {
308: return(0);
309: } else {
310: return(GEN_LEN(x));
311: }
312: }
313:
314: struct substr_args {
315: CordRep * sa_cord;
316: size_t sa_index;
317: };
318:
319: char CORD_index_access_fn(size_t i, void * client_data)
320: {
321: register struct substr_args *descr = (struct substr_args *)client_data;
322:
323: return(((char *)(descr->sa_cord))[i + descr->sa_index]);
324: }
325:
326: char CORD_apply_access_fn(size_t i, void * client_data)
327: {
328: register struct substr_args *descr = (struct substr_args *)client_data;
329: register struct Function * fn_cord = &(descr->sa_cord->function);
330:
331: return((*(fn_cord->fn))(i + descr->sa_index, fn_cord->client_data));
332: }
333:
334: /* A version of CORD_substr that simply returns a function node, thus */
335: /* postponing its work. The fourth argument is a function that may */
336: /* be used for efficient access to the ith character. */
337: /* Assumes i >= 0 and i + n < length(x). */
338: CORD CORD_substr_closure(CORD x, size_t i, size_t n, CORD_fn f)
339: {
340: register struct substr_args * sa = GC_NEW(struct substr_args);
341: CORD result;
342:
343: if (sa == 0) OUT_OF_MEMORY;
344: sa->sa_cord = (CordRep *)x;
345: sa->sa_index = i;
346: result = CORD_from_fn(f, (void *)sa, n);
347: ((CordRep *)result) -> function.header = SUBSTR_HDR;
348: return (result);
349: }
350:
351: # define SUBSTR_LIMIT (10 * SHORT_LIMIT)
352: /* Substrings of function nodes and flat strings shorter than */
353: /* this are flat strings. Othewise we use a functional */
354: /* representation, which is significantly slower to access. */
355:
356: /* A version of CORD_substr that assumes i >= 0, n > 0, and i + n < length(x).*/
357: CORD CORD_substr_checked(CORD x, size_t i, size_t n)
358: {
359: if (CORD_IS_STRING(x)) {
360: if (n > SUBSTR_LIMIT) {
361: return(CORD_substr_closure(x, i, n, CORD_index_access_fn));
362: } else {
363: register char * result = GC_MALLOC_ATOMIC(n+1);
364:
365: if (result == 0) OUT_OF_MEMORY;
366: strncpy(result, x+i, n);
367: result[n] = '\0';
368: return(result);
369: }
370: } else if (IS_CONCATENATION(x)) {
371: register struct Concatenation * conc
372: = &(((CordRep *)x) -> concatenation);
373: register size_t left_len;
374: register size_t right_len;
375:
376: left_len = LEFT_LEN(conc);
377: right_len = conc -> len - left_len;
378: if (i >= left_len) {
379: if (n == right_len) return(conc -> right);
380: return(CORD_substr_checked(conc -> right, i - left_len, n));
381: } else if (i+n <= left_len) {
382: if (n == left_len) return(conc -> left);
383: return(CORD_substr_checked(conc -> left, i, n));
384: } else {
385: /* Need at least one character from each side. */
386: register CORD left_part;
387: register CORD right_part;
388: register size_t left_part_len = left_len - i;
389:
390: if (i == 0) {
391: left_part = conc -> left;
392: } else {
393: left_part = CORD_substr_checked(conc -> left, i, left_part_len);
394: }
395: if (i + n == right_len + left_len) {
396: right_part = conc -> right;
397: } else {
398: right_part = CORD_substr_checked(conc -> right, 0,
399: n - left_part_len);
400: }
401: return(CORD_cat(left_part, right_part));
402: }
403: } else /* function */ {
404: if (n > SUBSTR_LIMIT) {
405: if (IS_SUBSTR(x)) {
406: /* Avoid nesting substring nodes. */
407: register struct Function * f = &(((CordRep *)x) -> function);
408: register struct substr_args *descr =
409: (struct substr_args *)(f -> client_data);
410:
411: return(CORD_substr_closure((CORD)descr->sa_cord,
412: i + descr->sa_index,
413: n, f -> fn));
414: } else {
415: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
416: }
417: } else {
418: char * result;
419: register struct Function * f = &(((CordRep *)x) -> function);
420: char buf[SUBSTR_LIMIT+1];
421: register char * p = buf;
422: register char c;
423: register int j;
424: register int lim = i + n;
425:
426: for (j = i; j < lim; j++) {
427: c = (*(f -> fn))(j, f -> client_data);
428: if (c == '\0') {
429: return(CORD_substr_closure(x, i, n, CORD_apply_access_fn));
430: }
431: *p++ = c;
432: }
433: *p = '\0';
434: result = GC_MALLOC_ATOMIC(n+1);
435: if (result == 0) OUT_OF_MEMORY;
436: strcpy(result, buf);
437: return(result);
438: }
439: }
440: }
441:
442: CORD CORD_substr(CORD x, size_t i, size_t n)
443: {
444: register size_t len = CORD_len(x);
445:
446: if (i >= len || n <= 0) return(0);
447: /* n < 0 is impossible in a correct C implementation, but */
448: /* quite possible under SunOS 4.X. */
449: if (i + n > len) n = len - i;
450: # ifndef __STDC__
451: if (i < 0) ABORT("CORD_substr: second arg. negative");
452: /* Possible only if both client and C implementation are buggy. */
453: /* But empirically this happens frequently. */
454: # endif
455: return(CORD_substr_checked(x, i, n));
456: }
457:
458: /* See cord.h for definition. We assume i is in range. */
459: int CORD_iter5(CORD x, size_t i, CORD_iter_fn f1,
460: CORD_batched_iter_fn f2, void * client_data)
461: {
462: if (x == 0) return(0);
463: if (CORD_IS_STRING(x)) {
464: register const char *p = x+i;
465:
466: if (*p == '\0') ABORT("2nd arg to CORD_iter5 too big");
467: if (f2 != CORD_NO_FN) {
468: return((*f2)(p, client_data));
469: } else {
470: while (*p) {
471: if ((*f1)(*p, client_data)) return(1);
472: p++;
473: }
474: return(0);
475: }
476: } else if (IS_CONCATENATION(x)) {
477: register struct Concatenation * conc
478: = &(((CordRep *)x) -> concatenation);
479:
480:
481: if (i > 0) {
482: register size_t left_len = LEFT_LEN(conc);
483:
484: if (i >= left_len) {
485: return(CORD_iter5(conc -> right, i - left_len, f1, f2,
486: client_data));
487: }
488: }
489: if (CORD_iter5(conc -> left, i, f1, f2, client_data)) {
490: return(1);
491: }
492: return(CORD_iter5(conc -> right, 0, f1, f2, client_data));
493: } else /* function */ {
494: register struct Function * f = &(((CordRep *)x) -> function);
495: register size_t j;
496: register size_t lim = f -> len;
497:
498: for (j = i; j < lim; j++) {
499: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
500: return(1);
501: }
502: }
503: return(0);
504: }
505: }
506:
507: #undef CORD_iter
508: int CORD_iter(CORD x, CORD_iter_fn f1, void * client_data)
509: {
510: return(CORD_iter5(x, 0, f1, CORD_NO_FN, client_data));
511: }
512:
513: int CORD_riter4(CORD x, size_t i, CORD_iter_fn f1, void * client_data)
514: {
515: if (x == 0) return(0);
516: if (CORD_IS_STRING(x)) {
517: register const char *p = x + i;
518: register char c;
519:
520: for(;;) {
521: c = *p;
522: if (c == '\0') ABORT("2nd arg to CORD_riter4 too big");
523: if ((*f1)(c, client_data)) return(1);
524: if (p == x) break;
525: p--;
526: }
527: return(0);
528: } else if (IS_CONCATENATION(x)) {
529: register struct Concatenation * conc
530: = &(((CordRep *)x) -> concatenation);
531: register CORD left_part = conc -> left;
532: register size_t left_len;
533:
534: left_len = LEFT_LEN(conc);
535: if (i >= left_len) {
536: if (CORD_riter4(conc -> right, i - left_len, f1, client_data)) {
537: return(1);
538: }
539: return(CORD_riter4(left_part, left_len - 1, f1, client_data));
540: } else {
541: return(CORD_riter4(left_part, i, f1, client_data));
542: }
543: } else /* function */ {
544: register struct Function * f = &(((CordRep *)x) -> function);
545: register size_t j;
546:
547: for (j = i; ; j--) {
548: if ((*f1)((*(f -> fn))(j, f -> client_data), client_data)) {
549: return(1);
550: }
551: if (j == 0) return(0);
552: }
553: }
554: }
555:
556: int CORD_riter(CORD x, CORD_iter_fn f1, void * client_data)
557: {
558: return(CORD_riter4(x, CORD_len(x) - 1, f1, client_data));
559: }
560:
561: /*
562: * The following functions are concerned with balancing cords.
563: * Strategy:
564: * Scan the cord from left to right, keeping the cord scanned so far
565: * as a forest of balanced trees of exponentialy decreasing length.
566: * When a new subtree needs to be added to the forest, we concatenate all
567: * shorter ones to the new tree in the appropriate order, and then insert
568: * the result into the forest.
569: * Crucial invariants:
570: * 1. The concatenation of the forest (in decreasing order) with the
571: * unscanned part of the rope is equal to the rope being balanced.
572: * 2. All trees in the forest are balanced.
573: * 3. forest[i] has depth at most i.
574: */
575:
576: typedef struct {
577: CORD c;
578: size_t len; /* Actual length of c */
579: } ForestElement;
580:
581: static size_t min_len [ MAX_DEPTH ];
582:
583: static int min_len_init = 0;
584:
585: int CORD_max_len;
586:
587: typedef ForestElement Forest [ MAX_DEPTH ];
588: /* forest[i].len >= fib(i+1) */
589: /* The string is the concatenation */
590: /* of the forest in order of DECREASING */
591: /* indices. */
592:
593: void CORD_init_min_len()
594: {
595: register int i;
596: register size_t last, previous, current;
597:
598: min_len[0] = previous = 1;
599: min_len[1] = last = 2;
600: for (i = 2; i < MAX_DEPTH; i++) {
601: current = last + previous;
602: if (current < last) /* overflow */ current = last;
603: min_len[i] = current;
604: previous = last;
605: last = current;
606: }
607: CORD_max_len = last - 1;
608: min_len_init = 1;
609: }
610:
611:
612: void CORD_init_forest(ForestElement * forest, size_t max_len)
613: {
614: register int i;
615:
616: for (i = 0; i < MAX_DEPTH; i++) {
617: forest[i].c = 0;
618: if (min_len[i] > max_len) return;
619: }
620: ABORT("Cord too long");
621: }
622:
623: /* Add a leaf to the appropriate level in the forest, cleaning */
624: /* out lower levels as necessary. */
625: /* Also works if x is a balanced tree of concatenations; however */
626: /* in this case an extra concatenation node may be inserted above x; */
627: /* This node should not be counted in the statement of the invariants. */
628: void CORD_add_forest(ForestElement * forest, CORD x, size_t len)
629: {
630: register int i = 0;
631: register CORD sum = CORD_EMPTY;
632: register size_t sum_len = 0;
633:
634: while (len > min_len[i + 1]) {
635: if (forest[i].c != 0) {
636: sum = CORD_cat(forest[i].c, sum);
637: sum_len += forest[i].len;
638: forest[i].c = 0;
639: }
640: i++;
641: }
642: /* Sum has depth at most 1 greter than what would be required */
643: /* for balance. */
644: sum = CORD_cat(sum, x);
645: sum_len += len;
646: /* If x was a leaf, then sum is now balanced. To see this */
647: /* consider the two cases in which forest[i-1] either is or is */
648: /* not empty. */
649: while (sum_len >= min_len[i]) {
650: if (forest[i].c != 0) {
651: sum = CORD_cat(forest[i].c, sum);
652: sum_len += forest[i].len;
653: /* This is again balanced, since sum was balanced, and has */
654: /* allowable depth that differs from i by at most 1. */
655: forest[i].c = 0;
656: }
657: i++;
658: }
659: i--;
660: forest[i].c = sum;
661: forest[i].len = sum_len;
662: }
663:
664: CORD CORD_concat_forest(ForestElement * forest, size_t expected_len)
665: {
666: register int i = 0;
667: CORD sum = 0;
668: size_t sum_len = 0;
669:
670: while (sum_len != expected_len) {
671: if (forest[i].c != 0) {
672: sum = CORD_cat(forest[i].c, sum);
673: sum_len += forest[i].len;
674: }
675: i++;
676: }
677: return(sum);
678: }
679:
680: /* Insert the frontier of x into forest. Balanced subtrees are */
681: /* treated as leaves. This potentially adds one to the depth */
682: /* of the final tree. */
683: void CORD_balance_insert(CORD x, size_t len, ForestElement * forest)
684: {
685: register int depth;
686:
687: if (CORD_IS_STRING(x)) {
688: CORD_add_forest(forest, x, len);
689: } else if (IS_CONCATENATION(x)
690: && ((depth = DEPTH(x)) >= MAX_DEPTH
691: || len < min_len[depth])) {
692: register struct Concatenation * conc
693: = &(((CordRep *)x) -> concatenation);
694: size_t left_len = LEFT_LEN(conc);
695:
696: CORD_balance_insert(conc -> left, left_len, forest);
697: CORD_balance_insert(conc -> right, len - left_len, forest);
698: } else /* function or balanced */ {
699: CORD_add_forest(forest, x, len);
700: }
701: }
702:
703:
704: CORD CORD_balance(CORD x)
705: {
706: Forest forest;
707: register size_t len;
708:
709: if (x == 0) return(0);
710: if (CORD_IS_STRING(x)) return(x);
711: if (!min_len_init) CORD_init_min_len();
712: len = LEN(x);
713: CORD_init_forest(forest, len);
714: CORD_balance_insert(x, len, forest);
715: return(CORD_concat_forest(forest, len));
716: }
717:
718:
719: /* Position primitives */
720:
721: /* Private routines to deal with the hard cases only: */
722:
723: /* P contains a prefix of the path to cur_pos. Extend it to a full */
724: /* path and set up leaf info. */
725: /* Return 0 if past the end of cord, 1 o.w. */
726: void CORD__extend_path(register CORD_pos p)
727: {
728: register struct CORD_pe * current_pe = &(p[0].path[p[0].path_len]);
729: register CORD top = current_pe -> pe_cord;
730: register size_t pos = p[0].cur_pos;
731: register size_t top_pos = current_pe -> pe_start_pos;
732: register size_t top_len = GEN_LEN(top);
733:
734: /* Fill in the rest of the path. */
735: while(!CORD_IS_STRING(top) && IS_CONCATENATION(top)) {
736: register struct Concatenation * conc =
737: &(((CordRep *)top) -> concatenation);
738: register size_t left_len;
739:
740: left_len = LEFT_LEN(conc);
741: current_pe++;
742: if (pos >= top_pos + left_len) {
743: current_pe -> pe_cord = top = conc -> right;
744: current_pe -> pe_start_pos = top_pos = top_pos + left_len;
745: top_len -= left_len;
746: } else {
747: current_pe -> pe_cord = top = conc -> left;
748: current_pe -> pe_start_pos = top_pos;
749: top_len = left_len;
750: }
751: p[0].path_len++;
752: }
753: /* Fill in leaf description for fast access. */
754: if (CORD_IS_STRING(top)) {
755: p[0].cur_leaf = top;
756: p[0].cur_start = top_pos;
757: p[0].cur_end = top_pos + top_len;
758: } else {
759: p[0].cur_end = 0;
760: }
761: if (pos >= top_pos + top_len) p[0].path_len = CORD_POS_INVALID;
762: }
763:
764: char CORD__pos_fetch(register CORD_pos p)
765: {
766: /* Leaf is a function node */
767: struct CORD_pe * pe = &((p)[0].path[(p)[0].path_len]);
768: CORD leaf = pe -> pe_cord;
769: register struct Function * f = &(((CordRep *)leaf) -> function);
770:
771: if (!IS_FUNCTION(leaf)) ABORT("CORD_pos_fetch: bad leaf");
772: return ((*(f -> fn))(p[0].cur_pos - pe -> pe_start_pos, f -> client_data));
773: }
774:
775: void CORD__next(register CORD_pos p)
776: {
777: register size_t cur_pos = p[0].cur_pos + 1;
778: register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
779: register CORD leaf = current_pe -> pe_cord;
780:
781: /* Leaf is not a string or we're at end of leaf */
782: p[0].cur_pos = cur_pos;
783: if (!CORD_IS_STRING(leaf)) {
784: /* Function leaf */
785: register struct Function * f = &(((CordRep *)leaf) -> function);
786: register size_t start_pos = current_pe -> pe_start_pos;
787: register size_t end_pos = start_pos + f -> len;
788:
789: if (cur_pos < end_pos) {
790: /* Fill cache and return. */
791: register size_t i;
792: register size_t limit = cur_pos + FUNCTION_BUF_SZ;
793: register CORD_fn fn = f -> fn;
794: register void * client_data = f -> client_data;
795:
796: if (limit > end_pos) {
797: limit = end_pos;
798: }
799: for (i = cur_pos; i < limit; i++) {
800: p[0].function_buf[i - cur_pos] =
801: (*fn)(i - start_pos, client_data);
802: }
803: p[0].cur_start = cur_pos;
804: p[0].cur_leaf = p[0].function_buf;
805: p[0].cur_end = limit;
806: return;
807: }
808: }
809: /* End of leaf */
810: /* Pop the stack until we find two concatenation nodes with the */
811: /* same start position: this implies we were in left part. */
812: {
813: while (p[0].path_len > 0
814: && current_pe[0].pe_start_pos != current_pe[-1].pe_start_pos) {
815: p[0].path_len--;
816: current_pe--;
817: }
818: if (p[0].path_len == 0) {
819: p[0].path_len = CORD_POS_INVALID;
820: return;
821: }
822: }
823: p[0].path_len--;
824: CORD__extend_path(p);
825: }
826:
827: void CORD__prev(register CORD_pos p)
828: {
829: register struct CORD_pe * pe = &(p[0].path[p[0].path_len]);
830:
831: if (p[0].cur_pos == 0) {
832: p[0].path_len = CORD_POS_INVALID;
833: return;
834: }
835: p[0].cur_pos--;
836: if (p[0].cur_pos >= pe -> pe_start_pos) return;
837:
838: /* Beginning of leaf */
839:
840: /* Pop the stack until we find two concatenation nodes with the */
841: /* different start position: this implies we were in right part. */
842: {
843: register struct CORD_pe * current_pe = &((p)[0].path[(p)[0].path_len]);
844:
845: while (p[0].path_len > 0
846: && current_pe[0].pe_start_pos == current_pe[-1].pe_start_pos) {
847: p[0].path_len--;
848: current_pe--;
849: }
850: }
851: p[0].path_len--;
852: CORD__extend_path(p);
853: }
854:
855: #undef CORD_pos_fetch
856: #undef CORD_next
857: #undef CORD_prev
858: #undef CORD_pos_to_index
859: #undef CORD_pos_to_cord
860: #undef CORD_pos_valid
861:
862: char CORD_pos_fetch(register CORD_pos p)
863: {
864: if (p[0].cur_start <= p[0].cur_pos && p[0].cur_pos < p[0].cur_end) {
865: return(p[0].cur_leaf[p[0].cur_pos - p[0].cur_start]);
866: } else {
867: return(CORD__pos_fetch(p));
868: }
869: }
870:
871: void CORD_next(CORD_pos p)
872: {
873: if (p[0].cur_pos < p[0].cur_end - 1) {
874: p[0].cur_pos++;
875: } else {
876: CORD__next(p);
877: }
878: }
879:
880: void CORD_prev(CORD_pos p)
881: {
882: if (p[0].cur_end != 0 && p[0].cur_pos > p[0].cur_start) {
883: p[0].cur_pos--;
884: } else {
885: CORD__prev(p);
886: }
887: }
888:
889: size_t CORD_pos_to_index(CORD_pos p)
890: {
891: return(p[0].cur_pos);
892: }
893:
894: CORD CORD_pos_to_cord(CORD_pos p)
895: {
896: return(p[0].path[0].pe_cord);
897: }
898:
899: int CORD_pos_valid(CORD_pos p)
900: {
901: return(p[0].path_len != CORD_POS_INVALID);
902: }
903:
904: void CORD_set_pos(CORD_pos p, CORD x, size_t i)
905: {
906: if (x == CORD_EMPTY) {
907: p[0].path_len = CORD_POS_INVALID;
908: return;
909: }
910: p[0].path[0].pe_cord = x;
911: p[0].path[0].pe_start_pos = 0;
912: p[0].path_len = 0;
913: p[0].cur_pos = i;
914: CORD__extend_path(p);
915: }
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