Annotation of OpenXM_contrib2/asir2000/gc/cord/cordbscs.c, Revision 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: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to cordbscs.c CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [local] / OpenXM_contrib2 / asir2000 / gc / cord