[BACK]Return to cordbscs.c CVS log [TXT][DIR] Up to [local] / OpenXM_contrib / gc / cord

Annotation of OpenXM_contrib/gc/cord/cordbscs.c, Revision 1.1.1.1

1.1       maekawa     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>