editors/ed.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Copyright (c) 2002 by David I. Bell
   4  * Permission is granted to use, distribute, or modify this source,
   5  * provided that this copyright notice remains intact.
   6  *
   7  * The "ed" built-in command (much simplified)
   8  */
   9
  10 #include "libbb.h"
  11
  12 typedef struct LINE {
  13         struct LINE *next;
  14         struct LINE *prev;
  15         int len;
  16         char data[1];
  17 } LINE;
  18
  19
  20 #define searchString bb_common_bufsiz1
  21
  22 enum {
  23         USERSIZE = sizeof(searchString) > 1024 ? 1024
  24                  : sizeof(searchString) - 1, /* max line length typed in by user */
  25         INITBUF_SIZE = 1024, /* initial buffer size */
  26 };
  27
  28 struct globals {
  29         int curNum;
  30         int lastNum;
  31         int bufUsed;
  32         int bufSize;
  33         LINE *curLine;
  34         char *bufBase;
  35         char *bufPtr;
  36         char *fileName;
  37         LINE lines;
  38         smallint dirty;
  39         int marks[26];
  40 };
  41 #define G (*ptr_to_globals)
  42 #define curLine            (G.curLine           )
  43 #define bufBase            (G.bufBase           )
  44 #define bufPtr             (G.bufPtr            )
  45 #define fileName           (G.fileName          )
  46 #define curNum             (G.curNum            )
  47 #define lastNum            (G.lastNum           )
  48 #define bufUsed            (G.bufUsed           )
  49 #define bufSize            (G.bufSize           )
  50 #define dirty              (G.dirty             )
  51 #define lines              (G.lines             )
  52 #define marks              (G.marks             )
  53 #define INIT_G() do { \
  54         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  55 } while (0)
  56
  57
  58 static void doCommands(void);
  59 static void subCommand(const char *cmd, int num1, int num2);
  60 static int getNum(const char **retcp, smallint *retHaveNum, int *retNum);
  61 static int setCurNum(int num);
  62 static void addLines(int num);
  63 static int insertLine(int num, const char *data, int len);
  64 static void deleteLines(int num1, int num2);
  65 static int printLines(int num1, int num2, int expandFlag);
  66 static int writeLines(const char *file, int num1, int num2);
  67 static int readLines(const char *file, int num);
  68 static int searchLines(const char *str, int num1, int num2);
  69 static LINE *findLine(int num);
  70 static int findString(const LINE *lp, const char * str, int len, int offset);
  71
  72
  73 static int bad_nums(int num1, int num2, const char *for_what)
  74 {
  75         if ((num1 < 1) || (num2 > lastNum) || (num1 > num2)) {
  76                 bb_error_msg("bad line range for %s", for_what);
  77                 return 1;
  78         }
  79         return 0;
  80 }
  81
  82
  83 static char *skip_blank(const char *cp)
  84 {
  85         while (isblank(*cp))
  86                 cp++;
  87         return (char *)cp;
  88 }
  89
  90
  91 int ed_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  92 int ed_main(int argc UNUSED_PARAM, char **argv)
  93 {
  94         INIT_G();
  95
  96         bufSize = INITBUF_SIZE;
  97         bufBase = xmalloc(bufSize);
  98         bufPtr = bufBase;
  99         lines.next = &lines;
 100         lines.prev = &lines;
 101
 102         if (argv[1]) {
 103                 fileName = xstrdup(argv[1]);
 104                 if (!readLines(fileName, 1)) {
 105                         return EXIT_SUCCESS;
 106                 }
 107                 if (lastNum)
 108                         setCurNum(1);
 109                 dirty = FALSE;
 110         }
 111
 112         doCommands();
 113         return EXIT_SUCCESS;
 114 }
 115
 116 /*
 117  * Read commands until we are told to stop.
 118  */
 119 static void doCommands(void)
 120 {
 121         const char *cp;
 122         char *endbuf, buf[USERSIZE];
 123         int len, num1, num2;
 124         smallint have1, have2;
 125
 126         while (TRUE) {
 127                 /* Returns:
 128                  * -1 on read errors or EOF, or on bare Ctrl-D.
 129                  * 0  on ctrl-C,
 130                  * >0 length of input string, including terminating '\n'
 131                  */
 132                 len = read_line_input(": ", buf, sizeof(buf), NULL);
 133                 if (len <= 0)
 134                         return;
 135                 endbuf = &buf[len - 1];
 136                 while ((endbuf > buf) && isblank(endbuf[-1]))
 137                         endbuf--;
 138                 *endbuf = '\0';
 139
 140                 cp = skip_blank(buf);
 141                 have1 = FALSE;
 142                 have2 = FALSE;
 143
 144                 if ((curNum == 0) && (lastNum > 0)) {
 145                         curNum = 1;
 146                         curLine = lines.next;
 147                 }
 148
 149                 if (!getNum(&cp, &have1, &num1))
 150                         continue;
 151
 152                 cp = skip_blank(cp);
 153
 154                 if (*cp == ',') {
 155                         cp++;
 156                         if (!getNum(&cp, &have2, &num2))
 157                                 continue;
 158                         if (!have1)
 159                                 num1 = 1;
 160                         if (!have2)
 161                                 num2 = lastNum;
 162                         have1 = TRUE;
 163                         have2 = TRUE;
 164                 }
 165                 if (!have1)
 166                         num1 = curNum;
 167                 if (!have2)
 168                         num2 = num1;
 169
 170                 switch (*cp++) {
 171                 case 'a':
 172                         addLines(num1 + 1);
 173                         break;
 174
 175                 case 'c':
 176                         deleteLines(num1, num2);
 177                         addLines(num1);
 178                         break;
 179
 180                 case 'd':
 181                         deleteLines(num1, num2);
 182                         break;
 183
 184                 case 'f':
 185                         if (*cp && !isblank(*cp)) {
 186                                 bb_error_msg("bad file command");
 187                                 break;
 188                         }
 189                         cp = skip_blank(cp);
 190                         if (*cp == '\0') {
 191                                 if (fileName)
 192                                         printf("\"%s\"\n", fileName);
 193                                 else
 194                                         printf("No file name\n");
 195                                 break;
 196                         }
 197                         free(fileName);
 198                         fileName = xstrdup(cp);
 199                         break;
 200
 201                 case 'i':
 202                         addLines(num1);
 203                         break;
 204
 205                 case 'k':
 206                         cp = skip_blank(cp);
 207                         if ((*cp < 'a') || (*cp > 'z') || cp[1]) {
 208                                 bb_error_msg("bad mark name");
 209                                 break;
 210                         }
 211                         marks[*cp - 'a'] = num2;
 212                         break;
 213
 214                 case 'l':
 215                         printLines(num1, num2, TRUE);
 216                         break;
 217
 218                 case 'p':
 219                         printLines(num1, num2, FALSE);
 220                         break;
 221
 222                 case 'q':
 223                         cp = skip_blank(cp);
 224                         if (have1 || *cp) {
 225                                 bb_error_msg("bad quit command");
 226                                 break;
 227                         }
 228                         if (!dirty)
 229                                 return;
 230                         len = read_line_input("Really quit? ", buf, 16, NULL);
 231                         /* read error/EOF - no way to continue */
 232                         if (len < 0)
 233                                 return;
 234                         cp = skip_blank(buf);
 235                         if ((*cp | 0x20) == 'y') /* Y or y */
 236                                 return;
 237                         break;
 238
 239                 case 'r':
 240                         if (*cp && !isblank(*cp)) {
 241                                 bb_error_msg("bad read command");
 242                                 break;
 243                         }
 244                         cp = skip_blank(cp);
 245                         if (*cp == '\0') {
 246                                 bb_error_msg("no file name");
 247                                 break;
 248                         }
 249                         if (!have1)
 250                                 num1 = lastNum;
 251                         if (readLines(cp, num1 + 1))
 252                                 break;
 253                         if (fileName == NULL)
 254                                 fileName = xstrdup(cp);
 255                         break;
 256
 257                 case 's':
 258                         subCommand(cp, num1, num2);
 259                         break;
 260
 261                 case 'w':
 262                         if (*cp && !isblank(*cp)) {
 263                                 bb_error_msg("bad write command");
 264                                 break;
 265                         }
 266                         cp = skip_blank(cp);
 267                         if (!have1) {
 268                                 num1 = 1;
 269                                 num2 = lastNum;
 270                         }
 271                         if (*cp == '\0')
 272                                 cp = fileName;
 273                         if (cp == NULL) {
 274                                 bb_error_msg("no file name specified");
 275                                 break;
 276                         }
 277                         writeLines(cp, num1, num2);
 278                         break;
 279
 280                 case 'z':
 281                         switch (*cp) {
 282                         case '-':
 283                                 printLines(curNum - 21, curNum, FALSE);
 284                                 break;
 285                         case '.':
 286                                 printLines(curNum - 11, curNum + 10, FALSE);
 287                                 break;
 288                         default:
 289                                 printLines(curNum, curNum + 21, FALSE);
 290                                 break;
 291                         }
 292                         break;
 293
 294                 case '.':
 295                         if (have1) {
 296                                 bb_error_msg("no arguments allowed");
 297                                 break;
 298                         }
 299                         printLines(curNum, curNum, FALSE);
 300                         break;
 301
 302                 case '-':
 303                         if (setCurNum(curNum - 1))
 304                                 printLines(curNum, curNum, FALSE);
 305                         break;
 306
 307                 case '=':
 308                         printf("%d\n", num1);
 309                         break;
 310                 case '\0':
 311                         if (have1) {
 312                                 printLines(num2, num2, FALSE);
 313                                 break;
 314                         }
 315                         if (setCurNum(curNum + 1))
 316                                 printLines(curNum, curNum, FALSE);
 317                         break;
 318
 319                 default:
 320                         bb_error_msg("unimplemented command");
 321                         break;
 322                 }
 323         }
 324 }
 325
 326
 327 /*
 328  * Do the substitute command.
 329  * The current line is set to the last substitution done.
 330  */
 331 static void subCommand(const char *cmd, int num1, int num2)
 332 {
 333         char *cp, *oldStr, *newStr, buf[USERSIZE];
 334         int delim, oldLen, newLen, deltaLen, offset;
 335         LINE *lp, *nlp;
 336         int globalFlag, printFlag, didSub, needPrint;
 337
 338         if (bad_nums(num1, num2, "substitute"))
 339                 return;
 340
 341         globalFlag = FALSE;
 342         printFlag = FALSE;
 343         didSub = FALSE;
 344         needPrint = FALSE;
 345
 346         /*
 347          * Copy the command so we can modify it.
 348          */
 349         strcpy(buf, cmd);
 350         cp = buf;
 351
 352         if (isblank(*cp) || (*cp == '\0')) {
 353                 bb_error_msg("bad delimiter for substitute");
 354                 return;
 355         }
 356
 357         delim = *cp++;
 358         oldStr = cp;
 359
 360         cp = strchr(cp, delim);
 361         if (cp == NULL) {
 362                 bb_error_msg("missing 2nd delimiter for substitute");
 363                 return;
 364         }
 365
 366         *cp++ = '\0';
 367
 368         newStr = cp;
 369         cp = strchr(cp, delim);
 370
 371         if (cp)
 372                 *cp++ = '\0';
 373         else
 374                 cp = (char*)"";
 375
 376         while (*cp) switch (*cp++) {
 377                 case 'g':
 378                         globalFlag = TRUE;
 379                         break;
 380                 case 'p':
 381                         printFlag = TRUE;
 382                         break;
 383                 default:
 384                         bb_error_msg("unknown option for substitute");
 385                         return;
 386         }
 387
 388         if (*oldStr == '\0') {
 389                 if (searchString[0] == '\0') {
 390                         bb_error_msg("no previous search string");
 391                         return;
 392                 }
 393                 oldStr = searchString;
 394         }
 395
 396         if (oldStr != searchString)
 397                 strcpy(searchString, oldStr);
 398
 399         lp = findLine(num1);
 400         if (lp == NULL)
 401                 return;
 402
 403         oldLen = strlen(oldStr);
 404         newLen = strlen(newStr);
 405         deltaLen = newLen - oldLen;
 406         offset = 0;
 407         nlp = NULL;
 408
 409         while (num1 <= num2) {
 410                 offset = findString(lp, oldStr, oldLen, offset);
 411
 412                 if (offset < 0) {
 413                         if (needPrint) {
 414                                 printLines(num1, num1, FALSE);
 415                                 needPrint = FALSE;
 416                         }
 417                         offset = 0;
 418                         lp = lp->next;
 419                         num1++;
 420                         continue;
 421                 }
 422
 423                 needPrint = printFlag;
 424                 didSub = TRUE;
 425                 dirty = TRUE;
 426
 427                 /*
 428                  * If the replacement string is the same size or shorter
 429                  * than the old string, then the substitution is easy.
 430                  */
 431                 if (deltaLen <= 0) {
 432                         memcpy(&lp->data[offset], newStr, newLen);
 433                         if (deltaLen) {
 434                                 memcpy(&lp->data[offset + newLen],
 435                                         &lp->data[offset + oldLen],
 436                                         lp->len - offset - oldLen);
 437
 438                                 lp->len += deltaLen;
 439                         }
 440                         offset += newLen;
 441                         if (globalFlag)
 442                                 continue;
 443                         if (needPrint) {
 444                                 printLines(num1, num1, FALSE);
 445                                 needPrint = FALSE;
 446                         }
 447                         lp = lp->next;
 448                         num1++;
 449                         continue;
 450                 }
 451
 452                 /*
 453                  * The new string is larger, so allocate a new line
 454                  * structure and use that.  Link it in in place of
 455                  * the old line structure.
 456                  */
 457                 nlp = xmalloc(sizeof(LINE) + lp->len + deltaLen);
 458
 459                 nlp->len = lp->len + deltaLen;
 460
 461                 memcpy(nlp->data, lp->data, offset);
 462                 memcpy(&nlp->data[offset], newStr, newLen);
 463                 memcpy(&nlp->data[offset + newLen],
 464                         &lp->data[offset + oldLen],
 465                         lp->len - offset - oldLen);
 466
 467                 nlp->next = lp->next;
 468                 nlp->prev = lp->prev;
 469                 nlp->prev->next = nlp;
 470                 nlp->next->prev = nlp;
 471
 472                 if (curLine == lp)
 473                         curLine = nlp;
 474
 475                 free(lp);
 476                 lp = nlp;
 477
 478                 offset += newLen;
 479
 480                 if (globalFlag)
 481                         continue;
 482
 483                 if (needPrint) {
 484                         printLines(num1, num1, FALSE);
 485                         needPrint = FALSE;
 486                 }
 487
 488                 lp = lp->next;
 489                 num1++;
 490         }
 491
 492         if (!didSub)
 493                 bb_error_msg("no substitutions found for \"%s\"", oldStr);
 494 }
 495
 496
 497 /*
 498  * Search a line for the specified string starting at the specified
 499  * offset in the line.  Returns the offset of the found string, or -1.
 500  */
 501 static int findString(const LINE *lp, const char *str, int len, int offset)
 502 {
 503         int left;
 504         const char *cp, *ncp;
 505
 506         cp = &lp->data[offset];
 507         left = lp->len - offset;
 508
 509         while (left >= len) {
 510                 ncp = memchr(cp, *str, left);
 511                 if (ncp == NULL)
 512                         return -1;
 513                 left -= (ncp - cp);
 514                 if (left < len)
 515                         return -1;
 516                 cp = ncp;
 517                 if (memcmp(cp, str, len) == 0)
 518                         return (cp - lp->data);
 519                 cp++;
 520                 left--;
 521         }
 522
 523         return -1;
 524 }
 525
 526
 527 /*
 528  * Add lines which are typed in by the user.
 529  * The lines are inserted just before the specified line number.
 530  * The lines are terminated by a line containing a single dot (ugly!),
 531  * or by an end of file.
 532  */
 533 static void addLines(int num)
 534 {
 535         int len;
 536         char buf[USERSIZE + 1];
 537
 538         while (1) {
 539                 /* Returns:
 540                  * -1 on read errors or EOF, or on bare Ctrl-D.
 541                  * 0  on ctrl-C,
 542                  * >0 length of input string, including terminating '\n'
 543                  */
 544                 len = read_line_input("", buf, sizeof(buf), NULL);
 545                 if (len <= 0) {
 546                         /* Previously, ctrl-C was exiting to shell.
 547                          * Now we exit to ed prompt. Is in important? */
 548                         return;
 549                 }
 550                 if ((buf[0] == '.') && (buf[1] == '\n') && (buf[2] == '\0'))
 551                         return;
 552                 if (!insertLine(num++, buf, len))
 553                         return;
 554         }
 555 }
 556
 557
 558 /*
 559  * Parse a line number argument if it is present.  This is a sum
 560  * or difference of numbers, '.', '$', 'x, or a search string.
 561  * Returns TRUE if successful (whether or not there was a number).
 562  * Returns FALSE if there was a parsing error, with a message output.
 563  * Whether there was a number is returned indirectly, as is the number.
 564  * The character pointer which stopped the scan is also returned.
 565  */
 566 static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
 567 {
 568         const char *cp;
 569         char *endStr, str[USERSIZE];
 570         int value, num;
 571         smallint haveNum, minus;
 572
 573         cp = *retcp;
 574         value = 0;
 575         haveNum = FALSE;
 576         minus = 0;
 577
 578         while (TRUE) {
 579                 cp = skip_blank(cp);
 580
 581                 switch (*cp) {
 582                         case '.':
 583                                 haveNum = TRUE;
 584                                 num = curNum;
 585                                 cp++;
 586                                 break;
 587
 588                         case '$':
 589                                 haveNum = TRUE;
 590                                 num = lastNum;
 591                                 cp++;
 592                                 break;
 593
 594                         case '\'':
 595                                 cp++;
 596                                 if ((*cp < 'a') || (*cp > 'z')) {
 597                                         bb_error_msg("bad mark name");
 598                                         return FALSE;
 599                                 }
 600                                 haveNum = TRUE;
 601                                 num = marks[*cp++ - 'a'];
 602                                 break;
 603
 604                         case '/':
 605                                 strcpy(str, ++cp);
 606                                 endStr = strchr(str, '/');
 607                                 if (endStr) {
 608                                         *endStr++ = '\0';
 609                                         cp += (endStr - str);
 610                                 } else
 611                                         cp = "";
 612                                 num = searchLines(str, curNum, lastNum);
 613                                 if (num == 0)
 614                                         return FALSE;
 615                                 haveNum = TRUE;
 616                                 break;
 617
 618                         default:
 619                                 if (!isdigit(*cp)) {
 620                                         *retcp = cp;
 621                                         *retHaveNum = haveNum;
 622                                         *retNum = value;
 623                                         return TRUE;
 624                                 }
 625                                 num = 0;
 626                                 while (isdigit(*cp))
 627                                         num = num * 10 + *cp++ - '0';
 628                                 haveNum = TRUE;
 629                                 break;
 630                 }
 631
 632                 value += (minus ? -num : num);
 633
 634                 cp = skip_blank(cp);
 635
 636                 switch (*cp) {
 637                         case '-':
 638                                 minus = 1;
 639                                 cp++;
 640                                 break;
 641
 642                         case '+':
 643                                 minus = 0;
 644                                 cp++;
 645                                 break;
 646
 647                         default:
 648                                 *retcp = cp;
 649                                 *retHaveNum = haveNum;
 650                                 *retNum = value;
 651                                 return TRUE;
 652                 }
 653         }
 654 }
 655
 656
 657 /*
 658  * Read lines from a file at the specified line number.
 659  * Returns TRUE if the file was successfully read.
 660  */
 661 static int readLines(const char *file, int num)
 662 {
 663         int fd, cc;
 664         int len, lineCount, charCount;
 665         char *cp;
 666
 667         if ((num < 1) || (num > lastNum + 1)) {
 668                 bb_error_msg("bad line for read");
 669                 return FALSE;
 670         }
 671
 672         fd = open(file, 0);
 673         if (fd < 0) {
 674                 bb_simple_perror_msg(file);
 675                 return FALSE;
 676         }
 677
 678         bufPtr = bufBase;
 679         bufUsed = 0;
 680         lineCount = 0;
 681         charCount = 0;
 682         cc = 0;
 683
 684         printf("\"%s\", ", file);
 685         fflush_all();
 686
 687         do {
 688                 cp = memchr(bufPtr, '\n', bufUsed);
 689
 690                 if (cp) {
 691                         len = (cp - bufPtr) + 1;
 692                         if (!insertLine(num, bufPtr, len)) {
 693                                 close(fd);
 694                                 return FALSE;
 695                         }
 696                         bufPtr += len;
 697                         bufUsed -= len;
 698                         charCount += len;
 699                         lineCount++;
 700                         num++;
 701                         continue;
 702                 }
 703
 704                 if (bufPtr != bufBase) {
 705                         memcpy(bufBase, bufPtr, bufUsed);
 706                         bufPtr = bufBase + bufUsed;
 707                 }
 708
 709                 if (bufUsed >= bufSize) {
 710                         len = (bufSize * 3) / 2;
 711                         cp = xrealloc(bufBase, len);
 712                         bufBase = cp;
 713                         bufPtr = bufBase + bufUsed;
 714                         bufSize = len;
 715                 }
 716
 717                 cc = safe_read(fd, bufPtr, bufSize - bufUsed);
 718                 bufUsed += cc;
 719                 bufPtr = bufBase;
 720
 721         } while (cc > 0);
 722
 723         if (cc < 0) {
 724                 bb_simple_perror_msg(file);
 725                 close(fd);
 726                 return FALSE;
 727         }
 728
 729         if (bufUsed) {
 730                 if (!insertLine(num, bufPtr, bufUsed)) {
 731                         close(fd);
 732                         return -1;
 733                 }
 734                 lineCount++;
 735                 charCount += bufUsed;
 736         }
 737
 738         close(fd);
 739
 740         printf("%d lines%s, %d chars\n", lineCount,
 741                 (bufUsed ? " (incomplete)" : ""), charCount);
 742
 743         return TRUE;
 744 }
 745
 746
 747 /*
 748  * Write the specified lines out to the specified file.
 749  * Returns TRUE if successful, or FALSE on an error with a message output.
 750  */
 751 static int writeLines(const char *file, int num1, int num2)
 752 {
 753         LINE *lp;
 754         int fd, lineCount, charCount;
 755
 756         if (bad_nums(num1, num2, "write"))
 757                 return FALSE;
 758
 759         lineCount = 0;
 760         charCount = 0;
 761
 762         fd = creat(file, 0666);
 763         if (fd < 0) {
 764                 bb_simple_perror_msg(file);
 765                 return FALSE;
 766         }
 767
 768         printf("\"%s\", ", file);
 769         fflush_all();
 770
 771         lp = findLine(num1);
 772         if (lp == NULL) {
 773                 close(fd);
 774                 return FALSE;
 775         }
 776
 777         while (num1++ <= num2) {
 778                 if (full_write(fd, lp->data, lp->len) != lp->len) {
 779                         bb_simple_perror_msg(file);
 780                         close(fd);
 781                         return FALSE;
 782                 }
 783                 charCount += lp->len;
 784                 lineCount++;
 785                 lp = lp->next;
 786         }
 787
 788         if (close(fd) < 0) {
 789                 bb_simple_perror_msg(file);
 790                 return FALSE;
 791         }
 792
 793         printf("%d lines, %d chars\n", lineCount, charCount);
 794         return TRUE;
 795 }
 796
 797
 798 /*
 799  * Print lines in a specified range.
 800  * The last line printed becomes the current line.
 801  * If expandFlag is TRUE, then the line is printed specially to
 802  * show magic characters.
 803  */
 804 static int printLines(int num1, int num2, int expandFlag)
 805 {
 806         const LINE *lp;
 807         const char *cp;
 808         int ch, count;
 809
 810         if (bad_nums(num1, num2, "print"))
 811                 return FALSE;
 812
 813         lp = findLine(num1);
 814         if (lp == NULL)
 815                 return FALSE;
 816
 817         while (num1 <= num2) {
 818                 if (!expandFlag) {
 819                         write(STDOUT_FILENO, lp->data, lp->len);
 820                         setCurNum(num1++);
 821                         lp = lp->next;
 822                         continue;
 823                 }
 824
 825                 /*
 826                  * Show control characters and characters with the
 827                  * high bit set specially.
 828                  */
 829                 cp = lp->data;
 830                 count = lp->len;
 831
 832                 if ((count > 0) && (cp[count - 1] == '\n'))
 833                         count--;
 834
 835                 while (count-- > 0) {
 836                         ch = (unsigned char) *cp++;
 837                         fputc_printable(ch | PRINTABLE_META, stdout);
 838                 }
 839
 840                 fputs("$\n", stdout);
 841
 842                 setCurNum(num1++);
 843                 lp = lp->next;
 844         }
 845
 846         return TRUE;
 847 }
 848
 849
 850 /*
 851  * Insert a new line with the specified text.
 852  * The line is inserted so as to become the specified line,
 853  * thus pushing any existing and further lines down one.
 854  * The inserted line is also set to become the current line.
 855  * Returns TRUE if successful.
 856  */
 857 static int insertLine(int num, const char *data, int len)
 858 {
 859         LINE *newLp, *lp;
 860
 861         if ((num < 1) || (num > lastNum + 1)) {
 862                 bb_error_msg("inserting at bad line number");
 863                 return FALSE;
 864         }
 865
 866         newLp = xmalloc(sizeof(LINE) + len - 1);
 867
 868         memcpy(newLp->data, data, len);
 869         newLp->len = len;
 870
 871         if (num > lastNum)
 872                 lp = &lines;
 873         else {
 874                 lp = findLine(num);
 875                 if (lp == NULL) {
 876                         free((char *) newLp);
 877                         return FALSE;
 878                 }
 879         }
 880
 881         newLp->next = lp;
 882         newLp->prev = lp->prev;
 883         lp->prev->next = newLp;
 884         lp->prev = newLp;
 885
 886         lastNum++;
 887         dirty = TRUE;
 888         return setCurNum(num);
 889 }
 890
 891
 892 /*
 893  * Delete lines from the given range.
 894  */
 895 static void deleteLines(int num1, int num2)
 896 {
 897         LINE *lp, *nlp, *plp;
 898         int count;
 899
 900         if (bad_nums(num1, num2, "delete"))
 901                 return;
 902
 903         lp = findLine(num1);
 904         if (lp == NULL)
 905                 return;
 906
 907         if ((curNum >= num1) && (curNum <= num2)) {
 908                 if (num2 < lastNum)
 909                         setCurNum(num2 + 1);
 910                 else if (num1 > 1)
 911                         setCurNum(num1 - 1);
 912                 else
 913                         curNum = 0;
 914         }
 915
 916         count = num2 - num1 + 1;
 917         if (curNum > num2)
 918                 curNum -= count;
 919         lastNum -= count;
 920
 921         while (count-- > 0) {
 922                 nlp = lp->next;
 923                 plp = lp->prev;
 924                 plp->next = nlp;
 925                 nlp->prev = plp;
 926                 free(lp);
 927                 lp = nlp;
 928         }
 929
 930         dirty = TRUE;
 931 }
 932
 933
 934 /*
 935  * Search for a line which contains the specified string.
 936  * If the string is "", then the previously searched for string
 937  * is used.  The currently searched for string is saved for future use.
 938  * Returns the line number which matches, or 0 if there was no match
 939  * with an error printed.
 940  */
 941 static NOINLINE int searchLines(const char *str, int num1, int num2)
 942 {
 943         const LINE *lp;
 944         int len;
 945
 946         if (bad_nums(num1, num2, "search"))
 947                 return 0;
 948
 949         if (*str == '\0') {
 950                 if (searchString[0] == '\0') {
 951                         bb_error_msg("no previous search string");
 952                         return 0;
 953                 }
 954                 str = searchString;
 955         }
 956
 957         if (str != searchString)
 958                 strcpy(searchString, str);
 959
 960         len = strlen(str);
 961
 962         lp = findLine(num1);
 963         if (lp == NULL)
 964                 return 0;
 965
 966         while (num1 <= num2) {
 967                 if (findString(lp, str, len, 0) >= 0)
 968                         return num1;
 969                 num1++;
 970                 lp = lp->next;
 971         }
 972
 973         bb_error_msg("can't find string \"%s\"", str);
 974         return 0;
 975 }
 976
 977
 978 /*
 979  * Return a pointer to the specified line number.
 980  */
 981 static LINE *findLine(int num)
 982 {
 983         LINE *lp;
 984         int lnum;
 985
 986         if ((num < 1) || (num > lastNum)) {
 987                 bb_error_msg("line number %d does not exist", num);
 988                 return NULL;
 989         }
 990
 991         if (curNum <= 0) {
 992                 curNum = 1;
 993                 curLine = lines.next;
 994         }
 995
 996         if (num == curNum)
 997                 return curLine;
 998
 999         lp = curLine;
1000         lnum = curNum;
1001         if (num < (curNum / 2)) {
1002                 lp = lines.next;
1003                 lnum = 1;
1004         } else if (num > ((curNum + lastNum) / 2)) {
1005                 lp = lines.prev;
1006                 lnum = lastNum;
1007         }
1008
1009         while (lnum < num) {
1010                 lp = lp->next;
1011                 lnum++;
1012         }
1013
1014         while (lnum > num) {
1015                 lp = lp->prev;
1016                 lnum--;
1017         }
1018         return lp;
1019 }
1020
1021
1022 /*
1023  * Set the current line number.
1024  * Returns TRUE if successful.
1025  */
1026 static int setCurNum(int num)
1027 {
1028         LINE *lp;
1029
1030         lp = findLine(num);
1031         if (lp == NULL)
1032                 return FALSE;
1033         curNum = num;
1034         curLine = lp;
1035         return TRUE;
1036 }