2 * sed.c - very minimalist version of sed
4 * Copyright (C) 1999,2000,2001 by Lineo, inc.
5 * Written by Mark Whitley <markw@lineo.com>, <markw@codepoet.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 Supported features and commands in this version of sed:
27 - address matching: num|/matchstr/[,num|/matchstr/|$]command
28 - commands: (p)rint, (d)elete, (s)ubstitue (with g & I flags)
29 - edit commands: (a)ppend, (i)nsert, (c)hange
30 - file commands: (r)ead
31 - backreferences in substitution expressions (\1, \2...\9)
33 (Note: Specifying an address (range) to match is *optional*; commands
34 default to the whole pattern space if no specific address match was
39 - transliteration (y/source-chars/dest-chars/) (use 'tr')
40 - no pattern space hold space storing / swapping (x, etc.)
41 - no labels / branching (: label, b, t, and friends)
42 - and lots, lots more.
46 #include <unistd.h> /* for getopt() */
48 #include <string.h> /* for strdup() */
50 #include <ctype.h> /* for isspace() */
55 extern void xregcomp(regex_t *preg, const char *regex, int cflags);
56 extern int optind; /* in unistd.h */
57 extern char *optarg; /* ditto */
60 static int be_quiet = 0;
67 char delimiter; /* The delimiter used to separate regexps */
70 int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */
71 int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
72 regex_t *beg_match; /* sed -e '/match/cmd' */
73 regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
76 char cmd; /* p,d,s (add more at your leisure :-) */
79 /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
81 /* sed -e 's/sub_match/replace/' */
84 unsigned int num_backrefs:4; /* how many back references (\1..\9) */
85 /* Note: GNU/POSIX sed does not save more than nine backrefs, so
86 * we only use 4 bits to hold the number */
87 unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
88 unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
91 /* EDIT COMMAND (a,i,c) SPEICIFIC FIELDS */
96 /* FILE COMMAND (r) SPEICIFIC FIELDS */
102 static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
103 static int ncmds = 0; /* number of sed commands */
105 /*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
107 #ifdef BB_FEATURE_CLEAN_UP
108 static void destroy_cmd_strs()
110 if (sed_cmds == NULL)
113 /* destroy all the elements in the array */
114 while (--ncmds >= 0) {
116 if (sed_cmds[ncmds].beg_match) {
117 regfree(sed_cmds[ncmds].beg_match);
118 free(sed_cmds[ncmds].beg_match);
120 if (sed_cmds[ncmds].end_match) {
121 regfree(sed_cmds[ncmds].end_match);
122 free(sed_cmds[ncmds].end_match);
124 if (sed_cmds[ncmds].sub_match) {
125 regfree(sed_cmds[ncmds].sub_match);
126 free(sed_cmds[ncmds].sub_match);
128 if (sed_cmds[ncmds].replace)
129 free(sed_cmds[ncmds].replace);
132 /* destroy the array */
140 * index_of_next_unescaped_regexp_delim - walks left to right through a string
141 * beginning at a specified index and returns the index of the next regular
142 * expression delimiter (typically a forward * slash ('/')) not preceeded by
145 static int index_of_next_unescaped_regexp_delim(struct sed_cmd *sed_cmd, const char *str, int idx)
147 for ( ; str[idx]; idx++) {
148 if (str[idx] == sed_cmd->delimiter && str[idx-1] != '\\')
152 /* if we make it to here, we've hit the end of the string */
157 * returns the index in the string just past where the address ends.
159 static int get_address(struct sed_cmd *sed_cmd, const char *str, int *line, regex_t **regex)
161 char *my_str = strdup(str);
164 olddelimiter = sed_cmd->delimiter;
165 sed_cmd->delimiter = '/';
167 if (isdigit(my_str[idx])) {
170 } while (isdigit(my_str[idx]));
172 *line = atoi(my_str);
174 else if (my_str[idx] == '$') {
178 else if (my_str[idx] == '/') {
179 idx = index_of_next_unescaped_regexp_delim(sed_cmd, my_str, ++idx);
181 error_msg_and_die("unterminated match expression");
183 *regex = (regex_t *)xmalloc(sizeof(regex_t));
184 xregcomp(*regex, my_str+1, REG_NEWLINE);
185 idx++; /* so it points to the next character after the last '/' */
188 error_msg("get_address: no address found in string\n"
189 "\t(you probably didn't check the string you passed me)");
194 sed_cmd->delimiter = olddelimiter;
198 static char *strdup_substr(const char *str, int start, int end)
200 int size = end - start + 1;
201 char *newstr = xmalloc(size);
202 memcpy(newstr, str+start, size-1);
203 newstr[size-1] = '\0';
207 static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
209 int oldidx, cflags = REG_NEWLINE;
215 * the string that gets passed to this function should look like this:
216 * s/match/replace/gIp
220 * (all three of the '/' slashes are mandatory)
223 /* verify that the 's' is followed by something. That something
224 * (typically a 'slash') is now our regexp delimiter... */
226 error_msg_and_die("bad format in substitution expression");
228 sed_cmd->delimiter=substr[idx];
230 /* save the match string */
232 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
234 error_msg_and_die("bad format in substitution expression");
235 match = strdup_substr(substr, oldidx, idx);
237 /* determine the number of back references in the match string */
238 /* Note: we compute this here rather than in the do_subst_command()
239 * function to save processor time, at the expense of a little more memory
240 * (4 bits) per sed_cmd */
242 /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */
243 for (j = 0; match[j]; j++) {
244 /* GNU/POSIX sed does not save more than nine backrefs */
245 if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
246 sed_cmd->num_backrefs++;
249 /* save the replacement string */
251 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
253 error_msg_and_die("bad format in substitution expression");
254 sed_cmd->replace = strdup_substr(substr, oldidx, idx);
256 /* process the flags */
257 while (substr[++idx]) {
258 switch (substr[idx]) {
269 /* any whitespace or semicolon trailing after a s/// is ok */
270 if (strchr("; \t\v\n\r", substr[idx]))
273 error_msg_and_die("bad option in substitution expression");
278 /* compile the match string into a regex */
279 sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
280 xregcomp(sed_cmd->sub_match, match, cflags);
286 static int parse_edit_cmd(struct sed_cmd *sed_cmd, const char *editstr)
289 int slashes_eaten = 0;
290 char *ptr; /* shorthand */
293 * the string that gets passed to this function should look like this:
297 * | this backslash (immediately following the edit command) is mandatory
304 * as soon as we hit a TEXT line that has no trailing '\', we're done.
305 * this means a command like:
314 if (editstr[1] != '\\' && (editstr[2] != '\n' || editstr[2] != '\r'))
315 error_msg_and_die("bad format in edit expression");
317 /* store the edit line text */
318 /* make editline big enough to accomodate the extra '\n' we will tack on
320 sed_cmd->editline = xmalloc(strlen(&editstr[3]) + 2);
321 strcpy(sed_cmd->editline, &editstr[3]);
322 ptr = sed_cmd->editline;
324 /* now we need to go through * and: s/\\[\r\n]$/\n/g on the edit line */
326 while (ptr[idx] != '\\' || (ptr[idx+1] != '\n' && ptr[idx+1] != '\r')) {
332 /* move the newline over the '\' before it (effectively eats the '\') */
333 memmove(&ptr[idx], &ptr[idx+1], strlen(&ptr[idx+1]));
334 ptr[strlen(ptr)-1] = 0;
336 /* substitue \r for \n if needed */
337 if (ptr[idx] == '\r')
342 /* this accounts for discrepancies between the modified string and the
343 * original string passed in to this function */
344 idx += slashes_eaten;
346 /* figure out if we need to add a newline */
347 if (ptr[idx-1] != '\n') {
352 /* terminate string */
354 /* adjust for opening 2 chars [aic]\ */
361 static int parse_file_cmd(struct sed_cmd *sed_cmd, const char *filecmdstr)
367 * the string that gets passed to this function should look like this:
372 * optional whitespace
374 * re: the file to be read, the GNU manual says the following: "Note that
375 * if filename cannot be read, it is treated as if it were an empty file,
376 * without any error indication." Thus, all of the following commands are
379 * sed -e '1r noexist'
384 /* the file command may be followed by whitespace; move past it. */
385 while (isspace(filecmdstr[++idx]))
388 /* the first non-whitespace we get is a filename. the filename ends when we
389 * hit a normal sed command terminator or end of string */
390 filenamelen = strcspn(&filecmdstr[idx], "; \n\r\t\v\0");
391 sed_cmd->filename = xmalloc(sizeof(char) * filenamelen + 1);
392 strncpy(sed_cmd->filename, &filecmdstr[idx], filenamelen);
393 sed_cmd->filename[filenamelen] = 0;
395 return idx + filenamelen;
399 static char *parse_cmd_str(struct sed_cmd *sed_cmd, const char *cmdstr)
404 * format is: [addr][,addr]cmd
409 /* first part (if present) is an address: either a number or a /regex/ */
410 if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/')
411 idx = get_address(sed_cmd, cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
413 /* second part (if present) will begin with a comma */
414 if (cmdstr[idx] == ',')
415 idx += get_address(sed_cmd, &cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
417 /* last part (mandatory) will be a command */
418 if (cmdstr[idx] == '\0')
419 error_msg_and_die("missing command");
420 sed_cmd->cmd = cmdstr[idx];
422 /* if it was a single-letter command that takes no arguments (such as 'p'
423 * or 'd') all we need to do is increment the index past that command */
424 if (strchr("pd", cmdstr[idx])) {
427 /* handle (s)ubstitution */
428 else if (sed_cmd->cmd == 's') {
429 idx += parse_subst_cmd(sed_cmd, &cmdstr[idx]);
431 /* handle edit cmds: (a)ppend, (i)nsert, and (c)hange */
432 else if (strchr("aic", cmdstr[idx])) {
433 if (sed_cmd->end_line || sed_cmd->end_match)
434 error_msg_and_die("only a beginning address can be specified for edit commands");
435 idx += parse_edit_cmd(sed_cmd, &cmdstr[idx]);
437 /* handle file cmds: (r)ead */
438 else if (sed_cmd->cmd == 'r') {
439 if (sed_cmd->end_line || sed_cmd->end_match)
440 error_msg_and_die("Command only uses one address");
441 idx += parse_file_cmd(sed_cmd, &cmdstr[idx]);
444 error_msg_and_die("invalid command");
447 /* give back whatever's left over */
448 return (char *)&cmdstr[idx];
451 static void add_cmd_str(const char *cmdstr)
453 char *mystr = (char *)cmdstr;
457 /* trim leading whitespace and semicolons */
458 memmove(mystr, &mystr[strspn(mystr, "; \n\r\t\v")], strlen(mystr));
459 /* if we ate the whole thing, that means there was just trailing
460 * whitespace or a final / no-op semicolon. either way, get out */
461 if (strlen(mystr) == 0)
463 /* if this is a comment, jump past it and keep going */
464 if (mystr[0] == '#') {
465 mystr = strpbrk(mystr, ";\n\r");
469 sed_cmds = xrealloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds));
470 /* zero new element */
471 memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd));
472 /* load command string into new array element, get remainder */
473 mystr = parse_cmd_str(&sed_cmds[ncmds-1], mystr);
475 } while (mystr && strlen(mystr));
479 static void load_cmd_file(char *filename)
485 cmdfile = xfopen(filename, "r");
487 while ((line = get_line_from_file(cmdfile)) != NULL) {
488 /* if a line ends with '\' it needs the next line appended to it */
489 while (line[strlen(line)-2] == '\\' &&
490 (nextline = get_line_from_file(cmdfile)) != NULL) {
491 line = xrealloc(line, strlen(line) + strlen(nextline) + 1);
492 strcat(line, nextline);
495 /* eat trailing newline (if any) --if I don't do this, edit commands
496 * (aic) will print an extra newline */
503 static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch)
507 /* go through the replacement string */
508 for (i = 0; replace[i]; i++) {
509 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
510 if (replace[i] == '\\' && isdigit(replace[i+1])) {
514 ++i; /* i now indexes the backref number, instead of the leading slash */
515 tmpstr[0] = replace[i];
517 backref = atoi(tmpstr);
518 /* print out the text held in regmatch[backref] */
519 for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
520 fputc(line[j], stdout);
523 /* if we find a backslash escaped character, print the character */
524 else if (replace[i] == '\\') {
526 fputc(replace[i], stdout);
529 /* if we find an unescaped '&' print out the whole matched text.
530 * fortunately, regmatch[0] contains the indicies to the whole matched
531 * expression (kinda seems like it was designed for just such a
533 else if (replace[i] == '&' && replace[i-1] != '\\') {
535 for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++)
536 fputc(line[j], stdout);
538 /* nothing special, just print this char of the replacement string to stdout */
540 fputc(replace[i], stdout);
544 static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
546 char *hackline = (char *)line;
548 regmatch_t *regmatch = NULL;
550 /* we only proceed if the substitution 'search' expression matches */
551 if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == REG_NOMATCH)
554 /* whaddaya know, it matched. get the number of back references */
555 regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
557 /* and now, as long as we've got a line to try matching and if we can match
558 * the search string, we make substitutions */
559 while (*hackline && (regexec(sed_cmd->sub_match, hackline,
560 sed_cmd->num_backrefs+1, regmatch, 0) == 0) ) {
563 /* print everything before the match */
564 for (i = 0; i < regmatch[0].rm_so; i++)
565 fputc(hackline[i], stdout);
567 /* then print the substitution string */
568 print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
570 /* advance past the match */
571 hackline += regmatch[0].rm_eo;
572 /* flag that something has changed */
575 /* if we're not doing this globally, get out now */
588 static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
592 switch (sed_cmd->cmd) {
605 * Some special cases for 's' printing to make it compliant with
606 * GNU sed printing behavior (aka "The -n | s///p Matrix"):
608 * -n ONLY = never print anything regardless of any successful
611 * s///p ONLY = always print successful substitutions, even if
612 * the line is going to be printed anyway (line will be printed
615 * -n AND s///p = print ONLY a successful substitution ONE TIME;
616 * no other lines are printed - this is the reason why the 'p'
617 * flag exists in the first place.
620 /* if the user specified that they didn't want anything printed (i.e., a -n
621 * flag and no 'p' flag after the s///), then there's really no point doing
623 if (be_quiet && !sed_cmd->sub_p)
626 /* we print the line once, unless we were told to be quiet */
628 altered = do_subst_command(sed_cmd, line);
630 /* we also print the line if we were given the 'p' flag
631 * (this is quite possibly the second printing) */
633 altered = do_subst_command(sed_cmd, line);
639 fputs(sed_cmd->editline, stdout);
644 fputs(sed_cmd->editline, stdout);
648 fputs(sed_cmd->editline, stdout);
655 file = fopen(sed_cmd->filename, "r");
658 /* else if we couldn't open the file, no biggie, just don't print anything */
667 static void process_file(FILE *file)
670 static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
671 unsigned int still_in_range = 0;
675 /* go through every line in the file */
676 while ((line = get_line_from_file(file)) != NULL) {
682 /* for every line, go through all the commands */
683 for (i = 0; i < ncmds; i++) {
685 /* are we acting on a range of matched lines? */
686 if (sed_cmds[i].beg_match && sed_cmds[i].end_match) {
687 if (still_in_range || regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) {
688 line_altered += do_sed_command(&sed_cmds[i], line);
689 if (still_in_range && regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0)
696 /* are we trying to match a single line? */
697 else if (sed_cmds[i].beg_match) {
698 if (regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0)
699 line_altered += do_sed_command(&sed_cmds[i], line);
702 /* are we acting on a range of line numbers? */
703 else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line != 0) {
704 if (linenum >= sed_cmds[i].beg_line &&
705 (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
706 line_altered += do_sed_command(&sed_cmds[i], line);
709 /* are we acting on a specified line number */
710 else if (sed_cmds[i].beg_line > 0) {
711 if (linenum == sed_cmds[i].beg_line)
712 line_altered += do_sed_command(&sed_cmds[i], line);
715 /* not acting on matches or line numbers. act on every line */
717 line_altered += do_sed_command(&sed_cmds[i], line);
721 /* we will print the line unless we were told to be quiet or if the
722 * line was altered (via a 'd'elete or 's'ubstitution), in which case
723 * the altered line was already printed */
724 if (!be_quiet && !line_altered)
731 extern int sed_main(int argc, char **argv)
735 #ifdef BB_FEATURE_CLEAN_UP
736 /* destroy command strings on exit */
737 if (atexit(destroy_cmd_strs) == -1)
738 perror_msg_and_die("atexit");
741 /* do normal option parsing */
742 while ((opt = getopt(argc, argv, "ne:f:")) > 0) {
751 load_cmd_file(optarg);
758 /* if we didn't get a pattern from a -e and no command file was specified,
759 * argv[optind] should be the pattern. no pattern, no worky */
761 if (argv[optind] == NULL)
764 add_cmd_str(argv[optind]);
770 /* argv[(optind)..(argc-1)] should be names of file to process. If no
771 * files were specified or '-' was specified, take input from stdin.
772 * Otherwise, we process all the files specified. */
773 if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
779 for (i = optind; i < argc; i++) {
780 file = fopen(argv[i], "r");
782 perror_msg("%s", argv[i]);