2 * sed.c - very minimalist version of sed
4 * Copyright (C) 1999,2000 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 - backreferences in substitution expressions (\1, \2...\9)
32 (Note: Specifying an address (range) to match is *optional*; commands
33 default to the whole pattern space if no specific address match was
38 - transliteration (y/source-chars/dest-chars/) (use 'tr')
39 - no pattern space hold space storing / swapping (x, etc.)
40 - no labels / branching (: label, b, t, and friends)
41 - and lots, lots more.
45 #include <unistd.h> /* for getopt() */
47 #include <string.h> /* for strdup() */
49 #include <ctype.h> /* for isspace() */
53 extern int optind; /* in unistd.h */
54 extern char *optarg; /* ditto */
57 static int be_quiet = 0;
64 char delimiter; /* The delimiter used to separate regexps */
67 int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */
68 int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
69 regex_t *beg_match; /* sed -e '/match/cmd' */
70 regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
73 char cmd; /* p,d,s (add more at your leisure :-) */
76 /* SUBSTITUTION COMMAND SPECIFIC FIELDS */
78 /* sed -e 's/sub_match/replace/' */
81 unsigned int num_backrefs:4; /* how many back references (\1..\9) */
82 /* Note: GNU/POSIX sed does not save more than nine backrefs, so
83 * we only use 4 bits to hold the number */
84 unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
85 unsigned int sub_p:2; /* sed -e 's/foo/bar/p' (print substitution) */
88 /* EDIT COMMAND (a,i,c) SPEICIFIC FIELDS */
94 static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
95 static int ncmds = 0; /* number of sed commands */
97 /*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
99 #ifdef BB_FEATURE_CLEAN_UP
100 static void destroy_cmd_strs()
102 if (sed_cmds == NULL)
105 /* destroy all the elements in the array */
106 while (--ncmds >= 0) {
108 if (sed_cmds[ncmds].beg_match) {
109 regfree(sed_cmds[ncmds].beg_match);
110 free(sed_cmds[ncmds].beg_match);
112 if (sed_cmds[ncmds].end_match) {
113 regfree(sed_cmds[ncmds].end_match);
114 free(sed_cmds[ncmds].end_match);
116 if (sed_cmds[ncmds].sub_match) {
117 regfree(sed_cmds[ncmds].sub_match);
118 free(sed_cmds[ncmds].sub_match);
120 if (sed_cmds[ncmds].replace)
121 free(sed_cmds[ncmds].replace);
124 /* destroy the array */
132 * index_of_next_unescaped_regexp_delim - walks left to right through a string
133 * beginning at a specified index and returns the index of the next regular
134 * expression delimiter (typically a forward * slash ('/')) not preceeded by
137 static int index_of_next_unescaped_regexp_delim(struct sed_cmd *sed_cmd, const char *str, int idx)
139 for ( ; str[idx]; idx++) {
140 if (str[idx] == sed_cmd->delimiter && str[idx-1] != '\\')
144 /* if we make it to here, we've hit the end of the string */
149 * returns the index in the string just past where the address ends.
151 static int get_address(struct sed_cmd *sed_cmd, const char *str, int *line, regex_t **regex)
153 char *my_str = strdup(str);
156 if (isdigit(my_str[idx])) {
159 } while (isdigit(my_str[idx]));
161 *line = atoi(my_str);
163 else if (my_str[idx] == '$') {
167 else if (my_str[idx] == '/') {
168 idx = index_of_next_unescaped_regexp_delim(sed_cmd, my_str, ++idx);
170 error_msg_and_die("unterminated match expression\n");
172 *regex = (regex_t *)xmalloc(sizeof(regex_t));
173 xregcomp(*regex, my_str+1, 0);
174 idx++; /* so it points to the next character after the last '/' */
177 error_msg("get_address: no address found in string\n"
178 "\t(you probably didn't check the string you passed me)\n");
186 static char *strdup_substr(const char *str, int start, int end)
188 int size = end - start + 1;
189 char *newstr = xmalloc(size);
190 memcpy(newstr, str+start, size-1);
191 newstr[size-1] = '\0';
195 static int parse_subst_cmd(struct sed_cmd *sed_cmd, const char *substr)
197 int oldidx, cflags = REG_NEWLINE;
203 * the string that gets passed to this function should look like this:
204 * s/match/replace/gIp
208 * (all three of the '/' slashes are mandatory)
211 /* verify that the 's' is followed by something. That something
212 * (typically a 'slash') is now our regexp delimiter... */
214 error_msg_and_die("bad format in substitution expression\n");
216 sed_cmd->delimiter=substr[idx];
218 /* save the match string */
220 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
222 error_msg_and_die("bad format in substitution expression\n");
223 match = strdup_substr(substr, oldidx, idx);
225 /* determine the number of back references in the match string */
226 /* Note: we compute this here rather than in the do_subst_command()
227 * function to save processor time, at the expense of a little more memory
228 * (4 bits) per sed_cmd */
230 /* sed_cmd->num_backrefs = 0; */ /* XXX: not needed? --apparently not */
231 for (j = 0; match[j]; j++) {
232 /* GNU/POSIX sed does not save more than nine backrefs */
233 if (match[j] == '\\' && match[j+1] == '(' && sed_cmd->num_backrefs <= 9)
234 sed_cmd->num_backrefs++;
237 /* save the replacement string */
239 idx = index_of_next_unescaped_regexp_delim(sed_cmd, substr, ++idx);
241 error_msg_and_die("bad format in substitution expression\n");
242 sed_cmd->replace = strdup_substr(substr, oldidx, idx);
244 /* process the flags */
245 while (substr[++idx]) {
246 switch (substr[idx]) {
257 /* any whitespace or semicolon trailing after a s/// is ok */
258 if (strchr("; \t\v\n\r", substr[idx]))
261 error_msg_and_die("bad option in substitution expression\n");
266 /* compile the match string into a regex */
267 sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
268 xregcomp(sed_cmd->sub_match, match, cflags);
274 static int parse_edit_cmd(struct sed_cmd *sed_cmd, const char *editstr)
277 int slashes_eaten = 0;
278 char *ptr; /* shorthand */
281 * the string that gets passed to this function should look like this:
285 * | this backslash (immediately following the edit command) is mandatory
292 * as soon as we hit a TEXT line that has no trailing '\', we're done.
293 * this means a command like:
302 if (editstr[1] != '\\' && (editstr[2] != '\n' || editstr[2] != '\r'))
303 error_msg_and_die("bad format in edit expression\n");
305 /* store the edit line text */
306 /* make editline big enough to accomodate the extra '\n' we will tack on
308 sed_cmd->editline = xmalloc(strlen(&editstr[3]) + 2);
309 strcpy(sed_cmd->editline, &editstr[3]);
310 ptr = sed_cmd->editline;
312 /* now we need to go through * and: s/\\[\r\n]$/\n/g on the edit line */
314 while (ptr[idx] != '\\' && (ptr[idx+1] != '\n' || ptr[idx+1] != '\r')) {
320 /* move the newline over the '\' before it (effectively eats the '\') */
321 memmove(&ptr[idx], &ptr[idx+1], strlen(&ptr[idx+1]));
322 ptr[strlen(ptr)-1] = 0;
324 /* substitue \r for \n if needed */
325 if (ptr[idx] == '\r')
333 /* this accounts for discrepancies between the modified string and the
334 * original string passed in to this function */
335 idx += slashes_eaten;
337 /* this accounts for the fact that A) we started at index 3, not at index
338 * 0 and B) that we added an extra '\n' at the end (if you think the next
339 * line should read 'idx += 4' remember, arrays are zero-based) */
346 static char *parse_cmd_str(struct sed_cmd *sed_cmd, const char *cmdstr)
351 * format is: [addr][,addr]cmd
357 /* first part (if present) is an address: either a number or a /regex/ */
358 if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/')
359 idx = get_address(sed_cmd, cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
361 /* second part (if present) will begin with a comma */
362 if (cmdstr[idx] == ',')
363 idx += get_address(sed_cmd, &cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
365 /* last part (mandatory) will be a command */
366 if (cmdstr[idx] == '\0')
367 error_msg_and_die("missing command\n");
368 if (!strchr("pdsaic", cmdstr[idx])) /* <-- XXX add new commands here */
369 error_msg_and_die("invalid command\n");
370 sed_cmd->cmd = cmdstr[idx];
372 /* special-case handling for (s)ubstitution */
373 if (sed_cmd->cmd == 's') {
374 idx += parse_subst_cmd(sed_cmd, &cmdstr[idx]);
376 /* special-case handling for (a)ppend, (i)nsert, and (c)hange */
377 else if (strchr("aic", cmdstr[idx])) {
378 if (sed_cmd->end_line || sed_cmd->end_match)
379 error_msg_and_die("only a beginning address can be specified for edit commands\n");
380 idx += parse_edit_cmd(sed_cmd, &cmdstr[idx]);
382 /* if it was a single-letter command (such as 'p' or 'd') we need to
383 * increment the index past that command */
387 /* give back whatever's left over */
388 return (char *)&cmdstr[idx];
391 static void add_cmd_str(const char *cmdstr)
393 char *mystr = (char *)cmdstr;
397 /* trim leading whitespace and semicolons */
398 memmove(mystr, &mystr[strspn(mystr, "; \n\r\t\v")], strlen(mystr));
399 /* if we ate the whole thing, that means there was just trailing
400 * whitespace or a final / no-op semicolon. either way, get out */
401 if (strlen(mystr) == 0)
403 /* if this is a comment, jump past it and keep going */
404 if (mystr[0] == '#') {
405 mystr = strpbrk(mystr, ";\n\r");
409 sed_cmds = xrealloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds));
410 /* zero new element */
411 memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd));
412 /* load command string into new array element, get remainder */
413 mystr = parse_cmd_str(&sed_cmds[ncmds-1], mystr);
415 } while (mystr && strlen(mystr));
419 static void load_cmd_file(char *filename)
425 cmdfile = xfopen(filename, "r");
427 while ((line = get_line_from_file(cmdfile)) != NULL) {
428 /* if a line ends with '\' it needs the next line appended to it */
429 while (line[strlen(line)-2] == '\\' &&
430 (nextline = get_line_from_file(cmdfile)) != NULL) {
431 line = xrealloc(line, strlen(line) + strlen(nextline) + 1);
432 strcat(line, nextline);
435 /* eat trailing newline (if any) --if I don't do this, edit commands
436 * (aic) will print an extra newline */
437 if (line[strlen(line)-1] == '\n')
438 line[strlen(line)-1] = 0;
444 static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch)
448 /* go through the replacement string */
449 for (i = 0; replace[i]; i++) {
450 /* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
451 if (replace[i] == '\\' && isdigit(replace[i+1])) {
455 ++i; /* i now indexes the backref number, instead of the leading slash */
456 tmpstr[0] = replace[i];
458 backref = atoi(tmpstr);
459 /* print out the text held in regmatch[backref] */
460 for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
461 fputc(line[j], stdout);
464 /* if we find a backslash escaped character, print the character */
465 else if (replace[i] == '\\') {
467 fputc(replace[i], stdout);
470 /* if we find an unescaped '&' print out the whole matched text.
471 * fortunately, regmatch[0] contains the indicies to the whole matched
472 * expression (kinda seems like it was designed for just such a
474 else if (replace[i] == '&' && replace[i-1] != '\\') {
476 for (j = regmatch[0].rm_so; j < regmatch[0].rm_eo; j++)
477 fputc(line[j], stdout);
479 /* nothing special, just print this char of the replacement string to stdout */
481 fputc(replace[i], stdout);
485 static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
487 char *hackline = (char *)line;
489 regmatch_t *regmatch = NULL;
491 /* we only proceed if the substitution 'search' expression matches */
492 if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == REG_NOMATCH)
495 /* whaddaya know, it matched. get the number of back references */
496 regmatch = xmalloc(sizeof(regmatch_t) * (sed_cmd->num_backrefs+1));
498 /* and now, as long as we've got a line to try matching and if we can match
499 * the search string, we make substitutions */
500 while (*hackline && (regexec(sed_cmd->sub_match, hackline,
501 sed_cmd->num_backrefs+1, regmatch, 0) == 0) ) {
504 /* print everything before the match */
505 for (i = 0; i < regmatch[0].rm_so; i++)
506 fputc(hackline[i], stdout);
508 /* then print the substitution string */
509 print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
511 /* advance past the match */
512 hackline += regmatch[0].rm_eo;
513 /* flag that something has changed */
516 /* if we're not doing this globally, get out now */
521 /* if there's anything left of the line, print it */
523 fputs(hackline, stdout);
531 static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
535 switch (sed_cmd->cmd) {
548 * Some special cases for 's' printing to make it compliant with
549 * GNU sed printing behavior (aka "The -n | s///p Matrix"):
551 * -n ONLY = never print anything regardless of any successful
554 * s///p ONLY = always print successful substitutions, even if
555 * the line is going to be printed anyway (line will be printed
558 * -n AND s///p = print ONLY a successful substitution ONE TIME;
559 * no other lines are printed - this is the reason why the 'p'
560 * flag exists in the first place.
563 /* if the user specified that they didn't want anything printed (i.e. a -n
564 * flag and no 'p' flag after the s///), then there's really no point doing
566 if (be_quiet && !sed_cmd->sub_p)
569 /* we print the line once, unless we were told to be quiet */
571 altered = do_subst_command(sed_cmd, line);
573 /* we also print the line if we were given the 'p' flag
574 * (this is quite possibly the second printing) */
576 altered = do_subst_command(sed_cmd, line);
582 fputs(sed_cmd->editline, stdout);
587 fputs(sed_cmd->editline, stdout);
591 fputs(sed_cmd->editline, stdout);
599 static void process_file(FILE *file)
602 static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
603 unsigned int still_in_range = 0;
607 /* go through every line in the file */
608 while ((line = get_line_from_file(file)) != NULL) {
613 /* for every line, go through all the commands */
614 for (i = 0; i < ncmds; i++) {
616 /* are we acting on a range of matched lines? */
617 if (sed_cmds[i].beg_match && sed_cmds[i].end_match) {
618 if (still_in_range || regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) {
619 line_altered += do_sed_command(&sed_cmds[i], line);
621 if (regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0)
626 /* are we trying to match a single line? */
627 else if (sed_cmds[i].beg_match) {
628 if (regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0)
629 line_altered += do_sed_command(&sed_cmds[i], line);
632 /* are we acting on a range of line numbers? */
633 else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line != 0) {
634 if (linenum >= sed_cmds[i].beg_line &&
635 (sed_cmds[i].end_line == -1 || linenum <= sed_cmds[i].end_line))
636 line_altered += do_sed_command(&sed_cmds[i], line);
639 /* are we acting on a specified line number */
640 else if (sed_cmds[i].beg_line > 0) {
641 if (linenum == sed_cmds[i].beg_line)
642 line_altered += do_sed_command(&sed_cmds[i], line);
645 /* not acting on matches or line numbers. act on every line */
647 line_altered += do_sed_command(&sed_cmds[i], line);
651 /* we will print the line unless we were told to be quiet or if the
652 * line was altered (via a 'd'elete or 's'ubstitution), in which case
653 * the altered line was already printed */
654 if (!be_quiet && !line_altered)
661 extern int sed_main(int argc, char **argv)
665 #ifdef BB_FEATURE_CLEAN_UP
666 /* destroy command strings on exit */
667 if (atexit(destroy_cmd_strs) == -1)
668 perror_msg_and_die("atexit");
671 /* do normal option parsing */
672 while ((opt = getopt(argc, argv, "hne:f:")) > 0) {
684 load_cmd_file(optarg);
689 /* if we didn't get a pattern from a -e and no command file was specified,
690 * argv[optind] should be the pattern. no pattern, no worky */
692 if (argv[optind] == NULL)
695 add_cmd_str(argv[optind]);
701 /* argv[(optind)..(argc-1)] should be names of file to process. If no
702 * files were specified or '-' was specified, take input from stdin.
703 * Otherwise, we process all the files specified. */
704 if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
710 for (i = optind; i < argc; i++) {
711 file = fopen(argv[i], "r");
713 perror_msg("%s", argv[i]);