hush/sed.c

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1999-10-28 16:06:25 +00:00
/*
* sed.c - very minimalist version of sed
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*
* Copyright (C) 1999,2000 by Lineo, inc.
* Written by Mark Whitley <markw@lineo.com>, <markw@enol.com>
*
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* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*
Supported features and commands in this version of sed:
- comments ('#')
- Address matching: num|/matchstr/[,num|/matchstr/|$]command
- Commands: p, d, s/match/replace/[g]
(Note: Specifying an address (range) to match is *optional*; commands
default to the whole pattern space if no specific address match was
requested.)
Unsupported features:
- transliteration (y/source-chars/dest-chars/) (use 'tr')
- no support for characters other than the '/' character for regex matches
- no pattern space hold space storing / swapping (x, etc.)
- no labels / branching (: label, b, t, and friends)
- and lots, lots more.
*/
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#include <stdio.h>
#include <stdlib.h> /* for realloc() */
#include <unistd.h> /* for getopt() */
#include <regex.h>
#include <string.h> /* for strdup() */
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#include <errno.h>
#include <ctype.h> /* for isspace() */
#include "internal.h"
/* externs */
extern int optind; /* in unistd.h */
extern char *optarg; /* ditto */
/* options */
static int be_quiet = 0;
struct sed_cmd {
/* address storage */
int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */
int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
regex_t *beg_match; /* sed -e '/match/cmd' */
regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
/* the command */
char cmd; /* p,d,s (add more at your leisure :-) */
/* substitution command specific fields */
regex_t *sub_match; /* sed -e 's/sub_match/replace/' */
char *replace; /* sed -e 's/sub_match/replace/' XXX: who will hold the \1 \2 \3s? */
unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
};
/* globals */
static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
static int ncmds = 0; /* number of sed commands */
/*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
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static const char sed_usage[] =
"sed [-Vhnef] pattern [files...]\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
"\n"
"-n\tsuppress automatic printing of pattern space\n"
"-e script\tadd the script to the commands to be executed\n"
"-f scriptfile\tadd the contents of script-file to the commands to be executed\n"
"-h\tdisplay this help message\n"
"-V\toutput version information and exit\n"
"\n"
"If no -e or -f is given, the first non-option argument is taken as the\n"
"sed script to interpret. All remaining arguments are names of input\n"
"files; if no input files are specified, then the standard input is read.\n"
#endif
;
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static void destroy_cmd_strs()
{
if (sed_cmds == NULL)
return;
/* destroy all the elements in the array */
while (--ncmds >= 0) {
if (sed_cmds[ncmds].beg_match) {
regfree(sed_cmds[ncmds].beg_match);
free(sed_cmds[ncmds].beg_match);
}
if (sed_cmds[ncmds].end_match) {
regfree(sed_cmds[ncmds].end_match);
free(sed_cmds[ncmds].end_match);
}
if (sed_cmds[ncmds].sub_match) {
regfree(sed_cmds[ncmds].sub_match);
free(sed_cmds[ncmds].sub_match);
}
if (sed_cmds[ncmds].replace)
free(sed_cmds[ncmds].replace);
}
/* destroy the array */
free(sed_cmds);
sed_cmds = NULL;
}
static void exit_sed(int retcode, const char *message)
{
destroy_cmd_strs();
if (message)
fputs(message, stderr);
exit(retcode);
}
/*
* trim_str - trims leading and trailing space from a string
*
* Note: This returns a malloc'ed string so you must store and free it
* XXX: This should be in the utility.c file.
*/
static char *trim_str(const char *str)
{
int i;
char *retstr = strdup(str);
/* trim leading whitespace */
memmove(retstr, &retstr[strspn(retstr, " \n\t\v")], strlen(retstr));
/* trim trailing whitespace */
i = strlen(retstr) - 1;
while (isspace(retstr[i]))
i--;
retstr[++i] = 0;
/* Aside:
*
* you know, a strrspn() would really be nice cuz then we could say:
*
* retstr[strlen(retstr) - strrspn(retstr, " \n\t\v") + 1] = 0;
*/
return retstr;
}
/*
* index_of_unescaped_slash - walks left to right through a string beginning
* at a specified index and returns the index of the next unescaped slash.
*/
static int index_of_next_unescaped_slash(int idx, const char *str)
{
do {
idx++;
/* test if we've hit the end */
if (str[idx] == 0)
return -1;
} while (str[idx] != '/' && str[idx - 1] != '\\');
return idx;
}
/*
* returns the index in the string just past where the address ends.
*/
static int get_address(const char *str, int *line, regex_t **regex)
{
char *my_str = strdup(str);
int idx = 0;
if (isdigit(my_str[idx])) {
do {
idx++;
} while (isdigit(my_str[idx]));
my_str[idx] = 0;
*line = atoi(my_str);
*regex = NULL;
}
else if (my_str[idx] == '$') {
*line = -1;
*regex = NULL;
idx++;
}
else if (my_str[idx] == '/') {
idx = index_of_next_unescaped_slash(idx, my_str);
if (idx == -1)
exit_sed(1, "sed: unterminated match expression\n");
my_str[idx] = '\0';
*regex = (regex_t *)xmalloc(sizeof(regex_t));
if (bb_regcomp(*regex, my_str+1, REG_NEWLINE) != 0) {
free(my_str);
exit_sed(1, NULL);
}
}
else {
fprintf(stderr, "sed.c:get_address: no address found in string\n");
fprintf(stderr, "\t(you probably didn't check the string you passed me)\n");
idx = -1;
}
free(my_str);
return idx;
}
static char *strdup_substr(const char *str, int start, int end)
{
int size = end - start + 1;
char *newstr = xmalloc(size);
memcpy(newstr, str+start, size-1);
newstr[size-1] = '\0';
return newstr;
}
static void parse_cmd_str(struct sed_cmd *sed_cmd, const char *cmdstr)
{
int idx = 0;
/* parse the command
* format is: [addr][,addr]cmd
* |----||-----||-|
* part1 part2 part3
*/
/* first part (if present) is an address: either a number or a /regex/ */
if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/')
idx = get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
/* second part (if present) will begin with a comma */
if (cmdstr[idx] == ',')
idx += get_address(&cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
/* last part (mandatory) will be a command */
if (cmdstr[idx] == '\0')
exit_sed(1, "sed: missing command\n");
if (!strchr("pds", cmdstr[idx])) /* <-- XXX add new commands here */
exit_sed(1, "sed: invalid command\n");
sed_cmd->cmd = cmdstr[idx];
/* special-case handling for 's' */
if (sed_cmd->cmd == 's') {
int oldidx, cflags = REG_NEWLINE;
char *match;
/* format for substitution is:
* s/match/replace/gI
* | ||
* mandatory optional
*/
/* verify that we have an 's' followed by a 'slash' */
if (cmdstr[++idx] != '/')
exit_sed(1, "sed: bad format in substitution expression\n");
/* save the match string */
oldidx = idx+1;
idx = index_of_next_unescaped_slash(idx, cmdstr);
if (idx == -1)
exit_sed(1, "sed: bad format in substitution expression\n");
match = strdup_substr(cmdstr, oldidx, idx);
/* save the replacement string */
oldidx = idx+1;
idx = index_of_next_unescaped_slash(idx, cmdstr);
if (idx == -1)
exit_sed(1, "sed: bad format in substitution expression\n");
sed_cmd->replace = strdup_substr(cmdstr, oldidx, idx);
/* process the flags */
while (cmdstr[++idx]) {
switch (cmdstr[idx]) {
case 'g':
sed_cmd->sub_g = 1;
break;
case 'I':
cflags |= REG_ICASE;
break;
default:
exit_sed(1, "sed: bad option in substitution expression\n");
}
}
/* compile the regex */
sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
if (bb_regcomp(sed_cmd->sub_match, match, cflags) != 0) {
free(match);
exit_sed(1, NULL);
}
free(match);
}
}
static void add_cmd_str(const char *cmdstr)
{
char *my_cmdstr = trim_str(cmdstr);
/* if this is a comment, don't even bother */
if (my_cmdstr[0] == '#') {
free(my_cmdstr);
return;
}
/* grow the array */
sed_cmds = realloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds));
/* zero new element */
memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd));
/* load command string into new array element */
parse_cmd_str(&sed_cmds[ncmds-1], my_cmdstr);
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}
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static void load_cmd_file(char *filename)
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{
FILE *cmdfile;
char *line;
cmdfile = fopen(filename, "r");
if (cmdfile == NULL)
exit_sed(1, strerror(errno));
while ((line = get_line_from_file(cmdfile)) != NULL) {
line[strlen(line)-1] = 0; /* eat newline */
add_cmd_str(line);
free(line);
}
}
static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
{
int altered = 0;
switch (sed_cmd->cmd) {
case 'p':
fputs(line, stdout);
break;
case 'd':
altered++;
break;
case 's': /* oo, a fun one :-) */
/* we only substitute if the substitution 'search' expression matches */
if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == 0) {
regmatch_t regmatch;
int i;
char *ptr = (char *)line;
while (*ptr) {
/* if we can match the search string... */
if (regexec(sed_cmd->sub_match, ptr, 1, &regmatch, 0) == 0) {
/* print everything before the match, */
for (i = 0; i < regmatch.rm_so; i++)
fputc(ptr[i], stdout);
/* then print the substitution in its place */
fputs(sed_cmd->replace, stdout);
/* then advance past the match */
ptr += regmatch.rm_eo;
/* and let the calling function know that something
* has been changed */
altered++;
/* if we're not doing this globally... */
if (!sed_cmd->sub_g)
break;
}
/* if we COULD NOT match the search string (meaning we've gone past
* all previous instances), get out */
else
break;
}
/* is there anything left to print? */
if (*ptr)
fputs(ptr, stdout);
}
break;
}
return altered;
}
static void process_file(FILE *file)
{
char *line = NULL;
static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
unsigned int still_in_range = 0;
int line_altered;
int i;
/* go through every line in the file */
while ((line = get_line_from_file(file)) != NULL) {
linenum++;
line_altered = 0;
/* for every line, go through all the commands */
for (i = 0; i < ncmds; i++) {
/* are we acting on a range of matched lines? */
if (sed_cmds[i].beg_match && sed_cmds[i].end_match) {
if (still_in_range || regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) {
line_altered += do_sed_command(&sed_cmds[i], line);
still_in_range = 1;
if (regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0)
still_in_range = 0;
}
}
/* are we trying to match a single line? */
else if (sed_cmds[i].beg_match) {
if (regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0)
line_altered += do_sed_command(&sed_cmds[i], line);
}
/* are we acting on a range of line numbers? */
else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line > 0) {
if (linenum >= sed_cmds[i].beg_line && linenum <= sed_cmds[i].end_line)
line_altered += do_sed_command(&sed_cmds[i], line);
}
/* are we acting on a specified line number */
else if (sed_cmds[i].beg_line > 0) {
if (linenum == sed_cmds[i].beg_line)
line_altered += do_sed_command(&sed_cmds[i], line);
}
/* not acting on matches or line numbers. act on every line */
else
line_altered += do_sed_command(&sed_cmds[i], line);
}
/* we will print the line unless we were told to be quiet or if the
* line was altered (via a 'd'elete or 's'ubstitution) */
if (!be_quiet && !line_altered)
fputs(line, stdout);
free(line);
}
}
extern int sed_main(int argc, char **argv)
{
int opt;
/* do special-case option parsing */
if (argv[1] && (strcmp(argv[1], "--help") == 0))
usage(sed_usage);
/* do normal option parsing */
while ((opt = getopt(argc, argv, "Vhne:f:")) > 0) {
switch (opt) {
case 'V':
printf("Print Busybox version here\n");
exit(0);
break;
case 'h':
usage(sed_usage);
break;
case 'n':
be_quiet++;
break;
case 'e':
add_cmd_str(optarg);
break;
case 'f':
load_cmd_file(optarg);
break;
}
}
/* if we didn't get a pattern from a -e and no command file was specified,
* argv[optind] should be the pattern. no pattern, no worky */
if (ncmds == 0) {
if (argv[optind] == NULL)
usage(sed_usage);
else {
add_cmd_str(argv[optind]);
optind++;
}
}
/* argv[(optind)..(argc-1)] should be names of file to process. If no
* files were specified or '-' was specified, take input from stdin.
* Otherwise, we process all the files specified. */
if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
process_file(stdin);
}
else {
int i;
FILE *file;
for (i = optind; i < argc; i++) {
file = fopen(argv[i], "r");
if (file == NULL) {
fprintf(stderr, "sed: %s: %s\n", argv[i], strerror(errno));
} else {
process_file(file);
fclose(file);
}
}
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}
exit_sed(0, NULL);
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/* not reached */
return 0;
}