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sed: fix zero chars match/replace

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function                                             old     new   delta
process_files                                       2099    2181     +82

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2012-06-04 14:44:47 +02:00
parent 21f620f6e5
commit 21f6fbf545
2 changed files with 50 additions and 24 deletions
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64
editors/sed.c
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@ -673,7 +673,7 @@ static void do_subst_w_backrefs(char *line, char *replace)
/* go through the replacement string */
for (i = 0; replace[i]; i++) {
/* if we find a backreference (\1, \2, etc.) print the backref'ed * text */
/* if we find a backreference (\1, \2, etc.) print the backref'ed text */
if (replace[i] == '\\') {
unsigned backref = replace[++i] - '0';
if (backref <= 9) {
@ -707,8 +707,10 @@ static void do_subst_w_backrefs(char *line, char *replace)
static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
{
char *line = *line_p;
int altered = 0;
unsigned match_count = 0;
bool altered = 0;
bool prev_match_empty = 1;
bool tried_at_eol = 0;
regex_t *current_regex;
current_regex = sed_cmd->sub_match;
@ -737,46 +739,64 @@ static int do_subst_command(sed_cmd_t *sed_cmd, char **line_p)
do {
int i;
/* Work around bug in glibc regexec, demonstrated by:
* echo " a.b" | busybox sed 's [^ .]* x g'
* The match_count check is so not to break
* echo "hi" | busybox sed 's/^/!/g'
*/
if (!G.regmatch[0].rm_so && !G.regmatch[0].rm_eo && match_count) {
pipe_putc(*line++);
goto next;
}
match_count++;
/* If we aren't interested in this match, output old line to
end of match and continue */
* end of match and continue */
if (sed_cmd->which_match
&& (sed_cmd->which_match != match_count)
) {
for (i = 0; i < G.regmatch[0].rm_eo; i++)
pipe_putc(*line++);
/* Null match? Print one more char */
if (G.regmatch[0].rm_so == i && *line)
pipe_putc(*line++);
goto next;
}
/* print everything before the match */
/* Print everything before the match */
for (i = 0; i < G.regmatch[0].rm_so; i++)
pipe_putc(line[i]);
/* then print the substitution string */
do_subst_w_backrefs(line, sed_cmd->string);
/* Then print the substitution string,
* unless we just matched empty string after non-empty one.
* Example: string "cccd", pattern "c*", repl "R":
* result is "RdR", not "RRdR": first match "ccc",
* second is "" before "d", third is "" after "d".
* Second match is NOT replaced!
*/
if (prev_match_empty || i != 0) {
dbg("inserting replacement at %d in '%s'", i, line);
do_subst_w_backrefs(line, sed_cmd->string);
} else {
dbg("NOT inserting replacement at %d in '%s'", i, line);
}
/* advance past the match */
/* If matched string is empty (f.e. "c*" pattern),
* copy verbatim one char after it before attempting more matches
*/
prev_match_empty = (G.regmatch[0].rm_eo == i);
if (prev_match_empty && line[i]) {
pipe_putc(line[i]);
G.regmatch[0].rm_eo++;
}
/* Advance past the match */
dbg("line += %d", G.regmatch[0].rm_eo);
line += G.regmatch[0].rm_eo;
/* flag that something has changed */
altered++;
/* Flag that something has changed */
altered = 1;
/* if we're not doing this globally, get out now */
if (sed_cmd->which_match != 0)
break;
next:
if (*line == '\0')
break;
/* Exit if we are at EOL and already tried matching at it */
if (*line == '\0') {
if (tried_at_eol)
break;
tried_at_eol = 1;
}
//maybe (G.regmatch[0].rm_eo ? REG_NOTBOL : 0) instead of unconditional REG_NOTBOL?
} while (regexec(current_regex, line, 10, G.regmatch, REG_NOTBOL) != REG_NOMATCH);
@ -1127,7 +1147,7 @@ static void process_files(void)
case 's':
if (!do_subst_command(sed_cmd, &pattern_space))
break;
dbg("do_subst_command succeeeded:'%s'", pattern_space);
dbg("do_subst_command succeeded:'%s'", pattern_space);
substituted |= 1;
/* handle p option */