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authorGravatar Denys Vlasenko <vda.linux@googlemail.com>2012-06-04 14:44:47 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2012-06-04 14:44:47 +0200
commit21f6fbf545e7fa58f0eaa444001a9d25bc37c4eb (patch)
tree17be754928b225ce5412faf1cbe613189fee14cd /editors/sed.c
parent21f620f6e5f72c4cbecfecaf63a901c33911c00c (diff)
downloadbusybox-21f6fbf545e7fa58f0eaa444001a9d25bc37c4eb.tar.gz
busybox-21f6fbf545e7fa58f0eaa444001a9d25bc37c4eb.tar.bz2
sed: fix zero chars match/replace
function old new delta process_files 2099 2181 +82 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'editors/sed.c')
-rw-r--r--editors/sed.c64
1 files changed, 42 insertions, 22 deletions
diff --git a/editors/sed.c b/editors/sed.c
index a2df93165..87fc755eb 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -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);
+ }
+
+ /* 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 */
+ /* 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 */