Fix a problem with unsatisfied backrefs (noted by Martin Bene).

2 files changed, 12 insertions, 8 deletions

diff --git a/editors/sed.c b/editors/sed.c
index a18cfc7c3..352c5c94f 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -490,7 +490,7 @@ static void load_cmd_file(char *filename)
         }
 }
 
-static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch)
+static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch, int matches)
 {
         int i;
 
@@ -506,8 +506,9 @@ static void print_subst_w_backrefs(const char *line, const char *replace, regmat
                         tmpstr[1] = 0;
                         backref = atoi(tmpstr);
                         /* print out the text held in regmatch[backref] */
-                        for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
-                                fputc(line[j], stdout);
+                        if (backref <= matches && regmatch[backref].rm_so != -1)
+                                for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
+                                        fputc(line[j], stdout);
                 }
 
                 /* if we find a backslash escaped character, print the character */
@@ -555,7 +556,8 @@ static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
                         fputc(hackline[i], stdout);
 
                 /* then print the substitution string */
-                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
+                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch,
+                                sed_cmd->num_backrefs);
 
                 /* advance past the match */
                 hackline += regmatch[0].rm_eo;
diff --git a/sed.c b/sed.c
index a18cfc7c3..352c5c94f 100644
--- a/sed.c
+++ b/sed.c
@@ -490,7 +490,7 @@ static void load_cmd_file(char *filename)
         }
 }
 
-static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch)
+static void print_subst_w_backrefs(const char *line, const char *replace, regmatch_t *regmatch, int matches)
 {
         int i;
 
@@ -506,8 +506,9 @@ static void print_subst_w_backrefs(const char *line, const char *replace, regmat
                         tmpstr[1] = 0;
                         backref = atoi(tmpstr);
                         /* print out the text held in regmatch[backref] */
-                        for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
-                                fputc(line[j], stdout);
+                        if (backref <= matches && regmatch[backref].rm_so != -1)
+                                for (j = regmatch[backref].rm_so; j < regmatch[backref].rm_eo; j++)
+                                        fputc(line[j], stdout);
                 }
 
                 /* if we find a backslash escaped character, print the character */
@@ -555,7 +556,8 @@ static int do_subst_command(const struct sed_cmd *sed_cmd, const char *line)
                         fputc(hackline[i], stdout);
 
                 /* then print the substitution string */
-                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch);
+                print_subst_w_backrefs(hackline, sed_cmd->replace, regmatch,
+                                sed_cmd->num_backrefs);
 
                 /* advance past the match */
                 hackline += regmatch[0].rm_eo;