fix: bad ruler substitution

[N-R-K]

Closes: #22

---

Some before and after:

$ printf "- - -\ntest\n- - -\n" | ./smu-1.5             
<hr />
test
<hr />
$ printf "- - -\ntest\n- - -\n" | ./smu-master 
<hr />

test
<hr />
-
$ printf "- - -\ntest\n- - -\n" | ./smu-fixed 
<hr />
test
<hr />

Note that certain cases, for example - - - without any blank lines before, are still kinda broken:

$ printf "- - -\n\ntest\n- - -\n" | ./smu-1.5
<hr />

test
<hr />
$ printf "- - -\n\ntest\n- - -\n" | ./smu-master
<hr />
<p>test
<hr />
-</p>
$ printf "- - -\n\ntest\n- - -\n" | ./smu-fixed
<hr />
<p>test
<hr />
</p>

Reverting 7228740 is probably a viable fix as well.

[N-R-K]

@karlb giving a ping, since you were the author of 7228740 and the issue persists on your fork as well.

[karlb]

Thanks, I can reproduce the problem. However, I think the real source of the problem is
https://github.com/Gottox/smu/blob/master/smu.c#L195-L196
where we consume one character without increasing the number of consumed characters returned by dolineprefix.

The following quick hack fixes the problem without breaking any of my tests:

--- a/smu.c
+++ b/smu.c
@@ -226,12 +226,14 @@ dolineprefix(const char *begin, const char *end, int newblock) {
        unsigned int i, j, l;
        char *buffer;
        const char *p;
+       int foo = 0;
 
        if (newblock)
                p = begin;
-       else if (*begin == '\n')
+       else if (*begin == '\n') {
                p = begin + 1;
-       else
+               foo = 1;
+       } else
                return 0;
        for (i = 0; i < LENGTH(lineprefix); i++) {
                l = strlen(lineprefix[i].search);
@@ -244,7 +246,7 @@ dolineprefix(const char *begin, const char *end, int newblock) {
                fputs(lineprefix[i].before, stdout);
                if (lineprefix[i].search[l-1] == '\n') {
                        fputc('\n', stdout);
-                       return l - 1;
+                       return l - 1 + foo;
                }
                if (!(buffer = malloc(BUFSIZ)))
                        eprint("Malloc failed.");

[N-R-K]

Your proposed patch works in my test scenarios as well. Note that the following case is still sorta broken, but I think that's probably a separate issue:

$ printf "- - -\n\ntest\n- - -\n" | ./smu-1.5
<hr />

test
<hr />
$ printf "- - -\n\ntest\n- - -\n" | ./smu-karlb-patch
<hr />
<p>test
<hr />
</p>