[PATCH v6 2/7] grep.c: expose matched column in match_line()

[Taylor Blau]

When calling match_line(), callers presently cannot determine the
relative offset of the match because match_line() discards the
'regmatch_t' that contains this information.

Instead, teach match_line() to take in a 'regmatch_t *' so that callers
can inspect the match's starting and ending offset from the beginning of
the line. This additional argument has no effect when opt->extended is
non-zero.

We will later pass the starting offset from 'regmatch_t *' to
show_line() in order to display the column number of the first match.

Signed-off-by: Taylor Blau <m...@ttaylorr.com>
---
 grep.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/grep.c b/grep.c
index 65b90c10a3..1c25782355 100644
--- a/grep.c
+++ b/grep.c
@@ -1299,17 +1299,17 @@ static int match_expr(struct grep_opt *opt, char *bol, 
char *eol,
 }
 
 static int match_line(struct grep_opt *opt, char *bol, char *eol,
-                     enum grep_context ctx, int collect_hits)
+                     regmatch_t *match, enum grep_context ctx,
+                     int collect_hits)
 {
        struct grep_pat *p;
-       regmatch_t match;
 
        if (opt->extended)
                return match_expr(opt, bol, eol, ctx, collect_hits);
 
        /* we do not call with collect_hits without being extended */
        for (p = opt->pattern_list; p; p = p->next) {
-               if (match_one_pattern(p, bol, eol, ctx, &match, 0))
+               if (match_one_pattern(p, bol, eol, ctx, match, 0))
                        return 1;
        }
        return 0;
@@ -1699,6 +1699,7 @@ static int grep_source_1(struct grep_opt *opt, struct 
grep_source *gs, int colle
        int try_lookahead = 0;
        int show_function = 0;
        struct userdiff_driver *textconv = NULL;
+       regmatch_t match;
        enum grep_context ctx = GREP_CONTEXT_HEAD;
        xdemitconf_t xecfg;
 
@@ -1788,7 +1789,7 @@ static int grep_source_1(struct grep_opt *opt, struct 
grep_source *gs, int colle
                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
                        ctx = GREP_CONTEXT_BODY;
 
-               hit = match_line(opt, bol, eol, ctx, collect_hits);
+               hit = match_line(opt, bol, eol, &match, ctx, collect_hits);
                *eol = ch;
 
                if (collect_hits)
-- 
2.17.0