Function show_pre_context

grep.c:1378–1439

static int is_empty_line(const char *bol, const char *eol);

static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
			     const char *bol, const char *end, unsigned lno)
{
	unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
	int funcname_needed = !!opt->funcname, comment_needed = 0;

	if (opt->pre_context < lno)
		from = lno - opt->pre_context;
	if (from <= opt->last_shown)
		from = opt->last_shown + 1;
	orig_from = from;
	if (opt->funcbody) {
		if (match_funcname(opt, gs, bol, end))
			comment_needed = 1;
		else
			funcname_needed = 1;
		from = opt->last_shown + 1;
	}

	/* Rewind. */
	while (bol > gs->buf && cur > from) {
		const char *next_bol = bol;
		const char *eol = --bol;

		while (bol > gs->buf && bol[-1] != '\n')
			bol--;
		cur--;
		if (comment_needed && (is_empty_line(bol, eol) ||
				       match_funcname(opt, gs, bol, eol))) {
			comment_needed = 0;
			from = orig_from;
			if (cur < from) {
				cur++;
				bol = next_bol;
				break;
			}
		}
		if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
			funcname_lno = cur;
			funcname_needed = 0;
			if (opt->funcbody)
				comment_needed = 1;
			else
				from = orig_from;
		}
	}

	/* We need to look even further back to find a function signature. */
	if (opt->funcname && funcname_needed)
		show_funcname_line(opt, gs, bol, cur);

	/* Back forward. */
	while (cur < lno) {
		const char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';

		while (*eol != '\n')
			eol++;
		show_line(opt, bol, eol, gs->name, cur, 0, sign);