static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
{
struct grep_pat *p;
struct grep_expr *header_expr;
struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
enum grep_header_field fld;
if (!opt->header_list)
return NULL;
for (p = opt->header_list; p; p = p->next) {
if (p->token != GREP_PATTERN_HEAD)
die("bug: a non-header pattern in grep header list.");
if (p->field < GREP_HEADER_FIELD_MIN ||
GREP_HEADER_FIELD_MAX <= p->field)
die("bug: unknown header field %d", p->field);
compile_regexp(p, opt);
}
for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
header_group[fld] = NULL;
for (p = opt->header_list; p; p = p->next) {
struct grep_expr *h;
struct grep_pat *pp = p;
h = compile_pattern_atom(&pp);
if (!h || pp != p->next)
die("bug: malformed header expr");
if (!header_group[p->field]) {
header_group[p->field] = h;
continue;
}
header_group[p->field] = grep_or_expr(h, header_group[p->field]);
}
header_expr = NULL;
for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
if (!header_group[fld])
continue;
if (!header_expr)
header_expr = grep_true_expr();
header_expr = grep_or_expr(header_group[fld], header_expr);
}
return header_expr;
}
static struct grep_expr *compile_pattern_not(struct grep_pat **list)
{
struct grep_pat *p;
struct grep_expr *x;
p = *list;
switch (p->token) {
case GREP_NOT:
if (!p->next)
die("--not not followed by pattern expression");
*list = p->next;
x = xcalloc(1, sizeof (struct grep_expr));
x->node = GREP_NODE_NOT;
x->u.unary = compile_pattern_not(list);
if (!x->u.unary)
die("--not followed by non pattern expression");
return x;
default:
return compile_pattern_atom(list);
}
}