From 342e39eb61bf583d582938ceaad3949c9b0665f5 Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Tue, 15 Jan 2013 20:02:53 +0100
Subject: [PATCH] add helpers for easier token construction and access to
sequence elements
---
examples/dns.c | 154 +++++++++++++++++++++++++++++++------------------
1 file changed, 97 insertions(+), 57 deletions(-)
diff --git a/examples/dns.c b/examples/dns.c
index 6db8bf82..01442c80 100644
--- a/examples/dns.c
+++ b/examples/dns.c
@@ -11,9 +11,79 @@
#define false 0
#define true 1
+
+///
+// API Additions
+///
+
#define H_RULE(rule, def) const HParser *rule = def
#define H_ARULE(rule, def) const HParser *rule = h_action(def, act_ ## rule)
+// The action equivalent of h_ignore.
+const HParsedToken *act_ignore(const HParseResult *p)
+{
+ return NULL;
+}
+
+// Helper to build HAction's that pick one index out of a sequence.
+const HParsedToken *act_index(int i, const HParseResult *p)
+{
+ if(!p) return NULL;
+
+ const HParsedToken *tok = p->ast;
+
+ if(!tok || tok->token_type != TT_SEQUENCE)
+ return NULL;
+
+ const HCountedArray *seq = tok->seq;
+ size_t n = seq->used;
+
+ if(i<0 || (size_t)i>=n)
+ return NULL;
+ else
+ return tok->seq->elements[i];
+}
+
+const HParsedToken *act_index0(const HParseResult *p)
+{
+ return act_index(0, p);
+}
+
+HParsedToken *h_make_token(HArena *arena, HTokenType type, void *value) {
+ HParsedToken *ret = h_arena_malloc(arena, sizeof(HParsedToken));
+ ret->token_type = type;
+ ret->user = value;
+ return ret;
+}
+
+#define H_MAKE(TYP) \
+ ((TYP ## _t *) h_arena_malloc(p->arena, sizeof(TYP ## _t)))
+
+#define H_MAKE_TOKEN(TYP, VAL) \
+ h_make_token(p->arena, TT_ ## TYP, VAL)
+
+HParsedToken *h_carray_index(const HCountedArray *a, size_t i) {
+ assert(i < a->used);
+ return a->elements[i];
+}
+
+HParsedToken *h_seq_index(const HParsedToken *p, size_t i) {
+ assert(p->token_type == TT_SEQUENCE);
+ return h_carray_index(p->seq, i);
+}
+
+void *h_seq_index_user(HTokenType type, const HParsedToken *p, size_t i) {
+ HParsedToken *elem = h_seq_index(p, i);
+ assert(elem->token_type == (HTokenType)type);
+ return elem->user;
+}
+
+#define H_SEQ_INDEX(TYP, SEQ, IDX) \
+ ((TYP ## _t *) h_seq_index_user(TT_ ## TYP, SEQ, IDX))
+
+#define H_FIELD(TYP, IDX) \
+ H_SEQ_INDEX(TYP, p->ast, IDX)
+
bool is_zero(HParseResult *p) {
if (TT_UINT != p->ast->token_type)
@@ -21,6 +91,11 @@ bool is_zero(HParseResult *p) {
return (0 == p->ast->uint);
}
+
+///
+// Semantic Actions
+///
+
/**
* Every DNS message should have QDCOUNT entries in the question
* section, and ANCOUNT+NSCOUNT+ARCOUNT resource records.
@@ -268,10 +343,6 @@ void set_rr(struct dns_rr rr, HCountedArray *rdata) {
}
const HParsedToken* act_header(const HParseResult *p) {
- HParsedToken *ret = h_arena_malloc(p->arena, sizeof(HParsedToken));
- ret->token_type = TT_dns_header;
- ret->user = h_arena_malloc(p->arena, sizeof(dns_header_t));
-
HParsedToken **fields = p->ast->seq->elements;
dns_header_t header_ = {
.id = fields[0]->uint,
@@ -287,16 +358,15 @@ const HParsedToken* act_header(const HParseResult *p) {
.authority_count = fields[10]->uint,
.additional_count = fields[11]->uint
};
- *(dns_header_t *)ret->user = header_;
- return ret;
+ dns_header_t *header = H_MAKE(dns_header);
+ *header = header_;
+
+ return H_MAKE_TOKEN(dns_header, header);
}
const HParsedToken* act_label(const HParseResult *p) {
- HParsedToken *ret = h_arena_malloc(p->arena, sizeof(HParsedToken));
- ret->token_type = TT_dns_label;
- ret->user = h_arena_malloc(p->arena, sizeof(dns_label_t));
- dns_label_t *r = (dns_label_t *)ret->user;
+ dns_label_t *r = H_MAKE(dns_label);
r->len = p->ast->seq->used;
r->label = h_arena_malloc(p->arena, r->len + 1);
@@ -304,41 +374,31 @@ const HParsedToken* act_label(const HParseResult *p) {
r->label[i] = p->ast->seq->elements[i]->uint;
r->label[r->len] = 0;
- return ret;
+ return H_MAKE_TOKEN(dns_label, r);
}
const HParsedToken* act_question(const HParseResult *p) {
- HParsedToken *ret = h_arena_malloc(p->arena, sizeof(HParsedToken));
- ret->token_type = TT_dns_question;
- ret->user = h_arena_malloc(p->arena, sizeof(dns_question_t));
-
- dns_question_t *q = (dns_question_t *)ret->user;
+ dns_question_t *q = H_MAKE(dns_question);
HParsedToken **fields = p->ast->seq->elements;
// QNAME is a sequence of labels. Pack them into an array.
q->qname.qlen = fields[0]->seq->used;
q->qname.labels = h_arena_malloc(p->arena, sizeof(dns_label_t)*q->qname.qlen);
for(size_t i=0; i<fields[0]->seq->used; i++) {
- assert(fields[0]->seq->elements[i]->token_type == (HTokenType)TT_dns_label);
- q->qname.labels[i] = *(dns_label_t *)fields[0]->seq->elements[i]->user;
+ q->qname.labels[i] = *H_SEQ_INDEX(dns_label, fields[0], i);
}
q->qtype = fields[1]->uint;
q->qclass = fields[2]->uint;
- return ret;
+ return H_MAKE_TOKEN(dns_question, q);
}
const HParsedToken* act_message(const HParseResult *p) {
h_pprint(stdout, p->ast, 0, 2);
+ dns_message_t *msg = H_MAKE(dns_message);
- HParsedToken *ret = h_arena_malloc(p->arena, sizeof(HParsedToken));
- ret->token_type = TT_dns_message;
- ret->user = h_arena_malloc(p->arena, sizeof(dns_message_t));
- dns_message_t *msg = ret->user;
-
- assert(p->ast->seq->elements[0]->token_type == (HTokenType)TT_dns_header);
- dns_header_t *header = (dns_header_t *)p->ast->seq->elements[0]->user;
+ dns_header_t *header = H_FIELD(dns_header, 0);
msg->header = *header;
HParsedToken *qs = p->ast->seq->elements[1];
@@ -387,42 +447,17 @@ const HParsedToken* act_message(const HParseResult *p) {
}
msg->additional = additional;
- return ret;
-}
-
-// The action equivalent of h_ignore.
-const HParsedToken *act_ignore(const HParseResult *p)
-{
- return NULL;
-}
-
-// Helper to build HAction's that pick one index out of a sequence.
-const HParsedToken *act_index(int i, const HParseResult *p)
-{
- if(!p) return NULL;
-
- const HParsedToken *tok = p->ast;
-
- if(!tok || tok->token_type != TT_SEQUENCE)
- return NULL;
-
- const HCountedArray *seq = tok->seq;
- size_t n = seq->used;
-
- if(i<0 || (size_t)i>=n)
- return NULL;
- else
- return tok->seq->elements[i];
-}
-
-const HParsedToken *act_index0(const HParseResult *p)
-{
- return act_index(0, p);
+ return H_MAKE_TOKEN(dns_message, msg);
}
#define act_hdzero act_ignore
#define act_qname act_index0
+
+///
+// Parser / Grammar
+///
+
const HParser* init_parser() {
static const HParser *ret = NULL;
if (ret)
@@ -476,6 +511,11 @@ const HParser* init_parser() {
return ret;
}
+
+///
+// Program Logic for a Dummy DNS Server
+///
+
int start_listening() {
// return: fd
int sock;
--
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