Create rnet_message to encode messages.

rnet_message allows us to encode messages in the form used for
ReceitaNet, which is a kind of set of key/values.

diff --git a/rnet_message.c b/rnet_message.c
new file mode 100644 (file)
index 0000000..cd7cfa0
--- /dev/null
+++ b/rnet_message.c
@@ -0,0 +1,107 @@
+/*
+ *  Copyright (C) 2013  Thadeu Lima de Souza Cascardo <cascardo@minaslivre.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "rnet_message.h"
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <netdb.h>
+
+#ifndef MAX
+#define MAX(a,b) (a >= b) ? a : b
+#endif
+
+static int rnet_message_expand(struct rnet_message **message, size_t len)
+{
+       struct rnet_message *msg = *message;
+       struct rnet_message *nmsg;
+       if (msg)
+               len += msg->alen;
+       nmsg = realloc(msg, sizeof(*msg) + len);
+       if (!nmsg)
+               return -1;
+       nmsg->alen = len;
+       if (!msg)
+               nmsg->len = 0;
+       *message = nmsg;
+       return 0;
+}
+
+struct rnet_message * rnet_message_new(void)
+{
+       struct rnet_message *msg = NULL;
+       int r;
+       r = rnet_message_expand(&msg, 1118);
+       if (r)
+               return NULL;
+       return msg;
+}
+
+void rnet_message_del(struct rnet_message *message)
+{
+       free(message);
+}
+
+static int add_field(struct rnet_message *msg, char *key, int klen, char *val, int vlen)
+{
+       int n = 0;
+       char *buffer;
+       if ((msg->alen - msg->len) < (klen + vlen + 3)) {
+               if (rnet_message_expand(&msg, MAX(msg->len, klen + vlen + 3)))
+                       return -ENOMEM;
+       }
+       buffer = msg->buffer + msg->len;
+       if (klen > 0x7f || klen < 0)
+               return -EINVAL;
+       if (vlen > 0x7fff || vlen < 0)
+               return -EINVAL;
+       buffer[0] = klen & 0x7f;
+       if (vlen > 0x7f)
+               buffer[0] |= 0x80;
+       buffer++;
+       n++;
+       memcpy(buffer, key, klen);
+       buffer += klen;
+       n += klen;
+       if (vlen > 0x7f) {
+               buffer[0] = (vlen >> 8) & 0x7f;
+               buffer[1] = vlen & 0xff;
+               buffer += 2;
+               n += 2;
+       } else {
+               buffer[0] = vlen & 0x7f;
+               buffer++;
+               n++;
+       }
+       memcpy(buffer, val, vlen);
+       n += vlen;
+       msg->len += n;
+       return n;
+}
+
+int rnet_message_add_u32(struct rnet_message *msg, char *key, uint32_t val)
+{
+       uint32_t nval = htonl(val);
+       return add_field(msg, key, strlen(key), (char *) &nval, sizeof(val));
+}
+
+int rnet_message_add_ascii(struct rnet_message *msg, char *key, char *val)
+{
+       return add_field(msg, key, strlen(key), val, strlen(val));
+}

diff --git a/rnet_message.h b/rnet_message.h
new file mode 100644 (file)
index 0000000..8348987
--- /dev/null
+++ b/rnet_message.h
@@ -0,0 +1,36 @@
+/*
+ *  Copyright (C) 2013  Thadeu Lima de Souza Cascardo <cascardo@minaslivre.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _RNET_MESSAGE_H
+#define _RNET_MESSAGE_H
+
+#include <stdint.h>
+
+struct rnet_message {
+       int len;
+       int alen;
+       char buffer[];
+};
+
+struct rnet_message * rnet_message_new(void);
+void rnet_message_del(struct rnet_message *message);
+
+int rnet_message_add_u32(struct rnet_message *msg, char *key, uint32_t val);
+int rnet_message_add_ascii(struct rnet_message *msg, char *key, char *val);
+
+#endif