start on message.c

lib/dns/message.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 1999  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+/***
+ *** Imports
+ ***/
+
+#include <config.h>
+
+#include <stddef.h>
+#include <string.h>
+
+#include <isc/assertions.h>
+
+#include <dns/message.h>
+#include <dns/rdataset.h>
+
+#define MESSAGE_MAGIC		0x4d534740U	/* MSG@ */
+#define VALID_MESSAGE_MAGIC(magic)  ((magic) == MESSAGE_MAGIC)
+
+static inline void
+dns_msgblock_free(isc_mem_t *, dns_msgblock_t *);
+#define dns_msgblock_get(block, type) \
+	((type *)dns_msgblock__get(block, sizeof(type)))
+
+static inline void *
+dns_msgblock__get(dns_msgblock_t *, unsigned int);
+
+static inline dns_msgblock_t *
+dns_msgblock_allocate(isc_mem_t *, unsigned int, unsigned int);
+
+/*
+ * Allocate a new dns_msgblock_t, and return a pointer to it.  If no memory
+ * is free, return NULL.
+ */
+static inline dns_msgblock_t *
+dns_msgblock_allocate(isc_mem_t *mctx, unsigned int sizeof_type,
+		      unsigned int count)
+{
+	dns_msgblock_t *block;
+	unsigned int length;
+
+	length = sizeof(dns_msgblock_t) + (sizeof_type * count);
+
+	block = isc_mem_get(mctx, length);
+	if (block == NULL)
+		return NULL;
+
+	block->length = length;
+	block->remaining = count;
+
+	ISC_LINK_INIT(block, link);
+
+	return (block);
+}
+
+/*
+ * Return an element from the msgblock.  If no more are available, return
+ * NULL.
+ */
+static inline void *
+dns_msgblock__get(dns_msgblock_t *block, unsigned int sizeof_type)
+{
+	void *ptr;
+
+	if (block->remaining == 0)
+		return (NULL);
+
+	block->remaining--;
+
+	ptr = (((unsigned char *)block)
+	       + sizeof(dns_msgblock_t)
+	       + (sizeof_type * block->remaining));
+
+	return (ptr);
+}
+
+/*
+ * Release memory associated with a message block.
+ */
+static inline void
+dns_msgblock_free(isc_mem_t *mctx, dns_msgblock_t *block)
+{
+	isc_mem_put(mctx, block, block->length);
+}