Add generic buffer code

Represents a block of memory that can be added to, parsed and so on

1 files changed, 180 insertions, 0 deletions

diff --git a/common/buffer.c b/common/buffer.c
new file mode 100644
index 0000000..a91623e
--- /dev/null
+++ b/common/buffer.c
@@ -0,0 +1,180 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+/* buffer.c - Generic data buffer, used by openssh, gnome-keyring
+
+   Copyright (C) 2007, 2012 Stefan Walter
+   Copyright (C) 2013 Red Hat Inc.
+
+   The Gnome Keyring Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The Gnome Keyring Library 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the Gnome Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   Author: Stef Walter <stef@thewalter.net>
+*/
+
+#include "config.h"
+
+#include "buffer.h"
+#include "debug.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
+static bool
+buffer_realloc (p11_buffer *buffer,
+                size_t size)
+{
+	void *data;
+
+	/* Memory owned elsewhere can't be reallocated */
+	return_val_if_fail (buffer->frealloc != NULL, false);
+
+	/* Reallocate built in buffer using allocator */
+	data = (buffer->frealloc) (buffer->data, size);
+	if (!data && size > 0) {
+		p11_buffer_fail (buffer);
+		return_val_if_reached (false);
+	}
+
+	buffer->data = data;
+	buffer->size = size;
+	return true;
+}
+
+bool
+p11_buffer_init (p11_buffer *buffer,
+                 size_t reserve)
+{
+	p11_buffer_init_full (buffer, NULL, 0, 0, realloc, free);
+	return buffer_realloc (buffer, reserve);
+}
+
+bool
+p11_buffer_init_null (p11_buffer *buffer,
+                      size_t reserve)
+{
+	p11_buffer_init_full (buffer, NULL, 0, P11_BUFFER_NULL, realloc, free);
+	return buffer_realloc (buffer, reserve);
+}
+
+void
+p11_buffer_init_full (p11_buffer *buffer,
+                      void *data,
+                      size_t len,
+                      int flags,
+                      void * (* frealloc) (void *, size_t),
+                      void (* ffree) (void *))
+{
+	memset (buffer, 0, sizeof (*buffer));
+
+	buffer->data = data;
+	buffer->len = len;
+	buffer->size = len;
+	buffer->flags = flags;
+	buffer->frealloc = frealloc;
+	buffer->ffree = ffree;
+
+	return_if_fail (!(flags & P11_BUFFER_FAILED));
+}
+
+void
+p11_buffer_uninit (p11_buffer *buffer)
+{
+	return_if_fail (buffer != NULL);
+
+	if (buffer->ffree && buffer->data)
+		(buffer->ffree) (buffer->data);
+	memset (buffer, 0, sizeof (*buffer));
+}
+
+void *
+p11_buffer_steal (p11_buffer *buffer,
+                  size_t *length)
+{
+	void *data;
+
+	return_val_if_fail (p11_buffer_ok (buffer), NULL);
+
+	if (length)
+		*length = buffer->len;
+	data = buffer->data;
+
+	buffer->data = NULL;
+	buffer->size = 0;
+	buffer->len = 0;
+	return data;
+}
+
+bool
+p11_buffer_reset (p11_buffer *buffer,
+                  size_t reserve)
+{
+	buffer->flags &= ~P11_BUFFER_FAILED;
+	buffer->len = 0;
+
+	if (reserve < buffer->size)
+		return true;
+	return buffer_realloc (buffer, reserve);
+}
+
+void *
+p11_buffer_append (p11_buffer *buffer,
+                   size_t length)
+{
+	unsigned char *data;
+	size_t terminator;
+	size_t newlen;
+	size_t reserve;
+
+	return_val_if_fail (p11_buffer_ok (buffer), NULL);
+
+	terminator = (buffer->flags & P11_BUFFER_NULL) ? 1 : 0;
+	reserve = terminator + length + buffer->len;
+
+	if (reserve > buffer->size) {
+
+		/* Calculate a new length, minimize number of buffer allocations */
+		newlen = buffer->size * 2;
+		if (!newlen)
+			newlen = 16;
+		if (reserve > newlen)
+			newlen = reserve;
+
+		if (!buffer_realloc (buffer, newlen))
+			return_val_if_reached (NULL);
+	}
+
+	data = buffer->data;
+	data += buffer->len;
+	buffer->len += length;
+	if (terminator)
+		data[length] = '\0';
+	return data;
+}
+
+void
+p11_buffer_add (p11_buffer *buffer,
+                const void *data,
+                ssize_t length)
+{
+	void *at;
+
+	if (length < 0)
+		length = strlen (data);
+
+	at = p11_buffer_append (buffer, length);
+	return_if_fail (at != NULL);
+	memcpy (at, data, length);
+}