util: pull Buffer code out of VNC module

The Buffer code in the VNC server is useful for the IO channel
code, so pull it out into a shared module, QIOBuffer.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

2 files changed, 66 insertions, 0 deletions

diff --git a/util/Makefile.objs b/util/Makefile.objs
index d8d7e7a..1363d1f 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -21,3 +21,4 @@ util-obj-y += rcu.o
 util-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
 util-obj-y += qemu-coroutine-sleep.o
 util-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
+util-obj-y += buffer.o
diff --git a/util/buffer.c b/util/buffer.c
new file mode 100644
index 0000000..cedd055
--- /dev/null
+++ b/util/buffer.c
@@ -0,0 +1,65 @@
+/*
+ * QEMU generic buffers
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/buffer.h"
+
+void buffer_reserve(Buffer *buffer, size_t len)
+{
+    if ((buffer->capacity - buffer->offset) < len) {
+        buffer->capacity += (len + 1024);
+        buffer->buffer = g_realloc(buffer->buffer, buffer->capacity);
+    }
+}
+
+gboolean buffer_empty(Buffer *buffer)
+{
+    return buffer->offset == 0;
+}
+
+uint8_t *buffer_end(Buffer *buffer)
+{
+    return buffer->buffer + buffer->offset;
+}
+
+void buffer_reset(Buffer *buffer)
+{
+    buffer->offset = 0;
+}
+
+void buffer_free(Buffer *buffer)
+{
+    g_free(buffer->buffer);
+    buffer->offset = 0;
+    buffer->capacity = 0;
+    buffer->buffer = NULL;
+}
+
+void buffer_append(Buffer *buffer, const void *data, size_t len)
+{
+    memcpy(buffer->buffer + buffer->offset, data, len);
+    buffer->offset += len;
+}
+
+void buffer_advance(Buffer *buffer, size_t len)
+{
+    memmove(buffer->buffer, buffer->buffer + len,
+            (buffer->offset - len));
+    buffer->offset -= len;
+}