From f8d53635e4aadb4ca5d2cc759590f6cefbe4ab30 Mon Sep 17 00:00:00 2001
From: Andri Yngvason <andri@yngvason.is>
Date: Sat, 25 Jan 2020 15:29:25 +0000
Subject: [PATCH] Create a reference counted buffer

---
 include/rcbuf.h | 32 ++++++++++++++++++++++
 meson.build     |  1 +
 src/rcbuf.c     | 71 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 include/rcbuf.h
 create mode 100644 src/rcbuf.c

diff --git a/include/rcbuf.h b/include/rcbuf.h
new file mode 100644
index 0000000..cabd488
--- /dev/null
+++ b/include/rcbuf.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2020 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or 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 THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
+ */
+
+#pragma once
+
+#include <unistd.h>
+
+struct rcbuf {
+	void* payload;
+	size_t size;
+	int ref;
+};
+
+struct rcbuf* rcbuf_new(void* payload, size_t size);
+struct rcbuf* rcbuf_from_string(const char* str);
+struct rcbuf* rcbuf_from_mem(const void* addr, size_t size);
+
+void rcbuf_ref(struct rcbuf* self);
+void rcbuf_unref(struct rcbuf* self);
diff --git a/meson.build b/meson.build
index eb0d4d9..b1773ba 100644
--- a/meson.build
+++ b/meson.build
@@ -48,6 +48,7 @@ sources = [
 	'src/pixels.c',
 	'src/damage.c',
 	'src/fb.c',
+	'src/rcbuf.c',
 	'contrib/miniz/miniz.c',
 ]
 
diff --git a/src/rcbuf.c b/src/rcbuf.c
new file mode 100644
index 0000000..80862ee
--- /dev/null
+++ b/src/rcbuf.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2020 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or 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 THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
+ */
+
+#include "rcbuf.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+struct rcbuf* rcbuf_new(void* payload, size_t size)
+{
+	struct rcbuf* self = calloc(1, sizeof(*self));
+	if (!self)
+		return NULL;
+
+	self->ref = 1;
+	self->payload = payload;
+	self->size = size;
+
+	return self;
+}
+
+struct rcbuf* rcbuf_from_string(const char* str)
+{
+	char* value = strdup(str);
+	return value ? rcbuf_new(value, strlen(str)) : NULL;
+}
+
+struct rcbuf* rcbuf_from_mem(const void* addr, size_t size)
+{
+	void* mem = malloc(size);
+	if (!mem)
+		return NULL;
+
+	memcpy(mem, addr, size);
+
+	struct rcbuf* rcbuf = rcbuf_new(mem, size);
+	if (!rcbuf)
+		free(mem);
+
+	return rcbuf;
+}
+
+void rcbuf_ref(struct rcbuf* self)
+{
+	self->ref++;
+}
+
+void rcbuf_unref(struct rcbuf* self)
+{
+	assert(self->ref > 0);
+
+	if (--self->ref > 0)
+		return;
+
+	free(self->payload);
+	free(self);
+}