[*] Initial commit

lonetix/include/df/bgp/bytebuf.h

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+/**
+ * \file bgp/bytebuf.h
+ *
+ * Allocator optimized for trivial BGP workflows.
+ *
+ * \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
+ * \author    Lorenzo Cogotti
+ */
+
+#ifndef DF_BGP_MEMBUF_H_
+#define DF_BGP_MEMBUF_H_
+
+#include "mem.h"
+
+/// Memory alignment for `Bgpbytebuf` allocations.
+#define BGP_MEMBUF_ALIGN 4
+
+// NOTE: Need at least 4 bytes alignment for TABLE_DUMPV2 peer lookup tables!
+
+/**
+ * \brief Basic fixed-size packed single-threaded byte buffer.
+ *
+ * Nearly zero-overhead byte pool optimized for typical BGP message
+ * allocations. Returns chunks from an internal fixed-size byte buffer
+ */
+typedef struct {
+	size_t size;                                        ///< Buffer block size in bytes
+	size_t pos;                                         ///< Current position inside block
+	ALIGNED(BGP_MEMBUF_ALIGN, Uint8 base[FLEX_ARRAY]);  ///< Block buffer
+} Bgpbytebuf;
+
+/**
+ * \brief Create `Bgpbytebuf` with statically sized fixed buffer
+ *        (as opposed to a flexible array buffer).
+ *
+ * This is useful when the buffer should be placed in statically
+ * allocated variable, e.g.
+ * ```c
+ * static BGP_FIXBYTEBUF(4096) bgp_msgBuf = { 4096 };
+ * ```
+ *
+ * May also be used for a `typedef`:
+ * ```c
+ * typedef BGP_FIXBYTEBUF(1024) Bgpsmallbuf;
+ * ```
+ *
+ * Variables generated by this macro may be used
+ * as `allocp` of any API expecting a `MemOps` interface.
+ */
+#define BGP_FIXBYTEBUF(bufsiz) \
+	struct { \
+		size_t size;                                   \
+		size_t pos;                                    \
+		ALIGNED(BGP_MEMBUF_ALIGN, Uint8 base[bufsiz]); \
+	}
+
+/// `MemOps` operating over `Bgpbytebuf`, use pointer to `Bgpbytebuf` as `allocp`.
+extern const MemOps *const Mem_BgpBufOps;
+
+#endif