From ce201a40cefb7f25fd5460271130b57afae7c48d Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Tue, 14 Oct 2025 11:29:40 +0200
Subject: [PATCH] MINOR: ncbmbuf: define new ncbmbuf type

---
 Makefile                    |  2 +-
 include/haproxy/ncbmbuf-t.h | 29 +++++++++++++++++
 include/haproxy/ncbmbuf.h   | 24 ++++++++++++++
 src/ncbmbuf.c               | 64 +++++++++++++++++++++++++++++++++++++
 4 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 include/haproxy/ncbmbuf-t.h
 create mode 100644 include/haproxy/ncbmbuf.h
 create mode 100644 src/ncbmbuf.c

diff --git a/Makefile b/Makefile
index 88c7548e8..59b706ec3 100644
--- a/Makefile
+++ b/Makefile
@@ -999,7 +999,7 @@ OBJS += src/mux_h2.o src/mux_h1.o src/mux_fcgi.o src/log.o		\
         src/ebsttree.o src/freq_ctr.o src/systemd.o src/init.o		\
         src/http_acl.o src/dict.o src/dgram.o src/pipe.o		\
         src/hpack-huff.o src/hpack-enc.o src/ebtree.o src/hash.o	\
-        src/httpclient_cli.o src/version.o
+        src/httpclient_cli.o src/version.o src/ncbmbuf.o
 
 ifneq ($(TRACE),)
   OBJS += src/calltrace.o
diff --git a/include/haproxy/ncbmbuf-t.h b/include/haproxy/ncbmbuf-t.h
new file mode 100644
index 000000000..518a3ffe4
--- /dev/null
+++ b/include/haproxy/ncbmbuf-t.h
@@ -0,0 +1,29 @@
+#ifndef _HAPROXY_NCBMBUF_T_H
+#define _HAPROXY_NCBMBUF_T_H
+
+#include <haproxy/ncbuf_common-t.h>
+
+/* Non-contiguous bitmap buffer
+ *
+ * This module is an alternative implementation to ncbuf type. Its main
+ * difference is that filled blocks and gaps are encoded via a bitmap.
+ *
+ * The main advantage of the bitmap is that contrary to ncbuf type there is no
+ * limitation on the minimal size of gaps. Thus, operation such as add and
+ * advance are guaranteed to succeed.
+ *
+ * Storage is reserved for the bitmap at the end of the buffer area,
+ * representing roughly 1/9 of the total space. Thus, usable buffer storage is
+ * smaller than the default ncbuf type.
+ */
+
+#define NCBMBUF_NULL ((struct ncbmbuf){ })
+
+struct ncbmbuf {
+	char *area;
+	char *bitmap;
+	ncb_sz_t size;
+	ncb_sz_t head;
+};
+
+#endif /* _HAPROXY_NCBMBUF_T_H */
diff --git a/include/haproxy/ncbmbuf.h b/include/haproxy/ncbmbuf.h
new file mode 100644
index 000000000..04b1a2514
--- /dev/null
+++ b/include/haproxy/ncbmbuf.h
@@ -0,0 +1,24 @@
+#ifndef _HAPROXY_NCBMBUF_H
+#define _HAPROXY_NCBMBUF_H
+
+#include <haproxy/ncbmbuf-t.h>
+
+static inline int ncbmb_is_null(const struct ncbmbuf *buf)
+{
+	return buf->size == 0;
+}
+
+struct ncbmbuf ncbmb_make(char *area, ncb_sz_t size, ncb_sz_t head);
+
+/* Returns the usable size of <buf> for data storage. This is the size of the
+ * allocated buffer without the bitmap space.
+ */
+static inline ncb_sz_t ncbmb_size(const struct ncbmbuf *buf)
+{
+	if (ncbmb_is_null(buf))
+		return 0;
+
+	return buf->size;
+}
+
+#endif /* _HAPROXY_NCBMBUF_H */
diff --git a/src/ncbmbuf.c b/src/ncbmbuf.c
new file mode 100644
index 000000000..8cb61b8a4
--- /dev/null
+++ b/src/ncbmbuf.c
@@ -0,0 +1,64 @@
+#include <haproxy/ncbmbuf.h>
+
+#include <string.h>
+
+/* Construct a ncbmbuf with all its parameters. */
+struct ncbmbuf ncbmb_make(char *area, ncb_sz_t size, ncb_sz_t head)
+{
+	struct ncbmbuf buf;
+	ncb_sz_t bitmap_sz;
+
+	bitmap_sz = (size + 8) / 9;
+
+	buf.area = area;
+	buf.bitmap = area + size - bitmap_sz;
+	buf.size = size - bitmap_sz;
+	buf.head = head;
+
+	memset(area, 0, size);
+
+	return buf;
+}
+
+ncb_sz_t ncbmb_total_data(const struct ncbmbuf *buf)
+{
+	/* TODO */
+	return 0;
+}
+
+int ncbmb_is_empty(const struct ncbmbuf *buf)
+{
+	/* TODO */
+	return 0;
+}
+
+int ncbmb_is_full(const struct ncbmbuf *buf)
+{
+	/* TODO */
+	return 0;
+}
+
+int ncbmb_is_fragmented(const struct ncbmbuf *buf)
+{
+	/* TODO */
+	return 0;
+}
+
+ncb_sz_t ncbmb_data(const struct ncbmbuf *buf, ncb_sz_t off)
+{
+	/* TODO */
+	return 0;
+}
+
+enum ncb_ret ncbmb_add(struct ncbmbuf *buf, ncb_sz_t off,
+                       const char *data, ncb_sz_t len, enum ncb_add_mode mode)
+{
+	/* TODO */
+	return NCB_RET_OK;
+}
+
+enum ncb_ret ncbmb_advance(struct ncbmbuf *buf, ncb_sz_t adv)
+{
+	/* TODO */
+	return NCB_RET_OK;
+}
-- 
2.47.3