Split out buf

adsbus/buf.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <stddef.h>
+
+#define BUF_LEN_MAX 256
+struct buf {
+	char buf[BUF_LEN_MAX];
+	size_t start;
+	size_t length;
+};
+#define BUF_INIT { \
+	.start = 0, \
+	.length = 0, \
+}
+
+#define buf_chr(buff, at) ((buff)->buf[(buff)->start + (at)])
+#define buf_at(buff, at) (&buf_chr(buff, at))
+
+void buf_init(struct buf *);
+ssize_t buf_fill(struct buf *, int);
+void buf_consume(struct buf *, size_t);