+#ifndef _BUFIO_HEADER
+#define _BUFIO_HEADER
+
+#include <ev.h>
+
+/* BUFFER CHAIN */
+typedef struct bufio_chain_entry bufio_chain_entry;
+
+struct bufio_chain_entry {
+ bufio_chain_entry *next;
+ void *buf;
+ size_t len;
+ off_t used;
+};
+
+typedef struct {
+ bufio_chain_entry *head, *tail;
+} bufio_chain;
+
+/**
+ * Enqueues the given buffer for writing. After writing, it will be freed.
+ * Returns -1 if calloc failed.
+ */
+int bufio_chain_append(bufio_chain *bc, void *buf, size_t len);
+
+/**
+ * Flush as much data as possible into the given FD.
+ * Returns -1 for errors, 0 for ok. errno is left
+ * intact on errors, so you might want to check for
+ * EAGAIN or so.
+ */
+int bufio_chain_flush(bufio_chain *bc, int fd);
+
+/**
+ * Clear the buffer chain without sending any data.
+ */
+void bufio_chain_clear(bufio_chain *bc);
+
+
+
+/* CONNECTION */
+typedef struct bufio_connection bufio_connection;
+
+typedef void (*bufio_connection_error_cb_t)(bufio_connection *con);
+typedef void (*bufio_connection_data_cb_t)(bufio_connection *con);
+
+struct bufio_connection {
+ ev_io rw; /* readonly */
+ ev_io ww; /* readonly */
+ struct ev_loop *loop; /* readonly */
+ void *inbuf; /* readonly */
+ size_t inbuf_size; /* readonly */
+ size_t inbuf_used; /* readonly */
+ bufio_chain outbuf; /* readonly */
+
+ /**
+ * Called when an error has occured. You should react to it by destroying
+ * the connection. This property can be changed manually at any time.
+ */
+ bufio_connection_error_cb_t err_cb;
+
+ /**
+ * Called when your read buffer has been filled completely. When this is
+ * called, nothing will be read anymore until you set a new read buffer.
+ * This property can be changed manually at any time.
+ */
+ bufio_connection_data_cb_t data_cb;
+
+ /**
+ * Not touched by this library.
+ */
+ void *data;
+};
+
+/**
+ * Creates a bufio connection around an existing file descriptor.
+ * This call already activates the watcher without initializing some
+ * important stuff, so set it before returning to the eventloop/entering
+ * it:
+ *
+ * - the input buffer – set it using `bufio_connection_set_read_buffer`
+ * - the callbacks (`err_cb` and `data_cb`) – set them directly
+ */
+bufio_connection *bufio_connection_create(struct ev_loop *loop, int fd);
+
+void bufio_connection_set_read_buffer(bufio_connection *con, void *buf, size_t size);
+
+/**
+ * This stops our watcher and clears and frees the output buffers and the
+ * connection struct, but it doesn't touch the input buffer or the fd.
+ */
+void bufio_connection_destroy(bufio_connection *con);
+
+/**
+ * This enqueues a chunk of data to be written. You are not allowed to
+ * touch the buffer anymore after calling this function!
+ */
+int bufio_connection_write(bufio_connection *con, void *buf, size_t len);
+
+#endif