work in progress on implementing a send buffer

1 files changed, 117 insertions, 0 deletions

diff --git a/libglouglou/sendbuf.c b/libglouglou/sendbuf.c
new file mode 100644
index 0000000..078d6a6
--- /dev/null
+++ b/libglouglou/sendbuf.c
@@ -0,0 +1,117 @@
+#include "sendbuf.h"
+
+/*
+ * Public
+ */
+
+/*
+ * Create a sendbuf
+ * send_func should return the number of successfuly sent bytes
+ */
+struct sendbuf *
+sendbuf_init(struct event_base *ev_base, int size, int sndbuf_max, int msec_max,
+              int (*send_func)(void *, int, void *), void *usrdata)
+{
+  struct sendbuf *sbuf = NULL;
+  struct event ev_timer;
+  struct timeval *tv;
+  void *buffer;
+  void *data;
+
+  sbuf = calloc(1, sizeof(struct sendbuf));
+  if (!sbuf)
+    return NULL;
+  sbuf->ev_base = ev_base;
+  sbuf->sndbuf_max = sndbuf_max;
+  sbuf->msec_max = msec_max;
+  sbuf->usrdata = usrdata;
+  sbuf->send_func = send_func;
+  sbuf->buffer_size = size;
+  sbuf->buffer = malloc(sbuf->buffer_size);
+  if (!sbuf->buffer)
+    goto err;
+
+  ev_timer = evtimer_new(ev_base, cb_timer, sbuf);
+  sbuf->ev_timer = ev_timer;
+  sbuf->ev_timer_tv.tv_usec = msec_max * 1000;
+  evtimer_add(ev, &sbuf->ev_timer_tv);
+
+  return sbuf;
+
+err:
+  sendbuf_shutdown(sbuf);
+  return NULL;
+}
+
+void
+sendbuf_shutdown(struct sendbuf *sbuf)
+{
+  if (sbuf->send_timer)
+    event_del(sbuf->send_timer);
+  if (sbuf->buffer && sbuf->send_func)
+    flushbuf(sbuf);
+  if (sbuf->buffer)
+    free(sbuf->buffer);
+  free(sbuf);
+}
+
+/*
+ * Returns a buffer to write data to be sent
+ * might return NULL if the sendbuf is temporary full
+ */
+void *
+sendbuf_getoken(struct sendbuf *sbuf, int size)
+{
+  if (sbuf->buffer_pos + size >= sbuf->buffer_size)
+    if (flushbuf(sbuf) == -1)
+      return NULL;
+
+  return sbuf->buffer_pos;
+}
+
+/*
+ * Private
+ */
+
+/*
+ * Note that you can still add data to the buffer even if flushing is in
+ * progress
+ */
+int
+flushbuf(struct sendbuf *sbuf)
+{
+  int sent;
+  int sent_total;
+  int len;
+
+  sbuf->flushing = 1;
+
+  do {
+    pos = sbuf->buffer + sbuf->flushed_len;
+    if (sbuf->buffer_pos > sbuf->sndbuf_max)
+      tosend = sbuf->sndbuf_max;
+    else
+      tosend = sbuf->buffer_pos;
+    sent = sbuf->send_func(sbuf->buffer + pos, tosend, sbuf->usrdata);
+    sbuf->flushed_len = sbuf->flushed_len + sent;
+    if (sent == -1) {
+      // XXX handle erorr
+    } else if (sent < tosend) {
+      return -1;
+    }
+  } while (sbuf->flushed_len < sbuf->buffer_pos)
+
+  sbuf->flushing = 0;
+  sbuf->flushed_len = 0;
+  return 0;
+}
+
+void
+cb_timer(evutil_socket_t fd, short what, void *arg)
+{
+  struct sendbuf *sbuf;
+
+  sbuf = arg;
+  flushbuf(sbuf);
+  evtimer_add(sbuf->ev_timer, &sbuf->ev_timer_tv);
+}