1 files changed, 176 insertions, 0 deletions
diff --git a/iolooper-select.c b/iolooper-select.c
new file mode 100644
index 0000000..74a5a3a
--- /dev/null
+++ b/iolooper-select.c
@@ -0,0 +1,176 @@
+#include "iolooper.h"
+#include "qemu-common.h"
+
+/* An implementation of iolooper.h based on Unix select() */
+#ifdef _WIN32
+#  include <winsock2.h>
+#else
+#  include <sys/types.h>
+#  include <sys/select.h>
+#endif
+
+struct IoLooper {
+    fd_set   reads[1];
+    fd_set   writes[1];
+    fd_set   reads_result[1];
+    fd_set   writes_result[1];
+    int      max_fd;
+    int      max_fd_valid;
+};
+
+IoLooper*
+iolooper_new(void)
+{
+    IoLooper*  iol = qemu_malloc(sizeof(*iol));
+    iolooper_reset(iol);
+    return iol;
+}
+
+void
+iolooper_free( IoLooper*  iol )
+{
+    qemu_free(iol);
+}
+
+void
+iolooper_reset( IoLooper*  iol )
+{
+    FD_ZERO(iol->reads);
+    FD_ZERO(iol->writes);
+    iol->max_fd = -1;
+    iol->max_fd_valid = 1;
+}
+
+static void
+iolooper_add_fd( IoLooper*  iol, int fd )
+{
+    if (iol->max_fd_valid && fd > iol->max_fd) {
+        iol->max_fd = fd;
+    }
+}
+
+static void
+iolooper_del_fd( IoLooper*  iol, int fd )
+{
+    if (iol->max_fd_valid && fd == iol->max_fd)
+        iol->max_fd_valid = 0;
+}
+
+static int
+iolooper_fd_count( IoLooper*  iol )
+{
+    int  max_fd = iol->max_fd;
+    int  fd;
+
+    if (iol->max_fd_valid)
+        return max_fd + 1;
+
+    /* recompute max fd */
+    for (fd = 0; fd < FD_SETSIZE; fd++) {
+        if (!FD_ISSET(fd, iol->reads) && !FD_ISSET(fd, iol->writes))
+            continue;
+
+        max_fd = fd;
+    }
+    iol->max_fd       = max_fd;
+    iol->max_fd_valid = 1;
+
+    return max_fd + 1;
+}
+
+void
+iolooper_add_read( IoLooper*  iol, int  fd )
+{
+    if (fd >= 0) {
+        iolooper_add_fd(iol, fd);
+        FD_SET(fd, iol->reads);
+    }
+}
+
+void
+iolooper_add_write( IoLooper*  iol, int  fd )
+{
+    if (fd >= 0) {
+        iolooper_add_fd(iol, fd);
+        FD_SET(fd, iol->writes);
+    }
+}
+
+void
+iolooper_del_read( IoLooper*  iol, int  fd )
+{
+    if (fd >= 0) {
+        iolooper_del_fd(iol, fd);
+        FD_CLR(fd, iol->reads);
+    }
+}
+
+void
+iolooper_del_write( IoLooper*  iol, int  fd )
+{
+    if (fd >= 0) {
+        iolooper_del_fd(iol, fd);
+        FD_CLR(fd, iol->reads);
+    }
+}
+
+int
+iolooper_poll( IoLooper*  iol )
+{
+    int     count = iolooper_fd_count(iol);
+    int     ret;
+    fd_set  errs;
+
+    if (count == 0)
+        return 0;
+
+    FD_ZERO(&errs);
+
+    do {
+        struct timeval  tv;
+
+        tv.tv_sec = tv.tv_usec = 0;
+
+        iol->reads_result[0]  = iol->reads[0];
+        iol->writes_result[0] = iol->writes[0];
+
+        ret = select( count, iol->reads_result, iol->writes_result, &errs, &tv);
+    } while (ret < 0 && errno == EINTR);
+
+    return ret;
+}
+
+int
+iolooper_wait( IoLooper*  iol, int64_t  duration )
+{
+    int     count = iolooper_fd_count(iol);
+    int     ret;
+    fd_set  errs;
+
+    if (count == 0)
+        return 0;
+
+    FD_ZERO(&errs);
+
+    do {
+        iol->reads_result[0]  = iol->reads[0];
+        iol->writes_result[0] = iol->writes[0];
+
+        ret = select( count, iol->reads_result, iol->writes_result, &errs, NULL);
+    } while (ret < 0 && errno == EINTR);
+
+    return ret;
+}
+
+
+int
+iolooper_is_read( IoLooper*  iol, int  fd )
+{
+    return FD_ISSET(fd, iol->reads_result);
+}
+
+int
+iolooper_is_write( IoLooper*  iol, int  fd )
+{
+    return FD_ISSET(fd, iol->writes_result);
+}