From 71e97ec2bc954e57b6955b3ec3fc49379116efc7 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Sat, 27 Oct 2018 22:45:41 +0200
Subject: put scrolling into separate thread; activate minutely updates;
 cleanup

---
 multiplexer.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 57 insertions(+), 4 deletions(-)

(limited to 'multiplexer.c')

diff --git a/multiplexer.c b/multiplexer.c
index c81864b..52c7af1 100644
--- a/multiplexer.c
+++ b/multiplexer.c
@@ -7,6 +7,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <pthread.h>
+#include <assert.h>
 
 #include "multiplexer.h"
 
@@ -108,10 +109,54 @@ void *put_on_display(void *param)
   return NULL;
 } // put_on_display
 
-pthread_t multiplexer_setup_non_root(t_display_data *display_data)
+// scroll the text over the display
+void *scroll_it(void *param)
 {
-  pthread_t thread_id;
+  t_scroll_data *scroll_data = (t_scroll_data *) param;
+  t_scroll_buffer buf[3];
+  for (int i=0; i<3; i++)
+    memset(&buf[i], 0, sizeof(buf[i]));
+  t_display_data display_data;
+  multiplexer_setup_non_root(&display_data);
+  int is_buf = 0;
+  int column = 0;
+  while (scroll_data -> keep_running) {
+    if (scroll_data -> update) {
+      if ((buf[is_buf] . len != scroll_data -> input_len) || (memcmp(&buf[is_buf] . buf[buf[is_buf] . start], scroll_data -> input, scroll_data -> input_len) != 0)) {
+        is_buf = (is_buf + 1) % 2;
+        // copy the currently visible, old content
+        memcpy(buf[is_buf] . buf, &buf[(is_buf + 1) % 2] . buf[column + 1], 39);
+        buf[is_buf] . start = 39;
+        // set the length of the new content
+        buf[is_buf] . len = scroll_data -> input_len;
+        // copy the new content from input
+        for (int i=0; i<2; i++)
+          memcpy(
+            &buf[is_buf] . buf[39 + i * buf[is_buf] . len],
+            scroll_data -> input,
+            buf[is_buf] . len
+          );
+        column = 0;
+      }
+      // clear update flag
+      scroll_data -> update = 0;
+    }
+    for (int i=0; i<40; i++)
+      display_data . buf[(display_data . should_buf + 1) % 3][i] =
+        buf[is_buf] . buf[column + i];
+    display_data . should_buf = (display_data . should_buf + 1) % 3;
+    column++;
+    if (buf[is_buf] . len > 0)
+      while (column >= buf[is_buf] . start + buf[is_buf] . len)
+        column -= buf[is_buf] . len;
+    usleep(100000);
+  }
+  display_data . keep_running = 0;
+  pthread_join(display_data . thread_id, NULL);
+} // scroll_it
 
+void multiplexer_setup_non_root(t_display_data *display_data)
+{
 #ifndef SKIP_GPIO
   // must use INP_GPIO before we can use OUT_GPIO
   INP_GPIO(SER_DAT_PIN);
@@ -130,6 +175,14 @@ pthread_t multiplexer_setup_non_root(t_display_data *display_data)
   display_data -> is_buf = 0;
   display_data -> should_buf = 0;
   display_data -> keep_running = 1;
-  pthread_create(&thread_id, NULL, put_on_display, display_data);
-  return thread_id;
+  pthread_create(&display_data -> thread_id, NULL, put_on_display, display_data);
+  return;
 } // multiplexer_setup_non_root
+
+void multiplexer_setup_scroll(t_scroll_data *scroll_data)
+{
+  scroll_data -> update = 0;
+  scroll_data -> keep_running = 1;
+  pthread_create(&scroll_data -> thread_id, NULL, scroll_it, scroll_data);
+  return;
+} // multiplexer_setup_scroll
-- 
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